ROADM NUGENAIA Roadmap P2013 - SNETP

ROADMAPNUGENIA Roadmap 2013

NUGENIA Roadmap 2013

Table of Content

Foreword by the president 5

Executive summary 7

I. Introduction to NUGENIA 8

I.1. History and objectives 8I.2. Technical areas and high level objectives 9I.3. Organisation and responsibilities 10I.4. Role of technical area leaders 10I.5. Members 11I.6. End Users 11

II. NUGENIA Processes 13

II.1. Membership application procedure 13II.2. Administration 13II.3. Project Management 13II.4. Knowledge and information management 14II.5. External relations and communication 14II.6. Road-mapping and prioritisation processes 14

III. Technical area objectives and challenges 16

III.1. Technical Area 1 (TA1), Plant safety and risk assessment 16III.2. Technical Area 2 (TA2), Severe accidents 21III.3. Technical Area 3 (TA3), Improved Reactor Operation 26III.4. Technical Area 4 (TA4), Integrity assessment of Systems, Structures and Components 31III.5. Technical Area 5 (TA5) Fuel Development, Waste and Spent Fuel Management

and Decommissioning 38III.6. Technical Area 6 (TA6), Innovative LWR design and technology 42III.7. Technical Area 7 (TA7), Harmonisation 46III.8. Technical Area 8 (TA8) In-service Inspection and Non Destructive Examination 48

IV. Prioritisation of area challenges along main objectives 51

IV.1. Main initial objectives 51IV.2. Limitations of the prioritisation exercise and future directions 52

List of contributors 55

List of acronyms 55


3

FOREWORD

Foreword by thepresident

Since its official establishment in 2011,NUGENIA has achieved very importantsteps towards the consolidation of itsstructure, the clarification of its vision, the deployment of its strategy and last

but not least the increasing of its visibility and the strengthening of its position. The mainaccomplishments are summarised as follows:

• NUGENIA highly qualified experts havebeen organised and structured in technicalareas to develop, short, mid and long termscientific challenges.

• Expert groups of NUGENIA members havebeen active in elaborating an R&D roadmapwhich contributed to the updating of the 2013SNETP Strategic Research Innovation Agenda(SRIA), and is the basis of this document.

• NUGENIA’s ExCom and its secretariat havebeen active in defining a project creationprocess aimed at the identification of themost promising research ideas to be shared,discussed within the NUGENIA communityand elaborated into proposals endorsed fortheir high quality level.

• NUGENIA community has contributedsignificantly in the building of a commonprioritisation process based on high levelpriorities which are aligned with the existingproposals expressed in the full roadmap;this prioritisation process contributed to theroadmap coherency and highlighted themain initial objectives of NUGENIA.

• NUGENIA is now a reality, thanks to theeffort of all members but especially theExCom, Technical areas and the secretariatmembers who are taking care of the dailyactivities on a voluntary basis.

Its ambitious character will continue to drive itsprogress to become the reference associationconcerning R&D on Gen II and III. The road is clearahead of us, allowing NUGENIA to play it’sexpected role in the co-programming of Gen II andIII Nuclear R&D of public-public and public-privateinterest aimed at ensuring the safe and efficientlong term operation of the existing NPPs,recognised as a sustainable and valuablecontribution to the energy mix scenario underconsideration in Europe and worldwide.

NUGENIA, based on the long standing expertise ofits members, will have to play a significant role inharmonising the knowledge concerning safetyculture, increasing the awareness of the public,facilitating the education of the young generationof future experts and more importantly integratingthe European R&D in the field of Gen and III.

In addition to its own activities, NUGENIA will besupported by the new project NUGENIA+ partlyfunded by the European Commission, DG RTDunder Euratom-FP7, expected to kick off in October2013, with the aim to strengthen our position andenlarge our ability to provide technical andscientific solutions based on collaborative R&D.

J.P. West, President


5

SUMMARY

Executivesummary

This publication - NUGENIA roadmap,challenges and priorities - has beenproduced to provide a single reference

document for NUGENIA members and the widernuclear generation II and III R&D community inEurope and around the World.

NUGENIA was established on the 14thNovember 2011 and now includes and embracesthe technical objectives of all the EU Generation IIand II R&D networks (NULIFE, Gen II/III TWG,SARNET, ENIQ) under the umbrella of SNETP (theSustainable Nuclear Energy Technology Platform).In less than 2 years it has defined a clear technicalstructure for generation II and III research,developed a detailed technical roadmap based on6 technical areas and 2 cross cutting areas:

Technical area leaders (TAL) and sub area leaders(SAL) are appointed for each area. In addition, TheExCom has appointed a coordinator to ensurecompleteness and coherency between topic areas.The full roadmap allows for the identification of keychallenges and major technical issues.

NUGENIA has identified high level objectives inorder to help the prioritisation of the main R&Dissues, these also help in initiating, following andvalorising projects related to each of the areas aswell as identifying possible cross-cutting topics:

� Improve safety in operation and by design,� Reach high reliability and optimised

functionality of systems,� Reach high reliability of components,� Improve modelling of phenomena in NPPs,� Increase public awareness,� Efficiently integrate NPPs in the energy mix,� Prepare the future to avoid technology

obsolescence, and seek for innovation,� Manage performance and ageing of NPPs

for long term operation.

NUGENIA has developed an organisation andstructure which supports these objectives and allowsall members to participate yearly through GeneralAssembly and the various technical Fora. Dailyorganisation and management are carried out bythe Executive Committee (ExCom) and Secretariat.

In order to maintain the efficiency andeffectiveness of NUGENIA, the ExCom hasdeveloped a set of rules and procedures coveringall aspects of its operation from membershipapplications, through to administration andfinancial processes, to an online project creationprocess and innovation platform (NOIP). Projectperformance and progress will be monitored andsupported throughout by the ExCom and fullypublic reports will be published and made availableon the knowledge management platform currentlybeing developed. NUGENIA also manages awebsite for member and public communication.

This document provides a summary of the 8 technical area roadmaps detailing the technicalchallenges for today and for the future. It alsolaunches the list of prioritised cross – cuttingchallenges to meet the objectives of NUGENIA - tocoordinate and support R&D for the safe andefficient operation of Gen II and development ofGeneration III NPPs in Europe and beyond.


7

INTROD

I.1.History and objectives

UGENIA (“NUclear GENeration II & IIIAssociation”), an international non-profit-making association according to Belgian

law, was established on 14th November, 2011 tobecome the unique framework for collaborativeR&D in the scope of Generation II & III nuclearsystems. The main mission of NUGENIA is to be theintegrated framework for programmingcollaborative R&D between industry (e.g.manufacturers, vendors, utilities, small and mediumenterprises), research organisations (e.g.universities, national research centres, technicalsafety organisations) and member states publicbodies (see Figure 1). All collaborative R&D iscarried out in order to enhance the safety, reliabilityand competitiveness of Generation II and III nuclearpower plants in Europe and around the world.

