Status: Draft prepared by the consultancy meeting, 3-7 ... · smelting, phosphate fertilizer...

Management of Radioactive Residues from Mining, Mineral Processing, and other

NORM Related Activities

DRAFT SAFETY GUIDE

No. DS 459

New Safety Guide

Status: Draft prepared by the consultancy

meeting, 4-8 November 2013

This Review - March 2014

FOREWORD

by

Director General

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Contents

1. INTRODUCTION .................................................................................................................. 4

BACKGROUND.............................................................................................................................. 4 OBJECTIVES .................................................................................................................................. 7 SCOPE ............................................................................................................................................. 7 STRUCTURE .................................................................................................................................. 8

2. ADMINISTRATIVE, LEGAL AND REGULATORY FRAMEWORK ............................ 10

INTRODUCTION.......................................................................................................................... 10 NATIONAL POLICY AND STRATEGY .................................................................................... 10 RESPONSIBILITIES ..................................................................................................................... 13 MEMBER STATES ....................................................................................................................... 14 REGULATORY BODY ................................................................................................................ 15 OPERATOR ................................................................................................................................... 18 SCOPE OF REGULATORY CONTROL ..................................................................................... 19 GRADED APPROACH FOR IMPOSING CONTROL ................................................................ 23 SCREENING ASSESSMENTS ..................................................................................................... 24

3. PROTECTION OF PEOPLE AND THE ENVIRONMENT .............................................. 27

INTRODUCTION.......................................................................................................................... 27 GENERAL PRINCIPLES .............................................................................................................. 27 RADIATION PROTECTION ........................................................................................................ 28

4. GENERAL ASPECTS OF RESIDUE MANAGEMENT ................................................... 34

INTRODUCTION.......................................................................................................................... 34 INVENTORY OF PROCESSES GENERATING NORM RESIDUES ........................................ 35 CHARACTERIZATION AND SEGREGATION ......................................................................... 37 OPTIONS FOR RESIDUE MANAGEMENT .............................................................................. 37 REMEDIATION OF RESIDUE FACILITIES .............................................................................. 54

5. LIFE CYCLE MANAGEMENT OF NORM RESIDUES .................................................. 55

INTRODUCTION.......................................................................................................................... 55 SITING ........................................................................................................................................... 56 DESIGN AND CONSTRUCTION ................................................................................................ 57 OPERATION ................................................................................................................................. 70 CLOSURE ..................................................................................................................................... 76 REMOVAL OF REGULATORY CONTROL .............................................................................. 81 INSTITUTIONAL CONTROL...................................................................................................... 81

6. SAFETY ASSESSMENT AND SAFETY CASE ............................................................... 83

INTRODUCTION.......................................................................................................................... 83 GRADED APPROACH FOR SAFETY ASSESSMENT.............................................................. 84 SCOPE OF THE SAFETY ASSESSMENT .................................................................................. 86 CONDUCTING A SAFETY ASSESSMENT ............................................................................... 87 DOCUMENTATION OF SAFETY CASE AND SUPPORTING SAFETY ASSESSMENT ...... 93 PERIODIC SAFETY REVIEWS................................................................................................... 94

7. MANAGEMENT SYSTEMS .............................................................................................. 95

MANAGEMENT RESPONSIBILITY .......................................................................................... 96 RESOURCE MANAGEMENT ..................................................................................................... 97 PROCESS IMPLEMENTATION .................................................................................................. 98

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MEASUREMENT, ASSESSMENT AND IMPROVEMENT ...................................................... 99

8. MONITORING AND SURVEILLANCE .................................................................... 101

OVERVIEW OF MONITORING AND SURVEILLANCE ....................................................... 101 RESPONSIBILITIES OF THE OPERATOR AND REGULATORY BODY ............................ 102 OBJECTIVES AND DESIGN OF THE MONITORING ........................................................... 103

9. FINANCIAL ASSURANCE ........................................................................................ 106

REFERENCES ....................................................................................................................... 110

ANNEX I. ORIGIN AND CATEGORIZATION OF NORM RESIDUES ..................... 112

ANNEX II. REUSE AND RECYCLING OF NORM RESIDUES .................................. 115

ANNEX III. PRACTICAL TECHNIQUES FOR DETERMINING RADIONUCLIDE

ACTIVITY CONCENTRATIONS .............................................................................. 119

INTRODUCTION ...................................................................................................................... 119 SAMPLING OF MATERIAL ................................................................................................... 119 MEASUREMENT ACCURACY AND QUALITY ASSURANCE ....................................... 120 ANALYTICAL TECHNIQUES ............................................................................................... 120

1. INTRODUCTION

BACKGROUND

1.1 Radionuclides of natural origin are ubiquitous in the environment, and in some

geological formations have become sufficiently concentrated for the formations to be

exploited as uranium or thorium ores. The mining and processing of uranium and

thorium ores, including the management of the resulting residues, have long been

recognized as needing to be subject to regulatory control. However, significant

concentration of radionuclides of natural origin may also occur in other commercially

exploited minerals and/or in the residues from the processing of these minerals, where

the presence of such radionuclides is incidental and unwanted.

1.2 Residues are of particular importance in this regard, because the extraction

and processing of a mineral may have changed the properties of the raw material so as

to increase its potential radiological impact on workers, members of the public, or the

environment, for example by modifying the solubility, speciation or activity

concentration of the radioactive elements of concern. Until recently, relatively little

attention has been given to the possible need for regulatory control of radioactive

residues from mining and minerals processing other than those associated with

uranium or thorium extraction. As a result, residues from such operations, irrespective

of whether they are recycled, used in other applications or disposed of as waste, may

not have been subject to regulatory control in the past, even though they may contain

levels of radionuclides of regulatory significance in radiation protection terms. The

residues generated in mining and milling activities differ from those generated at, for

example, nuclear power plants or medical facilities. An important difference affecting

their management is the very large volumes of many of these residues. This has

important consequences to the possible siting and engineering options that are

available. In addition, radon and many of the very long half-lived radionuclides

presented in these residues implies that long term concerns should be fully addressed

in term of the protection of future generations against radiation risk.

1.3 For the purposes of the Standards, NORM is defined as: “Radioactive material

containing no significant amounts of radionuclides other than naturally occurring

Formatted: IAEA Heading 1

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radionuclides” [1]. It includes material in the natural state as well as material in which

the activity concentrations of the naturally occurring radionuclides may have been

changed by man-made processes, including the residues from these processes.

Radioactive material is defined as “Material designated in national law or by a

regulatory body as being subject to regulatory control because of its radioactivity“.

All residues from the mining and processing of raw materials that are subject to

regulatory control in terms of the IAEA’s safety standards, including residues from

uranium and thorium mining and processing, fall within the definition of NORM and

are thus known as NORM residues. A NORM residue is defined as “Material that

remains from a process and comprises or is contaminated by naturally occurring

radioactive material (NORM)”. NORM waste is defined as “Naturally occurring

radioactive material (NORM) for which no further use is foreseen” [1]. A NORM

residue therefore may or may not be waste.

1.4 Various publications in the IAEA Safety Standards Series have some

relevance to NORM and NORM residues, covering issues such as the management of

wastes from uranium and thorium mining, clearance and exemption levels for

radionuclides of natural origin, and worker protection in mining and mineral

processing related industries [2-7][SF-1, GSR-Part1, SSR-5, RS-G-1.7, RS-G-1.6,

WS-G-2.3]. However, there has been relatively little guidance specifically on the

management of NORM residues (including NORM residues designated as waste)

arising from other industries such as titanium dioxide pigment industries, metal

smelting, phosphate fertilizer production, oil and gas, coal, mineral sand exploitation,

and water treatment. This Safety Guide is intended to fill that gap, by focusing on the

identification and implementation of appropriate measures for protection of members

of the public and the environment against radiological hazards associated with the

management of all types of NORM residue encountered across a range of industrial

operations.

1.5 Many Member States have established regulations and guidance for the

licensing and control of waste arising from existing operations for the processing of

uranium and thorium ores. Uranium and thorium containing ores, beneficiated

mineral, and associated mining waste such as overlying rock or sediment

(overburden) at closed mine sites, waste liquids and sludges, contaminated plant and

Formatted: Highlight



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equipment, tailings from the extraction of the uranium and thorium wastes at a closed

processing facility or legacy sites may also be considered to be NORM residues.

1.6 Many of the industries and processes whichthat generate NORM residues have

not traditionally been considered to have an association with radioactivity. Thus, the

introduction of radiation protection requirements, in compliance with the Standards,

can potentially cause considerable public concern, especially where industries have

been located in or near areas of high population. Equally, the introduction of such

requirements can have a significant impact on the industries themselves. This guide is

intended to assist such industries in assessing their radiation protection obligations;

and to assist regulatory authorities to determine the appropriate level of control to be

implemented.

1.7 NORM residues are often produced in very large volumes, although the

activity concentration of radionuclides is relatively low. However, there are some

residues where the volumes are smaller and where the levels of radioactivity are

relatively high. There is also the possibility that a NORM residue from one industry

may be regarded as a waste, whereas in another industry or another country, the same

material may be regarded as a raw material or a feedstock for further processing.

1.8 The radionuclides contained in NORM residues may not be the only potential

hazard to individuals and the environment. Other chemical constituents within the

material may be capable of causing harm. These include heavy metals, inorganic

elements (e.g. arsenic) and various organic compounds. The potential for such non-

radiological substances to cause detriment needs to be considered when planning the

management of NORM residues. Achieving a consistent regulatory approach to

protect against these different hazards is a challenge for national regulators. This

publication is focused on the management of the radiological hazards associated with

the waste. However,, there is a particular need for regulators to take account of the

non-radiological hazards that in some cases may represent the primary risk to people

and the environment..

1.9 This publication supersedes Management of Radioactive Waste from the

Mining and Milling of Ores, Safety Guide Series No. WS-G-1.2, issued in 2002 [8]. Formatted: Highlight

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OBJECTIVES

1.10 The objective of this safety guide is to provide recommendations and guidance

to regulatory bodies, operating organizations, technical support organizations, and

other interested parties on safe management of radioactive residues including those

designated as waste, arising from the mining, milling and processing of ores

(primarily uranium and thorium), and from other activities generating NORM

residues, in accordance with the relevant Safety Requirements for protection of

human health and the environment from exposure to ionizing radiation now and in the

future [GS-R-13], DS353,, WS-G-2.3[7]. The guidance will address new facilities;

however, this guide may also be relevant to the review and upgrading of existing

facilities where reasonably practicable. The guide is to address residues arising during

all phases of a facility lifetime. However, in accordance with national policies,

appropriate steps may be taken to review the safety of existing facilities (including

legacy sites) and, where reasonably practicable, to upgrade their safety in line with the

relevant recommendations set out in this Safety Guide.

SCOPE

1.11 The scope of this Safety Guide covers pre-operational, operational, closure

and post-closure activities at facilities that deal with NORM residues.

1.12 The Safety Guide will provide life cycle guidance on the site selection and

evaluation and design of NORM residue management facilities, and on their

construction, operation and closure, decommissioning and transfer to institutional

control, including organizational and regulatory requirements (GSR Part 1[3]). The

guide includes guidance on the development of a safety case and safety assessment

for facilities and activities involving NORM residues, as required by GSR Part 4[9],

[10].and GSR Part 5 [GSR Part 4; GSR Part 5].

1.13 This guide is intended to be applicable to the mining and milling of ores for

the extraction of uranium or thorium, to other industries including mining and

processing of other ores, the oil and gas industry, the phosphate industry, and other

activities resulting in the production of NORM residues. Regulatory bodies should


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determine the extent to which this guidance should be applied to particular industries

in accordance with a graded approach.

1.14 This guide applies to both small volume and bulk amount of residues, and not

discrete sources, such as radium sources for which management is covered in other

IAEA documents. In this Safety Guide, the term “bulk residues” generally refers to

large volume wastes of the sort typically generated by mining and mineral processing

activities and includes tailings, waste rock, mineralized waste rock and large volumes

of liquid wastes (process water, leaching fluids, seepage and run-off). It may also

include large volumes of downstream processing wastes (such as fly ash or bottom

ash from power generation).

1.15 This guide is also intended to cover management of contaminated plant and

equipment, as well as the radioactive residues generated by the decontamination

process.

1.16 This Safety Guide is principally directed towards the management of residues

generated by new facilities, and residues arising from the proposed decommissioning

and remediation activities associated with those facilities1. It may not be practical to

apply all of these recommendations to existing facilities and in such cases the

regulatory body should decide the extent to which these recommendations apply.

1.17 Radiological safety in the production and processing of U/Th ores is addressed

in other IAEA publications [6], [7]. The control of occupational and public exposures

and environmental impacts due to routine radioactive releases or transport of waste is

also discussed in other IAEA safety standards2 [11].

STRUCTURE

1.18 The administrative, legal and regulatory framework, and scope of regulatory

control needed for the safe management of NORM residues, is described in Section 2.

Protection of people and the environment for safety management of NORM residues

is described in Section 3. Strategies for managing residues are discussed in Section 4.

1 Note the distinction between usage of the terms “Closure” and “Decommissioning” in IAEA Glossary Ref[1].

2 Including DS353: in preparation.

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Safety considerations in long-term management of residues generated in all phases of

the lifetime of a management facility are discussed in Section 5. A process for

considering all the relevant issues associated with developing a NORM residue

management strategy and residue management facilities to ensure that human health

and the environment are afforded an acceptable level of protection (the ‘safety

assessment and safety case’) is discussed in Section 6. Guidance on the design and

implementation of a management system for residue management is provided in

Section 7. A monitoring and surveillance programme for residue management

facilities is discussed in Section 8. Financial assurance for the long-term safety of

residue management facilities is discussed in Section 9.

REFERENCES – Chapter 1.

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2. ADMINISTRATIVE, LEGAL AND REGULATORY FRAMEWORK

INTRODUCTION

2.1 This Section outlines the legal and regulatory framework, and scope of

regulatory control needed for the safe management of NORM residues. The key points

are as follows:

The general responsibilities of Member States, the Regulatory Body, and the

Operator are summarized,

The development of a national inventory of industries concerned with the

production and processing of NORM is proposed, including a national

inventory of active and legacy sites and wastes produced by these industries,

The application of the concepts of exclusion, exemption and clearance, and use

of a graded approach are described,

Residue management strategies are discussed with an emphasis placed on re-use

and recycling of NORM residues where safe and appropriate to do so.

NATIONAL POLICY AND STRATEGY

2.2 Member States planning to engage in activities that generate, utilize or, require

management or disposal of NORM residues, are required to develop:

An appropriate national legal and organizational framework within which

NORM residue management activities can be planned and carried out safely;

A national policy for managing NORM activities and NORM residues,

including any waste associated with such operations;

A strategy for implementing this policy, including the provision of necessary

resources [GSR-13].

2.3 The policy and strategy should reflect, and be consistent with, the principles for

radioactive waste management as set out in Ref GSR[3] -1 and in Sections 3–6 of this

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publication. It should address and encourage the recycling of NORM residues and

their reuse in other applications, where safe and appropriate to do so. Recycling and

reuse of NORM residues is discussed further in Section 4 as options for residue

management, and more information on the application of these options is given in

Annex 2.

2.4 Member States should consider the need for, and the extent of, public

involvement and consultation during the regulatory process. Increasing public

consultation is a feature of the authorization process in many Member States.

However, the responsibility for the regulatory decision remains with the regulatory

body. The decision making process should be transparent, independent and defensible,

such that if a decision is challenged the regulatory body can explain how it was

reached.

2.5 The development of a residues management strategy is usually a complex

process that has the aim of achieving a reasonable balance between two, often

conflicting, goals: maximization of risk reduction and minimization of financial

expenditure. The process is one of optimization of protection in which the available

alternatives for siting, design and construction, operation, management of residues,

and closure are evaluated and compared, with account taken of all associated benefits

and detriments and any constraints (such as an annual dose constraint) that are

required to be imposed. The characteristics of the alternatives (or options) that should

be considered include:

The radiological and non-radiological impacts on human health and the

environment during operation and in the future;

The requirements for monitoring, maintenance and control during operation and

after closure;

Any restrictions on the future use of property or water resources;

The financial costs of the various alternatives and the resources available for

implementing the alternatives;

The volumes of the various residues to be managed;

The socioeconomic impacts, including matters relating to public acceptance;

Good engineering practices.

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2.6 The steps taken towards deciding how to manage the residues arising from

NORM facilities should include:

Definition of the criteria for human health and environmental protection;

Characterization of the residues;

Identification and characterization of the site options;

Identification and characterization of the residues management options,

including engineering controls;

Identification and description of options for institutional control;

Identification and description of potential failures of institutional and

engineering controls;

Definition and characterization of the representative person of the population;

Estimation of the radiological and other consequences for each combination of

options being considered (the ‘safety analysis’), including scenarios of potential

exposure for each option;

Comparison of the estimated doses and risks with appropriate constraints;

Optimization of protection so as to arrive at the preferred management option.

2.7 The evaluation criteria and procedures used to select the preferred options and to

develop the residues management strategy that will achieve the optimal balance

among the above considerations should be clearly defined and presented to the

different interested parties in the project, including the public.

2.8 The design of NORM residue generating facilities will influence the

optimization of protection from exposure due to radioactive residue and should

therefore be considered with residue management in mind. The NORM generating

activities should be designed to reduce, as far as practicable, the amount of waste to be

managed. This can be accomplished through the choice of appropriate NORM

processes, and the recycle and reuse of equipment, materials and residues.

2.9 The closure of the residues management facilities should be considered in all

phases of the NORM operation, that is, during siting, design, construction and

operation. Planning for the management of NORM residues at closure should already

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be addressed in the siting and design phase, and not be delayed until the closure stage.

For example, taking measures at an early stage to reduce the migration of water-borne

and airborne contamination to the surrounding environment will facilitate

management of the closure phase.

2.10 The design, construction, operation and closure of facilities for the handling,

storage and disposal of residues from NORM operations should be in accordance with

the elements of a management system as outlined in Section 7. In particular, facilities

should be constructed, operated and closed only according to approved plans and

procedures.

2.11 Section 5 of this guide outlines the important characteristics and desirable

features of the options that should be considered in the siting and management of

residues from NORM activities, including considerations inin the siting, design,

construction, operation and closure of facilities, the release of materials and the factors

for institutional control.

RESPONSIBILITIES

2.12 According to the Safety Requirements, governments of Member States are

required to have an appropriate legal and governmental infrastructure for nuclear,

radiation, radioactive waste and transport safety (see para 2.1). The principal parties

responsible for facilities and activities (the operator), also have responsibility for

protection and safety [(GSR-311)]. Furthermore, responsibilities associated with

management of radioactive waste are laid out in Refs [4] &(SSR-5; GSR-5[10]). The

requirements and responsibilities with specific relevance to the management of

NORM residues are considered in this Section.

2.13 Processing of minerals and raw materials may result in radioactive

contamination of equipment and items such as pumps, separators, piping, tanks,

containers and filters. When Member States are developing a national policy and

strategy for NORM residues, they should ensure that the management of such

contaminated items (including decontamination, storage and disposal) is taken into

account.

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2.14 The responsibility for regulatory decision-making rests with the regulatory body.

However, the process of making decisions should be independent and transparent. The

process should also be defensible. The process should include adequate provision for

public consultation and to ensure that the views of all stakeholders have been taken

into account to the extent practicable.

2.15 A graded approach to regulation is one of the key principles embodied in the

Standards, and this is especially relevant in respect of activities involving NORM,

including the management of NORM residues, where exposures are generally

moderate, even in the event of accidents, and where occupational health and safety

(OHS) measures and environmental protection measures are already in place3 4

(Requirement 7 of Ref [GSR Part 3: Requirement [117]).

2.16 The detailed requirements for the responsibilities of each of the participants

involved in the management of NORM residues have been set out in Refs. [GS-R-13]

and [WS-R-311]. General requirements, relevant to the management of NORM

residues are described in Section 4. below.

MEMBER STATES

2.17 Member States are required to establish and maintain a regulatory body and

ensure that it is “effectively independent in its safety related decision making and that

it has functional separation from entities that have responsibilities or interest that

could unduly influence its decision making” [3[GSR-1; Requirement 4]. This

requirement applies equally to NORM industries, from which the regulatory body

should be independent. Also, the regulatory body “shall have sufficient authority and

sufficient staffing and shall have access to sufficient financial resources for the proper

discharge of its assigned responsibilities” [GSR-1; (Requirement 4 of Ref [3])]. In

some cases the potential radiological significance of NORM processing industries is

3 Such measures are applied to control other (non-radiological) hazards in the workplace, but may well provide

some protection against radiological hazards as well. The most common examples are measures to restrict airborne

dust in the workplace and measures to limit the pollution of water sources in the environment.

4 Such measures are applied to control other (non-radiological) hazards in the workplace, but may well

provide some protection against radiological hazards as well.. The most common examples are measures to

restrict airborne dust in the workplace and measures to limit the pollution of water sources in the

environment.

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only now being recognized, and it should also be recognized that a commensurate

increase in regulatory body resources may be required. However, it is also possible for

an existing regulatory body to simply incorporate management of radiological hazards

into its existing requirements.

2.18 Member States should determine which industries within their jurisdiction are

concerned with the production and processing of NORM. A national inventory of sites

and wastes produced by these industries should be compiled, as discussed in Section

4. Member States should also consider compiling a national inventory of legacy sites,

i.e. sites known to contain significant quantities of NORM residues from discontinued

and past practices. The combined (past and present) quantities of NORM residues

should then be used as a basis for determining what residues management facilities are

required.

2.19 Member States should make provisions for dealing with situations where an

operator is not able to meet their responsibilities. These include situations involving

operational facilities (e.g. where the operator becomes insolvent) and legacy situations

(i.e. where no legally responsible operator exists)) [WS-R-8; para 4.4]..

2.20 A system for archiving, retrieval and amendment of all important records

concerning the initial characterization of the area, the choice of options for

remediation and the implementation of remedial measures, including all restrictions

and the results of all monitoring and surveillance programprogrammes, shall be

established and maintained in all cases. Member States should ensure that the

appropriate arrangements are made for record keeping.

REGULATORY BODY

2.21 The regulatory body is responsible for authorization, regulatory review and

assessment, inspection and enforcement, and for establishing safety principles,

criteria, regulations and guides [GSR-510]. In establishing a regulatory system the

complete life cycle of each NORM processing industry should be considered, so that a

consistent regulatory approach to the production and management of residues is

achieved. Within such a regulatory system, it is quite possible that only a few facilities

or processes may require regulatory control.

