Monitored Natural Attenuation as a Remediation Strategy for Nuclear Power Plant Applications Sean...

Monitored Natural Attenuation as a Remediation Strategy for Nuclear Power Plant Applications

Sean Bushart- EPRI

Karen Kim- EPRI

NRC RIC Conference-

Panel on Subsurface Environmental Characterization, Modeling, Monitoring and Remediation

March 11, 2009

2© 2009 Electric Power Research Institute, Inc. All rights reserved.

What is MNA? (From 1999 EPA Directive)

“The term ‘monitored natural attenuation,’ as used in this Directive, refers to the reliance on natural attenuation processes to achieve site-specific remedial objectives within a time frame that is reasonable compared to that offered by other more active methods.”


Implementing MNA as a Remedial Strategy

• MNA is NOT a “do-nothing” or “no action” alternative– Knowledge/science/engineering based remedy– Requires monitoring of the natural attenuation processes

• Incorporates three important factors:– Risk to human health and the environment– Contaminant mobility and/or decay– Time

• Appropriately implemented MNA saves remediation costs


Presentation Overview

• Background: Industry Groundwater Protection Initiative and EPRI Role

• MNA Applications for Non-Radioactive Site Contaminants and for Radioactive Contaminants

• Published EPRI Report on MNA


2002 2013

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

Nuclear Industry Groundwater Events

EPRI Groundwater Protection Projects

June 2007NEI 07-07 Finalized

August 2005

Indian Point 2September 2002

Salem

September 2005

Groundwater Monitoring Guidancefor Nuclear Power Plants

(1011730)

NEI 07-07 Industry Groundwater

Protection Initiative

June 2006

Callaway

November 2007

EPRI Groundwater ProtectionGuidelines for

Nuclear Power Plants(1015118)

September 2005

1st Annual EPRI GroundwaterProtection Workshop

(Decommissioning TechnicalInformation Workshop)

December 2005

1st GroundwaterAssessment

20132008

2009 2010 2011 2012

March 2006

Braidwood

June 2006Industry Groundwater Protection

Initiative Announced

2012

Technology Demonstration:Tritium Separation Pilot Plant

Advanced Technologies for Groundwater Protection

2009 - 2010

Groundwater Data Managementand Modeling Tools

Demonstration at Southern Hatch PlantSeptember 2008

MNA Guidance forNuclear Power Plants

(1016764)

2009

Atmospheric Deposition of Tritium

2010 - 2011

Revision 1EPRI Groundwater Protection Guidelines

2009

Technology Innovation:Soil Vapor Extraction System

Pilot Testing

2007

Groundwater Protection for New Plants


EPRI Task Force for Groundwater Protection

Challenge:Contaminant Characterization

& Mitigation

Challenge:Root Cause Determination

ANT Program:Incorporating lessons learned

to new plant design.

Equipment Reliability Program:Leak integrity improvement.

LLW-RM Program:Tritium Modeling

Groundwater AssessmentsGroundwater Protection

Guidelines

Decommissioning:Capturing experiences

Environment Group:Capturing experiencesGroundwater Modeling

RemediationData Management

Materials Group:Stress corrosion cracking

Leakage mechanism determination

NDE Center:System / Component

Inspection


EPRI Groundwater Protection Guidelines for Nuclear Power Plants (1015118)

Graded Approach– Baseline Program for all users– Toolbox of Elevated Program Elements for increased understanding of site

hydrogeology.

Evaluation of Systems, Structures, Components (SSCs) and Work Practices– Risk of groundwater contamination– Design and condition of SSCs

Understanding Site Hydrogeology and Characteristics– Transport of potential groundwater contamination– Developing Conceptual Site Model

Implementing Groundwater Monitoring Program– Installing and sampling groundwater monitoring wells– Data analysis and management– Review and update of monitoring program over time


Examples of Structures, Systems and Components (SSCs) Evaluated in Utility Groundwater Protection Programs

These SSCs contain radioactive liquids and have the potential to contribute to groundwater contamination

• Outside Storage/Transfer Areas

• Spent Fuel Pool & Transfer Canal

• Underground Piping

• Underground Tanks


Which Radionuclides are Most Important in NPP Ground Water Investigations?