Figure 1: NUGENIA based membership.

NUGENIA is one of the “three pillars” ofSustainable Nuclear Energy Technology Platform(SNETP), as shown in Figure 2, these are:

1. Current technology and its evolution(Generation II & III),

2. Future technology (Generation IV, FastBreeder Reactors),

3. Cogeneration of power and heat.

Figure 2: The Position of NUGENIA as one of the threepillars of SNETP.

SNETP mandates NUGENIA to act as the body incharge of coordinating at EU level theimplementation of the R&D within this technicalscope. Under this mandate NUGENIA isresponsible for the following activities:

• Define detailed roadmaps and R&Dpriorities,

• Facilitate the emergence of projectsimplementing R&D in the field of Gen II & III,

• Identify all relevant funding sources for GenII & III R&D,

• Generally promote European nuclear Gen II& III collaborative R&D,

• Facilitate cooperation with internationalcounterparts on Gen II & III R&D.

The mandate under the umbrella of SNETP givesNUGENIA rights as well as obligations: NUGENIAis acting as the driving force to represent the GenII/III pillar of SNETP and is supported by SNETP tofacilitate the dialogue with high level stakeholdersand forums (such as ENEF, ENSREG, and otherTechnology Platforms). On the other side,

I. Introductionto NUGENIA

8

DUCTION

NUGENIA periodically reports to the managementbodies of SNETP, including brief reports on projectslaunched under its umbrella. NUGENIA contributesto the production and updating of SNETP’s strategicdocuments and acknowledges SNETP in its publiccommunication.

Since its creation NUGENIA has been successful inintegrating several European Networks ofExcellence such as NULIFE on Plant Life Prediction,SARNET on Severe Accident and ENIQ theEuropean Network on Inspection and Qualificationand the SNETP GenII/III TWG. It gathers togetherthe major European nuclear stakeholders withmembers from the industry, utilities, researchinstitutions, SMEs, universities and technical safetyorganisations.

To summarise the historical emergence ofNUGENIA, the following steps have beensuccessfully achieved:

2006-2010: the building blocks in Europe• Development of several Europeans networks

addressing different aspects of Gen II & IIIresearch: FP6-NULIFE, FP6/FP7-SARNET,SNETP Gen II/III TWG… that achievedinternational reputation and recognition.

2011: the consolidation process

• March: First joint meeting of SNETP TWG GenII&III, NULIFE and MMOTION.

• March: SNETP Governing Board supports fullintegration between TWG Gen II& IIIand NULIFE.

• November: Legal establishment ofNUGENIA with 7 initial members.

2012: the birth of NUGENIA

• February: ENIQ supports the joint integrationwith NUGENIA.

• March: SARNET supports the joint integrationwith NUGENIA.

• March: Official launch and First GeneralAssembly.

• March: Signature of mandate from SNETP toNUGENIA.

• March: First NUGENIA Plenary meeting.• April: NUGENIA reaches its 50th member.

2013: NUGENIA is a reality

• February: Publication of the first NUGENIAvision within the SNETP SRIA.

• February: Identification of emerging projectideas.

• March: Consolidation of the first NUGENIAproject portfolio.

• March: second NUGENIA General Assemblyand election of a new ExCom.

• March: second annual NUGENIA FORUM.• April: Launch of NUGENIA Open Innovation

Platform (NOIP).• June: Identification of cross-cutting issues

between different technical areas.• September: publication of the NUGENIA

roadmap.

I.2.Technical areas and high level objectives

oining forces to reach scientific and technicalexcellence is the main value of NUGENIA. Inorder to bring to all members the best available

competences, facilities and technologies, the workof NUGENIA is organised along the main stakesinto eight Technical Areas (TAs):

1. Plant safety and risk assessment,2. Severe accidents,3. Improved Reactor Operation,4. Integrity assessment of systems, structures

and components,5. Fuel Development, Waste and Spent Fuel

Management and Decommissioning,6. Innovative LWR design and technology,7. Harmonisation,8. In-service Inspection and Non Destructive

Examination.

The main challenges related to each of thesetechnical areas are described in Chapter III. Severaltechnical domains are interconnected with morethan one area; in particular area 7 and 8 are crosscutting areas over all other areas; for clarity of thedocument, the inter connections and cross cuttingaspects are not described but they are consideredwith great attention in the daily work. High levelobjectives are described in chapter IV, and are


9

INTROD

defined as the most important topics to which eachof the technical areas should significantly contribute.Both these are key inputs to the prioritisationprocedure described in Chapter II and IV.

I.3.Organisation and responsibilities

or its legal creation, NUGENIA has adopteda general status according to the requirementof the Belgian law which are supplemented by

internal rules that define the way that each of itsconstitutive body interact with each other.

The NUGENIA Association is represented by thePresident and Vice-president. The roles ofNUGENIA decision making bodies, namely theGeneral Assembly and the Executive Committee arepresented in the scheme below and can bedescribed briefly as follows.

Figure 3: NUGENIA governance

• General Assembly: is the highest decisionmaking body of the Association andapproves the changes to the purpose, themission, the general policy and the strategyof NUGENIA. The General Assembly iscomposed of one legal representative foreach Member. It elects a President, a Vicepresident and the members of the ExecutiveCommittee from among its members for atwo–year period and appoints the membersof the Secretariat. It is also its duty, toappoint business auditors, approve the

annual activity plan and related budgets,approve the annual report of activities,approve the annual accounts, ratify themembership of the Honorary Members,among others. All the decisions arevalidated during its annual meeting hostedon a voluntary basis by one of the members.

• Executive Committee (ExCom): iscomposed of maximum 14 electedindividuals on the basis of 50 % of themembers represent R&D organisations,technical safety organisations or publicbodies and 50 % of the members representthe industry. The Executive Committee isresponsible for the operational managementand administration of NUGENIA, by:� proposing and implementing internal rules, � producing the annual activity plan and

related budget,� taking operational decisions to follow and

implement the activity plans and strategy,� implementing the decisions taken by the

General Assembly, � coordinating the evaluation, planning

and monitoring of the endorsed R&Dprojects.

The Executive Committee is supported in its tasksby the Secretariat for the daily administration ofNUGENIA.

I.4.Role of technical area leaders

ach Technical Area (TA) is coordinated by anexpert appointed by the Executive Committee.This TA leader (TAL) is mandated to:

• Develop with the help of sub-area leaders(SAL) and all the members the content of thetechnical and scientific roadmap,highlighting the common understandings,the gaps and the challenges.