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2.22 In establishing the safety principles, criteria, regulations and guides, the

regulatory body should address and encourage the recycling of NORM residues and

their use in other applications where safe and appropriate to do so. This may include

making provision for regulating the recycling of lightly contaminated materials (e.g.

steel) where it is safe and appropriate to do so.

2.23 The regulatory body is responsible for determining which facilities or processes

require regulatory controls. An example of the regulatory process for a new NORM

facility is provided in Fig. 1 (below), from which the regulatory process in individual

States may differ in detail. The regulatory body should ensure that all legal

requirements have been fulfilled by the operator. A graded approach should be

adopted to achieve the optimum level of radiation protection. This should include a

consideration of the benefits that can be achieved in practice, and the social and

economic factors involved. Small operations or local community services (e.g.

drinking water treatment plants) may be jeopardized economically by the need to

implement regulatory controls. In such cases a decision should be made on the most

appropriate manner in which to implement adequate controls to achieve a clear overall

benefit.

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Fig 1. {Inserted Fig 1 of WS-G-1.2 [Ref 9.] here, NOTE for the secretariat: to adapt

text in the figure and in the title (waste = residue; mining and milling = NORM

operations) and to include the possibilities of recycling and reuse in the pre-

operational and operational phase}

2.24 The regulatory body is responsible for verifying that the operator has met all the

obligations under the appropriate regulations. When a NORM processing facility has

been closed down, there needs to be assurance that the operator has met all the

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obligations under the appropriate regulations. The dismantling of NORM processing

plants can reveal NORM residues and contamination that were not apparent during the

operational phase. This possibility should be considered by the operator prior to the

plant being dismantled.

2.25 The regulatory body should ensure that it maintains the necessary technical

expertise to evaluate NORM processes and the ways in which NORM residues are

produced and might be used in other applications. In addition the regulatory body

should have a good understanding of the technical and financial circumstances of the

operator of each NORM residues facility, so as to ensure that the facility is operated

safely and that sufficient funding has been allocated to allow for response to any

accidents. This should extend to the knowledge that operators have available sufficient

financial and human resources and provision for interim storage for the NORM

residues, to enable not only the safe and efficient management of NORM residues, but

also a capability to manage final closure operations and remediation as required.

OPERATOR

2.26 Operators shall be responsible for the safety of radioactive waste management

facilities or activities [10]. The operator shall carry out safety assessments and shall

develop a safety case, and shall ensure that the necessary activities for siting, design,

construction, commissioning, operation, shutdown and closure are carried out in

compliance with legal and regulatory requirements. These responsibilities apply where

necessary also to facilities where NORM residues are managed. The safety of facilities

should incorporate consideration of the protection of humans (workers and public) and

the environment. Guidance on the safety case and safety assessment for predisposal

management and disposal of radioactive waste is discussed further in Section 6.

2.27 The operator of facilities for managing NORM residues is responsible for all

aspects of safety of the facility, including the protection of workers, the public and the

environment from any hazards associated with the residues, up to and including the

completion of closure of the facilities. The operator is also required to be responsible

for complying with all legal requirements. If, for any reason, the operator can no

longer assume this responsibility, it should be assumed by a governmental

organization.

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2.28 The operator of NORM facilities should develop technical and administrative

proposals, within the framework of a management system for all aspects of the

protection of human health and the environment, which should be adopted subject to

review and approval by the regulatory body.

2.29 The operator is required to be responsible for the identification of the technical

possibilities and methods to minimize the generation of NORM residues, by means of

appropriate design measures and procedures, including the recycling of NORM

residues and their use in other applications where safe and appropriate to do so

(Principle 7 of Ref [2][SF-1, Principle 7]).

SCOPE OF REGULATORY CONTROL

2.30 The selection of appropriate criteria for defining the scope of regulatory control

is an issue for all NORM activities. The number of facilities involved in the

processing of minerals and raw materials is very large, but relatively few of them

represent significant radiological hazards. Inappropriate selection of criteria could

result in many of such facilities having to be regulated without any net benefit. For

this reason, the concepts of exclusion, exemption and clearance are especially

important in defining the scope of regulatory control of natural sources [RS-G-1.75],

including the management of NORM residues.

2.31 Once the regulatory body has decided that a NORM activity falls within the

scope of regulatory control a graded approach of control should be applied, in

accordance with the [GSR GSR Part 3 (Interim)]. 11]. The graded approach of control

shall be commensurate with the characteristics of the NORM activity and with the

magnitude and likelihood of the exposures.

Exclusion

2.32 It is usually unnecessary5 to apply regulatory controls to NORM activities,

including the management of NORM residues, where the activity concentration of

5 Materials with activity concentrations below the values in Table 1 should generally be

considered as being of no regulatory concern. However, as mentioned in paragraph 5.1 of

Ref. [5], there are some situations for which some type of regulatory control may still be

appropriate, for example the use of building materials containing certain NORM residues.




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radionuclides does not exceed the values in Table 1. (below) [5], [13]. These values,

based on the concept of exclusion (non-amenability to control), should be used to

define the scope of regulation. They are valid for the natural decay chains in secular

equilibrium, i.e. 238

U, 235

U and 232

Th with the value given being applied to the parent

of the decay chain. The values can also be used individually for each decay product in

the chains or the head of subsets of the chains, such as 226

Ra.

2.33 A specific use of the exclusion principle applies to the transport of NORM. The

Regulations for transporting radioactive materials are laid down in Ref [12]TS-R-1.

Table 1. Values of activity concentration for radionuclides of natural origin

Radionuclide Activity concentration (Bq/g)

40K 10

All other radionuclides of natural origin 1

Exemption

2.34 According to GRS Part 3, tThe general criteria for exemption [11] are that:

Radiation risks arising from the practice or a source within a practice are

sufficiently low as not to warrant regulatory control, with no appreciable

likelihood of situations that could lead to a failure to meet the general criterion

for exemption; or

Regulatory control of the practice or the source would yield no net benefit, in

that no reasonable control measures would achieve a worthwhile return in terms

of reduction of individual doses or of health risks.

2.35 Processing of raw materials with radioactive concentrations in excess of the

values in Table 21 may need to be considered by the regulatory body, but should not

automatically lead to regulatory control. The regulatory body may decide that the

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optimum protection option is not to apply regulatory requirements [RS-G-1.7, (Para

5.12 of Ref [5])].

2.36 The Basic Safety Standards [11] use the concept of exemption only within the

context of practices. Exemption determines a priori which practices, sources and

radioactive materials may be freed from the requirements for practices, and hence

regulatory control, based on certain criteria. Exemption should be granted if the

regulatory body is satisfied that the practices or sources meet the exemption criteria

specified by the regulatory body.

2.37 The likely doses from work with NORM at different activity concentrations

have been estimated [RS-G-1.5]&; RS-G-1.7[6], and may serve as the basis for

material-specific exemption levels. It should normally be unnecessary to apply

regulatory controls to work activities involving exposure to NORM if the effective

dose6 received by a worker or member of the public does not exceed about 1 mSv in a

year.

2.38 The doses arising to members of the public who live near NORM residue

management facilities with radionuclide specific activity concentrations of the natural

uranium (238

U-238) and natural thorium (232

Th-232) decay series of 1Bq/g or less, are

considered unlikely to exceed about 1 mSv in a year “excluding the contribution from

the emanation of radon” [RS-G-1.75].

Clearance

2.39 The general criteria for clearance [GSR Part 3 (Interim11)] are that:

Radiation risks arising from the cleared material are sufficiently low as not to

warrant regulatory control, with no appreciable likelihood of occurrence for

scenarios that could lead to a failure to meet the general criterion for clearance;

or

6 Excluding the contribution from radon, which is dealt with separately in the Standards.











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Continued regulatory control of the material would yield no net benefit, in that

no reasonable control measures would achieve a worthwhile return in terms of

reduction of individual doses or of health risks.

2.40 Clearance is intended to establish which sources under regulatory control can be

removed from this control. It is based on clearance levels, defined as 'values

established by the regulatory body and expressed in terms of activity concentrations...

at or below which sources of radiation may be released from regulatory control' [11].

2.41 In terms of the processing of NORM and the management of NORM residues,

the concepts of exclusion, exemption and clearance are often closely linked, or even

overlap, depending on the material involved. As such, it may be appropriate to

establish a single set of levels both for exemption and clearance, using the same basis

as that applied to exclusion of exposures from NORM. Below this level no further

regulatory consideration need be given to the material and it should be disposed of as

normal7 (non-radioactive) waste.

2.42 Clearance of NORM residues containing activity concentrations above 1 Bq/g

may still be appropriate, in certain situations, providing the regulatory body is satisfied

that future exposures from such materials will be insufficient to require the

reinstatement of controls.

2.43 For radionuclides of natural origin in residues that might be recycled into

construction materials8 or the disposal of which is liable to cause the contamination of

drinking water supplies, the activity concentration in the residues does not exceed

specific values derived so as to meet a dose criterion of the order of 1 mSv in a year,

commensurate with typical doses due to natural background levels of radiation.

2.44 Clearance may be granted by the regulatory body for specific situations, on the

basis of the criteria specified by the regulatory body, with account taken of the

physical or chemical form of the radioactive material, and its use or the means of its

7 Disposal of such materials may still be subject to control due to it having other hazardous properties.

8 Regulatory control of construction materials is addressed in Section 5 of Ref [11] as an existing exposure

situation.


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Page o f 125 23

disposal9. Such clearance levels may be specified in terms of activity concentration

per unit mass or per unit surface area.

After closure

2.45 The regulatory body is responsible for the regulation of all phases of

decommissioningclosure, from initial planning to termination of the practice or final

release of the facility from regulatory control. The responsibilities of the regulatory

body include establishing safety and environmental criteria for the

decommissioningclosure of facilities, including criteria for clearance of material

during decommissioningclosure and conditions on the end state of

decommissioningclosure and on the removal of controls.

GRADED APPROACH FOR IMPOSING CONTROL

2.46 It is important that a graded approach for imposing regulatory control is applied,

bearing in mind existing occupational health, safety and environmental control

measures, and only applying additional controls where these are necessary to reach an

optimum level of radiation protection. Due account should be taken of social and

economic factors when determining what is the optimum level of protection.

Notification

2.47 A NORM residue may be identified by the operator or the regulator. If the

NORM residue cannot be exempted, the second step in the graded approach to control

of the source has to be applied. In that case, the operator is required to formally submit

a notification to the regulatory body.

2.48 Notification alone could be sufficient where exposures are unlikely to exceed a

small fraction, specified by the regulatory body, of the relevant limits. In practical

terms, this is similar to exemption, but with the important difference that the

regulatory body is kept informed of all such operations or processes. The existence of

more general occupational health and safety measures would be an important factor in

deciding whether notification alone was the optimum regulatory option.

9 For example, specific clearance levels may be developed for metals, rubble from buildings and waste for

disposal in landfill sites.

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2.49 When the activity concentration exceeds 1 Bq/g for the U and Th-series

radionuclides or exceeds 10 Bq/g for K-40, the residue should be analyzed to identify

potential risk. First, a screening assessment should be conducted. This assessment

should be subjected to careful review.

SCREENING ASSESSMENTS

2.492.50 Upon receiving a notification, the regulator may require an initial

screening risk assessment to be made to estimate:

The magnitude of worker and member of public doses arising from the

operation;

The level of optimisation of radiation protection;

The long term impact of any residues on the environment in the case of

disposal;

The impact of residues containing NORM or contaminated materials that may

be recycled;

2.502.51 The screening assessment should be specific to the particular operation

and should be negotiated between the operator and regulator. The assessment may be

based on existing information relating to the operation, its processes and waste/residue

management methods, or be based on an agreed monitoring programme to provide

more data. Procedures for carrying out data collection are described in Annex 3.

2.512.52 Possible outcomes of the screening assessment include unconditional

exemption, conditional exemption (including periodic review), and authorisation

possibly including registration or licensing. This process is shown schematically in

Figure 2.

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Page o f 125 25

Figure 2: The basic process for management of NORM

2.53 If the screening assessment indicates that the exposure of workers and the public

to the natural radionuclides in the NORM residue gives rise to doses less than 1 mSv/y

and is likely to remain so throughout the lifetime of the residue, the residue may be

granted exemption from regulatory control, which is the first step in the graded

approach.

2.522.54 If the screening assessment indicates that the dose may exceed 1

mSv/y, a more detailed assessment may need to be conducted and may include:

more realistic assumptions and exposure scenarios;

the collection of more site data to improve the estimation of the source term and

transfer parameters;

more complex models if considered appropriate.

Identification by

regulator

Notification

by operator

Screening assessment

Unconditional

exemption

Authorization

(registration/

license)

Conditional

exemption

More detailed assessment

Pag e o f 1 25 26

2.532.55 In some cases the detailed assessment may indicate that exemption is

still appropriate, because the application of control measures will not improve the

level of radiation protection.

2.542.56 In the event of significant process change, or where external events

have impacted on the operation (flooding, fire, land slippage, subsidence) a new

assessment may be required. The operator and regulator should review the situation

after a mutually agreed period to check whether exemption is still appropriate.

Authorization

2.552.57 Where the nature of the hazard is such that further obligations beyond

notification need to be placed on the operator, the Standards require that application is

made to the regulatory body for an authorization. In accordance with the graded

approach to regulation, the authorization may take the form of either a registration or a

licence, the difference being essentially in the level of stringency of regulation.

Registration, which typically places only limited obligations on the legal person, may

provide a sufficient level of control in many operations involving significant, but

nevertheless moderate, exposures to NORM and/or radon.

2.562.58 In situations where optimized protection can only be achieved through

the enforcement of specific exposure control measures, licensing may be the more

appropriate form of authorization. Licensing represents the highest level in the graded

approach to regulation, and the need for licensing of operations giving rise to exposure

to NORM will probably be largely limited to operations involving significant

quantities of material with very high radionuclide activity concentrations.

Pag e o f 1 25 27

3. PROTECTION OF PEOPLE AND THE ENVIRONMENT

INTRODUCTION

3.1 This Section outlines the basic requirements for the radiological protection of

workers, the public, and the environment in relation to the management of NORM

residues. The key points are:

Referencing of primary guidance on radiation protection plans and the setting of

dose limits, dose constraints, and releases of NORM residues to the

environment.

Insuring the protection measures adopted should be commensurate with the

magnitude and likelihood of exposures from the particular NORM residues

present

GENERAL PRINCIPLES

3.2 National requirements for radiation protection are required to be established,

keeping in view the fundamental safety objective and fundamental safety principles

set out in Ref. [2] and in compliance with the International Basic Safety Standards

Interim [11]. In particular, doses to persons as a consequence of the storage or

disposal of NORM residues are required to be kept within specified dose limits and

radiation protection is required to be optimized within dose constraints.

3.3 The management of NORM residues is part of the management of a facility

and activity as defined in Ref [11] and radiation protection considerations are

therefore governed by the principles of justification, optimization and dose limitation.

The generation and management of NORM residues do not need to be justified since

this will have been taken into account in the justification of the entire practice.

3.4 If several radiation facilities and activities are located at the same site, the

dose constraints for public exposure should take into account all sources of exposure

that could be associated with activities at the site, leaving an appropriate margin for

foreseeable future activities at the site that may also give rise to exposure. Particularly

in such cases, the regulatory body should require the operating organization(s) of the

facility and activity on the site to develop constraints, subject to regulatory approval.

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Alternatively, the regulatory body may establish the dose constraint(s). Requirements

on dose constraints are established in Ref. [11] and recommendations are provided in

Ref. [6].

3.5 Discharges to the environment from NORM facilities and activities should be

controlled in accordance with the conditions imposed by the national regulatory body

and should be included when estimating doses to workers and to the public.

3.6 The adequacy of control measures taken to limit the radiation exposure of

workers and the public should be verified by monitoring and surveillance, both inside

and outside the facility.

3.7 In the generation of NORM residues, as well as in subsequent management

steps, a safety culture that encourages a questioning and learning attitude to protection

and safety and that discourages complacency, should be fostered and maintained [11].

RADIATION PROTECTION

3.8 The fundamental safety objective of managing NORM residues is to protect

people and the environment from harmful effects of ionizing radiation (SF-1 Section

2). To achieve this objective, radiological protection of workers, members of the

public and of the environment needs to be considered at all stages of management of

NORM residues. These stages include planning and designing of the processes and

equipment, operation, and the closure of the operation and rehabilitation of the site.

3.9 There are three types of radiation exposure situation that need to be

considered: planned exposure, emergency exposure, and existing exposure [11].

3.10 Planned exposure arises from a planned operation, and the planning will

include consideration of how exposures and their likelihood of occurrence can be

restricted. Exposure can be controlled by good design of facilities and operating

procedures, and by training.

3.11 Emergency exposure arises as the result of an accident or unexpected event

and requires prompt action to avoid or reduce the consequences. In general the

Pag e o f 1 25 29

concentration of radionuclides in NORM residues is not high enough to result in

doses that would produce radiological emergencies. Nevertheless emergency

situations can arise and prompt action may be necessary, for example in order to

safeguard the integrity of storage or disposal facilities. Appropriate contingency

plans must be developed prior to the operation of any facilities that manage or

produce NORM residues.

3.12 An existing exposure situation is one where the source of exposure and an

exposure pathway already exists. In the case of NORM residues this type of exposure

may arise from situations where NORM residues from past practices have been

abandoned or are otherwise not under regulatory control. However, where a decision

is made to remediate such residues, this will be a planned operation and exposures

arising from such remediation will be planned exposures.

3.13 In all cases it is important that a graded approach to radiation protection

should be adopted. That is, the protection measures adopted should be commensurate

with the magnitude and likelihood of exposures from the particular NORM residues

present.

Radiological Protection of Workers

3.14 Workers may be exposed during the generation of the NORM residues, during

operations to process, re-use or recycle the residues, or during the disposal of NORM

wastes. In all cases where the NORM residues are subject to regulatory control a

radiation protection plan (RPP) that complies with the relevant standards [11] must be

prepared and implemented.

3.15 Radiation protection in the generation of NORM residues is usually dealt with

as part of the radiation protection programprogramme for the overall process that is

producing the residues. For example radiation protection in the generation and

handling of uranium mill tailings will be a part of the overall radiation protection

program for the mill.

3.16 In other cases the NORM residue may be the only material in the whole

process where the concentration of radionuclides is sufficient to generate doses

Pag e o f 1 25 30

requiring management, in which case the radiation protection programme will be

specific to the NORM residue. This will also be the case where the NORM residues

are pre-existing.

3.17 In general, occupational radiation protection in the management of NORM

residues involves consideration of three main exposure pathways:

External exposure to radiation (primarily gamma radiation) emitted by the

material

Intakes of material (primarily through dust inhalation);

Inhalation of radon (and sometimes thoron) released from material into the air10

.

3.18 Other exposure pathways, such as ingestion from hand to mouth transfer, may

need consideration but the doses that may arise are usually much less than for the

other pathways.

3.19 In developing the RPP for management of NORM residues, the requirements

of [11] must be implemented, particularly the requirements for Planned Exposure

Situations. Dose limits for workers in planned exposure situations are detailed in

Schedule III of Ref [11]. In particular the occupational exposure of workers at

NORM processing facilities (including those who work with NORM residues,

whether on operational or legacy sites) from all sources should not exceed: an

effective dose of 20 mSv per year averaged over five consecutive years; an effective

dose of 50 mSv in any one year; an equivalent dose to the lens of the eye of 20 mSv

in a year, and an equivalent dose to the extremities (hands and feet) or skin of 500

mSv in one year [11].

3.20 It is also required that radiological protection be optimized so that doses to the

workforce are as low as reasonably achievable, social and economic factors being

taken into account11

[11].

10 The terms “radon” and “thoron” include not only the parent radionuclides, 222Rn and220Rn respectively, but

also their short-lived progeny.

11 More detailed guidance on preparation and implementation of a RPP is included in DS 453 Occupational

Radiation Protection in preparation.

Pag e o f 1 25 31

Radiological Protection of the Public

3.21 Radiation exposures to members of the public from NORM residues may

occur as existing exposures or as planned exposures. Existing Exposure Situations

involve those situations where pre-existing NORM residues are giving rise to

exposure of members of the public. Where members of the public have access to the

site on which NORM residues are disposed exposure can arise directly from those

residues, but exposure more commonly arises in the area surrounding the NORM

residues where radionuclides have been dispersed by airborne or waterborne

pathways.

3.22 The main pathways for exposure of members of the public in existing

exposure situations are:

External exposure to gamma radiation emitted by the material;

Intakes of material due to dust inhalation, either directly or via re-suspension;

Intakes of material by ingestion, either directly (e.g. inadvertent ingestion of

contaminated soil) or from ingestion of food or water;

Inhalation of radon (and, very rarely, thoron) released from material into the air.

3.23 As most if not all NORM radionuclides are normally present in the

environment, and contribute to natural background radiation, it is important that care

be taken to distinguish between exposures arising as a result of the presence of

NORM residues, and those arising from natural background.

3.24 The dose limits applicable to planned exposure situations do not apply to

existing exposure situations. Instead such exposures should be investigated to

determine if remedial actions or protective actions are justified, and that the extent of

such actions is optimized [11].

3.25 Planned exposure situations are those where members of the public are

exposed as a result of situations that are planned. These situations will include those

where exposure results from the generation of NORM residues, as the result of

Pag e o f 1 25 32

treatment of residues for re-use or recycling, or from remediation of existing NORM

storage or disposal sites.

3.26 The pathways for exposure of members of the public in planned exposures

situations are similar to those outlined for existing exposure, although it is possible

that re-use or recycling of NORM residues may introduce new pathways.

3.27 Dose limits to members of the public in planned exposure situations are

detailed in Schedule III of Ref [11]. The main limit applicable in the case of exposure

from NORM residues is an effective dose of 1 mSv in a year, with a provision that in

special circumstances a higher value of effective dose could apply in a single year

could apply, providing that the average effective dose over five consecutive years

does not exceed 1 mSv per year. An example of a case where such special

circumstances might be considered to apply is a transitory increase in exposure during

planned remediation measures, when those measures will lead to a subsequent

reduction in doses over the long term.

3.28 The dose limits should apply both during operations involving NORM

residues, such as generation, re-use or recycling, or storage or disposal, and to

exposures occurring after the cessation of such operations. During operations, doses

can be assessed through monitoring: either direct monitoring of radionuclides in for

example ambient air or foodstuffs, or indirectly by monitoring discharges and

modeling the subsequent intakes and doses to members of the public.

3.29 There should be reasonable assurance that these controls will remain effective

for a specified period, and that during this period the dose constraint determined by

the regulatory body will continue to be met.