Relative Rank Radionuclide

1 Sr-90

2 Cs-137

3 Co-60

4 H-3

5 Cs-134

6 I-129

7 Ni-63

8 C-14

9 Pu-238

10 Am-241

Reference: EPRI Report 1011730 “Groundwater Monitoring Guidance for Nuclear Power Plants”, 2005

Ranking Based Upon:

•Inventory (PWR)

•Relative Dose

•Solubility

•Ease of Transport Through Soil (Kd)


Original MNA Work:Based upon Biological Decay of Hydrocarbons

• Ex. For USTs containing BTEX (benzene, toluene, ethylbenzene, xylene)

– Benzene will biologically decay under the proper conditions:

C6H6 + 7.5O2 → 6CO2 + 3H2O

(aerobic biodegradation* of benzene)

* Biodegradation... a coupling of an oxidation (electron donor) to a reduction (electron acceptor) to gain energy for the organism


Example: Total BTEX Projection from MNA Site*

Modeled Projected Extentof Plume with

Advection,Dispersion,

and Sorption OnlyBiodegradation Omitted

8/93 7/94 9/95

1,450 ft

3,300 ft

* Reference: AFCEE


MNA Applications for Radionuclides

• DOE:– Sandia Labs: A Natural Attenuation Toolbox for Metals and

Radionuclides

– Decision-Making Framework Guide for the Evaluation and Selection of MNA Remedies at DOE Sites

• IAEA:– Applicability of Monitored Natural Attenuation at Radioactively

Contaminated Sites (STI/DOC/010/445, 2006)

• EPA:– 2007: Monitored Natural Attenuation of Inorganic Contaminants in

Ground Water, Volume 1: Technical Basis for Assessment

Radionuclides, particularly those relevant to NPPs, can be good candidates for MNA due to their known half lives and in some cases their biogeochemical behaviors


EPRI Report (1016764) “Technical Guidance for MNA at Nuclear Power Plants”

• Put in Place a Guidance Document Useful to Utility Site Managers

• Need Consistent Utility-Industry Approach

• MNA is Global Across Utilities:

– Media

• Soil-groundwater-surface water-sediments

– Contaminants

• PAHs, NAPL, metals, PCBs, and other inorganics

– Waste Streams

• Oil, combustion by-products, coal tars, transformer oils, solvents

Why a Utility MNA Compendium?


Monitored Natural Attenuation for Nuclear Power Plants

Monitored Natural Attenuation of Chlorinated Solvents, U.S. EPA REMEDIAL TECHNOLOGY FACT SHEET

http://www.clu-in.org/download/remed/chl-solv.pdf

Biological Chemical Volatilization Sorption Dispersion Dilution Radioactive Decay

Guidance for Superfund RCRA/CERCLA Sites:

Hanford Lawrence Livermore Savannah River

ATTENUATION PROCESS

U.S. EPA & DOE

Guidance for Manufactured Gas Plants

EPRI Environment Sector

Technical Guidance for Monitored Natural Attenuation for Nuclear Power Plants

EPRI Nuclear Sector

DOE Implementation

of MNA for Radionuclides

EPA Guidance

Inter-EPRI Collaboration



Includes Guidance on:

• Mechanisms for Migration and Retention of Radionuclides

• Evaluating Site Suitability for MNA

• Remediation Objectives and Site Remediation

• Monitoring Attenuation

• Assessing MNA Progress and the Contingency Plan



Evaluating Site Suitability for MNA• Site conceptual model integrating:

– plant layout

– potential contaminant sources

– site operating history

– site hydrogeology

• Site characterization to evaluate:

– nature and extent of the radioactive contamination in soil and groundwater

– hydrogeological and geochemical features of the site

– a stable or diminishing groundwater plume

• Evaluation of near-site receptors and near-site land and water use



“Triggers” for Assessing MNA Progress

• Are radioactive contamination levels decreasing at rates that meet or exceed predictions?