• Review, with the help of SALs, the projectideas submitted by NUGENIA members.

• Communicate with other TA leaders oncross-cutting issues and projects.

• Report to ExCom on status on each areaand associated projects.

10

DUCTION

In order to strengthen the coherency between theareas, a coordinator has been appointed by theExCom to fulfil the following tasks:

• Harmonising TAs approaches through TALsperiodic meetings.

• Development of the cross-cuttingchallenges facing NUGENIA.

• Assuring homogenous position on focusedtechnical topics throughout TAs.

• Representing NUGENIA technical arealeaders where relevant.

• Report to the ExCom at least twice a year.

I.5.Members

UGENIA has 2 types of membershipcategories - Full members and honorarymembers.

All members shall comply with the applicable laws,the NUGENIA Statutes, the NUGENIA internal rulesand decisions taken by the General Assembly andthe elected Executive Committee.

Full membersAny legal entity having expertise in the nuclear fieldcan apply for membership and becomes a memberif it is accepted by the ExCom.

1. Industry (non-SME)a. Utility b. Vendor, supplier, engineering / construction

company, other industrial companyc. Service companyd. Energy-intensive industry

2. R&D organisation a. Research & technology organisation b. Academiac. TSO: technical safety organisation (based

on ETSON definition)

3. SME: small and medium enterprises (basedon European Commission definition)

4. Public authorities (Safety authority, Ministry,National agency, ...)

5. Others are considered cases by case.

Honorary members Groupings such as: joint research centres of theEuropean commission, consortia, standardisationbodies, associations, networks, clusters, platforms,federations, organisations with particular statussuch as NGO’s, may apply to become honorarymembers of the association.

The status of a NUGENIA honorary member shallallow having access to the same flow of informationwithin NUGENIA as a full member, especiallyregarding the road mapping, setting up of prioritiesand monitoring the project creation process withinthe open innovation platform. The honorarymember is invited to participate in the generalassembly as an observer.

I.6.End Users

he primarily end users of the results obtainedfrom the NUGENIA endorsed projects are itsmembers. In addition and in order to facilitate

the harmonisation of knowledge on one hand andto take into account the needs of the society,market, economy and policy, on the other hand,NUGENIA has been establishing a global strategyfor collaborating with various European andinternational active groups such as FORATOM,IAEA, OECD, KIC-inno-energy etc. The interactionbetween NUGENIA and the end users is based onthe following principles:

For each user, NUGENIA undertakes to assume thegeneral responsibility with regard to:

• Organisation of periodical disseminationmeetings to share privileged information onthe submitted proposals and workperformed in on-going projects of theNUGENIA portfolio.

• Organisation of information exchanges(including topical meetings, web-communication etc.) between the end usersand the consortium of a specific projectupon bilateral agreement.


11

12

Each end user is invited to: • Be informed on the project’s objectives,

progress and success indicators,• Provide recommendations to NUGENIA and

its projects,• Provide R&D input to a specific NUGENIA

project from separately funded initiativesand finance additional R&D work theyconsider useful to expand a project scope.

It shall be noted that, to ensure the protection of theintellectual property rights of each of its members,NUGENIA encourages the establishment of aconsortium agreement between the active partnersof each project. This would ensure the possibility ofany user (member or non member of NUGENIA) tocollaborate under separate agreement with eachproject consortium.

13


PROCESSES

he management of an internationalassociation needs clear and transparentrules and procedures to ensure traceabilityof decisions and engagements.

II.1.Membership application procedure

o become a NUGENIA member, theauthorised representative of the interestedorganisation has to apply online. Thereafter,

details on the organisation should be provided aswell as the contact details of the authorisedrepresentative(s) and administrative/financialcontact persons. The NUGENIA ExecutiveCommittee examines the application and informsthe contact person of the decision.

To become officially a NUGENIA Honorarymember, the organisation or the person has to beinvited by the Executive Committee and ratified bythe NUGENIA General Assembly.

Each member is invited to appoint technicalrepresentative(s) for each technical area of interestto his activities.

II.2. Administration

he NUGENIA Secretariat manages the day-to-day back-office of the association. Thesecretariat appointed representatives to

interact with various external services, providers or

public authorities (lawyers, accountants, auditors,tax administration, bank representatives), followingwell established procedures decided by the ExCom.

II.3. Project Management

UGENIA manages for its members an openinnovation platform (NOIP) that is a webbased interactive working platform with the

aim to increase visibility, support transparency andassure the traceability of new R&D projects ideas.

Any member registered in NOIP, can submit an ideaby using the so-called “Template 1“ form. Thetechnical area (TAL) and sub-area (SAL) leadersthen review and evaluate this idea and providefeedback to the proposer.

The main points to be reviewed and evaluatedbefore the publication of the project idea underTemplate 1 to the NUGENIA community are thefollowing:

• Coherency with the priorities of the roadmap(according to its latest status).

• Quality of the proposal: scientific/technicalchallenges.

• Impact of the proposal: on NUGENIAcommunity and on the harmonisation ofknowledge.

Upon approval of the proposal, any member mayexpress its interest in participating/contributing tothe proposed project idea and/or provide technicalcomments.

This feedback in hand, the idea can be developedfurther into a project proposal description, includingits budget and partners, allowing the submission ofthe so called “Template 2” form, to be reviewed bythe corresponding technical area(s) representativesin order to evaluate:

• The Quality of the consortium in term ofcompetences and the facilities identified forthe accomplishment of the proposalobjectives.

• The pertinence of the deliverables to bemonitored by the appointed member of theExCom.

II. NUGENIAProcesses

NUGENIA 14

Depending on the readiness level of the projectproposal the NUGENIA Executive Committeeprovides recommendations, including guidance onpossible funding sources, if necessary. Mostimportantly, the ExCom decides on the attributionof NUGENIA label, the guarantee of a high-levelquality research proposal and a clear sign forpotential private and public funders.

Each labelled project will be attributed an ExComcontact with the role to assist in the projectmonitoring and to valorise its results by enhancingthe visibility through publications, credibility throughthe scientific and technical quality of thepublications and sustainability through thestrengthening of existing networks and building newones.

II.4.Knowledge andinformation management

ll documents related to NUGENIAadministration and management meetingsare available on the NUGENIA collaborative

platform (Members area).

A NUGENIA library (Knowledge ManagementPlatform) is under development to facilitate thesharing and transfer of scientific data resulting fromthe research work within the NUGENIA projectportfolio via databases, reports and other suitablemeans.

It will contain a public section for full public reportsand a restricted area for storage of reports that arereserved to NUGENIA members and/or consortiarunning projects within the NUGENIA projectportfolio.