3.30 Engineering controls may fail because of natural processes (such as erosion)

or events that result in the release of increased amounts of radionuclides to the

environment. Due consideration should be given to the probability of failure of such

controls and to the likely impact in terms of the overall integrity of the facility and

any public exposure or environmental consequences.

Pag e o f 1 25 33

3.31 The potential for public exposures in excess of the dose constraint arising

from possible future re-development of, or unplanned intrusion into, closed NORM

waste disposal facilities, should always be considered, and appropriate institutional

controls prepared.

3.32 RADIOLOGICAL PROTECTION OF THE ENVIRONMENT

3.333.32 Release of NORM contaminants into the environment has the potential

to irradiate non-human biota. Such exposure is most likely to occur as a result of

airborne or waterborne transport of radionuclides from a facility into the environment,

although it may also arise where plants or animals live on or in un-remediated NORM

residues.

3.343.33 The standard of radiation protection required to protect people from

harmful effects is generally considered to also provide appropriate protection of the

environment. Nevertheless there is a need to be able to demonstrate that the

environment is protected from the harmful effects of radiation exposure in any

situation in which NORM residues may be released into the environment [11].

3.353.34 Such a demonstration would usually be by means of an environmental

assessment that identifies any target organisms in the relevant environment, estimates

the doses that may arise from transport of NORM residues into that environment, and

the likelihood of such doses resulting in harmful effects. Methods for these

assessments have been developed12

[13]. Generally an assessment of potential

radiological effects on the environment would be part of a more general assessment of

the impacts of the operations being considered.

12 Including DS427: in preparation


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Pag e o f 1 25 34

4. GENERAL ASPECTS OF RESIDUE MANAGEMENT

INTRODUCTION

4.1 This Section deals with the general aspects of the management of NORM residues.

More specifically, it covers:

The establishment of an inventory of processes that lead to the generation and

handling of NORM residues;

The characterization of the residues in order to understand their physical,

chemical and radiological properties;

The segregation of the residues, in order to decide if the material can be

cleared, reused or recycled;

A description of the principles and approaches that can be applied to the

management of residues and waste;

A description of options to minimize waste production and to treat and

condition the residues, either for reuse, recycling or disposal as waste;

A description of the main types of NORM residues and waste.

INVENTORY OF PROCESSES GENERATING NORM RESIDUES

4.1 This Section deals with the general aspects of the management of NORM

residues. More specifically this Section covers:

The establishment of an inventory of processes that lead to the generation and

handling of NORM residues;

The characterization of the residues in order to understand their physical,

chemical and radiological properties;

The segregation of the residues, in order to decide if the material can be cleared,

reused or recycled;

A description of the principles and approaches that can be applied to the

management of residues and waste;

A description of options to minimize waste production and to treat and

condition the residues, either for reuse, recycling or disposal as waste;

A description of the main types of NORM residues and waste.


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INVENTORY OF PROCESSES GENERATING NORM RESIDUES

4.2 4.2 The Safety Requirements [10] state, “to ensure effective and efficient

management and control of radioactive waste, the government shall establish a

national policy and strategy on radioactive waste management…appropriate for the

nature and amount of radioactive waste in the country”. NORM residues may or may

not be waste, but in order to develop a comprehensive national policy and strategy on

the management of NORM residues, the nature and amounts of NORM residues need

to be investigated and quantified, regardless if any future use of the residues is

foreseen.

4.3 4.3 An important first step in the development of regulatory systems and

management practices for NORM residues is to understand how, when and where

elevated concentrations of naturally occurring radionuclides could occur. Mining and

milling of uranium ores has always been considered as part of the nuclear fuel cycle,

and therefore it has been regulated under this regime. Other industrial sectors,

materials and processes involving NORM may also require some form of regulatory

consideration. A list of industry sectors is:

Mining and milling of uranium ores;

Extraction of rare earth elements;

Production and use of thorium and its compounds;

Production of niobium and ferro-niobium;

Mining of ores other than uranium ore;

Production of oil and gas;

Manufacture of titanium dioxide pigments;

The phosphate industry;

The zircon and zirconia industry;

Production of tin, copper, aluminium, iron and steel, zinc, and lead;

Combustion of coal;

Water treatment.

4.14.4 Operation of these industries can result in a need for developing a national

inventory of NORM residues. An overview of the major industrial processes which


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Pag e o f 1 25 36

generate NORM residues, their occurrence, and the types of products, wastes and

residues generated is given in Table 2.

Pag e o f 1 25 37

Table 2 Major industrial activities that generate NORM residues

Industry Products NORM residues

Mining and milling Mineral Tailings, waste rock,

process water

Mineral processing Metal Tailings, slag

Phosphate industry Fertiliser, phosphoric acid Phosphogypsum, scales

Power generation

(fossil fuels)

Electricity Ash, scales

Oil & gas production Oil, gas Scales, sludges, process

water

Water treatment Potable water Sludges, bio-solids, scales

CHARACTERIZATION AND SEGREGATION

4.5 4.5 Due to the diversity of NORM residues, in terms of activity

concentration, volume, physical and chemical state, identification based on certain

criteria and procedures is the first step to impose control of NORM residues. Proper

characterization and segregation of residues are very important factors in residue

management. Characterization helps in developing a complete understanding of the

physical, chemical and radiological characteristics of residue for sorting and shipping,

either for selected processing, reuse and recycle, or for storage and disposal.

Segregation favors the maximization of clearance, reuse or recycling of residues and

can reduce the volume of waste that requires final disposal. Proper sorting requires

staff training and additional space and containers in the residue collection and storage

areas.

OPTIONS FOR RESIDUE MANAGEMENT

Principles, approaches and options

4.6 4.6 Radioactive residues management comprises managerial,

administrative and technical steps associated with the safe handling and management



Pag e o f 1 25 38

of residues, from generation to release from further regulatory control or to its

acceptance at a storage or disposal facility. It is important that the NORM residues

management strategy forms an integral part of the overall waste management strategy

for the operation. Non-radiological aspects such as chemical toxicity also need to be

considered, since these will influence the selection of the optimal residues

management options. For sludges in particular, the constraints on waste disposal or

processing options imposed by non-radioactive contaminants will in many cases be

greater than those imposed by radioactive components.

4.24.7 4.7In view of the range of NORM residue types that can be generated in

industries at different times and the possibility of changes occurring in the ways in

which they are generated and managed, particular attention needs to be given to the

radiation protection issues which may arise in their management and regulatory

control. Because of the nature of the industry, and the fact that the activity

concentrations are often relatively low, there is often limited knowledge among the

staff about the radiation protection aspects of residues management. While the safety

principles are the same for managing any amount of radioactive residues regardless of

its origin, there may be significant differences in the practical focus of residues

management programmes.

4.8 4.8 The development of a waste management strategy is usually a complex

process that has the aim of achieving a reasonable balance between two, often

conflicting, goals: maximization of risk reduction and minimization of financial

expenditure. The process is one of optimization of protection in which the available

alternatives for siting, design and construction, operation, management of waste

streams, and closure are evaluated and compared, with account taken of all associated

benefits and detriments and any constraints (such as an annual dose constraint) that are

required to be imposed. The characteristics of the alternatives (or options) that should

be considered include:

The radiological and non-radiological impacts on human health and the

environment during operation and in the future

The requirements for monitoring, maintenance and control during operation and

after closure;



Pag e o f 1 25 39

Any restrictions on the future use of property or water resources;

o The financial costs of the various alternatives and the resources available for

implementing the alternatives;

The volumes of the various residues to be managed;

The socioeconomic impacts, including matters relating to public acceptance;

Good engineering practices.

o4.9 Table 2 shows a variety of residues generated by NORM industries, each of

them with specific characteristics. A major distinction in the management options for

residues relates to the volume of material under consideration. For the management of

large volumes of residues, such as those from uranium mining and milling and from

processing of ores, the options are different from comparatively small volumes of

residues such as sludge and scales.

4.34.10 A key element of the Safety Requirements [10] is that “Radioactive

waste arising shall be kept to the minimum practicable”. This is especially the case

with many NORM residues, where options for further safe use should always be

explored first. This includes re-use or recycling within the process itself or use as an

input material to a different process or product. NORM residues should only be

designated as NORM waste where no further viable, safe use for the material can be

identified. Further details on re-use and recycling of NORM residues is given in

Annex 2.

o4.11 The three principle approaches to the management of radioactive waste are:

Delay and decay;

Concentrate and contain;

Dilute and disperse.

o4.12 The first principle, delay and decay, involves holding the waste in storage until

the desired reduction in activity has occurred through radioactive decay. Many NORM

residues contain radionuclides with long half-lives (e.g. 238

U, 232

Th, 226

Ra) and this is

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Pag e o f 1 25 40

not a realistic management option for such wastes. It is, however, a realistic option for

residues containing only shorter-lived radionuclides, most commonly 210

Pb and/or

210Po.

4.44.13 The second principle, concentrate and contain, is widely used in the

management of wastes. The principle of concentrate and contain is predominantly

applied in the mineral processing industry. Though the containment of NORM

residues may be the best disposal option, this preference should not automatically be

assumed.

4.54.14 In all cases, the three principles for radioactive waste management are

not contradictive. Instead, they are complementary. An activity that generates

radioactive waste may use the first principle to allow for decay of short-lived

radionuclides and use the second principle for waste containing long-lived

radionuclides. For activities with artificial radionuclides this is the normal practice.

For many NORM residues, the third principle may be applied as being the

management principle of choice. In any case, every activity involving radioactive

waste needs to allow for the release of radionuclides by discharges, which might be

regulated by a license. The discharge is in fact the application of the third principle of

radioactive waste management.

4.64.15 When considering disposal options and any associated mitigating

options to reduce the impact on the public, account must always be taken of both the

radiological and other (non-radiological) hazards associated with NORM waste. In

many cases non-radiological hazards may well be the dominant factor to consider in

the selection of a disposal method. The selected disposal method should maximize the

protection of the public from all the hazards arising from the waste.

4.74.16 NORM residue management options include use as a raw material in

another process, re-use and recycling, and disposal. The selection of the most

appropriate management option depends on the regulatory requirements, type of

waste, form of the waste (e.g. particle size, liquid versus solid, etc.), quantities and

hazards associated with that particular waste, geographic location and geological

Pag e o f 1 25 41

conditions. The selection of management options for different categories of NORM

residues is discussed in the following sections.

Waste minimization

o4.17 Principle 7 of the Safety Fundamentals [2], states that radioactive waste must

be managed in such a way as to avoid imposing an undue burden on future

generations. This implies that the generations that produce the waste must seek and

apply safe, practicable and environmentally acceptable solutions for its long-term

management.

o4.18 Measures to control the generation of NORM residues, in terms of both

volume and radioactivity content, have to be considered before the construction of a

facility, beginning with the design phase, and throughout the lifetime of the facility.

These measures include the selection of the materials used for its construction, the

control of the materials and the selection of the processes, equipment and procedures

used throughout its operation and decommissioningclosure. Provided that protection

objectives are met, the control measures are generally applied in the following order:

reduce NORM residues generation, reuse items as originally intended, recycle

materials and, finally, consider disposal as waste.

o4.19 Authorized discharge of effluent and clearance of materials from regulatory

control, after some appropriate processing and/or a sufficiently long period of storage,

together with reuse and recycling of material, can be effective in reducing the amount

of residues that needs further processing or storage. The operator has to ensure that

these management options, if implemented, are in compliance with the conditions and

criteria established in regulations or by the regulatory body. The regulatory body also

has to ensure that the operator gives due consideration to non-radiological hazards in

applying such options.

o4.20 The general scheme for minimizing the volume of waste is presented in Fig. 3.

Pretreatment of waste is the initial step in waste management that occurs after waste

generation. It consists of, for example, collection, segregation, chemical adjustment

and decontamination and may include a period of interim storage. This initial step is

extremely important because it provides in many cases the best opportunity to


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Pag e o f 1 25 42

segregate waste streams, for example, for recycling within the process or for disposal

as ordinary non-radioactive waste when the quantities of radioactive materials they

contain are exempt from regulatory controls. It also provides the opportunity to

segregate radioactive waste, for example, for near surface or geological disposal.

Figure 3 Basic steps in residues and waste management

Pre-treatment

o4.21 The processing of NORM residues will include pre-treatment operations such

as residues collection, segregation, chemical adjustment and decontamination. Pre-

treatment may result in a reduction in the amount of residues needing further

processing and disposal. Actions can be performed to adjust the characteristics of the

residues, to make it more amenable to further processing, and to reduce or eliminate

certain hazards posed by the waste owing to its radiological, physical and chemical

properties. In mining and mineral processing, segregation of benign waste rock from

mineralized waste rock, which requires special handling, is a pretreatment activity.

Treatment

o4.22 Treatment of radioactive waste includes those operations intended to improve

safety or economy by changing the characteristics of the radioactive waste. The basic

treatment concepts are volume reduction, radionuclide removal and change of

composition. Examples of such operations are: incineration of combustible waste or

compaction of dry solid waste (volume reduction); evaporation, filtration or ion





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Pag e o f 1 25 43

exchange of liquid waste streams (radionuclide removal); and precipitation or

flocculation of chemical species (change of composition). Often several of these

processes are used in combination to provide effective decontamination of a liquid

waste stream. This may lead to several types of secondary radioactive waste to be

managed (contaminated filters, spent resins, sludges).

Conditioning

o4.23 Conditioning of radioactive waste involves those operations that transform

radioactive waste into a form suitable for handling, transportation, storage and

disposal. The operations may include immobilization of radioactive waste, placing the

waste into containers and providing additional packaging. Common immobilization

methods include solidification of liquid radioactive waste, for example in cement or

bitumen. Immobilized waste, in turn, may be packaged in containers ranging from

common 200 litre steel drums to highly engineered thick-walled containers, depending

on the nature of the radionuclides and their concentrations. In many instances,

treatment and conditioning take place in close conjunction with one another13

.

Immobilization of radionuclides in tailings

o4.24 Waste containing hazardous constituents that are mobile in the environment, or

constituents that enhance the mobility of radionuclides, should be immobilized or

stabilized. This is particularly important for the large volumes of mining and milling

tailings and stockpiles of NORM residues from processed raw materials, such as

phosphogypsum and red mud. Depending on the chemical composition of the natural

radionuclides and the physical matrix in which they are contained, the radionuclides

may be mobilized and contaminate the environment, i.e. the groundwater. Therefore,

measures to immobilize the radionuclides in the tailings and stockpiles should be

taken to assure the safety of the public in the surrounding environment. If hazardous

constituents are not immobilized or stabilized, it should be demonstrated for a facility

storing the waste that the constituents cannot migrate in a hazardous form or

concentration to the accessible environment.

Reuse and recycling

13 Further details on pretreatment, treatment, and conditioning can be found in DS 447.


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Pag e o f 1 25 44

4.84.25 The introduction of improved process technologies and waste

minimization techniques such as reuse, recycling and use of NORM residues for new

purposes should be pursued provided that such activities are in accordance with the

Safety Fundamentals. The policy and strategy of NORM residues management should

address and encourage the recycling of NORM residues and their use in other

applications.

o4.26 Reuse can be defined as the reutilization of materials for the original purpose

in their original form or in a recovered state. Recycling is the utilization of valuable

materials, tools and equipment for other than the original purposes, with or without

treatment. The reuse and recycle options are attractive because there is strong

economic incentive to use the large volume of residues, to avoid the costs associated

with long term storage or disposal. The decision of whether or not to reuse and recycle

residues depends on many factors that are specific to a given stream of residue or

industry or country. Implementation of reuse and recycling options requires the

availability of suitable criteria, such as conditional and unconditional clearance levels,

a suitable measurement methodology and suitable instrumentation. More information

on reuse and recycling of NORM residues is given in Annex 2.

Storage and retrieval of residues

o4.27 Storage refers to the placement of the NORM residues in a facility where

appropriate isolation and monitoring are provided, with the intent of retrieval. Storage

may take place between and within the basic radioactive waste management steps.

Storage may be used to facilitate the next step in radioactive waste management, to act

as a buffer within and between radioactive waste management steps, or in awaiting the

decay of radionuclides until authorized discharge, authorized use or clearance can be

allowed. The same accounts for the storage of NORM residues.

o4.28 NORM residues will in general be stored in solid form as raw, pretreated,

treated or conditioned material. The intention of storage is that the material will be

retrieved for authorized discharge, authorized use or clearance or for processing and/or

disposal at a later time. The criteria for acceptance of the material in a storage facility

shall therefore take account of the known or likely requirements for subsequent

radioactive waste disposal. Safety requirements for the protection of human health and







Pag e o f 1 25 45

the environment shall be met by appropriate design, construction, operation and

maintenance of the respective facilities, including provision for the eventual retrieval

of the waste.

Disposal of NORM waste

o4.29 When no future reuse or recycling of the NORM residues is foreseen, the

material shall be processed to meet the acceptance criteria for disposal established

with the approval of the regulatory body. These criteria define the radiological,

mechanical, physical, chemical and biological properties of the waste. More

information on the requirements for long-term management of NORM residues is

given in Chapter 5.

Bulk minerals processing residues other than uranium mill tailings

4.30 Of the different residues produced by NORM activities, bulk residues

represent the greatest challenge, despite their relatively low specific activity. This is

particularly true in terms of long-term management, because of the large volumes

produced, and the presence of very long lived radionuclides and (often) other

hazardous substances, such as heavy metals. Such residues include phosphogypsum,

red mud from alumina processing and metaliferous tailings. The preferred

management option will depend on specific conditions at the site, the characteristics of

the NORM, the processes to be used, and the characteristics of the bulk residue.

Section 5 provides guidance on the siting, design, construction and operation of large

volume NORM residue management facilities.

o

Waste rock, mineralized waste rock and similar residues

o4.31 While the radiological hazards associated with waste rock and mineralized

waste rock are usually much less significant than those for bulk minerals processing

residues, non-radiological hazards will remain and are often more important when

considering the most appropriate management options. There are many possible

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Pag e o f 1 25 46

options for managing waste rock and mineralized waste rock: the best option in

practice will depend on the particular mineralogy, radioactivity and chemical

reactivity of these wastes.

o4.32 Options for managing waste rock and mineralized waste rock include their use

as backfill materials in open pits and underground mines, and for construction at the

mine site. The need to cover mineralized waste rock with inert waste rock should be

taken into account. As with bulk minerals processing residues, the stability of piles of

waste rock, and their resistance to erosion and rainwater infiltration, should be

considered, to ensure that they do not result in unacceptable environmental impacts on

the water catchment area. Co-disposal of waste rock with tailings is a procedure that

can be considered for both underground and above ground disposal options in mining

situations however chemical compatibility of the comingled material should be

considered.

4.94.33 Some waste may be suitable for reincorporation into the original

environment by dilution back to activity concentrations comparable to the original

state. An example would be monazite sands being reincorporated uniformly into the

remediated workings of a minerals sands extraction operation.

o4.34 Waste rock can be divided into three broad categories:

Unmineralised waste: This generally represents waste rock that is geologically

distinct from the ore-body, for example sedimentary cover sequences above a

metamorphic host zone. This material in general has a radionuclide content

characteristic of typical background material, and well below levels of

regulatory significance. There are thus no radiological constraints on its

management or re-use.

Mineralised waste: This material usually exhibits radionuclide content

significantly above normal background levels, and may range up to near that of

ore, and so may or may not be of regulatory significance. Thus there may be

some constraints on the uses to which it may be put, or to the requirements for

long term storage or disposal.

Uneconomic mineralised material: This category is applicable to uranium or

thorium mining, and refers to material that has a uranium or thorium content


Pag e o f 1 25 47

that is, under present conditions, uneconomic to process. Such material may be

segregated so that should economic conditions change it could be processed, or

it might simply be included with mineralised waste. Its radionuclide content will

make it subject to regulatory control, and the uses to which it might be put will

be very limited and there will be significant radiological requirements on

storage and disposal.

It should be noted that all three categories may contain other (non-radiological)

contaminants that may affect re-use, storage or disposal requirements.

4.104.35 As noted above, there are no radiological constraints on unmineralised

waste rock, and it can be used either on-site (for construction purposes, impoundment

walls, mine backfill etc.) or off-site. The only significant requirement would be that

stringent procedures are in place to ensure that this material is properly segregated

from mineralized material and that it is not contaminated with material from the other

categories (or indeed ore).

4.114.36 Mineralised waste that is below regulatory concern should also be

available for use on- or off-site, however it should be demonstrated that the

mineralised waste is in fact below regulatory concern before it is used for these

purposes. Mineralised waste of regulatory concern can sometimes be used on-site, but

usually only in applications where it will not be a concern after rehabilitation. For

example it may be used for the walls of tailings impoundments, where it will

eventually be covered by inert material during rehabilitation. Uneconomic

mineralised material, if it is not processed during the later stages of the project has

very few potential uses, and will have significant requirements for storage or disposal.

Liquid waste

4.37 Liquid waste includes: process water; leaching fluids; rainfall runoff (from the

process plant area, waste management area, waste and ore stockpiles); seepage from

mill tailings, stockpiles and waste rock disposal areas; and mine water (for example,

groundwater which has entered open pits or underground mines). All liquid waste

should be managed on the basis of its quality and quantity, with account taken of

environmental and human health impacts, rather than on the basis of its sources.

Comment [AJ1]: Old paras 3.39 -3.41

deleted as repeats


Comment [AJ2]: Old para 3.42 split into two parts

Pag e o f 1 25 48

o4.38 The water management system should be designed to minimize the volume of

contaminated water. This could be achieved, for example, by the diversion of clean

water away from sources of contamination, the reuse of wastewater in the process

circuit and dust suppression. Where appropriate, liquid wastes should be treated to

separate any solid NORM residues from suspension. These may then be managed

separately. Residual liquid may be treated to achieve discharge quality. Such a

procedure will optimize the waste management by minimizing the volume of liquid

waste to be treated. Water treatment may also be required for other reasons than

management of NORM residues.

Contaminated items

o4.39 Scrap items such as pipes, process vessels, pumps and machinery that have

been contaminated with NORM residues should be decontaminated where practicable,

in the interest of waste minimization. Items that remain contaminated, and any

residues from the decontamination process, should be managed as solid or liquid

NORM waste, as appropriate.

Manufactured items containing NORM

o4.40 Some manufactured items may contain significant concentrations of 238

U or

232Th series radionuclides e.g. some turbine blades and thoriated lenses. When such

items are designated as waste, they should be managed in accordance with the

procedures developed for NORM waste. Attention should also be paid to residues that

might be generated following re-use, repair or refurbishment of such items. This could

include cuttings, turnings and dust.