• Migration of contaminants beyond established plume or compliance boundaries

• Contaminants detected at locations that potentially will pose unacceptable risks to receptors

• Contingency soil and groundwater remediation options should be evaluated

Triggers should be set so as to ensure that seasonal fluctuations or sampling variability do not trigger a contingency unnecessarily


Summary: Monitored Natural Attenuation for Nuclear Power Plants

Benefits of MNA for NPPs

• Effective, technically sound remediation methodology

• Relatively low cost compared to traditional remediation methods (i.e. excavation and soil replacement)

• Does not produce secondary waste

Applications of MNA at NPPs

• Decommissioning

– Yankee Rowe, Connecticut Yankee

• Operating Plants


Conclusions: Implementing MNA as a Remedial Strategy

• MNA is NOT a “do-nothing” or “no action” alternative– Knowledge/science/engineering based remedy– Requires monitoring of the natural attenuation processes

• Incorporates three important factors:– Risk to human health and the environment– Contaminant mobility and/or decay– Time

• Appropriately implemented MNA saves remediation costs


BACKUP SLIDES


EPRI Groundwater Protection/Remediation Guidance and Other Key MNA References

• Technical Guidance for Monitored Natural Attenuation at Nuclear Power Plants 1016764, EPRI, Sep.08

• Groundwater Protection Guidelines for Nuclear Power Plants: Public Edition 1016099, EPRI, Jan. 08

• Groundwater Monitoring Guidance for Nuclear Power Plants 1011730, EPRI, Dec. 05

• EPA 1999. Use of Monitored Natural Attenuation at Superfund, RCRA Corrective Action, and Underground Storage Tank Sites. Directive 9200.4-17P. U.S. Environmental Protection Agency. April 1999

• EPA 2007. Monitored Natural Attenuation of Inorganic Contaminants in Ground Water, Volume 1 – Technical Basis for Assessment. EPA/600/R-07/139. U.S. Environmental Protection Agency. October 2007.

• IAEA 2006. Applicability of Monitored Natural Attenuation at Radioactively Contaminated Sites. International Atomic Energy Agency. Technical Reports Series No. 445.

• Sandia 1999. Site Screening and Technical Guidance for Monitored Natural Attenuation at DOE Sites. SAND99-0464. Sandia National Laboratories. March 1999.

• Technical Protocol for Implementing Intrinsic Remediation with Long-Term Monitoring for Natural Attenuation of Fuel Contamination in Groundwater, Volume I and Volume II. Air Force Center for Environmental Excellence (AFCEE). 1995.

http://my.epri.com/portal/server.pt?Abstract_id=000000000001016764

http://my.epri.com/portal/server.pt?Abstract_id=000000000001011730


Monitoring MNA Biogeochemistry(for advanced investigations)

Reference: USEPA: Site Characterization for MNA of Radionuclides in Ground Water

Dominant Terminal Electron Accepting ProcessDominant Terminal Electron Accepting ProcessDominant Terminal Electron Accepting ProcessDominant Terminal Electron Accepting Process

+10+10+10+10

0000

-10-10-10-10

Electron AcceptorsElectron AcceptorsElectron AcceptorsElectron Acceptors

pEpE

AerobicRespiration

AerobicRespiration

O2O2

OrganicsOrganics

O2O2

SO4-SO4-

SulfateReduction

SulfateReduction

SO4-SO4-

H2SH2S

MethanogenesisMethanogenesis

CO2CO2

CH4CH4

H2H2

DenitrificationDenitrificationDenitrificationDenitrification

NONO33--NONO33--

NONO33--NONO33--

Iron (III)ReductionIron (III)

Reduction

Fe (III)Fe (III)

Fe (II)Fe (II)

Chemical SpeciesChemical SpeciesChemical SpeciesChemical Species

Eq

uiv

alen

tsE

qu

ival

ents

Eq

uiv

alen

tsE

qu

ival

ents

MNA BiogeochemistryMNA BiogeochemistryMNA BiogeochemistryMNA Biogeochemistry

PCE/TCE

Mn (IV)

Cr (VI)U (VI)

Reference: DOE LBNL VIMSS Institute


Together…Shaping the Future of Electricity

Monitored Natural Attenuation as a Remediation Strategy for Nuclear Power Plant Applications Sean...

Documents

Transcript of Monitored Natural Attenuation as a Remediation Strategy for Nuclear Power Plant Applications Sean...