The scientific output resulting from R&D projects willbe stored and managed within specific databases,such as STRESA (JRC database for data from severeaccident experiments), based on mutualagreements between the result owner(s) and thedatabase administrators and respecting the clausesof the agreement of each consortium. It isunderstood that the intellectual propriety rights shallbe dealt with at the level of each projectconsortium.

II.5.External relations and communication

UGENIA uses modern communicationtools to inform its members about itsactivities.

For public communication, the NUGENIA website(www.nugenia.org), delivery of quarterly onlineNewsletters and other public communications(PowerPoint presentations, brochures, posters,articles in focused publications, press releases etc.).

For internal communication, the NOIP offers acontinuous track of all projects under development.The secured Members area contains documentsrelated to the on-going activities of NUGENIAbodies.

In addition, the Annual Forum provides theopportunity for member’s management andtechnical representatives to share views on R&Dmatters.

II.6.Road-mapping and prioritisation processes

traight after the foundation of NUGENIA, theTA leaders in close collaboration with expertsfrom different member organisations started

considering their common needs to be part of theroadmap for each technical area. The roadmapsare organised to contain the objectives of each TA,based on the state-of-the-art, allowing theidentification of the main consensual challenges forthe future accompanied with R&D needs.

After the Fukushima-Daiichi accident SNETPdecided to revise its Strategic Research Agenda(SRA) to take account of the lessons learned andthe initiatives taken from re-viewing the safety ofpresent and future LWRs. NUGENIA has thereforeissued comprehensive summaries of each TAroadmap for the revision of the “Strategic Researchand Innovation Agenda (SRIA)” of SNETP, which waspublished in February 2013.

Following its second Forum (March 2013),NUGENIA decided to consolidate its detailedroadmap and to issue a condensed version,

Processes 15


aligned with the published part of SRIA, with thegoal to harmonise its objectives, to clarify itschallenges and to prioritise its R&D needs in aconsensual manner. For this purpose, each TAleader has initiated focused discussions with theappropriate experts from member organisations todefine their interests and the national/internationalframework in which the defined activities are beingpursued. Thus, the technical experts identified thegaps in their technical field of competenceintegrating the knowledge gained through nationaland international programmes and seekingcommon interest. This bottom-up exercise allowedan almost exhaustive listing of the R&D topics to beconsidered in each technical area.

Subsequently, the ExCom and the TALs haveinitiated a top-down prioritisation exercise, in orderto establish a global vision of NUGENIA overallprogram and to provide high level objectives. Thisexercise improved the consistency andcollaboration between the different TAs andhighlighted cross cutting challenges.

The comparison of both approaches showed thatbottom-up identified challenges are necessary toachieve the high level objectives strengthening thecohesion of the NUGENIA community and thecoherency of the overall methodology, whilstrecognising that the accomplishment of high levelobjectives would need complementary effort inseveral research fields.

TECHNICA

III. Technical areaobjectives and

challenges

This chapter is based primarily on the SNETPSRIA, amended by TALs and SALs to takeinto account the relevance of each topicwhen it comes to ensuring safe and reliable

operation of Gen II and III nuclear power plants,not only existing plants, but also those underconstruction or consideration for the future.

Each TA has been summarised using, as input, thefully developed NUGENIA R&D roadmap that isavailable to all NUGENIA members. The R&Dtopics have been selected in a consensual mannerby the experts and the challenges are those whichneed to be addressed with the widest possiblecollaboration at the international level.

III.1.Technical Area 1 (TA1), Plant safety and risk assessment

III.1.1. Scope

he TA1 is devoted to improving the physicalunderstanding and the numerical modellingof the relevant phenomena involved in

Nuclear Power Plants (NPPs) incidents andaccidents, to increase the capacity andcomprehensiveness of the plant behaviour and toenhance the accuracy of safety margin assessmentaccordingly. The main challenges identified withinthe TA1 are:

• The comprehensive adoption and use of theProbabilistic Safety Assessment (PSA) forunderstanding and pointing out safety risks,including quantitative aspects for risk andmargin evaluation, methodologies to assessshut-down states, and external events,quantification of the risk inherent to spentfuel pool, best practice for probabilisticsafety assessment (PSA) application andappreciation of residual risk.

• The deterministic assessment of plant transients,mainly focussing on the improvement andvalidation of models and tools for planttransient analysis, including reactor physics andthermal hydraulics, design and evaluation ofpassive safety systems, coupled multi-physicssimulations, containment behaviour, and fluid-structure interactions.

• The impact of external loads (includingelectrical disturbances) and other hazardson the safety functions.

• The advanced safety assessmentmethodologies: safety margins and bestestimate methods, integrating thedeterministic and probabilistic safetyassessments.

• The design of new reactor safety systems.

Figure 4: Grohnde power plant (Source: E.ON)

III.1.2. Objectives

n the TA1 roadmap, the above mentioned issuesare addressed either in specifically identified sub-technical area, as it is the case for PSA, the

16

AL AREA 1

impact of external loads and disturbances, theadvanced safety systems and methodologies or incross-cutting topics, as it is the case for humanfactor and organisational issues. The mainobjectives that have been identified are:

III.1.3. State of the art

he R&D activities on safety approach and riskevaluation have relied, for a long-time uponwide support from international organisations,

such as the European Framework Research andDevelopment Programmes (FP), the programs of theOECD working-groups and several others. Themain issues that have been addressed are relatedto the probabilistic and deterministic methods, theimpact of external loads and hazards on the safetyfunctions, the consequences on the safety functionreliability of external electrical disturbances and theadvanced methodologies for safety assessment andtheir harmonisation, for example: the OECDWorking Group-risk, addressing risk assessmentmethodologies, the European FP6 and FP7 seekingfor harmonisation among practices on PSA2 andaddressing man-machine interface and ergonomicaspects. As for the deterministic assessment of planttransients several international and Europeanprograms have been performed or still ongoingeither to address the transient and severe accidentphenomenology, mainly for Light Water Reactors(LWR) assessment methodologies and toimprovement of the computation tools and chains.The impact of external loads and hazards on thesafety functions has been the subject of severalnational and international programs, as well.

However, the proper assessment of safety and risksneeds a continuous effort to reduce the uncertaintiesand gaps in the existing methodologies and validatethem at the appropriate level but also to develop aharmonised safety culture that takes into account thelatest R&D results.

III.1.4. Challenges

III.1.4.1. Data, Methods and Tools for Risk Assessment

As far as the quantitative aspects of the probabilisticsafety assessment (PSA) are concerned, thefollowing major challenges should be addressed:

• Methodologies to quantify initiating eventfrequencies for low probability events withsevere consequences, including externalevents, Common Cause Failures (CCF)events and combination of events (includinginternal and external ones).