Low-volume Hhigher activity waste

o4.41 Some waste may comprise a relatively small volume but be of relatively higher

activity concentration; this is frequently the case for scale and sludges that may be

accumulate in pipes or process vessels. Such waste may be managed either in the

original or a modified form. Small volumes of unmodified waste may be sealed into

suitable containers and deposited in designated containments or special landfills, or

possibly placed deep within tailings management facilities that are destined for

closure. An option for some liquid residues may be borehole injection into suitable

geological formations.




Pag e o f 1 25 49

o4.42 After an appropriate treatment, a low volume, high activity waste may be

suitable for dispersion and dilution evenly throughout a large volume of low activity

waste.

Uranium mill tailings

o4.43 Of the different waste streams produced by uranium mining and milling

operations, uranium mill tailings (“tailings”) represent the greatest challenge,

particularly in terms of long term management, because of the large volumes produced

and their content of very long lived radionuclides and heavy metals. Because of their

large volume it is generally impractical to transport the tailings significant distances,

and so storage and disposal is constrained to the vicinity of the mine or processing

plant. The preferred management option for achieving the protection goals will

depend on specific conditions at the site, the characteristics of the ore body, the

specifics of the mining and milling processes, and the characteristics of the tailings.

The siting and design of tailings management facilities is an essential part of the

overall project design, and must be addressed from the earliest stages of project

development.

o4.44 Tailings contains all the radionuclides in the original ore, at concentrations

near their concentration in ore, with the exception of the uranium isotopes and their

immediate short lived decay products. Approximately 75% of the original

radioactivity present in the uranium ore is retained in the tailings. Tailings will thus

always be subject to regulatory control.

o4.45 There are very few options for re-use of tailings. Tailings, and particularly the

coarser size fractions may be of use as a component of mine fill.

o4.46 Tailings are usually discharged as a slurry containing about 20-50% solids into

a purpose built water retaining structure generally referred to as a “tailings

impoundment”. The design and construction of tailings impoundments are discussed

further in Section 5.

o4.47 The option of relocating tailings to a more favorable site for closure would not

normally be expected to provide the optimum strategy for management because of the


Pag e o f 1 25 50

large volumes of mining and milling waste that would be involved. However, if

relocation of the waste is being considered, care should be taken to factor into the

optimization all the significant radiological and non-radiological impacts that may be

introduced by the relocation itself, including issues relating to the transport of large

volumes of waste.

o4.48 Other disposal strategies for mill tailings that take different approaches for risk

assessment may be appropriate and they should be evaluated on a case-by-case basis.

For example, small quantities of mill tailings may be acceptable for disposal in

facilities designed for low- level radioactive waste, provided that the waste acceptance

criteria of the facility are complied with.

Heap leach waste

4.124.49 Heap leaching is a method successfully used for processing low-grade

uranium ore and typically involves the treatment of crushed or pelletized ore grade

material with acid or alkali (or bacteria) on large engineered pads on the surface.

Stope or block leaching of basted ore underground is also conducted. In the case of

uranium extraction, the uranium rich “pregnant” leach solutions are commonly passed

through an ion exchange columns or solvent extraction process to extract the uranium

for further processing. The uranium depleted “barren” leach solution is then

reconstituted and re-used.

4.134.50 Surface heap leach facilities require efficient containment, base liners

and leak detection systems to protect the surface environment and groundwater

resources.

4.144.51 Heap leach wastes consist of process liquids generated during

operation, the leached ore and potentially, ongoing release of solutions from

infiltration of the closed facility. During operation, waste process solutions can be

collected, treated and sent to adjacent evaporation ponds and/or injected into deep

disposal wells. In some cases, a separate residue storage dam may be required with

characteristics similar to those of a tailings dam.

Pag e o f 1 25 51

4.154.52 An important consideration is locating the heap leach pad to permit

ease of closure and isolation of the resulting residues in place, without relocation.

Heap flushing and neutralization may be conducted at closure.

In-situ leaching waste

4.164.53 In-situ extraction is only possible where the ore-body is contained in an

aquifer with suitable porosity and permeability to allow circulation of leach liquors

through it. Extraction is carried out by drilling a pattern of injection and extraction

wells into the ore-body and circulating leach liquor. The uranium is extracted from the

resulting “pregnant” solution by conventional solvent extraction or ion exchange

methods and the now barren solution is reconstituted and re-injected into the leaching

field. No conventional “tailings” are produced, but large volumes of liquid waste can

be generated.

o4.54 A small fraction of the leach liquor is bled off, in part to reduce the build-up of

undesirable impurities in the leach liquor, but largely to ensure that there is a greater

volume of fluid extracted than injected. This imbalance leads to a net inflow of fluid

into the mining area, which maximizes recovery of the leach solution and prevents

migration of contaminants from the mining process into the surrounding aquifer. This

bleed stream constitutes the largest volume of liquid waste from the process.

o4.55 Large volumes of liquid waste can also be generated where reconstitution of

the ore-body aquifer is required following completion of mining. This may require

flushing of the aquifer with several pore-volumes of uncontaminated water, and the

extracted water will contain radionuclides and other contaminants.

4.174.56 Smaller volumes of liquid water are generated from normal plant

operation, including wash-down of equipment and spillages.

4.184.57 Liquid waste can be disposed of by evaporation, or discharged into

aquifers or surface water-bodies. Aquifer injection can be too deep, and preferably

well-confined aquifers, or into shallower aquifers, typically the mining aquifer itself.

In cases where the aquifer is of good quality or discharge is into surface waterbodies,

treatment of the waste to remove radioactive and other contaminants will generally be


Pag e o f 1 25 52

required. However in some cases the disposal aquifer is of such poor quality that no

practical use can be foreseen for the water, and in such cases no treatment of liquid

waste (other than settling of entrained sediments) will be required before disposal.

4.194.58 In all cases of disposal of liquid waste into aquifers careful and detailed

hydrogeological modeling of the situation will be required. Such modeling is also

required for the mining process itself. Modeling will need to include the basic

hydrogeological parameters (permeability, porosity, hydrostatic heads and natural

aquifer flow, connections with other aquifers etc.) and chemical consideration of both

the groundwater and the host sediment.

4.204.59 As noted there are no convention tailings associated with in-situ

mining, but there is a range of other solid wastes generated. The largest amount of

(radiological) waste generally arises from the bleed stream treatment. If the bleed

stream is evaporated, evaporites can contain significant concentrations of

radionuclides. If the bleed is treated chemically to remove radionuclides, these will

usually be recovered in solid or slurry form.

4.214.60 The ore body aquifer may require pre-treatment prior to mining,

commonly to remove calcium, and the resulting precipitates can contain quite high

radium concentrations.

4.224.61 General radioactive solid wastes generated in processing include

process sludges and precipitates, filter media, and contaminated pipes, and equipment.

o In all cases of disposal of liquid waste into aquifers careful and detailed

hydrogeological modeling of the situation will be required. Such modeling is also

required for the mining process itself. Modeling will need to include the basic

hydrogeological parameters (permeability, porosity, hydrostatic heads and natural

aquifer flow, connections with other aquifers etc.) and chemical consideration of both

the groundwater and the host sediment.

o Monitoring of the disposal area (and again also the mining area) will be

required, principally to detect any unplanned migration of wastes or mining fluids

Comment [AJ3]: Old paras 4.59 & 4.60 deleted – unrequired detail at this point.


Pag e o f 1 25 53

from the injection sites. This is commonly accomplished by a ring of monitoring wells

drilled into the relevant disposal (or mining) aquifer, and where relevant, aquifers

above and below the injection points. Parameters monitored may be hydrogeological

(for example hydrostatic heads) or chemical (radionuclide or other contaminant

concentrations, conductivity, pH, redox etc.).

o Definitions of what parameter changes will be regarded as constituting

evidence of an excursion of waste or mining fluid beyond approved boundaries will

need to be determined by regulatory authorities before operations commence, together

with the remedial actions that will be required in the event of such an excursion being

detected. Remedial actions can include cessation of injection, either until conditions

stabilize or permanently, or extraction of liquid from the disposal area and either

disposal in the same area after treatment or disposal in some other area. .

o As noted there are no convention tailings associated with in-situ mining, but

there is a range of other solid wastes generated. The largest amount of (radiological)

waste generally arises from the bleed stream treatment. If the bleed stream is

evaporated, evaporites can contain significant concentrations of radionuclides. If the

bleed is treated chemically to remove radionuclides, these will usually be recovered in

solid or slurry form.

o The ore body aquifer may require pre-treatment prior to mining, commonly to

remove calcium, and the resulting precipitates can contain quite high radium

concentrations.

o General radioactive solid wastes generated in processing include process

sludges and precipitates, filter media, and contaminated pipes, and equipment.

Heap Leaching Waste

o


Pag e o f 1 25 54

REMEDIATION OF RESIDUE FACILITIES

o4.62 For a NORM contaminated site, remediation may be needed for the purpose of

protecting human health or the environment, or for the purpose of another land use.

Remediation is defined as an existing exposure situation and should be justified and

optimized.

o4.63 The major issues associated with sites contaminated through past practices

include the following:

Often little or no documentation of activities at the site is available;

It is difficult to assign responsibility for any remediation that may be required;

Characterization of the site can be difficult as in many cases the local

demographics have changed, and sites that were used or industrial activity are

now used for residential purposes;

Impact assessment can be complicated, for the same reasons that make site

characterization difficult.

o4.64 In dealing with a legacy site, a national remediation policy and strategy should

be developed, in which remediation of NORM residue should be taken into account.

Issues mentioned above should be well addressed in the remediation policy and

strategy.



Pag e o f 1 25 55

5. LIFE CYCLE MANAGEMENT OF NORM RESIDUES

INTRODUCTION

5.1 The management of bulk NORM residues needs to be planned when the mine,

processing plant or proposed industrial activity is first being developed and effectively

managed and controlled over the entire lifecycle of the facility. This section:

Provides guidance in the siting, design, construction, operation, closure and

decommissioningclosure of facilities to be used in the handling, treatment,

conditioning, storage and disposal of bulk NORM residues and the

management of small volumes of high activity wastes.

Discusses matters related to institutional controls including long -term

monitoring and access controls that may be needed to ensure the long -term

protection of people and environment at a facility containing NORM residues.

Treatment and Conditioning Considerations

5.2 The treatment and conditioning of NORM residues may be required to meet

established acceptance criteria for their storage and possible disposal. For example,

this may include treatment and conditioning to neutralize the residues to prevent

leaching of radiological and non-radiological contaminants. The conditioning may

also involve the chemical or physical alteration of the residues to reduce the hydraulic

conductivity of the residues or reduce the solubility of various contaminants.

Reference [10] provides guidance on the steps in predisposal management of

radioactive wastes that may be applicable to the treatment and conditioning of NORM

residues prior to long- term storage or disposal14

.

5.3 Where the management of bulk NORM residues includes eventual disposal, but

no disposal facility is available, specific assumptions should be made on the

requirements for the acceptance of the residues in a future repository in order to

provide guidance for its treatment, conditioning and storage. These assumptions

should be justified and agreed upon by the generator, the operator of the predisposal

management facility and the regulator.

14 Including Chapter 6 of IAEA Safety Guide, DS447:in preparation.

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Pag e o f 1 25 56

SITING

5.4 Consistent with Requirement 17 of Ref [11], facilities for the management of

bulk NORM residues should be located and designed so as to ensure safety for the

expected operating lifetime of the facilities under both normal and possible accident

conditions.

5.5 The siting of facilities required for the management of bulk NORM residues

should take into consideration the source of the residues and their overall chemical

and physical properties, their relative radiological and non-radiological hazard and

their volume.

5.6 The optimum site for residue management facilities will take into account the

protection of human health and the environment as well as economic considerations.

The siting of residue management facilities should provide for the effective collection

and containment of the residue and should prevent the diversion of residues from the

site other than by means of authorized discharges or by the authorized removal of

regulatory control.

5.7 Criteria for siting and methods that could be used in a graded approach to the

siting of a facility for the long-term management of NORM residues can be found in

Refs [14], [15] & [16].

5.8 A preliminary evaluation of site characteristics should be made so as to identify

any restrictions, in terms of radiological and environmental factors, at each proposed

location, and to allow the selection of a small number of locations and possible

preliminary design concepts for which the impacts can then be evaluated in detail. The

final optimized choice of site obtained using the conceptual design for residue

management should be assessed and the resulting safety assessment, which might be

part of the environmental impact assessment, should be submitted to the regulatory

body for review. Section 6 provides further guidance on the approaches to conducting

safety assessments.

Pag e o f 1 25 57

5.9 In selecting the site for long term management of large volumes of NORM

residues, the important considerations in the optimization process that should be taken

into account, particularly in reducing the need for long term institutional controls after

closure, include the following:

(a) Climatology and meteorology;

(b) Geography, geomorphology, demography and land use;

(c) Structural geology and seismology;

(d) Geochemistry;

(e) Mineralogy;

(f) Surface water and groundwater hydrology;

(g) Flora and fauna;

(h) Archaeological and heritage issues;

(i) Natural background levels of radiation;

(j) Public acceptance issues.

5.10 In selecting the site for management of bulk NORM residues, consideration

should be given to the benefits of consolidating residues to limit the number of residue

management sites.

DESIGN AND CONSTRUCTION

5.11 Requirement 18 of Ref [10] states that: “Predisposal radioactive waste

management facilities shall be constructed in accordance with the design as described

in the safety case and approved by the regulatory body. Commissioning of the facility

shall be carried out to verify that the equipment, structures, systems and components,

and the facility as a whole perform as planned.” This requirement is equally

applicable to NORM residue management facilities.

5.12 The major design consideration for the management of bulk NORM residues is

the need to ensure proper containment and isolation of the residues and to control

releases of any contaminants. Good waste management practices should be followed

to the extent practicable and consistently with the requirements for radiological

protection, such that the design of the residue management facilities:


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(a) Maximizes the use of natural materials and natural barriers for

containment;

(b) Minimizes potential erosion and accidental release of solids outside of

containment by maximizing the placement of residue material below ground

level, or in some cases under water;

(c) Minimizes the surface area of the area impacted by the facility

(d) Minimizes the impact on the surrounding environment during

operations and after closure;

(d) Minimizes the need to retrieve or relocate the residue at closure;

(e) Minimizes the need for surveillance, maintenance and controls during

operations and post-closure; and

(f) minimizes the number of residue management sites through

consolidation of residues.

5.13 In addition when designing a facility for the long term management of NORM

residues, due consideration should be given to the:

(a) sSite characteristics as detailed in paragraph 5.9,

(b) rResidue characteristics including volume, chemical, physical and radiological

properties

(c) rResidue conditioning including neutralization, precipitation, thickening and

evaporation

(d) pPotential for retrieval of NORM residues either for relocation or re-processing

for further resource extraction;

(e) mManagement of liquids including seepage collection and treatment;

(f) rRadiation protection measures which may include shielding, containment, and,

radon and dust control;

(g) aAccess control including site access and the control of movement between

radiation zones and contamination zones;

(h) iInspection of the residues and their containment;

(i) vVentilation in surface facilities including the filtration of airborne releases of

radioactive material;


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(j) eEnvironmental monitoring of the facility including ground water well

installations, water and air sampling stations downstream of any effluent or

airborne releases

(k) Maintenance work and eventual decommissioningclosure

(l) Re-vegetation;

(m) Long term stability and erosion control (e.g. dams, berms, slopes, covers) in

relation to natural weathering processes and extreme natural events (e.g.

flooding, droughts, tornadoes, earthquakes)

Control of inadvertent intrusion by people, plants or animals.

(n) Bulk NORM Residues

5.14 Facilities for the long -term management of bulk NORM residues should have

sufficient capacity to process all such residues generated and, where the facilities are

intended to provide storage only, the storage capacity should be sufficient to account

for uncertainties in the availability of facilities for final disposal. The capacity should

also be sufficient to process residues that may arise from incidents and accidents, and

for the future decommissioning and dismantling of the support facilities.

5.15 The facility design should take into consideration the potential effects that the

residues and the environmental conditions may have on the capabilities of the facility

to provide long term containment and isolation, and to control the release of

contaminants into the environment. Processes and properties that should be

considered include, for example, drainage and water management, the acid generating

potential of the residues, the effect of extreme changes in climate including

precipitation and temperature and extreme external events such as earthquakes, floods,

tornadoes, hurricanes, typhoons, forest fires, etc.

5.155.16 To conform to the principles for managing radioactive waste [2], access

to and dispersion in the environment of the hazardous constituents of the tailings

should be restricted for long periods into the future. Preference should always be given

to designs that minimize the requirement for application of institutional controls.

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5.16 Drainage and water management are major considerations in the design of a

facility for the management of bulk residues. Installed drainage systems can help in

terms of consolidating bulk residues before closure and reducing excess pore water

pressure. In the case of a surface impoundment or a pit, this could be achieved by the

installation of a drainage system prior to or during the emplacement of bulk residue, or

by the use of wicks driven into the bulk residue after emplacement. The base and cap

of the impoundment should be built of a material of low permeability, if possible

using material of natural origin. In other cases, uncontrolled drainage is a problem that

needs to be addressed, for example by the use of appropriate liners. The addition of a

stabilizing agent (such as cement) to the bulk residue prior to its deposition can

significantly reduce the permeability of the bulk residue mass, thus retarding the

transport of contaminants and binding any pore water.

5.17 Soil moisture can also significantly affect radon transport and release from the

residue containment facility. Moist and saturated soil conditions in cover materials

tend to slow the rate of diffusion to the surface. The diffusion coefficient through a

saturated soil may be several orders of magnitude smaller compared with that of a dry

soil. In certain cases, a water covering or saturated cover layer may serve as an

effective radon barrier. In dry environments, a different approach is required.

5.18 Factors that influence the selection of cover material include climate, availability

of materials, properties of the residue, regulatory requirements and other site-specific

needs or issues (e.g. generation of acid rock drainage, water infiltration, erosion).

5.19 Cover materials that have been effective in reducing radon emissions include

water, earthen materials, geosynthetics such as geomembranes and geosynthetic clay

liners, and evapotranspirative barriers. Simple covers may contain one type of

material; however, combinations of different materials are often required.

5.20 A conventional cover system designed to limit infiltration and radon emissions

from an above ground impoundment, may have a lateral drainage layer consisting of

either coarse sand or gravel, to limit head buildup above a low permeability clay layer,

and a top layer of durable rock for erosion protection. Depending on the climate and

Pag e o f 1 25 61

environment, this rock may also support a vegetative cover for erosion control,

stabilization and limiting infiltration.

5.21 The decision on which drainage/dewatering approach to take should be

optimized, so as to match barrier characteristics with available site conditions. For

disposal in underground mines, the increased structural integrity from adding concrete

to the bulk residue may allow adjacent mining to continue. Prior to adopting this

strategy, possible chemical interactions between the stabilizing agent, the bulk residue

and the host rock should be carefully investigated.Sub-Surface Disposal

5.22 In addition to the disposal of bulk residue in above ground impoundments, open

pits and underground mine voids, there are other options for waste management, such

as the deposition of bulk residue in lakes. However, options such as this should

involve careful study and evaluation. Preference should always be given to designs

that minimize the requirement for application of institutional controls.

5.23 It is possible that the underground disposal of mine bulk residue at a particular

site may not be feasible, either due to site-specific problems for which no engineering

solutions can be identified, or due to prohibitive cost. In such cases, the use of

engineered surface impoundments may be the only viable option and should be

considered.

5.17 Practical engineering solutions can be identified for some below-ground bulk

residue disposal facilities. For example, if the hydraulic conductivity of the bulk

residue mass is greater than that of the surrounding host rock, the use of a highly

permeable envelope surrounding the bulk residue should be considered as a means of

diverting groundwater around the bulk residue. In the case of a small and confined

aquifer intersecting a pit or underground mine wall, localized grouting should be

considered.

5.245.18 In the case of disposal in underground mines, the increase in structural

integrity gained by using concrete with the tailings mass may allow mining to be

continued immediately adjacent to the tailings. Prior to adopting this strategy, possible

chemical interactions between the stabilizing agent, the tailings and the host rock


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Pag e o f 1 25 62

should be carefully investigated to ensure that the transport of contaminants would not

be enhanced at some time in the future.

5.19 The successful closure of an in-pit emplacement may be achieved either by

backfilling and capping with natural materials or by the establishment of a permanent

water pond over the bulk residue. The latter option should include the application of a

low permeability cover for the waste to reduce contact with the pond water. The sub-

surface conditions should be fully investigated in order to ensure that the hydraulic

pressure over the backfilled pit will not result in future groundwater contamination.

5.25 Surface Disposal

5.20 The underground disposal of mine bulk residue at a particular site may not be

feasible, either due to site-specific problems for which no engineering solutions can be

identified, or due to prohibitive cost. In such cases, the use of engineered surface

impoundments may be the only viable option and should be considered.

5.265.21 For above ground impoundments, the bulk residue can be contained

within low permeability, engineered structures that reduce seepage. An above ground

closure option would usually necessitate greater institutional control than an

underground disposal option. Monitoring and maintenance programprogrammes

should be implemented during the operational, closure and post-closure phases. Thus

the above ground approach would be likely to entail lower initial (capital) costs but

higher ongoing (operating) costs.

5.27 The relocation of bulk residue to a more favorable site for closure would not

normally be the optimum management strategy because of the large volumes involved.

However, if relocation is being considered, all the significant radiological and non-

radiological impacts associated with relocation, including impacts relating to the

transport of large volumes of waste, should be assessed.

5.28 Other disposal strategies for bulk residues may be appropriate, and they should

be evaluated on a case-by-case basis.



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5.295.22 The containment walls may be entirely constructed above grade, or a

small valley may be utilized. In this latter case it is essential that any run-off from

rainfall be diverted around the tailings repository area. The tailings impoundment is

generally the final repository for the tailings, although on occasion the tailings may

later be removed to another site (typically the worked out pit) for final disposition.

Alternatively, tailings impoundments are made from former open pit mines, where

available, or purpose-built pits. Other options, such as discharge to the bed of a lake,

exist as alternatives. However, they are rarely the preferred option and may not be

acceptable to regulators or the public. In any scenario, a safety case which

demonstrates protection of workers, the public and the environment should be

required..

5.23 The design of a facility for the management of tailings should incorporate

drainage systems to consolidate tailings before closure and to reduce excess pore

water pressure. Removal of excess water from the tailings is generally important, both

to reduce the potential for seepage of tailings liquor from the structure, and to allow

the tailings to consolidate to produce a firm mass which will bear the weight of

machinery during rehabilitation. This may be achieved by deposition in thin layers,

with each section being allowed to drain and dry by evaporation before the next layer

is deposited. Alternatively tThe excess liquor can be decanted and disposed of as a

liquid waste as described elsewhere. Alternatively, this could be achieved by the

installation of a drainage system prior to or during the emplacement of tailings, or by

the use of wicks driven into the tailings after emplacement.

5.30

5.24 To conform to the principles for managing radioactive waste [2], access to and

dispersion in the environment of the hazardous constituents of the tailings should be

restricted for long periods into the future. The base and cap of the impoundment

should be built of a material of low permeability, if possible using material of natural

origin. Uncontrolled drainage is a problem that needs to be addressed, for example by

the use of appropriate liners. The addition of a stabilizing agent (such as cement) to

the bulk residue prior to its deposition can significantly reduce the permeability of the




Pag e o f 1 25 64

bulk residue mass, thus retarding the transport of contaminants and binding any pore

water.

5.31

5.25 The design of a facility for the management of tailings should incorporate

drainage systems to consolidate tailings before closure and to reduce excess pore

water pressure. In the case of a surface impoundment or a pit, this could be achieved

by the installation of a drainage system prior to or during the emplacement of tailings,

or by the use of wicks driven into the tailings after emplacement. The base and cap of

the impoundment should be built of a material of low permeability, if possible using

material of natural origin. The addition of a stabilizing agent (such as cement) to the

tailings immediately prior to their deposition has the potential to reduce significantly

the permeability of the tailings mass, thus retarding the transport of contaminants and

binding any pore water. However, in certain cases, a confined, water covering in a pit

may possess excellent characteristics as a radon barrier, thereby obviating the need to

perform dewatering to any significant degree. Decommissioning Closure plans, which

rely on water coverings must consider the ability of the cover to be both present and

passively maintained over the long term. The decision on which drainage/dewatering

approach to take should be optimized, so as to match barrier characteristics with

available site conditions.

Radon Barriers

5.26 Soil moisture can also significantly affect radon transport and release from the

residue containment facility. Moist and saturated soil conditions in cover materials

tend to slow the rate of diffusion to the surface. The diffusion coefficient through a

saturated soil may be several orders of magnitude smaller compared with that of a dry

soil. In certain cases, a water covering or saturated cover layer may serve as an

effective radon barrier. In dry environments, a different approach is required.

5.27 Factors that influence the selection of cover material include climate, availability

of materials, properties of the residue, regulatory requirements and other site-specific

needs or issues (e.g. generation of acid rock drainage, water infiltration, erosion).





Pag e o f 1 25 65

5.28 Cover materials that have been effective in reducing radon emissions include

water, earthen materials, geosynthetics such as geomembranes and geosynthetic clay

liners, and evapotranspirative barriers. Simple covers may contain one type of

material; however, combinations of different materials are often required.

5.325.29 A conventional cover system designed to limit infiltration and radon

emissions from an above ground impoundment, may have a lateral drainage layer

consisting of either coarse sand or gravel, to limit head buildup above a low

permeability clay layer, and a top layer of durable rock for erosion protection.

Depending on the climate and environment, this rock may also support a vegetative

cover for erosion control, stabilization and limiting infiltration.

5.30 The decision on which approach to take should be optimized so as to match

barrier characteristics with available site conditions. In the case of disposal in

underground mines, the increase in structural integrity gained by using concrete with

the tailings mass may allow mining to be continued immediately adjacent to the

tailings. Prior to adopting this strategy, possible chemical interactions between the

stabilizing agent, the tailings and the host rock should be carefully investigated to

ensure that the transport of contaminants would not be enhanced at some time in the

future.

5.31 Other disposal strategies for bulk residues may be appropriate, and they should

be evaluated on a case-by-case basis. The relocation of bulk residue to a more

favorable site for closure would not normally be the optimum management strategy

because of the large volumes involved. However, if relocation is being considered, all

the significant radiological and non-radiological impacts associated with relocation,

including impacts relating to the transport of large volumes of waste, should be

assessed.

Higher activity low volume waste

5.32 Some waste may comprise a relatively small volume but be of higher activity

concentration. This may be the case for a wide range of materials including:



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Scales and sludge that may be accumulate in pipes or process vessels in oil and

gas production, coal production with radium rich inflow water, and rare earth

production;

Anode slimes from electro-wining processes;

Precipitated smelting dusts and slags;

Rare earth extraction residues;

Contaminated equipment, process filters.

5.33 These precipitates, scales and residues are mostly enhanced in specific

radionuclides and to levels that depend more on chemical conditions than on the

original ore grade or feedstock radionuclide contents.

5.34 Such waste may be managed either in the original or in a modified form. There

is a range of disposal options for these materials, depending on the nature of the

material and its waste classification [17]. The radionuclide content may necessitate

management of these materials as Low Level Waste or Intermediate Level Wastes.

Some wastes may be suitable for interim storage to allow for decay of short-lived

radionuclides such as most 210

Pb and/or 210

Po.

5.35 After an appropriate treatment, a low volume, high activity waste may be

suitable for dispersion and dilution evenly throughout a large volume of low activity

waste.

5.36 Small volumes of unmodified waste may be sealed into suitable containers and

deposited in designated containments, special landfills or specially engineered

boreholes [18], or possibly placed deep within tailings dams that are destined for

closure. An option for some liquid residues may be borehole injection into suitable

geological formations.

Passive Design

5.33

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5.345.37 The principle that undue burdens should not be placed on future

generations leads to the conclusion that a passive approach to design for closure is

preferable to a design that needs significant and ongoing maintenance. Such a passive

approach is generally best achieved by disposal in pits excavated specifically for this

purpose, in mined out pits or in underground mine voids in geologically stable sites.

This option may eliminate or significantly reduce the need for surface disposal of

tailings. Disposal of waste below ground level is typically less susceptible to surface

erosion of material to the environment and to intrusion, and generally necessitates less

maintenance than surface tailings impoundments. Closure entails sealing the openings

to the underground disposal facility, thereby isolating it from the surface.

5.355.38 For the disposal of underground tailings underground, provided that the

probabilities of geological disturbance to the site and of human intrusion into the site

are deemed to be sufficiently low, no further controls may be necessary beyond

archiving details of the location and characteristics of the waste and monitoring the

site for a limited period.

5.365.39 The passive approach to design should be considered an option more

likely to be realistic in optimizing radiological protection in new waste management

facilities. For example, where tailings can be deposited in mined out pits, passive

designs may be partially or even fully realizable and may provide the basis for the

optimum strategy.

5.37 It is possible that the underground disposal of mine tailings at a particular site

may not be feasible, owing either to site specific problems for which no engineering

solutions can be identified or to prohibitive cost. In such cases, the use of engineered

surface impoundments may be the only viable option and should be considered.

5.38 Practical engineering solutions can be identified for some site specific problems

associated with below ground level tailings disposal facilities. For example, if the

hydraulic conductivity of the tailings mass is greater than that of the surrounding host

rock, the use of a highly permeable envelope surrounding the tailings should be

considered as a means of diverting groundwater around the tailings. In the case of a

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small and confined aquifer intersecting a pit or underground mine wall, localized

grouting should be considered.

5.395.40 The desired passivity in the closure of an in-pit emplacement may be

achieved either by backfilling and capping with natural materials or by the

establishment of a permanent water pond over the tailings. The latter option should

include the application of a low permeability cover for the waste to reduce contact

with the pond water. The subsurface conditions should be fully investigated in order to

gain sufficient understanding to be able to ensure that the hydraulic pressure over the

backfilled pit will not result in problems of groundwater contamination arising in the

future.

5.40 As regards options involving the management of tailings in above ground

impoundments, the tailings should be contained within low permeability engineered

structures so as to reduce seepage. An above ground closure option would usually

necessitate having greater institutional control than an underground disposal option.

Monitoring and maintenance programs should be implemented during the operational,

closure and post-closure phases. This approach would entail lower initial costs but

higher continuing costs.

5.41 Detailed engineering design of the residue management facilities can proceed

after the site and the conceptual design have been approved by the regulatory body. At

this stage, a further safety assessment, including optimization of protection, should be

performed. Figure 1 shows an example of the regulatory process for new facilities for

the management of NORM residues. If significant changes are made to the design of

the residue management facilities at any stage, a further safety assessment, including

optimization of protection, should be undertaken.

5.42 The detailed design should be supported, where appropriate, by fieldwork and

laboratory or pilot plant studies and by radiological and environmental impact

assessments. The design should include a waste management plan covering the

management of residues, residue treatment and conditioning and any applicable

effluent treatment, seepage controls and operational monitoring.

Pag e o f 1 25 69

5.43 A preliminary closure plan should be prepared during the design of the facilities,

which, at a conceptual level, identifies and ranks the available options for their closure

according to the results of the safety assessment and the optimization of protection. It

should also specify the financial provisions necessary for the preferred option. The

preliminary closure plan should be submitted to the regulatory body for approval.

5.44 When considering the design for long term control of facilities for bulk NORM

residues, passive institutional controls are preferable to a design that needs significant

and ongoing maintenance. This is generally best achieved by disposal in pits

excavated specifically for this purpose, in mined-out pits or in underground mine

voids in geologically stable sites. This option may eliminate or significantly reduce the

need for surface disposal of bulk residue. Disposal of waste below ground level is

typically less susceptible to surface erosion resulting in possible breach of a

containment and release of waste to the environment. Furthermore, below ground

containments are less susceptible to intrusion, and generally require less maintenance

than surface bulk residue impoundments. Closure entails sealing the openings to the

underground disposal facility, thereby isolating it from the surface.

5.45 For the disposal of bulk residue underground, provided that the probabilities of

geological disturbance and human intrusion are deemed sufficiently low, no further

controls may be necessary beyond the keeping of appropriate records of the location

and characteristics of the waste for a defined period.

5.46 The passive design approach is more likely to be a successfully realized in new

waste management facilities. For example, where bulk residue can be deposited in

mined out pits, passive designs may be partially or even fully attainable and may

provide the basis for the optimum strategy.

5.475.44 Unlike surface buildings where many corrections may still be made

during the commissioning stage, the construction of storage and disposal facilities for

large volume NORM residues are such that correction of major deficiencies will be

cost prohibitive and in some cases practically impossible. As a result, for long term

management facilities for large volume NORM residues, it is important that effective

verification and quality control measures are in place to ensure that the construction of

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any engineered structures such as dams, berms, engineered liners, compacted layers

meet the design specifications. The quality control programprogramme will also

require testing of construction materials (e.g. tills and clay) to ensure they meet the

design specifications.

5.485.45 The construction quality control programprogramme should be

established at an early stage in the design process as an intrinsic part of the project to

facilitate its effective implementation. Arrangements should be established to cover:

(a) Specification of tests to be carried out (test objectives, design criteria to be met);

(b) Provision and approval of documentation;

(c) Responsibilities;

(d) Control of test work;

(e) Recording and review of test results;

(f) Interaction with the regulatory body;

5.495.46 Commissioning of the NORM residue management facilities should

follow similar processes and protocols that would apply to any waste management

facility15

.

OPERATION

5.505.47 Requirement 18 of Ref [4] states that: The disposal facility shall be

operated in accordance with the conditions of the licence and the relevant regulatory

requirements so as to maintain safety during the operational period and in such a

manner as to preserve the safety functions assumed in the safety case that are

important to safety after closure.

5.515.48 The facilities should be operated in accordance with the residue

management strategy, the safety assessment, the authorization or license, and a residue

management plan. The residue management plan should describe in detail all aspects

of the management of the residues. In addition, the plan is a key component of the

management system and should include provision for:

15 DS447 (in preparation) also provides further guidance on the approach to commissioning.


Pag e o f 1 25 71

Detailed and documented procedures for operation, maintenance, monitoring

and safety;

Training of personnel in the implementation of the procedures;

Adequate surveillance and maintenance of all the structures, systems and

components of the facility that are important to safety;

A system of controlled and supervised areas and clearance procedures for

materials removed from the site;

Timely submissions to the regulatory body of inspection reports, monitoring

results and reports on unusual occurrences;

The development and exercise, where appropriate, of contingency plans for

potential failures of the residue management facilities that may result in

significant increased risk to human health or the environment.

5.525.49 Measures should be taken during operations, and consistently with the

safety assessment, to limit the amount and rates of release to the environment of

contaminants in liquid and airborne effluents. Measures should be used to ensure that

residues remain under proper control so that their potential misuse is avoided.

Releases of radon or radioactive dusts into the atmosphere and of radium and other

radionuclides into surface water and groundwater by surface runoff or leaching from

residues should be minimized.

5.535.50 Facilities for long-term management of NORM residues should be

operated in accordance with written procedures prepared by the operating

organization. These documents and their updates should be prepared in cooperation

with the organizations responsible for the design of the facility. However, the

operating organization is responsible for ensuring that the procedures are prepared,

reviewed, approved and issued appropriately. These procedures should, as a minimum,

be such as to ensure compliance with the operational limits and conditions for the

facility and, more generally, with the safety assessment.

5.545.51 Instructions and procedures should be prepared for normal operations

of the facility and anticipated operational occurrences. Instructions and procedures

should be prepared so that the designated responsible person can readily perform each

action in the proper sequence. Responsibilities for approval of any deviations from

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operating procedures that may be necessary for operational reasons should be clearly

specified [21].

5.555.52 The maintenance and modification of any item of equipment, process

or document of the facility should be subject to specified procedures. These

procedures should be subject to authorization before they are implemented. The

procedures should describe the categorization of the modification in accordance with

its safety significance. Depending upon the safety categorization, each modification

will be subject to varying levels of review and approval by management of the facility

and the regulatory body.

5.565.53 The maintenance or modification of any item of equipment should be

appropriately recorded and documented together with its commissioning test results.

The documents should be revised immediately after completion of the maintenance or

modification.

5.575.54 Operating procedures should be developed for containment systems in

the facility (e.g. ventilation and filtration systems) to provide for their monitoring.

Such monitoring should be such that the operating organization will be able to

determine when corrective actions are necessary to maintain safe operational

conditions.

5.585.55 In addition to providing operating procedures and contingency

procedures as described above, the operating organization should also develop an

emergency plan. The plan should consider events such as the following:

Catastrophic equipment failures;

Loss of safety related facility process systems such as supplies of electricity,

process water, compressed air and ventilation;

Fires leading to the damage of items important to safety;

Natural events, such as extreme weather conditions and extreme natural events

such as flooding or earthquakes;

5.595.56 Operating experience and events at the facility and reported by similar

facilities should be collected, screened and analyzed in a systematic way. Conclusions

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should be drawn and implemented by means of an appropriate feedback procedure.

Any new standards, regulations or regulatory guidance should also be reviewed to

check for their applicability for safety at the facility.

5.605.57 Operational limits and conditions should be developed on the basis of

the following:

Design specifications and operating parameters and the results of

commissioning tests;

The sensitivity of items important to safety and the consequences of events

following the failure of items, the occurrence of specific events or variations in

operating parameters;

The accuracy and calibration of instrumentation equipment for measuring safety

related operating parameters;

Consideration of the technical specifications for each item important to safety

and the need to ensure that such items continue to function in the event of any

specified fault occurring or recurring;

The need for items important to safety to be available to ensure safety in

operational states including maintenance;

Specification of the equipment that should be available to enable a full and

proper response to postulated initiating events or design basis accidents;

The minimum staffing levels that needs to be available to operate the facility

safely.

5.615.58 Operational limits and conditions form an important part of the basis on

which operation is authorized and as such should be incorporated into the technical

and administrative arrangements that are binding on the operating organization and

operating personnel. Operational limits and conditions, which result from the need to

meet legal and regulatory requirements, should be developed by the operating

organization and subject to approval by the regulatory body as part of the license

conditions. The operating organization may wish to set an administrative margin

below the operational limits as an operational target to remain within the approved

limits and conditions.

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5.625.59 The aim of operational limits and conditions is to manage and control

the hazards associated with the facility. Operational limits and conditions should be

directed towards:

Preventing situations that might lead to the unplanned exposure of workers and

the public to radiation;

Mitigating the consequences of any such events, if they were to occur.

5.635.60 Personnel directly responsible for operation of the facility should be

thoroughly familiar with the facility’s operating procedures and the operational limits

and conditions to ensure compliance with their provisions. Systems and procedures

should be developed in accordance with the approved management system and

operating personnel should be able to demonstrate compliance with the operational

limits and conditions.

5.645.61 Operational limits and conditions should be kept under review and may

also have to be revised as necessary in accordance with the national regulatory

framework for the following reasons:

In the light of operating experience;

Following modifications made to the facility and the type of radioactive waste;

As part of the process of periodically reviewing the safety case (including as

part of periodic safety review) for the facility;

If there are changes in legal or regulatory conditions.

5.655.62 As a result of operating experience, technological progress or changes,

corresponding changes to operational conditions may be necessary. Such changes

should be justified through safety assessment and should be subject to approval by the

regulatory body.

5.665.63 Operation of a facility for the long term management of NORM

residues should include an appropriate programme of maintenance, inspection and

testing of items important to safety, i.e., structures, systems and components. Safe

access should be provided to all structures, systems, areas and components requiring

Pag e o f 1 25 75

periodic maintenance, inspection and testing. Such access should be adequate for the

safe operation of all necessary tools and equipment and for the installation of spares.

5.675.64 An operational radiation protection programme should be put in place

that ensures that areas of the facility are classified according to the radiation levels and

that access control is in place in accordance with the level of classification. It should

cover the monitoring of radiation levels in the facility and should include provision to

ensure that personnel working in the facility are provided with appropriate dosimetry.

A programme of work planning should also be put in place to ensure that radiation

exposure is kept as low as reasonably achievable.

5.685.65 The potential radiological impacts of incidents and accidents should be

assessed by the operating organization and reviewed by the regulatory body. Provision

should be made to ensure that there is an effective capability to respond to incidents

and accidents. Considerations should include the development of scenarios of

anticipated sequences of events and the establishment of emergency procedures and an

emergency plan to deal with each of the scenarios, including checklists and lists of

persons and organizations to be alerted.

5.695.66 Emergency response procedures should be documented, made available

to the personnel concerned and kept up to date. The need for exercises should be

assessed. If there is such a need, exercises should be held periodically to test the

emergency response plan and the degree of preparedness of the personnel. Inspections

should be performed regularly to ascertain whether equipment and other resources

necessary in the event of an emergency are available and in working order.

5.705.67 In some instances, the NORM residues may result in high radiation

exposures situations. For example, this may occur near stockpiles of active materials,

where radium scales or high activity thorium based residues are present, or where

dusts and fume are present. Where high radiation exposure activities are involved,

radiation doses should be kept as low as reasonably achievable by the use of features

such as remote handling techniques for operations and maintenance and by

establishing limits on the activities and dose rates for the items to be removed from

highly contaminated or radioactive areas to less contaminated or radioactive areas.

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When manual maintenance operations are foreseen, adequate protection should be

provided, for example, by the decontamination of equipment and the use of temporary

or permanent shielding.

CLOSURE

5.68 A preliminary plan for the decommissioning and dismantling of an operation’s

facilities, and the closure of a NORM residue management facility should be drawn up

at the design stage [4]. This plan should be reviewed and updated, as necessary,

throughout the operational life of the facility. Prior to closure, the operator should

prepare a final closure plan, and submit this to the regulatory authority for approval.

5.69 An important part of the planning for closure is confirming that the conceptual

design of the NORM residue management facility is still valid. The conceptual model

provides a description of the components of the system and the interactions between

these components. It also includes a set of assumptions concerning the geometry of the

system and the chemical, physical, hydrogeological, biological and mechanical

behavior of the system, consistent with the information and knowledge available.

5.71

5.725.70 The final closure plan should address at least the following elements:

Long-term monitoring and surveillance;

Remediation;

Disposition of NORM residues, including those arising from decontamination

of the facility;

Disposal of waste;

The potential for recycling or new use for residues, plant and items containing

or contaminated by NORM;

An assessment of the post-closure risks to individuals and the environment;

Final radiation survey of the site.

5.735.71 Following regulatory body approval, the operator should implement the

plan. Once closure has been achieved, the operator should make an assessment of the

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success of the work against the agreed closure criteria. The regulatory body should

undertake an assessment for compliance with the approved closure criteria. Once

compliance has been achieved and confirmed by the regulatory body the site may be

approved for release from regulatory control, with or without ongoing institutional

control.

5.745.72 Once any part of the waste management facilities is no longer needed,

it should be closed to the extent practicable during operations (e.g. closure of a waste

rock pile).

5.755.73 At a time agreed upon with the regulatory body, and at least five years

before the anticipated closure date, the operator should submit a final closure plan for

regulatory approval. The objectives of closure should be to ensure that the waste

management facilities are left in a condition that will ensure their continued

compliance with the requirements for the protection of human health and the

environment.

5.765.74 The closure plan should be harmonized to the extent practicable with

the schedule for decommissioning surface structures and equipment. The

decommissioning of these structures and equipment has been addressed in other IAEA

safety standards [1, 10]. The management of waste from decommissioning activities

may be combined with management of the closure of the facilities for the disposal of

waste from operations, provided that this will not introduce problems, for example, by

creating voids in the tailings mass. This is most effectively accomplished when

decommissioning is conducted prior to, or at the same time as, closure.

5.775.75 The primary goal of the disposal of radioactive waste is the protection

of people and the environment in the long term, after the disposal facility has been

closed. In this period, migration of radionuclides to the accessible biosphere,

dispersion of radionuclides into the accessible biosphere and the consequent exposure

of people may occur. This is a consequence of the slow degradation of engineered

components and the slow transport of radionuclides from the facility by natural

processes. Discrete events may lead to an earlier or greater release. Such events could

be of either natural or human origin.

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5.785.76 In the design of a facility for the long term management of NORM

residues consideration should be given to the eventual decommissioning closure of the

facility, as regards both facilitating the decommissioningclosure activities and keeping

the generation of radioactive waste to the minimum practicable,

5.795.77 A final goal of decommissioning closure should be to enable the partial

or complete removal of regulatory control from the facility. The safety objective is to

site, design, construct, operate and close a NORM residue management facility so that

protection after its closure is optimized, social and economic factors being taken into

account. A reasonable assurance also has to be provided that doses and risks to

members of the public in the long term will not exceed the dose constraints or risk

constraints that were used as design criteria.

5.805.78 A set of performance obectivesobjectives should be established for

assessing the success and overall effectiveness of the decommissioningclosure

activities. These performance objectives should hasve been initially established to

support the design of the facility and set engineering controls on the operations.