• Methods to establish component failure rates- with specific care to components with lowfailure rates and failure due to specific loads(such as loads due to fire, severe accidentconditions…).

• Data and methods to assess CCF insidesystem and among systems.

• Methods to assess human reliability andestablishing a database with reference casesfor assessments of human performance.

• Methods to account for time-dependence inPSA.

• Methods and data to quantify the effects ofaging on PSA-outputs.

• Methods and data to assess the failurefrequencies of digital components.

• Methodology and data for fire PSA.

For the PSA concerning source term issues (level 2PSA), recommendations on the best strategies tocouple level 1 and level 2 PSA should be made,and methodologies to assess shut-down state orexternal events should be developed.

�

R&D topics:

• Developing methodologies and toolsto allow the consideration of severalplants simultaneously affected, notably, inthe case of external events.

• Benchmarking existing PSA-studies tocheck their comparability and supportadoption of risk-aimed approach in plantmanagement.

• Developing guidance for safetyassessments.

• Assessing the risk related to spent fuelpool.


17

TECHNICA

• Developing techniques to model thefunctional dependencies in electrical andsafety instrumented systems.

• Establishing methodologies for level3-PSA (up to health effects) includingintegration with level 2-PSA.

�

Even if advanced PSA tools are widely available andextensively used, it is still extremely important tocheck their correct application in specific RiskInformed Decision Management (RIDM) strategies.If good methodology for development of “basic”PSA is necessary the need of a large practice ofwell-developed and harmonised RIDMmethodology is even more necessary.

III.1.4.2. Deterministic Assessment of Plant Transients

III.1.4.2.1. Improved thermal hydraulics evaluation for the existing plants

Plant behaviour is the result of complex tightlycoupled multidimensional physical phenomena. Inthe assessment of transients, new challenges are nowarising, but recurrent studies still need large efforts.

Figure 5: Safety assessment at Cruas NPP, France(Source: IRSN)

To fulfil the current and new goals, the mainpending challenges in thermal-hydraulics are:

• A better understanding and modelling of themulti-dimensional phenomena, in particularin vessels and pools.

• A better understanding and modelling of themultiphase (steam/water, non-condensablegases etc.) phenomena.

• The interaction with neutronics (in particularin reactivity transients), mechanics (fluid-structure interaction in steam generator forexample), and thermo-mechanics.

• Containment phenomena in dry-well likestratification and heat transfer into thecondensation pool and load assessmentfrom source to loads on walls underdifferent voiding conditions in thecondensation pool with the aim of reducinguncertainties.

• Develop modelling of 2–phase flow in thecore.

�

R&D topics

• Stratification in pools and vessels, inparticular for BWR- condensation poolswhen steam flow is low.

• Mixing in pools and vessels, inparticular at low flow rates, includingvessel pressurised thermal shock andboron mixing in reactor vessels.

• Instability in BWR-cores.

• 3D flows in the reactor pressure vessel(BWR/PWR/VVER).

• Effects of non-condensable gases inpipes for scenarios with gas intrusion.

�

III.1.4.2.2. Design and evaluation of passive safety systems

The major challenge to a generalised adoption ofpassive systems for safety purposes is theachievement of a convenient and exhaustive fullscale demonstration of their reliability in transientconditions.

�

R&D topics

• Provide evidence of the systemreliability despite the approximations andassumptions in the validation experimentsand to clear the way to extrapolation.

�

III.1.4.2.3. Coupled multi-physics simulations

Development of coupled multi-physics simulations isa widely acknowledged need. Such methodologiesare already well advanced, but they require furthereffort to address specific problems such as the re-criticality scenarios and the instability in BWR-cores.

18

AL AREA 1

III.1.4.2.4. Fluid structure interactions�

R&D topics

• Turbulent flows and its effects oncomponent aging.

• Fluid-structure interaction in steam-generator.

• Water hammer assessment.

• Coupling between CFD(Computational Fluid Dynamics) andsystem codes.

• Heat transfer along piping and vesselwalls during turbulent flows.

�

III.1.4.2.5. Fire risk�

R&D topics

• Comprehensive characterisation ofdifferent fire loads.

• Fire suppression models andsuppression technologies.

• Methods and criteria to assessmalfunction of electrical equipmentconsidering combined effects of soot andthermal stress.

�

III.1.4.2.6. Containment behaviour�

R&D topics

• Non condensable gas flows in thecontainment with and without spraying.

• Heat transfer in the gas phase of thecontainment including the interaction withwalls and pipes leak rates throughcontainment up to containment break.

• Clogging phenomena in strainers andfuel and associated assessmentmethodology.

• Fire and gas explosion simulationmethods and applications to reactor safety.

�

III.1.4.3. Impact of External Loads and Hazards

The external events have to be characterised byloads and frequency as well as by the risk for co-incident occurrences and the effects on non-safetysystems on the safety system. The potential forsuccessful preventive and mitigating human actionshas to be considered.

�

R&D topics

• Methods for frequency/magnitudeassessment for events with short and longreturn periods (from 100 to more than1000 years) need to be further developedin view of the major uncertaintiesinvolved. Estimates of the effects ofclimate change also indicate substantialimpacts on the frequency and magnitudeof certain natural external events. even inthe near future, which needs to beconsidered in the analysis of externalevents.

• Methods and methodologies toidentify single and multiple externalevents are also necessary to assess effectson a multi-unit plant, as well as how theeffects of external events on non-safetysystems could affect safety systems.

�

III.1.4.4. Effect of Electrical Grid Disturbanceson the safety functions

�

R&D topics

• Grid disturbance effects on the plantthrough the internal electrical buses andother electrical components important tosafety. It includes assessment of theeffects originating either from lightning orfrom motor magnetic fields on modernelectronics and/or digital equipmentwhich are far more sensitive to magneticfields than components used in the past.Other equipments like plant electrical andInstrumentation and Control (I&C)equipment, or diesel generators foremergency power may be also affected.

• The design of plant control andprotection systems has to be based on anincreased understanding of these effectsand the sources of these effects have to beinvestigated.

�

III.1.4.5. Effects of Human Errors and Reliability Evaluation

Typically, deterministic assessment relies onautomatic functions in short term (30 minutes).Human is supposed to handle actions where moretime is available for decisions. Human interactionsin short term will anyhow have impact on scenariodevelopments.


19

TECHNICA 20

Operators and maintenance actions that are notcovered by procedures are not assessed, neither indeterministic, nor in most of the risk assessmentsperformed so far. Actions are taken to include sucheffects in the risk assessments. Issues related toquantification of risk related to human failures in PSAassessment are the main subject for this sub-area.