5.815.79 Since NORM residues can present a long term radiological risk,

performance obectivesobjectives for radiation protection should be established using

dose criteria that are based on regulatory limits for exposures to the public. These can

include the following [Ref 4]:

The dose limit for members of the public for doses from all planned exposure

situations is an effective dose of 1 mSv in a year. This and its risk equivalent are

considered criteria that are not to be exceeded in the future.

To comply with this dose limit, a disposal facility (considered as a single

source) is so designed that the calculated dose or risk to the representative

person who might be exposed in the future as a result of possible natural

processes16

affecting the disposal facility does not exceed a dose constraint of

0.3 mSv in a year or a risk constraint of the order of 10–5

per year17

.

16 Natural processes include the range of conditions anticipated over the lifetime of the facility and

events that could occur with a lesser likelihood. However, extremely low probability events would be

outside the scope of consideration. 17

Risk due to the disposal facility in this context is to be understood as the probability of fatal cancer

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In relation to the effects of inadvertent human intrusion after closure, if such

intrusion is expected to lead to an annual dose of less than 1 mSv to those living

around the site, then efforts to reduce the probability of intrusion or to limit its

consequences are not warranted.

If human intrusion were expected to lead to a possible annual dose of more than

20 mSv to those living around the site, then alternative options for waste

disposal are to be considered, for example, disposal of the waste below the

surface, or separation of the radionuclide content giving rise to the higher dose.

If annual doses in the range 1–20 mSv are indicated, then reasonable efforts are

warranted at the stage of development of the facility to reduce the probability of

intrusion or to limit its consequences by means of optimization of the facility’s

design.

Similar considerations apply where the relevant thresholds for deterministic

effects in organs may be exceeded.

5.825.80 Disposal facilities for NORM residues may serve the additional

purpose of a repository for NORM contaminated materials which that may result from

routine operations or the dismantling of site facilities during decommissioning.

Decommissioning anCd closure design must consider comingling of materials from

various waste streams.

5.835.81 Decommissioning Closure of facilities for the long term management

of NORM residues comprises:

Design considerations and early decommissioningclosure planning;

Preparation and approval of the final decommissioningclosure plan;

The actual conduct of decommissioningclosure;

The management of waste resulting from closure decommissioning activities;

Release of the site for unrestricted or restricted use.

5.845.82 The key elements that should be considered for the decommissioning of

facilities associated with the long term management of NORM residues:

or serious hereditary effects.

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The selection of a decommissioning option in which the radionuclides in the

residual waste, technical factors, costs, schedules and institutional factors are

taken into account;

The development of a decommissioning plan;

The specification of the critical tasks involved in their decommissioning; in

particular decontamination, dismantling, demolition, surveillance and

conducting a final radiological survey;

The management functions important for their decommissioning, such as

training, organizational control, radiological monitoring, planning and the

control of waste management, physical protection, safeguards and quality

assurance.

5.855.83 Both the design and operational aspects that will have an influence on

decommissioning safety (e.g. the chemical processes or mechanical processes

involved) should be duly considered so as to facilitate the eventual decommissioning

of a facility. The design considerations for decommissioning and the decommissioning

measures should be consistent with the hazards expected to be associated with the

facility.

5.865.84 An initial version of the decommissioning plan should be prepared

during the design of the facility.

5.875.85 During the operation of the facility, the initial decommissioning plan

should be periodically reviewed and updated and should be made more comprehensive

with respect to:

Technological developments in decommissioning;

Possible human induced accidents and other incidents and natural events;

Modifications to systems and structures affecting the decommissioning plan;

Amendments to regulations and changes in government policy;

Cost estimates and financial provisions.



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5.885.86 Dismantling and decontamination techniques are required to be chosen

such that generation of waste and airborne contamination are minimized and

protection of workers and the public is optimized.

5.895.87 Before a site is released, for example for unrestricted use, it should be

monitored and, if necessary, cleaned up. A final survey should be performed to

demonstrate that the end point criteria, as established by the regulatory body, have

been met.

REMOVAL OF REGULATORY CONTROL

5.905.88 Prior to the release of material, equipment, structures or the site to the

public for general or restricted use, regulatory criteria should be established, such as

those for:

4.2 Removal of material, equipment, structures, soil and rock, from regulatory

control;

4.2 Authorized reuse or recycle of equipment, structures and material;

4.2 Release of the entire site for authorized use (depending on future plans) at the

end of closure.

5.91 Each of these sets of criteria should be established on the basis of realistic

exposure scenarios.

5.925.89 Guidance on removal from regulatory control and on cleanup levels can

be found in [19] & [20].

INSTITUTIONAL CONTROL

5.935.90 Institutional control comprises those actions, mechanisms and

arrangements implemented so as to maintain control or knowledge of a waste

management site after closure, as required by the regulatory body. This control may be

active (for example, by means of monitoring, surveillance, remedial work, and fences)

or passive (for example, by means of land use controls, markers, records, etc.). The

need for, and dependence on, active institutional controls should be minimized in the

design.





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5.945.91 It is anticipated that only a few NORM waste management facilities

will require active institutional controls to be applied in the long-term. Examples

include facilities containing uranium mill tailings and low-volume, high-activity scales

and sludges. In contrast, passive controls may be required for a minority of NORM

waste disposal sites.

5.955.92 The operator is responsible for preparing the programme for

institutional control, which should be reviewed and approved by the regulatory body.

The design of the programme should be based on a safety assessment, in which

impacts on human health and the environment over an appropriate period into the

future are considered.

5.965.93 The operator should determine the period over which institutional

controls can be assumed to remain effective and this determination should be

approved by the regulatory body. Scenarios postulating human intrusion, failure of

engineered structures and developments in the environment should be considered in

the safety assessment.

5.975.94 Establishment of the requirements for institutional control should be a

part of the optimization of the design for closure. The need for, and dependence on,

active institutional controls should be minimized in the design.

5.985.95 As part of an institutional control programme, all relevant records of

the location and characteristics of closed waste management facilities, restrictions on

land use and ongoing monitoring and/or surveillance requirements should be

maintained in accordance with applicable legal requirements. Legal provision should

be made for the regulatory body to withdraw or modify components of the

institutional control programme, as deemed appropriate in the light of results of

monitoring and surveillance. Information on the site, the required institutional controls

and the rationale or need for such controls should be documented and made publicly

available.

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6. SAFETY ASSESSMENT AND SAFETY CASE

INTRODUCTION

6.1 This section describes the approach to conducting safety assessments for

management of radioactive residues generated from NORM related facilities and

activities. The safety assessment should indicate how the residue management

facilities should be designed to provide optimum protection to workers, the public and

the environment.

The key points established in this section are as follows:

The safety assessment should take place at the design stage of facility

development and should cover the operational, closure and post-closure phases

of the facility

A graded approach should be taken in assessing the range of activities and

facilities related to NORM management

The safety assessments should be well documented and updated as necessary to

reflect changes in operation or regulatory requirements

GENERAL CONSIDERATIONS

6.2 Requirements for the safety assessment for all facilities and activities are set out

in Ref. [9]. Safety assessment for the management of NORM residues entails

assessing the facilities and activities that produce NORM residues, pre-disposal

management of residues, and disposal of radioactive wastes. Specific requirements

for the disposal of radioactive waste are described in Ref. [4].

6.3 The prime responsibility for safety throughout the lifetime of a facility lies with

the operating organization [3]. This includes responsibility for both assessing and

ensuring the safety of the facility throughout its lifecycle.

6.4 Safety assessment is undertaken in conjunction with the planning and design of

a proposed facility or activity. While planning a NORM residue facility and/or activity,

the operating organization should start to prepare and develop a safety case that

demonstrates the safety of the proposed facilities and/or activities and demonstrates

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that the proposed activities will be in compliance with the safety requirements and

criteria set out in national laws and regulations.

6.5 The operating organization should use the safety assessment to establish specific

operational limits, conditions and administrative controls. The operating organization

may wish to set an operational target level below the limits and controls to assist in

avoiding any breach of those that may be approved.

6.6 The results of the safety assessment should provide the primary input to the

authorizing documentation required to demonstrate compliance with regulatory

requirements with consideration of the integration of the whole of pre-disposal residue

management and disposal. An important outcome of the safety assessment is the

facilitation of communication between interested parties on issues relating to the

facility or activity. The results of the safety assessment can be used to determine any

necessary changes in the plans or design so that compliance with all requirements is

ensured. The results are also used to establish controls and limitations on the design,

construction and operation of the facility.

6.7 The various stages in the lifetime of the NORM residue facility (i.e. siting,

design, construction, operation and closure, and post closure) and activity (residue

generation, treatment, reuse/recycle, storage and disposal) should be taken into

account in the safety assessment. The safety assessment should be periodically

reviewed be revised as necessary to reflect changes in operation or regulatory

requirements.

GRADED APPROACH FOR SAFETY ASSESSMENT

6.8 A graded approach should be taken in developing safety case and conducting

safety assessments for the broad range of facilities and activities related to NORM

residue management. Three aspects [9] to be considered in a graded approach are:

Magnitude of the possible radiation risks;

The maturity of measures to manage risk;

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The complexity of the facility and/or activity.

6.9 Paragraph 3.3 of Ref [9] states ‘The main factor to be taken into consideration in

the application of a graded approach is that the safety assessment has to be consistent

with the magnitude of the possible radiation risks arising from the facility or activity’.

The safety case should be developed and assessment should be conducted only to a

level of detail that is appropriate both to the magnitude of the risks and to the stage of

development of the facility and activity. The approach should also account for any

releases of radioactive material in normal operation, the potential consequences of

anticipated operational occurrences and possible accidents, and the possibility of the

occurrence of very low probability events with potentially high consequences.

6.10 The consideration of maturity relates to the use of proven practices and

procedures, proven designs, data on operational performance of similar facilities or

activities, uncertainties in the performance of the facility or activity, and the

continuing and future availability of experienced manufacturers and constructors. In

this sense, consideration of maturity may refer to:

(i) tThe use of well-established practices, procedures and designs,;

(ii) tThe availability of knowledge of the operational performance of similar

facilities or practices (and the associated uncertainties); and,

6.10 (iii) tThe availability of experienced manufacturers, constructors and those

conducting safety assessment. In general, the necessary depth of assessment and

review efforts will be reduced with increasing levels of maturity.

6.11 Complexity relates to the extent and difficulty of the effort required to construct

a facility or to implement an activity, the number of related processes for which

control is necessary, the extent to which radioactive material has to be handled, the

longevity of the radioactive material, and the reliability and complexity of systems and

components, and their accessibility for maintenance, inspection, testing and repair.

6.12 The application of the graded approach should be reassessed as the safety

assessment progresses and a better understanding is obtained of the radiation risks

arising from the facility or activity. The scope and level of detail of the safety


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assessment are then modified as necessary and the level of resources to be applied is

adjusted accordingly.

SCOPE OF THE SAFETY ASSESSMENT

6.13 The scope and extent of the assessment should be commensurate with the site-

specific issues that should be addressed. The results of the initial safety assessment

should be factored into the selection of the site and design of the NORM management

facility. The assessment should consider the significant scenarios and pathways by

which workers, the public and the environment may be subject to radiological hazards.

The scope and depth should be sufficient to identify and evaluate relevant risk

components over the lifetime of the facility. The models or methods used should allow

the effects of the various hazards in the different management options to be compared

in a consistent manner.

6.14 A safety assessment should generally include aspects such as:

A description of the site and facility, including the maximum expected

inventory of NORM residue and its acceptance criteria, the management facility

and its characteristics, structures, systems and components, and the

characteristics of items important to the safety of facility and activity.

A description of NORM residue operations at the facility and management

options outside the facility, including inventory and characteristics of residues.

Systematic identification of hazards and scenarios associated with operational

states and accident conditions and external events, special attentions should be

paid to reuse and recycle due to long life cycle and uncertainty.

An evaluation of hazards and scenarios, including screening of their

combinations that may result in a release of radioactive material, to eliminate

those of low likelihood or low potential consequences.

Assessment of the probabilities and potential consequences of the release(s) of

radioactive material identified in the hazard evaluation by quantitative analysis

and comparison of the results of the assessment with regulatory limitations.

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Establishment of operational limits, conditions and administrative controls

based on the safety assessment. If necessary, the design of the NORM residue

should be modified and the safety assessment should be updated.

Documentation of safety analyses and the safety assessment for inclusion in the

documentation supporting the licensing of the facility.

The commissioning programme.

Organizational control of operations.

Procedures and operational manuals for activities with significant safety

implications.

A programme for periodic maintenance, inspection and testing.

Monitoring and surveillance programprogrammes.

The training programme for staff.

The emergency preparedness and response plan.

The management system.

Provisions for occupational radiation protection.

Provisions for the decommissioning and remediation, if applicable.

CONDUCTING A SAFETY ASSESSMENT

6.15 The safety assessment should be conducted iteratively step by step. In general, a

safety assessment should include context for the assessment, description of the facility

and activity, development and justification of scenario, formation and implementation

of an assessment models, performance of calculation and analysis of results, and

comparison with assessment criteria.

6.16 The context for the assessment involves the following key aspects: the purpose

of the assessment, the philosophy underlying the assessment, the regulatory

framework, the assessment endpoints, and the time frame for the assessment.

6.17 In determining the assessment time frame, account should be taken of the

characteristics of the particular facility or activity, the site and the design of the

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facility. Other factors that should be considered include natural external hazards and

social change.

6.18 Long term management facility of NORM residue, including long term storage

and disposal) may involve a period of time that exceeds the normal design lifetime of

civil structures, including short term storage facilities, and this will have implications

for the selection of construction materials, operating methods, and quality assurance

and quality control. The rationale for selection of the assessment time frame should be

explained and justified.

6.19 Storage is, by definition, an interim measure, but it can last for several decades

or even longer. The intention in storing NORM residue is that it can be retrieved for

reuse, recycle reprocessing or processing and/or disposal at a later time. In the safety

assessment, a plan for the safe handling of the NORM residue, following the period

of storage, should be considered and the potential effects of degradation of the facility

and/or any elements of the containment on the ability to retrieve and handle the

NORM residue should be assessed.

6.20 The possibility of inadvertent human intrusion should be considered relevant

when assessing the safety of a long term management facility because the facility may

require continued surveillance and maintenance not only during operation, but also

after closure. Prevention of intentional human intrusion requires adequate security

arrangements and these should be addressed in the safety assessment.

6.21 If the initial safety assessment yields results that are close to or exceed the

limiting performance objectives, it may be necessary to carry out a more rigorous

evaluation of the suitability of any generic data sources that may have been used,

and/or an inventory reduction or additional safety systems and controls may be

necessary.

6.22 With regard to quantitative regulatory criteria, Ref. [4] states that “doses or risk

to the representative person who might be exposed in the future as a result of possible

natural processes affecting the disposal facility does not exceed a dose constraint of

0.3 mSv in a year or a risk constraint of the order of 10-5

per year”.

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6.23 If several facilities exist or are planned for the same site, the impact of all

facilities should be taken into account in establishing which criteria to consider and

when comparing the results of the assessment with these criteria. This may not be

straightforward if a mixture of old and new facilities exists at a site, or if the periods

over which risks in principle could exist are different for each facility at the site. In

such situations, consultation between the operator and the regulatory body will usually

be necessary in order to specify what criteria are to be used in the assessment.

6.24 A clear description of the endpoints for the assessment should be provided,

together with a justification for their selection, including endpoints for radiological

impact such as dose or risk, other safety indicators such as concentrations and fluxes

of radionuclides, and impacts on non-human species.

6.25 For the assessment of reuse and recycle of NORM residue, the receptor should

be determined according to the life cycle of the reuse and recycle.

6.26 The safety assessment should have clear description of the facility, activity and

residue. The characteristics of the potential sites would determine the generation of

contaminants and their transport from the sites. These data should be used, as

appropriate, for the calibration and validation of models and to establish reference

levels for monitoring and surveillance activities during all phases in the lifetime of the

waste management facility.

6.27 Potential options for managing the residue should be identified according to the

considerations outlined in Section 4. A broad range of options should be considered

for the initial analysis. The behavior of the various options for managing the residue

should be modeled using appropriate models and parameter values.

6.28 The operator should determine which institutional controls may be applicable

after closure of the residue management facility and should describe their key

characteristics, including the period over which they may be assumed to remain

effective. These controls should be proposed to the regulatory body and should be

reviewed as part of the closure plan. Guidance is provided in Section 5.

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6.29 The set of safety assessment scenarios should take account of all relevant

existing and potential hazards arising for the facility or activity, and their interrelation

and evolution over the lifetime of the facility or activity according to the safety case

and the context for the assessment. The features, events and processes to be

considered in the safety analysis are to be selected on the basis As basis of the

development and justification of scenarios, of a systematic approach, and justification

has to be provided that the to identification and screening of hazards scenarios

relevant for safety is sufficiently comprehensive [9].hould be taken on the basis of the

description of facility and the activities. The following steps should be applied in an

iterative manner in order to identify scenarios for normal operation and anticipated

operational occurrences and accident conditions that could lead to the exposure of

workers and members of the public, or adversely impact the environment:

6.29

Identification of hazards and initiating events: This should consider the

inventory, activity, physical conditions and location of the waste and other

radioactive material, together with any additional hazards arising from activities

or processes for its management, and should identify where initiating events

create the potential for causing harm to human health and/or the environment;

Screening of hazards: The hazards identified should be quantified and screened

in order to direct efforts toward all significant and relevant hazards and

initiating events for the facility or activity;

Identification of scenarios: The safety analysis should identify all relevant

scenarios arising from either processes or accident situations in which the

screened hazards could be realized.

Screening Assessment Methodology

6.30 The hazards identified should be quantified and screened in order to direct

efforts towards all significant and relevant hazards for the facility or activity. Hazards

lacking the potential to cause harm to human health and/or the environment to a

degree that exceeds relevant safety requirements or criteria, or which cannot be

realized given the scope of the facility or activity being assessed, can be screened out




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from the subsequent hazard analysis. In the re-evaluation of a safety assessment, such

screening arguments should be reviewed to check that they remain valid.

6.31 Assessment scenarios for screened hazards should be generated in a systematic

manner (e.g. by the identification of postulated initiating events). Consideration

should be given to all postulated initiating events through which harm could be

realized, in particular:

External initiating events;

Internal initiating events at the facility or the site, e.g. fire, explosions, collapse

of structures, leakages or spillages, failure of ventilation, drops of heavy loads,

failure of protective measures (e.g. shielding, personal protective equipment);

and

Human induced initiating events such as operator errors and violations,

misidentifications, and the performance of incompatible activities.

Consideration should also be given to the potential for new initiating events to

be caused by actions taken during the evolution of an accident to mitigate the

consequences of the accident.

6.32 Once the scenarios have been developed, the corresponding assessments should

be carried out. This is commonly undertaken using assessment models. An assessment

model will generally be developed from the following components: a conceptual

model, a mathematical model, and a computer code. Often specific models have to be

developed for particular processes and/or system components. For the purposes of

safety assessment, these models will need to be linked in such a way that it is possible

to assess the potential radiological impacts of the facility or activity as a whole. The

model linking and the use of more detailed models to support simplifications made for

safety assessment purposes should be properly managed in accordance with relevant

quality assurance measures.

6.33 Both conservative and realistic calculations might be necessary in radiological

impact assessment for the period after closure, and both approaches can be used to

increase confidence in the safety of the disposal facility. For example, conservative

models can be used, especially in early phases of assessment, to assess quickly the

performance of part of or the entire disposal system. If the results of an initial

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screening assessment do not satisfy the screening criteria, a more realistic assessment

should be carried out followed by an even more detailed assessment if required.in an

iterative manner.

6.34 Simple conservative models may also be used to increase confidence in results

obtained with more complex models. Conservative models are also necessary to deal

with uncertainties that are not amenable to quantification. Conservative estimates may

be used in the assessment for some parameters, whilst realistic values based on

detailed characterization and/or more realistic models may be used for others.

6.35 The decision to use a conservative approach, a realistic approach, or both will

depend on a number of factors such as the nature and objective of the assessment,

regulatory requirements, the availability of data and scientific understanding, the

complexity of the site and the facility, and available resources.

6.36 The assessment cases should adequately address the appropriate scenarios using

the conceptual models and site and facility or activity design information. A sufficient

range of sensitivity and uncertainty analyses should be performed to contribute to

understanding of the system and to identify parameter correlations that have not been

treated in an appropriate way.

6.37 When presenting the output from safety assessment calculations, sufficient

results should be provided as are necessary for comparison with both the ultimate

assessment end points and any alternative or sub-system safety or performance

criteria. Guidance on the use of the safety assessment results should be provided. For

example, it should be explained whether the safety assessment results (end points) will

be compared directly with regulatory criteria (e.g. safety targets) or whether they will

be used for illustrative or other purposes.

6.38 It is not in itself sufficient that the calculated doses are less than a dose

constraint for acceptance of a safety case for a facility or activity, since protection is

also required to be optimized. If the safety assessment results do not demonstrate

compliance with safety requirements or criteria, the assessment should be revised. The

results of the revised assessment should be used to identify proposed amendments to

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the existing safety case, or to identify activities, engineering and protective safety

measures, and, where appropriate, additional safety measures to ensure compliance

with the requirements and criteria. The treatment or reduction of uncertainties in the

safety assessment should be reviewed and, where necessary, revised.

6.39 Any lessons learned in applying the models and interpreting the results should

be used to revisit assumptions and decisions made during the course of model

development. It is likely that such information can be used to refine the model,

perhaps by identifying particularly important processes or particularly sensitive

parameters.

6.40 The assessment of non-radiological impacts will be required and governed by

environmental protection legislation. This lies outside the scope of this Safety Guide.

Nevertheless, the approaches to assessment described in this Safety Guide may also be

of use in the assessment of hazards posed by non-radioactive waste and in

optimization of protection and safety against all potential hazards.

DOCUMENTATION OF SAFETY CASE AND SUPPORTING SAFETY

ASSESSMENT

6.41 The safety assessment shall be documented at a level of detail and to a quality

sufficient to demonstrate safety, to support the decision at each stage and to allow for

the independent review and approval of the safety case and safety assessment. The

documentation shall be clearly written and shall include arguments justifying the

approaches taken.

6.42 Particular consideration should be given to ensuring that the level of detail is

commensurateis commensurate with the importance to safety of the particular system

or component and its complexity, and that an independent reviewer will be able to

reach a conclusion on the adequacy of the assessment and the arguments employed,

both in their extent and in their depth. Assumptions used in the safety case must be

justified in the documentationdocumentation, as must the use of generic information.

6.43 Because of the long time frames potentially involved, a plan for adequate record

keeping over the expected time frame should be considered in the safety assessment.

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6.44 The regulatory framework governing the conduct of safety assessment should be

documented as part of the context for the assessment, and the safety assessment should

be conducted in a manner consistent with that framework. Thus, the safety criteria to

be used in the assessment typically will be specified by the regulatory framework.

PERIODIC SAFETY REVIEWS

6.45 The operator shall carry out periodic safety reviews and shall implement any

safety upgrades required by the regulatory body following this review. The results of

the periodic safety review shall be reflected in the updated version of the safety case

for the facility.

6.46 The safety assessment should be periodically reviewed in accordance with

regulatory requirements. The review of management systems should include aspects

of safety culture. In addition, the safety case and supporting safety assessment should

be reviewed and updated:

(a) When there is any significant change to the facility or to its radionuclide

inventory that may affect safety.

(b) When changes occur in the site characteristics that may impact on the

storage facility, e.g. industrial development or changes in the surrounding

population.

(c) When significant changes in knowledge and understanding occur (such as

from research data or from feedback of operating experience).

(d) When there is an emerging safety issue due to a regulatory concern or an

incident.

(e) Periodically, at predefined periods, as specified by the regulatory body.

Some States specify that a periodic safety review be carried out not less

frequently than once in ten years.


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7. MANAGEMENT SYSTEMS

7.1 This section provides a general overview of the management system

requirements with a particular emphasis on the long-term management aspects

associated with the management of NORM residues. Further direction and guidance

may be found in Reference [11] and associated guidance documents.

7.2 The requirements for establishing, implementing, assessing and continually

improving a management system to ensure the protection of people and the

environment for facilities and activities including those that generate NORM residues

are set out in Ref [11]. The requirements include:

Management responsibility including organization and planning;

Resource management including the provision of resources and training;

Process implementation including the control of work processes, documents,

records, materials and equipment: and,

Measurement and assessment including verification, self-assessment and audits.

7.3 Guidance on management systems for processing, handling, storage and

disposal of radioactive wastes including NORM residues can be found in Refs [21] &

[22].

7.4 The management system for the processing, handling, pre-disposal and disposal

of NORM residues must be developed, managed and integrated within the existing

management system that addresses all facilities and activities overseen by the

operating organization.

7.5 A management system is required to be established, implemented, assessed and

continually improved by the operating organization and it should be applied to all

stages of NORM residue management that have a bearing on health, safety or

environmental protection. It should be aligned with the goals of the operating

organization and should contribute to their achievement.

7.6 The use of a graded approach in the application of management system

requirements is particularly important in the management of NORM residues to ensure

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the degree of formalization, oversight, documentation and assessment is

commensurate with the complexity of the facility and activities and the overall risks

associated with the NORM residues to be managed.

MANAGEMENT RESPONSIBILITY

7.7 NORM residue management facilities, like any facility for the management of

long lived radioactive wastes, must be able to perform over very long periods of time.

As a result, the management system must be sufficiently robust but flexible so that it

can evolve over the life of the facility. Since the responsibility for the management of

NORM residues is expected to change during the life of the storage or disposal facility

from the generator, to possibly a third party oversight organization and finally

government, the management system and in particular the records management system

must take into account and facilitate the transfer of responsibility across these various

entities.

7.8 While early planning and effective controls are important elements of any

management system, this is particularly important in the management of NORM

residues. Several member states have faced extensive costs and significant technical

challenges to address legacy issues surrounding the long-term management of large

volumes of NORM residues. Proper planning in the generation, characterization,

processing, pre-disposal and disposal of NORM residues is essential to ensure long

term performance and minimize long term costs,

7.9 The long term nature of NORM residue management means that particular

consideration should be given to establishing and maintaining confidence that the

performance of the facilities and activities will meet the health, safety and

environmental protection requirements over the lifetime of the facility to the end of its

decommissioning and into institutional control. This includes the creation of the

funding arrangements that will be necessary to manage the facilities in the long term.

7.10 National and international policies and principles for NORM residue

management that currently constitute an accepted management arrangement can

evolve over the lifetime of the facility. Policy decisions, technological innovations and

advances or plans for re-processing of residues to further extract resources can lead to

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fundamental changes in the management strategy for NORM residues. However, the

operating organization retains its responsibility for all activities at all times and

continuous commitment by the organization remains a prerequisite to ensuring safety

and the protection of human health and the environment.

7.10

RESOURCE MANAGEMENT

7.11 NORM residue management activities will require financial and human

resources and the necessary infrastructure at the site where the facility is located.

Senior management should be responsible for making arrangements to provide

adequate resources to satisfy the demands imposed by the safety, health,

environmental, security, quality and economic aspects of the full range of activities

involved in the management of NORM residues and the potentially long duration of

such activities.

7.12 For the plans, goals and objectives that define the strategy for achieving an

integrated approach to safety, interactions with all interested parties should be

considered, as well as long term aspects such as:

(a) Provision of adequate resources (the adequacy of resources for maintenance

of facilities and equipment may need to be periodically reviewed over

operational periods that may extend over decades);

(b) Preservation of technology and knowledge and transfer of such knowledge

to people joining the programme or the organization in the future;

(c) Retention or transfer of ownership of NORM residue management facilities;

(d) Succession planning for the technical and managerial human resources;

7.12 (e) Continuation of arrangements for interacting with interested parties.

7.13 Arrangements for funding of future NORM residue management activities

including the funding of future institutional control should be specified and

responsibilities, mechanisms and schedules for providing the funds should be

established in due time. The generator of the NORM residues should be accountable

for providing appropriate funding.

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7.14 Management systems for NORM residue management activities should include

provision to deal with several funding challenges. This is discussed in further detail in

Section 9.

7.15 For long-term management activities, future infrastructural requirements should

be specified and plans should be made to ensure that these will be met. In such

planning, consideration should be given to the continuing need for support services,

spare parts for equipment that may eventually no longer be manufactured and

equipment upgrades to meet new regulations and operational improvements, and to the

evolution and inevitable obsolescence of records and document management software

and databases.

7.16 Everyone involved in the design, construction, commissioning, operation and

closure of NORM residue management facilities and whose performance could

influence safety should be trained to an appropriate and verified level. Accumulated

experience, including lessons learned from incidents and events, should be reviewed

periodically and should be used in revising training programprogrammes and in future

decision making.

PROCESS IMPLEMENTATION

7.17 The management system should ensure that there are adequate processes

including documented procedures and work instructions for siting, design,

commissioning, operation, maintenance, decommissioning closure and institutional

control. The management system should be designed to ensure that safety and

protection of human health and the environment is maintained, and that the quality of

the records and of subsidiary information on the inventories of NORM residues is

preserved, with account taken of the duration of any proposed storage period and the

consecutive management steps, for example, reprocessing or disposal. The

management system should also include provision to ensure that the fulfillment of its

goals can be demonstrated.

7.18 Models and codes used in the safety assessment should be validated and verified

to the extent possible. A feedback process should be established and the results of the

safety assessments should be taken into account appropriately during the design.

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7.19 All relevant records of the location and characteristics of closed NORM residue

management facilities, restrictions on land use and on-going maintenance and/or

surveillance requirements should be maintained in accordance with applicable legal

requirements. Legal provision should be made for the regulatory body to withdraw or

modify components of the institutional control programme, as deemed appropriate in

the light of results of monitoring and surveillance. Information on the site, the required

institutional controls and the rationale or need for such controls should be documented

and made publicly available.

7.20 Records concerning NORM residue management that need to be retained for an

extended period should be stored in a manner that minimizes the likelihood and

consequences of loss, damage or deterioration due to unpredictable events such as fire,

flooding or other natural or human initiated occurrences. Storage arrangements for

records should meet the requirements prescribed by the national authorities or the

regulatory body and the status of the records should be periodically assessed. If

records are inadvertently destroyed, the status of surviving records should be

examined and the importance of their retention and their necessary retention periods

should be re-evaluated.

MEASUREMENT, ASSESSMENT AND IMPROVEMENT

7.21 The effectiveness of the protection achieved in the management of NORM

residues should be assessed periodically. This includes re-assessing the overall

effectiveness of the management system to ensure that continues to meet the

organizational needs and regulatory expectations that are expected to evolve over

time.

7.22 Independent verification including inspections and audits of the design,

construction and the operation of the residue management facilities should be

undertaken in order to ensure that they are designed, constructed and operated as

intended, and that deficiencies are corrected. In so doing, it is essential that these

verifications are conducted prior to the initiation of any activities for which

implementation of any corrective measures would prove to be very difficult (e.g.

verification of liner construction prior to waste placement).

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7.23 Facilities for the long termlong-term management of NORM residues often

involve engineered structures that require routine and long-term inspection and

verification. Measures should be put in place to facilitate third party independent

verification including geotechnical inspections to ensure the engineered structures

such as berms and dams are performing as intended. This should form part of the

monitoring and surveillance programprogramme, which is further discussed in the

next chapter.

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8. MONITORING AND SURVEILLANCE OVERVIEW OF

MONITORING AND SURVEILLANCE

o

o This chapterSection outlines reminds the definition of the the objectives and

design of the monitoring monitoring and surveillance, and describes the

responsibilities of the operator and regulatory body and the objectives and design of

the monitoring.

o8.1 . The Kkey points are theas followings:

1) A graded approach is recommended to adapt the level of detail (duration

frequency, locations for sampling, parameters..) for monitoring and surveillance

programprogrammes with the level of the potential hazards associated with the

facility;

2) The monitoring and surveillance programprogramme should be reviewed

periodically by the operator and the regulatory body and also following any

major changes in waste management operations (including the period of lifetime

of the site);

3) It is necessary to establish the baseline conditions for comparison with later

monitoring results because radionuclides present in NORM residue are already

present in nature;

4) Consideration should be given to ensure transparency (communication to the

public).

OVERVIEW OF MONITORING AND SURVEILLANCE

8.2 Monitoring has been defined in various publications of the IAEA in different

ways [GSR-3], [RS-G-1.8], . Draft safety guide DS357 states that the term monitoring

refers to: consists of “Ccontinuous or periodic observations and measurements to help

evaluate the behaviourbehavior of the components of a waste disposal system, and the

impact of the waste disposal system on the public and the environment. More

specifically, it covers the measurement of radiological, environmental and engineering

parameters. “

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o

8.3 The duration and frequency of monitoring should be in accordance with the

time-scale of natural variations in the processes and in the parameters being measured,

as determined by regulatory requirements, and with changes in processes and

parameters associated with construction and operation of the disposal facility.

o

o In the draft safety guide DS357 the term surveillance refers to: “The physical

inspection of a waste disposal facility in order to verify the integrity of the safety

barrier”.

8.4 Surveillance is employed periodically to verify through inspection that

structures, systems and components continue to function as described in the safety

case. In this respect the function of surveillance is to facilitate the detection of changes

in the engineering structures and systems of the disposal facility that might affect the

performance of the disposal system. and integrity of the safety barriers.

o

8.5 The level of detail for monitoring and surveillance programprogrammes should

be consistent with the level of the potential hazards associated with the facility and a .

A graded approach is recommended., as in many cases

o

o8.6 The monitoring and surveillance programprogramme should be reviewed

periodically and also following any major changes in waste management operations

(including the period of lifetime of the site) or in regulatory requirements.

RESPONSIBILITIES OF THE OPERATOR AND REGULATORY BODY

o8.7 The operator of the waste disposal facility should be responsible for carrying

out the activities relating to monitoring and surveillance (design including record

keeping and archiving) that meets the requirements established by the regulatory body

for each period of the lifetime of the site and should: :

Records of the results of the programme should be maintained in a form readily

amenable to interrogation [23];.

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Prior to termination of the operator’s responsibility the operator should provide

the regulatory body with the results of a final radiological and environmental

survey and a closure completion report in order to document compliance with

the regulatory requirements for managing the waste..

o8.8 The regulatory body should:

pPeriodically review the regulations in force for monitoring and surveillance,

the monitoring and surveillance programmes and reporting arrangements;

rReview the monitoring and surveillance data provided by the operator against

established requirements;

vVerify that waste disposal facility is being appropriately monitored and

controlled by the operator; this may include the independent conduct of

monitoring and surveillance.

OBJECTIVES AND DESIGN OF THE MONITORING

8.9 Monitoring and surveillance activities must be adapted to each period in the

lifetime of a radioactive waste disposal facility : pre-operationnaloperational period,

operational period (including closure operation) and post closure period. Those

differents periods and correspondingand corresponding objectives can be further

described as follows:

o

o8.10 The pre-operational period includes concept definition, site evaluation

(selection, verification and confirmation), and safety assessment and design studies.

tThe objectives are the following:

• To contribute to the evaluation of suitability of the site;

• To provide input data for the design of the facility;

• To provide input data necessary for the operational and post-closure safety

cases;


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• To establish baseline conditions for comparison with later monitoring results;

This is especially important in respect of NORM residues, where the same

radionuclides are already present in nature

• To aid in designing the monitoring programme for the operational period.

o8.11 The operational period begins when waste is first received at the facility. From

this time, radiation exposures may occur as a result of waste management activities.

This period includes operations necessary to close the disposal site (such as

decommissioning, sealing, remediation, etc). The objectives of the monitoring

programme during the operational period are the following:

To provide data on the as-built properties of materials and structures, for

confirmation of the performance of elements of the disposal system, which may

be used to revise, improve or build confidence in the post-closure safety case;

To provide information necessary for checking whether systems for effluent

treatment and control are performing properly;

To provide early warning of any deviations from normal operation;

To provide data on the discharge of radionuclides to the environment, for use in

predictive modelling for estimating radiation levels and activity concentrations

in the environment and exposure of the public (e.g. rates of discharge and

radionuclide compositions).

o8.12 The post-closure period begins at the time when all the engineered

containment and isolation features have been put in place, operational buildings and

supporting services have been decommissioned, and the facility is in its final

configuration. Objectives of the monitoring programme for the period after closure are

to demonstrate that the facilities are performing as predicted in the design and include

the following.

To detect abnormal radiological concentration or activity in the environment

that could be attributable to the disposal facility;.

To verify the performance and integrity of barriers;

To validate the achievement of post-closure radiation exposure objectives;


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To inform the decision to move from a period of active institutional control to a

period of passive institutional control (established by means of, for example,

site markers and maintenance of ‘corporate memory’);,

To determine need for, and type of, monitoring and surveillance activities to be

conducted during the institutional control period.

o8.13 The monitoring and surveillance programme should specify the parameters to

be monitored, the locations and frequencies for sampling, and the procedures for

analysis and reporting including the setting of appropriate action levels. Such a

programme should include measurement of:

Indicators of environmental impacts, such as levels of radionuclides and non-

radiological contaminants in air, water and soil;

The physical integrity of structures and systems for waste containment;

Parameters that may assist in the interpretation of data, such as meteorological

data, operational process data and waste stream data.

o8.14 In order to ensure transparency, in the design of the monitoring programmme

consideration should be given to how the results are to be communicated to the public.

Transparency includes the responsibility to provide a clear interpretation of results and

the context for the measurements.

o8.15 The need to address public concern and expectations may also be considered in

defining the monitoring programme.



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9. FINANCIAL ASSURANCE

9.1 This Section outlines the financial assurance requirements necessary to

confirm that adequate funding is available at the time of decommissioning and

closure. The timing of establishing funding is critical, starting at the planning stage of

a project, and that periodic adjustments are made so that funding is in place before it

is needed.

9.2 Adequate legal requirements are needed so that accesses to the funds are

assured at the time of a potential default and that the funds are isolated for the for the

purpose of decommissioning of the project. Key points are the followings:

5) A financial surety mechanism to be used in the event of business insolvency is

crucial to assuring that management and decommissioning of residues occurs;

6) Consideration of the financial surety should begin in the planning stage of a

project and be periodically revised as estimates change;

7) Legal requirements are needed to assure that the funding can be accessed at the

time it is needed and that the funding is separated from other uses;

8) A graded approach should be used to ensure that the requirement for provision

of funds for the management of NORM residues be proportional to the

radiological risks involved.

9.3 Governments are required to establish a national policy and strategy for safety

which must include the provision of appropriate financial resources for

decommissioning of facilities and management of radioactive waste, including its

storage and disposal [3].

9.4 To avoid any undue burden on future generation, it is important that there be

sufficient funds set aside so that the financial resources are available for

decommissioning, remediation, radioactive waste disposal, and post closure

management. A liability on future generations would exist if these funds were absent

or insufficient.

9.5 There is an identified need for legal requirements to assure funding provision

and adequacy. Legal requirements are also necessary to protect against such factors as


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misuse of funds, claims on funds during potential financial crisis or, business

insolvency, such a bankruptcy or cessation of business. Mechanisms should be in

place to assure funds are structured and managed to keep pace with factors such as

inflation, changes in operational scale or technology, and to ensure transparency of

the process which must withstand the scrutiny of the operator/licensee, the regulator

and the public [21].

9.6 In keeping with a graded approach to the management of radioactive residues,

the regulator should ensure that the requirement for provision of funds for the

management of NORM residues be proportional to the radiological risks involved.

9.7 Funding arrangements for managing NORM residue disposal activities should

be specified, and responsibilities, mechanisms and schedules for providing funds

should be established before the funds are needed. In particular, the funds that will be

necessary should be ensured before termination of the practice that generates the

residue. In general, it is expected that the operator would fund the management of the

NORM residue, in keeping with the ‘polluter pays’ principle.

9.8 The regulator should ensure consideration is given to the provision of

adequate funding at the planning stage [21]. It should be recognized that it may be

difficult to make a realistic estimate of costs for residue management activities that

are still in the planning stage, especially where there may be considerable uncertainty.

Cost estimates for long-term management of residues should therefore be updated

periodically as planning certainty improves. The cost estimate for decommissioning

liabilities should be carried on the operator’s financial statements.

9.9 Regulatory requirements for the provision of financial assurance for NORM

residue management activities should consider several potential funding challenges:

1. Business insolvency: For various reasons (e.g. bankruptcy, cessation of

business), it may not be feasible to obtain the necessary funds at the time of

closure, especially if funds were not set aside at the time the benefits were

received from the activity.


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2. Transfer of ownership: Ownership of the NORM residues may be transferred

between parties; provisions for financial assurance must also be transferred.

3. Dedicated funding: If funds are to come from public sources, this will compete

with other demands for public funding and it may be difficult to gain access to

adequate funds on a timely basis.

4. Estimation uncertainty: It may be difficult to make realistic estimates of costs

that are still in the planning stage and for which no experience has been

accumulated.

5. Changing Expectations: It may be difficult to determine appropriate risk and

contingency factors to be built into estimates of future costs, owing to the

uncertainties associated with future changes in societal demands, changes to

standards, political imperatives, public opinion and the nature of unplanned

events that may require resources for dealing with them.

Longevity: It may be problematic to establish an adequate degree of confidence

in all the arrangements so that the necessary continuity of funding throughout

the entire series of activities is ensured.

6.

9.10 For these reasons, it is recommended that the regulator establish a suitable

process for estimating the cost of rehabilitation of a NORM residue generating

storage or disposal activity at any stage of the activity, and ensure adequate funding is

available at that stage and for each waste stream..

9.11 In addition, the planning for the NORM residue generating operation should

incorporate plans for managing decommissioning of facilities, remediation,

radioactive waste disposal, and post termination management of the facilities from the

beginning of the project, to ensure a safe, secure and stable end point that meets

licensing requirements.

9.12 It is not possible to establish a specific methodology for assuring funding

adequacy for all countries. However, the process typically will involve periodic

government or operator review and updating of derived estimates of costs.



Formatted: Indent: Left: 0 cm

Pag e o f 1 25 109

9.13 Based on the periodically updated cost estimate, the calculated sum may be

accumulated, or made available when required through the use of various financial

vehicles. These may include invested funds accumulated year-by-year over the

lifetime of the NORM generating activities, through the use of a standby trust, bonds,

irrevocable letters of credit, insurance, or expressed commitments from a government.

In some countries it is typical to use a contingency factor in the surety to deal with

cost uncertainty (e.g. 15-20%).

9.14 The method for making the funds available at the time of decommissioning

and rehabilitation will vary across Member States. Typically these will involve

spending limits relative to specific milestones.

9.14

9.15 The operator’s management system should include a documented set of

policies that establish the management’s plans objectives and priorities with regard to

safety, health, environmental, security, quality and economic considerations [24].

Those policies outline senior management’s commitments to attaining their goals and

objectives, and their priorities and means for continual improvement. This system

should include management commitments to estimating and providing the adequate

financial resources required by the regulator for NORM management.

Pag e o f 1 25 110

REFERENCES

[1] INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Safety Glossary, Terminology

used in Nuclear Safety and Radiation Protection, 2007 Edition, IAEA Vienna

[2] INTERNATIONAL ATOMIC ENERGY AGENCY, Fundamental Safety Principles,

Safety Fundamentals, Safety Standards Series No. SF-1, IAEA, Vienna (2006).

[3] INTERNATIONAL ATOMIC ENERGY AGENCY, Governmental, Legal and Regulatory

Framework for Safety, IAEA Safety Standards Series No. GSR Part 1, IAEA, Vienna

(2010).

[4] INTERNATIONAL ATOMIC ENERGY AGENCY, Disposal of Radioactive Wastes,

IAEA Specific Safety Requirements No. SSR-5, IAEA, Vienna (2011).

[5] INTERNATIONAL ATOMIC ENERGY AGENCY, Application of the Concepts of

Exclusion, Exemption and Clearance, IAEA Safety Standards Series No RS-G-1.7, IAEA,

Vienna (2004).

[6] INTERNATIONAL ATOMIC ENERGY AGENCY, Occupational Radiation Protection in

the Mining and Processing of Raw Materials, IAEA Safety Standards Series No RS-G-1.6,

IAEA, Vienna (2004).

[7] INTERNATIONAL ATOMIC ENERGY AGENCY, Regulatory Control of Radioactive

Discharges to the Environment, IAEA Safety Standards Series No.WS-G-2.3, IAEA,

Vienna (2000)

[8] INTERNATIONAL ATOMIC ENERGY AGENCY, Management of Radioactive Waste

from the Mining and Milling of Ores, IAEA Safety Standards Series No WS-G-1.2, IAEA,

Vienna (2002).