More research shall be envisaged to extend the endof cycle (EOC) analysis from the full power to thescenarios where EOC is more possible andimportant, e.g. shutdown situation, fire analysis.

Several methods are developed and applied forassessing human reliability for supporting commonrisk assessments of human performance but thereare still large uncertainties in these assessments.There is also a crucial need to develop detailedhuman reliability assessment (HRA) guidance forspecific applications.

�

R&D topics

• Issuing a guideline for a state of theart HRA for PSA purposes, based onperformed assessments, ensuring thatplant specific properties are properlytaken into account in the HRA.

• Selecting methods should be used fordifferent types of operator actions.

• Collecting human performance datafrom plant near-miss reports,incident/accident reports, digital systemsand simulator exercises. Detailed humanperformance data would helpunderstanding the important PSFs andsufficient human performance data wouldgreatly help in the quantification of thehuman failure events in PSA.

�

III.1.4.6. Advanced Safety Assessment Methodologies

The general challenge in this sub-area is to increaseknowledge about the existing safety margins of aplant. Several methodologies can be furtherdeveloped in order to improve the accuracy ofevaluations. The research will also developcommon understanding on how to use bestestimate methods for safety margin assessments.

�

R&D topics

• Risk informed methodologies, usuallydeveloped by operators, based ondecision-making theory and/or economicmodels can still be improved in order tooptimise the risk accuracy evaluation.

• Harmonised and accepted methods toperform best estimate assessments.

• Safety margins and best estimatemethods by integrating the deterministicand probabilistic safety assessments. Thisincludes development of methodologies(such as Dynamic PSA and Monte-Carloassessments or a combination) to be usedin parallel with existing methods forprobabilistic and deterministic assessments.

�

A challenge for these methods is to bettermodel/predict the dynamic behaviour of the systemincluding also time dependent scenarios withoutaffecting the assessment of uncertainties, which isto remain independent.

Application of these developments should addressbetter evaluation of safety margins for ReactorPressure Vessels (RPV)s, main containment, passivesystem and pipes in case of LOss of CoolantAccident (LOCA) or Pressurized Thermal Shock(PTS) events, but also for beyond design situationsor natural circulation conditions.

III.1.4.7. Design of Reactor Safety Systems

�

R&D topics

• Design of digital system withintegration into existing plants.

• Increased diversification androbustness of safety systems.

• Use of passive system for safetyfunction.

• Methods for reactivity measurementsunder accident conditions.

• Design of level measuring systems towithstand high temperatures.

�

AL AREA 2 21


III.2. Technical Area 2 (TA2), Severe accidents

III.2.1. Scope

he main public safety goal for nuclear poweris to prevent a societal calamity and hugeeconomic loss. With appropriate site risk

evaluations, plant designs and management,current Generation II and future Generation III NPPshow high levels of robustness and low probabilitiesfor severe accidents (SA). But, despite the highlyefficient accident prevention measures adopted forthe current Generation II and the still moredemanding ones for the Generation III plants, someaccident scenarios may, with a low probability,result in SA, as recently emphasized with theFukushima-Daiichi accidents in Japan. This SA canresult in core melting, plant damage and dispersalof radioactive materials outside of the plantcontainment, thus threatening public health and theenvironment.

This risk can be substantially decreased when state-of-the-art devices currently available for preventionand mitigation of severe accidents are installed.Lessons from the Fukushima-Daiichi accidents andconsequences related to Accident Managementprovisions from the recently completed ENSREG(European Nuclear Safety Regulators Group) stresstests and other national activities will lead to furtherenhancement of the safety of NPPs.

Figure 6: Phenomenology of severe accidents in areactor (Source: IRSN)

III.2.2. Objectives

ome predominant phenomena require abetter understanding in particular to improveSevere Accident Management Guidelines

(SAMGs) and to design new prevention devices orsystems for mitigation of SA consequences.

Seven sub-technical areas address the topics listedhere below, among which, topics 1 to 3 are directlylinked to mitigation processes, topics 4 to 6 to theassessment of the impact of the transients on theenvironment, and the last one to their managementand prevention. The main objectives that have beenidentified are:

New experimental efforts will be needed in mostsub-areas accompanied by modelling developmentand validation. The knowledge gained and themodelling improvements will allow the optimisationof SAMGs and the improvement of prevention andmitigation systems such as core reflooding systems,filtering systems, venting systems or recombiners inthe containment.


onsiderable knowledge has been gainedabout SA phenomenology through studiescarried out during the last 30 years. It is

based on experimentation, mostly out-of-pile, witha few in-pile programmes like Phebus, andtheoretical simulations, as the accidents at ThreeMiles Island (TMI2) in 1979 and at Chernobyl in1986 were the only major NPP reference cases untilthe Fukushima-Daiichi accident.

Since 2004, the state of the art is periodicallyupdated in the frame of the SARNET network(Severe Accident Research NETwork of Excellence),(see www.sar-net.eu). In particular, the ranking ofR&D priorities has been recently reviewed to takeinto account early feedback from the Fukushima-Daiichi accident. The identified challenges accountalso for the results of all past and on-goinginternational programmes (Euratom-FP7,OECD/NEA , ISTC/STCU …).

TECHNICA 22

III.2.4. Challenges

he highest priority safety challenges aredescribed in the following sub-areas: In-vesselcorium/debris coolability, Ex-vessel corium

interactions and coolability, Containment behaviourincluding hydrogen explosion risk, Source term, SAimpact on the environment, emergency andpreparedness management. One transversal sub-area concerns the SA scenarios.

III.2.4.1. In-vessel corium/debris coolability

Substantial knowledge exists concerning cooling ofintact rod-like core geometry. The main challengefor long term R&D will be to address the remaininguncertainties concerning the efficiency of cooling adegraded reactor core, with presence of coriumand/or solid debris, by water addition to limit orterminate the SA in-vessel progression.

The impact of the further analysis of the Fukushimaaccident will be taken into account, and,conversely, R&D will be important for the plantsdecommissioning.

�

R&D topics

• Debris bed formation and cooling; forin-vessel melt retention, corium poolcoolability in the reactor pressure vessel(RPV) lower head, especially for BWRswith presence of control rod andinstrumentation guide tubes; critical heatflux and RPV external cooling conditions.

�

III.2.4.2. Ex-vessel corium interactions and coolability

For ex-vessel corium situations after vessel lowerhead failure, the major safety challenge is topreserve containment integrity against rapid failure(steam explosions, Direct Containment Heating orDCH) or slower basement melt-through (by Molten-Core-Concrete-Interaction or MCCI) and/orcontainment over-pressurization.

�

R&D topics

• Fuel-water premixing and debrisformation and coolability; complementaryMCCI research to cover oxide-metal layerinteraction and all reactor concretecompositions; assessment of MCCI topflooding; and finally analytical work totranspose MCCI experiments to reactorscale.

• Reduce uncertainties in assessment ofsteam explosions.

�

III.2.4.3. Containment behaviour, including hydrogen explosion risk

The containment represents the ultimate barrier toprevent or limit the release of fission products to theenvironment during a SA. If local concentrations ofcombustible gases (hydrogen and carbonmonoxide) are present, gas combustion mightoccur and cause a pressure increase that couldeventually lead to containment failure.

Efforts in the short and mid-term should focus onextensive simulations of gas distribution in thepresence of mitigation systems using both Lumped-Parameter and CFD (Computational FluidDynamics) codes in order to interpret a whole setof different experiments with consistent models.More reliable models of deflagration anddeflagration-to-detonation transition should bedeveloped in order to improve the presentmodelling mainly based on empirical correlations.

�

R&D topics

• Containment atmosphere mixing(including BWR containments withnitrogen atmosphere) and gascombustion, which imply the followingphenomena: gas distribution in thecontainment with the influence ofmitigation systems, pressure increaseduring hydrogen combustion, anddeflagration to detonation transition.Scaling (qualitative and quantitative) ofphenomena from experimental facilitiesto actual containments should also beaddressed with priority.

�

III.2.4.4. Source term

The source term to the environment refers to theamount, chemical speciation and isotopicspeciation of all radio-elements that can bereleased to the environment. At present, theincreased safety requirements in both existing plantsand new designs aim at reducing the source termby proper measures for limitation of uncontrolledleaks from the containment and for improvement ofthe filtering efficiency of containment ventingsystems. The Fukushima accident underlined the

AL AREA 2 23


need for studying the impact on the source term ofthe filtered containment venting systems which areimportant radionuclide-removal processes.

�

R&D topics

• Impact of filtered containment ventingsystems on source term and developmentof improved devices; oxidizingenvironment impact on FP release fromfuel, in particular for ruthenium, i.e.under oxidation conditions or air ingressfor high burn-up and MOX fuels; hightemperature chemistry impact on FPbehaviour in the Reactor Cooling System(RCS), i.e. improving predictability ofiodine and ruthenium species exiting RCStowards the containment; containmentchemistry impact on source term, i.e.improving the predictability of iodine andruthenium chemistry in the containment.

�

Figure 7: Phebus.FP degraded bundles for real sourceterm (Source: IRSN)

III.2.4.5. Impact of severe accidents on the environment

The SA impact on the environment in the near-fieldaround the NPP must be assessed as part of theEnvironmental Impact Assessment (EIA) of a NPP inaccordance with European and national legislation.Here only the atmospheric dispersion of radio-nuclides is addressed. This will allow an interfacebetween PSA Level 2 and assessment ofradiological consequences and it will improve theemergency planning and zoning and the post-accidental situation management.

Strong links should be established in the future withthe NERIS platform (European Platform onPreparedness for Nuclear and RadiologicalEmergency Response and Recovery: see www.eu-neris.net).

�

R&D topics

• Accurate atmospheric dispersionmodels, in particular accounting forchemistry of radio-elements (integratingon-site experiments and use anddevelopment of specific CFD models);adaptation and development of“ensemble computations” (i.e. variationsof calculations for different initial weatherdata) for atmospheric dispersion of radio-elements from NPP.

• Effect of using different ventingstrategies in severe accident. Betterunderstand and quantify leakages fromthe containment and its dependence onpressure, humidity and temperature. Thisshould also include an increasedunderstanding of the containmentintegrity, which is related to topics in TA 4.

�

III.2.4.6. Severe accident scenarios

Integral codes (or system codes) are essential forsimulating all SA scenarios including the evaluationof the source term into the environment, as well asthe evaluation of SAM measures and the efficiencyof mitigation systems. The highest priority is tocontinue to capitalise knowledge inside these codes,particularly the ASTEC code (IRSN-GRS) consideredas the European reference tool, and to feedback theinterpretation of the Fukushima accident in thecoming years. Attention should be paid in particularto models of BWR core degradation and to theirvalidation.

In addition, the Fukushima accident has underlinedthe importance of the modelling of the behaviourof spent fuel pools in case of loss of cooling. Thecriticality risks in case of spent fuel pool dry-out orof damaged NPP core should also be assessed.

Another essential issue is the need to store inreliable and durable databanks the results of thehuge amount of SA experiments that wereperformed over more than 30 years. They shouldremain available for any further analysis of SAphenomena and for validation of simulation codes.

�

R&D topics

• Continuous capitalisation ofknowledge in the integral codes,particularly ASTEC, and improvement oftheir applicability to spent fuel pools. Thelatter will need further R&D on thefollowing phenomena: large-scale flowconvection, impact of partial dewatering

TECHNICA 24

of fuel assemblies on thermal runawayand fuel degradation, clad and fuelmechanical behaviour in air-steamatmosphere.

�

III.2.4.7. Emergency prparedness and response

In the emergency preparedness and response area,an accidental sequence can be roughly brokendown into two phases: the emergency phase(composed of a threat phase and a release phase)and the post-accidental phase.

In the threat phase, the objective of the emergencymanagement is to analyse the behaviour of theplant and to take actions or complementary meansin order to restore control on the heat generation,on the cooling capacity and on the radioactivitycontainment. In a more degraded situation, thisphase requires well established and sharedmethodologies as well as tools to evaluate the timebefore radioactive release, the consequences offurther palliative actions and to mitigate theconsequences of the accident, both for theenvironment and for protection of the populationaround the plant. This requires the availability of

reliable information from the plant, the capacity tooperate correctly under high stress and harmfulconditions, and the availability of efficient andreliable tools. The latter encompass well exercisedinformation systems and emergency organisations,instrumentation, fast computer systems to studymultiple future scenarios, highly trained andcomplementary teams with experts in informatics,reactor physics, reactor operation, meteorologicaldata, and integration of all the different aspects.

In the beginning of the release phase, themeasurement of the radioactivity around the plantis necessary to comfort the diagnosis of the plantaccident scenario and to improve the prognosisconcerning the source term. The management ofthe plant accident can extend a long time, like forthe Fukushima Daichi accident, because actions onthe plant may be required even if the source termemission is started for a long duration already.

The post-accidental phase needs information on thesource term in order to estimate the consequenceson the long term; this is addressed in the NERISproject, so that the scope dealt with in this paragraphincludes also addressing the environment andmaking the bridge between NUGENIA and NERISactivities.