[9] INTERNATIONAL ATOMIC ENERGY AGENCY, Safety Assessment for Facilities and

Activities, IAEA Safety Standards Series No. GSR Part 4, IAEA, Vienna (2009)

[10] INTERNATIONAL ATOMIC ENERGY AGENCY, Predisposal Management of

Radioactive Waste, General Safety Requirements GSR Part 5, IAEA Vienna (2009)

[11] INTERNATIONAL ATOMIC ENERGY AGENCY, Radiation Protection and Safety of

Radioactive Sources, General Safety Requirements, Interim Edition, GSR Part 3, IAEA

Vienna (2011).

[12] INTERNATIONAL ATOMIC ENERGY AGENCY, Regulations for the Safe Transport of

Radioactive Material, 2012 Edition, IAEA Specific Safety Requirements No. SSR-6,

IAEA, Vienna (2012).

[13] INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION, Scope of

Radiological Protection Control Measures, Publication 104, Elsevier Science, Oxford

(2007)

[14] INTERNATIONAL ATOMIC ENERGY AGENCY, Site Evaluations for Nuclear

Installations, IAEA Safety Standards Series NS-R-3, IAEA, Vienna (2003)

[15] INTERNATIONAL ATOMIC ENERGY AGENCY, Seismic Hazards in Site Evaluation

for Nuclear Installations, IAEA Safety Standards Series, SSG-9, IAEA, Vienna (2010)

Pag e o f 1 25 111

[16] INTERNATIONAL ATOMIC ENERGY AGENCY, Meteorological and Hydrological

Hazards in Site Evaluation for Nuclear Installations, IAEA Safety Standards Series, SSG-

18, IAEA, Vienna (2011)

[17] INTERNATIONAL ATOMIC ENERGY AGENCY, Classification of Radioactive Waste,

IAEA Safety Standards Series No. GSG-1, IAEA, Vienna (2009).

[18] INTERNATIONAL ATOMIC ENERGY AGENCY, Borehole Disposal Facilities for

Radioactive Waste, IAEA Safety Standards Series No. SSG-1, IAEA, Vienna (2009).

[19] INTERNATIONAL ATOMIC ENERGY AGENCY, Release of Sites from Regulatory

Control on Termination of Practices, IAEA Safety Standards Series No WS-G-5.1, IAEA,

Vienna (2006).

[20] INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION, Protection of

the Public in Situations of Prolonged Radiation Exposure, ICRP Publication 82, Elsevier

Science Ltd, Oxford (2000).

[21] INTERNATIONAL ATOMIC ENERGY AGENCY, The Management System for the

Processing, Handling and Storage of Radioactive Waste, IAEA Safety Standards Series No

GS-G-3.3, IAEA, Vienna (2008).

[22] INTERNATIONAL ATOMIC ENERGY AGENCY, The Management System for the

Disposal of Radioactive Waste, IAEA Safety Standards Series No GS-G-3.4, IAEA,

Vienna (2008).

[23] INTERNATIONAL ATOMIC ENERGY AGENCY, The Safety Case and Safety

Assessment for the Disposal of Radioactive Waste, IAEA Safety Standards Series, SSG-23,

IAEA, Vienna (2012)

[24] INTERNATIONAL ATOMIC ENERGY AGENCY, Application of the Management

System for Facilities and Activities, IAEA Safety Standards Series, GS-G-3.1, IAEA,

Vienna (2006)

Pag e o f 1 25 112

ANNEX I. ORIGIN AND CATEGORIZATION OF NORM RESIDUES

4.1 This Annex indicates a range of industry sectors where the management of

NORM residues may need consideration. A regulatory body would start

consideration by identifying which relevant industry sectors are operating in its

jurisdiction, or by receiving a notification from an industry that it is dealing with

NORM residues in its operations.

A1.1 This Annex indicates a range of industry sectors where the management of

NORM residues may need consideration. A regulatory body would start consideration

by identifying which relevant industry sectors are operating in its jurisdiction, or by

receiving a notification from an industry that it is dealing with NORM residues in its

operations.

A1.1 Having identified relevant industry sectors, priority should be given to the

the types of operation known from experience and current knowledge to be most

likely to require regulatory measures. The IAEA has identified those types of

operation likely to require regulatory control on the basis of worker doses. Table 3

below, has been adapted from Table 3 of Safety Report Series 49 [25].

Table 3: Industry sectors identified as being likely to require regulatory control

Type of

operation

Material involved

Description

Radionuclide(s)

with highest activity

concentration

Typical activity

concentration (Bq g-1

)

Mining and

milling of

uranium ores

Ore

Tailings

Waste Rock

Process water

Sludges

238U Series 12 – 2,500

1.2 - 250

X

X

X

Rare earth

extraction from

monazite

Monazite

Thorium

concentrate

Scale

Residue

232Th series 232

Th

228Ra 228Ra

40-600

Up to 800

1000

20-3000

Production of

thorium

compounds

Thorium

concentrate

Thorium

compounds

232Th

232Th

Up to 800

Up to 2000

Formatted: Indent: Left: 0.5 cm, Nobullets or numbering



Formatted Table

Comment [AJ5]: 0.1% - 20%

Comment [AJ6]: assume 90% U removal from ore

Pag e o f 1 25 113

A1.2 Ref [25] notes that “…the list is not exhaustive, but probably captures most of

the relevant types of operation. It shows that there are relatively few types of

operation that are likely to need formal regulation.”

A1.3 The above table does not refer to contaminated plant and equipment generated

during the operation or decommissioning of many of the above industrial process

facilities. Recycling of these and other materials identified in Table A1 is discussed in

Annex 2.

Manufacture of

thorium

containing

products

Thorium

compounds

Products

232Th

232

Th

Up to 2000

Up to 1000

Processing of

niobium/tantalum

ore

Ore

Pyrochlore

concentrate

Residue

Slag

232Th series 232

Th

228

Ra 232

Th

1-8

80

200-500

20-120

Some

underground

mines and similar

workplaces

Ore

Scales from Ra

rich water

226Ra, 228Ra

Up to 10

Up to 200

Oil and gas

production

Scales during

removal from

pipes/vessels

226Ra 0.1-15000

TiO2 pigment

production

Scales during

removal from

pipes/vessels

228Ra, 226Ra <1-1600

Thermal

phosphorus

production

Fume and

precipitator dust

210Pb Up to 1000

Fused zirconia

production

Fume and

precipitator dust

210Pb, 210Po Up to 600

Combustion of

Coal

Fly ash

Bottom ash

Scale

238-U, 232-Th, 40-K

210-Pb, 210-Po

238U Series

226-Ra, 228-Ra,

210-Pb

0.07 – 0.36

0.06 – 0.3

0.93 – 1.7

0.2

Up to 200

Water Treatment

Sludges 226-Ra 0.1 – 14.0 Formatted: Highlight


Comment [AJ7]: Are the units pCi/g or Bq/g?



Comment [AJ8]: From UNSCEAR 2000


Formatted: Font: (Default) TimesNew Roman

Pag e o f 1 25 114

A1.4 Consideration can also be given to other materials associated with the industry

sectors listed in Section ZZZ4 of this Safety Guide. Table 7 Table 4 below, based on

Table 1 of Ref [25], is a useful starting point.

Table 4: Residue categories to be assessed for possible regulatory control

Category Material/operation

Radionuclide(s)

with highest

activity

concentration

Typical activity

concentration

(Bq g-1

)

Residues Red mud (alumina production)

Phosphogypsum (H2SO4 process)

238U,

232Th

226Ra

0.1—3

0.015—3

Slags Niobium extraction

Tin smelting

Copper smelting

Thermal phosphorus production

232Th

232Th

226Ra

238U

20—120

0.07—15

0.4—2

0.3—2

Scales,

sludges and

sediments

Scale (oil and gas production)

Scale (phosphoric acid production)

Residue (rare earth extraction)

Scale (TiO2 pigment production)

Scale (rare earth extraction)

Sludge (oil and gas production)

Residue (niobium extraction)

Scale (coal mines with Ra rich

inflow water)

Scale (iron smelting)

Scale (coal combustion)

Sludge (iron smelting)

Residue (TiO2 pigment production)

Sludge (water treatment)

226Ra 226

Ra 228

Ra 228Ra, 226Ra 226

Ra, 228

Th 226Ra 228

Ra 226

Ra, 228

Ra

210

Pb, 210

Po 210Pb 210

Pb 232

Th, 228

Ra 226Ra

0.1—15000

0.003—4000

20—3000

<1—1600

1000

0.05—800

200—500

Up to 200

Up to 200

>100

12—100

<1—20

0.1—14

Precipitator

dust

Thermal phosphorus production

Fused zirconia production

Niobium extraction

Metal smelting

210Pb 210Po

210Pb, 210Po 210

Pb, 210

Po

1000

600

100—500

Up to 200

a Although this material has an activity concentration of less than 1 Bq g-1, it is included because it is a building material.

A1.5 Measurement of the activity concentration levels in these materials may

indicate further residue categories where regulatory oversight may be required.

A1.6 The Regulatory Authority should decide, in accordance with the graded

approach to regulation, whether the operations can be exempted, or whether they

should be subject to authorization. A graded approach means that, where the

regulatory authority has determined that regulatory controls are necessary, the






Pag e o f 1 25 115

regulatory measures should be commensurate with the level of risk associated with the

material/operation.

REFERENCES – ANNEX I

[25] INTERNATIONAL ATOMIC ENERGY AGENCY, Assessing the need for Radiation

Protection Measures in Work Involving Minerals and Raw Materials, IAEA Safety Report

Series, No 49, IAEA, Vienna (2006).

ANNEX II. REUSE AND RECYCLING OF NORM RESIDUES

A2.1 Reuse can be defined as the reutilization for materials for the original purpose

in their original form or in a recovered state. Recycling is the utilization of valuable

materials, tools and equipment for other than the original purposes, with or without

treatment. The reuse and recycle options is attractive because there is strong economic

incentive to use the large volume of residues, to avoid the costs associated with long

term storage or disposal. The decision of whether or not to reuse and recycle residues

depends on many factors that are specific to a given stream of residue or industry or

country. Implementation of reuse and recycling options requires the availability of

suitable criteria, a suitable measurement methodology and suitable instrumentation.

Some examples of reuse and recycling of NORM residues are given in the next

paragraphs.

Scrap metal

A2.2 Scrap metals from NORM industries that are contaminated, can in many cases

be decontaminated by various methods. Details of decontamination methods as well as

measurements principles and instrumentation for equipment in the oil and gas industry

are given in Safety Report 34 [26]. The decontaminated metals can be recycled, while

the rest of the material resulting from the decontamination process, which has

generally a small volume, may be treated as NORM waste. The contaminated scrap

may also be re-melted in specific ovens to decontaminate. The natural radionuclides

often go to the slag. The metals will be clean and can be reused. Depending on the

activity concentration, the slag may also be reused, as shown in the next paragraph.

Pag e o f 1 25 116

A2.3 Smelting of contaminated scrap should be a regulated practice, and comply

with requirements set by the regulatory body. Transport of contaminated items should

comply with the requirements of the transport regulations.

Slag

A2.4 Slag from NORM industries can be used as landfill or in road construction. An

example of the latter is the use of slag from the thermal phosphorus production

industry in road construction in Florida, USA and in the Netherlands [27].

Fly ash

A2.5 Fly ash from coal-fired stations is recycled in many cases in building materials,

for instance, as additives to concrete or in lightweight building materials. While use of

fly ash in concrete blocks for building construction may not be of concern in some

Member States, others regulate the resulting levels of permissible radiation in the

concrete blocks and importation of cement with activities exceeding certain radiation

limits.

Phosphogypsum

A2.6 There are several options for recycling of phosphogypsum, such as in

agriculture as a soil amendment, in road construction and as a building material.

Detailed information can be found in [27]

Recycling in agriculture

A2.7 Soils may either be saline, having a high content of soluble salts, or they may

be alkali in which case their cation exchange sites are largely occupied by sodium

ions. Alkaline soils generally are characterized by poor drainage, which is often

caused by a dispersal of colloidal clay particles resulting in surface crusts and blocked

Pag e o f 1 25 117

soil pores. The treatment of either saline, alkali or saline-alkali soils to improve

drainage is called reclamation. Leaching can usually reclaim saline soils. But

treatment of soils with an amendment prior to leaching is recommended for alkali or

saline alkali soils. The amendment most often employed is natural gypsum, but

phosphogypsum may be used as well.

A2.8 There are, however, not only radiological issues in the recycling of

phosphogypsum in agriculture. Also other contaminants, like cadmium or fluorine

may have an impact on the applicability of recycling of this residue in agriculture.

Recycling in road construction

A2.9 Phosphogypsum when subjected to compaction can be transformed into a solid

of valuable strength. Therefore, it can be used very effectively as a binder to stabilize

on-site soil and to replace shell and clay in secondary road and parking lot

construction. Test results from an experimental road in Florida, US, indicate that there

was no leaching occurring into the groundwater and drinking water samples.

Economic analysis on the construction of the experimental roads indicated tremendous

saving on the construction cost of utilizing phosphogypsum as compared to the

traditional method of construction. Radiation monitoring during the construction of

the roads, indicated no health hazards, either to the construction crews or the residents

living in the areas.

Recycling in construction materials

A2.10 There is quite some dispute about the applicability of phosphogypsum in

building materials. Some countries use activity concentration limits that prohibit in

practice the recycling of phosphogypsum in building materials. In other countries the

requirements are more relaxed.

REFERENCES ANNEX II

[26] INTERNATIONAL ATOMIC ENERGY AGENCY, Radiation Protection and the

Management of Radioactive Waste in the Oil and Gas Industry, IAEA Safety Report Series,

No 34, IAEA, Vienna (2003SRS)

Pag e o f 1 25 118

[27] INTERNATIONAL ATOMIC ENERGY AGENCY, Radiation Protection and

Management of NORM Residues in the Phosphate Industry, IAEA Safety Report Series,

No 78, IAEA, Vienna (2013)

Pag e o f 1 25 119

ANNEX III. PRACTICAL TECHNIQUES FOR DETERMINING

RADIONUCLIDE ACTIVITY CONCENTRATIONS

INTRODUCTION

A3.1 The investigation of a legacy site or industrial activities to determine the need

for, and extent of, regulatory control of exposure to natural sources of radioactive

material is likely to involve the sampling and analysis of various solid materials to

determine the activity concentrations of 238

U and 232

Th series radionuclides. These

more detailed investigations typically follow an initial screening assessment designed

to eliminate a site whichthat poses a low level hazard from further regulatory

consideration.

A3.2 The activity concentrations need to be compared with the activity

concentration value of 1 Bq/g, below which it is usually unnecessary to regulate. The

materials requiring sampling and analysis could be encountered in large quantities

with moderate or low activity concentrations (e.g. ore, tailings, slag) or in smaller

quantities with the possibility of high activity concentrations (e.g. mineral

concentrates, scale, sludge, precipitator dust. Accordingly, the sampling method and

analysis sensitivity requirements may vary depending on the assessment to be made.

A3.2 The most probable radionuclides of interest for which activity concentrations

need to be determined are:

• Uranium series: 238

U, 226

Ra, 210

Pb and 210

Po;

• Thorium series: 232

Th, 228

Ra and 228

Th.

•

SAMPLING OF MATERIAL

A3.3 The activity concentration values mentioned above refer to the average activity

concentration in the material concerned. The amount of material giving rise to

exposure at any one time could be large, and such material could therefore exhibit a

significant range of activity concentrations. The activity concentration may also vary

over the time periods normally of concern in occupational radiation protection (e.g.

Formatted: Left

Formatted: Font: Not Bold

Formatted: Justified, None, SpaceBefore: 0 pt, Bulleted + Level: 1 +Aligned at: 0.63 cm + Indent at: 1.27cm, Don't keep with next

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Pag e o f 1 25 120

one year). To the extent practicable, both of these variations are taken into account

when developing a suitable materials sampling strategy.

A3.4 The number of samples collected for analysis is important for obtaining a

reasonable estimate of the average activity concentration — the greater the number of

samples collected and analyzed, the greater the confidence in the figures that are

reported. There is a point, however, where any further gain in accuracy and power to

detect trends is no longer worth the time and resources needed to produce the data.

The accuracy is also affected by other factors such as the degree to which the samples

are representative of the material.

MEASUREMENT ACCURACY AND QUALITY ASSURANCE

A3.5 Adequate confidence in the results of analyses is ensured if the samples are

analysed at a suitably accredited laboratory and if the level of accuracy of the

analytical technique is commensurate with the activity concentration criterion against

which the material is being checked. If an accredited laboratory is not available, the

analytical techniques can at least be validated against appropriate reference materials.

Problems due to cross-contamination between samples and contamination of

equipment can be avoided by exercising an appropriate level of care during sampling

and at the laboratory.

A3.6 The distribution of activity concentrations in a material may span an order of

magnitude or more. In order not to distort the distribution at the low end, the lower

limit of detection (LLD) needs to be sufficiently below the activity level against which

the measurements are being compared. For instance, when a material is being

compared with the 1 Bq/g activity concentration value, an LLD of 0.1 Bq/g would be

appropriate.

ANALYTICAL TECHNIQUES

A3.7 Having defined the main radionuclides of interest and the required

measurement sensitivity, appropriate analytical protocols can be considered. Analysis

techniques for determining activity concentrations of individual radionuclides in solid

materials can be time-consuming and expensive. The techniques employed for a

particular sample therefore need to be chosen judiciously.

Pag e o f 1 25 121

A3.8 For general screening of the total radioactivity it is often adequate to perform

gross alpha–beta counting, applying suitable corrections for self-absorption. It is a

relatively quick and inexpensive technique for determining the total activities of the

alpha emitting and beta emitting radionuclides, from which the ratio of the two can be

obtained. On its own, this technique does not give reliable information on individual

radionuclides. However, the alpha–beta ratio can provide clues as to the radionuclide

composition, which may be useful in deciding upon subsequent analysis steps.

Obviously, if the total activity concentration is less than the activity concentration

criterion for individual radionuclides, then no further analysis is necessary. Counting

times are selected to obtain the required LLD for the materials concerned (i.e. about

10% of the applicable activity concentration level).

A3.9 For analysis of the individual radionuclides of interest, the following analytical

techniques can be applied:

X ray fluorescence (XRF) spectrometry:

o The XRF method is widely used to measure the elemental composition of

materials, and is well suited to the rapid determination of uranium and

thorium. There are two types of spectrometer, both of which can be used

for this application:

Wavelength dispersive spectrometers, in which photons are

separated by diffraction on an analysing crystal before being

detected;

Energy dispersive spectrometers, in which the detector allows the

determination of the energy of the photon when it is detected; these

spectrometers are smaller and cheaper than wavelength dispersive

spectrometers, and the measurement is faster, but the resolution

and detection limit are not as good.

Inductively coupled plasma atomic emission spectroscopy (ICP-AES):

o ICP-AES is used for the chemical analysis of aqueous solutions of rocks

and other materials, and is suitable for the determination of a wide range

of major elements and a limited number of trace elements.

Pag e o f 1 25 122

o Sample preparation involves the digestion of the powdered material with

40% v/v hydrofluoric acid mixed with either perchloric or nitric acid.

Some minerals such as chromite, zircon, rutile and tourmaline will not

completely dissolve using this digestion procedure. For samples containing

substantial amounts of these minerals, XRF analysis is probably more

appropriate.

Inductively coupled plasma mass spectroscopy (ICP-MS):

o ICP-MS is used to determine trace elements in aqueous solutions. The

technique is well suited for determination of uranium and thorium. The

sample preparation procedure is the same as that for ICP-AES.

High energy gamma spectrometry (high purity germanium crystal (HPGe)):

o This technique provides a quantification of the important radionuclide

226Ra, along with 228Ra and 228Th. The method can also be used to

quantify the 238U concentration, but with a higher LLD.

Low energy gamma spectrometry (HPGe):

o This technique entails a relatively short counting time of 4 h, and gives a

quantification of 238U and 210Pb (as well as 235U). It is possible for the

technique to also provide a determination of 226Ra (as well as

radionuclides of lesser interest: 227Ac, 231Pa and 230Th), but with a

higher LLD.

Sample digestion and alpha spectrometry:

o This technique is suitable for quantifying the 210Po concentration. It

involves a relatively long counting time.

The application of the above mentioned techniques is summarized in Table 5.

The minimum sample size needed is in each case about 10 g. When using the first four

techniques, the following conversions from ppm to Bq/g are required:

ThgBq0.004057thoriumppm1

UgBq012348.0uraniumppm1

232

238

A3.11 For material associated with most industrial processes it is adequate to have a

basic analytical infrastructure consisting of XRF in combination with a background

shielded thin-window HPGe gamma spectrometry system. Only in those processes

Pag e o f 1 25 123

where 210

Po is of concern will radiochemical techniques in combination with alpha

spectrometry be required. Although 40

K is unlikely to be of concern (see Section 3.3),

its activity concentration can be determined at no additional cost, especially if both

XRF and gamma spectrometry are used for radionuclide analyses. This may be useful

when 40

K is present in significant concentrations, since it can be used to deduce

information on other radionuclides and to improve the quality assurance of the

measurements.

TABLE 5. ANALYTICAL TECHNIQUES FOR DETERMINING

RADIONUCLIDE ACTIVITY CONCENTRATIONS

Radionuclide Suitable

technique Comment

238U,

232Th

(and 40

K)

XRF,

ICP-AES,

ICP-MS

Sensitivity of 1 ppm uranium or thorium achievable

with any of these techniques (equivalent to about 0.01

Bq/g 238

U and 0.004 Bq/g 232

Th)

226Ra,

228Ra,

228Th

(and 40

K)

High energy

gamma

spectrometry

(i) The presence of uranium may interfere with the

direct determination of 226

Ra

(ii) For indirect determination of 226

Ra, gas-tight

sealing for 3 weeks is needed to ensure equilibrium

with progeny (214

Pb, 214

Bi)

(iii) LLD of 0.1 Bq/g requires equipment that is well

shielded from background radiation

(iv) High sensitivity (>25%) and high resolution HPGe

detectors required

(v) Counting times of a few hours per sample will be

adequate

(vi) High density materials (>2.5 g/cm3) may need

self-absorption corrections

210Pb Low energy

gamma

spectrometry

(vii) Self-absorption corrections required

(viii) LLD of 0.1 Bq/g requires equipment that is

well shielded from background radiation

(ix) Counting times of a few hours per sample will be

adequate

210Po Sample digestion

+ alpha

spectrometry

(x) Microwave acid digestion required

(xi) Validated radiochemical separation techniques

required

(xii) Counting times of a few hours per sample will be

adequate to achieve an LLD of 0.1 Bq/g

Pag e o f 1 25 124

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