Figure 8: Emergency management phases (Source: IRSN)

AL AREA 2 25


�

R&D topics

• Concerning the threat phase, beyondwell established and testedmethodologies and emergencyorganisations, fast running tools arenecessary to make the diagnosis and theprognosis of the reactor behaviour, underseveral recovery strategies, and toevaluate the time to release and theamount released. If the time to releaseincreases more sophisticated tools mightbe useful.

• Development of fast running tools forsource term evaluation, relying uponaccurate environmental data andbenchmarks with similar codes in use,mainly focussing on an evaluation ofsource term to the atmosphere (by usinginverse atmospheric modelling andcomparisons with the environmentalmeasurements).

• Development and/or improvement ofsuitable instrumentation and informationtransmission tools for SA diagnosis and

management. This instrumentationshould include measurement devices anddata transmission, collection andelaboration tools, as well. Theimplementation of a suitable mobilemeasurement device, able to operate inthe hostile environment of a degradedsite to provide information on the reactorstatus, should also be considered. In suchcircumstances, precision is not the primeobjective: robustness and reliabilityshould be preferred. Accordingly, thedevice should be: quite small; easy tohandle, robust and reliable in suchextreme conditions of radiation,temperature and pressure, activity andhumidity.

• Improvement of organisation-dealingaspects (partly addressed in the STATICproject), e.g. to extend redundancyamong teams without slowing down theengineering capacity, and improvementsof knowledge on human behaviour understress conditions.

�

TECHNICA 26

III.3. Technical Area 3 (TA3), Improved Reactor Operation

III.3.1. Scope

A3 is devoted to improving the technical andeconomical characteristics of reactoroperation by various measures and also to

minimising the radiological impacts on the plantworkers, the environment and general public duringnormal reactor operation (covering also periods ofshut-down, reshuffling, abnormal operationalsituations and emergency states, but excludingsevere accidents).

The various R&D areas have been identifiedsupporting improvement of reactor operation andminimising impacts of its operation, many of thembeing in tight connection and relationship to thetopics addressed primarily in TA1, TA4 and TA5, butalso in other TAs:

• The impact of all key aspects related tohuman behaviour and decisions, andorganisational factors on the safe andsecure operation of the plant, including theinteraction between the control roomoperators and the plant.

• The implementation of innovativeapproaches, measures and tools to improveeconomics of operation of nuclear powerplants (including optimisation of outagesand lifetime management).

• The integration of advanced technologieswhich can support the operators in theirduty, namely the advanced digitalinformation and control technologies.

• The core management as a subject ofongoing R&D activities, since it has directimpact on the economy of the fuel cycle. Itencompasses core and fuel system designrelated calculations and numericalmodelling, evaluation of uncertainties, corereload optimisation and core monitoringand instrumentation.

• The water chemistry influencing corrosionand degradation of components andconsequently their life time.

• The impact of the plant on the environmentand public through minimisation ofemissions to the air, effluents towatercourses and radioactive waste to be

disposed into the appropriate finalrepositories. The minimisation of radiationdose received by plant workers as a balanceof the latest science-based quantification ofimpacts of radiation on human health andeconomic justification of protectionmeasures.

III.3.2. Objectives

safe, efficient and economically-competitiveoperation of the nuclear power plants is theresult of a number of interlinked human,

organisational and technical factors. Owners ofnuclear power plants currently mostly operating inderegulating competitive markets are under pressureto reduce operation cost to be more competitivewith other energy production options. To recoverhuge initial investment cost and to maintainnecessary level of profitability it is reasonable toprolong operation of plants where it is feasible,naturally without compromising safety and security.Along with traditional safety and reliabilityparameters, economic and financial factors areneeded to be taken into account in new perspectivesnowadays that is incomparable with formerregulated markets where utilities provided complexservice with inclusion of all reasonable costs.

Various areas thus can contribute for improvementof reactor and nuclear power plants operation.

Human and Organisational Factors (HOF) are keysubjects of analysis made with the aim to improvesafety, performance and efficiency characteristics ofnuclear power plants operation. After theFukushima accident, the focus of studies on HOFhas been moved towards the importance of thepreparedness for emergency management, butarea of prevention still need to be maintained(safety culture, safety versus efficiency, impact ofautomation etc.).

Implementation of modern digital technologiesoffers a unique opportunity for improvingoperational performance, enhancing nuclear safetyand supporting life extension of NPPs. Althoughsome European plants have gone through relevantmodernisation programs, many interventions stillhave to be performed under the constraint ofminimising the impact of the traditional way ofoperating, maintaining and managing the plant.

Improvements in core management are currentlybased on the continuous updating of the design and

AL AREA 3 27


analysis tools, with the aim of achieving higheraccuracy with well-established uncertaintyevaluation, through a strengthened understandingof the underlying physics and associated modellingrequirements, combined with enhancedcomputational efficiency. This task can be directlytranslated into large challenges in basic nucleardata, neutronics, material science, thermohydraulics, fuel fabrication and fuel storage.Coupling all these aspects (multi-physics) with thehelp of up-to-date advanced software is the driverfor replacing the current systems of codes used forsimulation of processes related to reactor operation.

Water chemistry and LLW management activitieshave the main target in optimisation of chemicalparameters of the primary, secondary and auxiliarycooling systems and in development of the optimumtechnologies for LLW treatment. Water chemistry isactually one of the most powerful tools, theoperators can use to improve the lifetime of plantcomponents and systems. Suitably designed waterchemistry can significantly reduce “randomly”occurred operational problems, including corrosion,erosion, deposition of corrosion products etc.

Radiation protection is a specific area to protectboth human beings and environment againstnegative impact and/or consequences of ionisationradiation. The main goal here is to keep the ALARAprinciples, i.e. to limit the exposure "as low asreasonably achievable".

The above-mentioned topics are addressed withinTA3 in six specifically identified ST-A, addressing, atopic each, as follows:


uring last two decades, the human andorganisational factors community has beensolving various R&D topics in several

international subjects and platforms, for example,in the OECD/NEA Working Group ofOrganisational and Human Factors (WGHOF),IAEA, in international cooperation organised by IFEHalden etc. A new roadmap for the area of humanand organisational factors (HOF) has been recentlydeveloped as a part of the FP7-MMOTION project.It is worth mentioning that HOFs are usually subjectof safety missions and peer reviews thus givinginputs for improvements at nuclear power plants.These improvements are quite frequently typicalwith high worth/cost rate from safety point of view,i.e. relatively inexpensive measures taken in thehuman factor area may lead to fairly significantdecreasing of risk of NPP operation.

Defining a strategy for the implementation of fulldigital systems into the processes of NPP operationcontrol is becoming a more and more urgent issuefor the life extension of the generation II reactors,as well as for the deployment of the Generation III.A various aspects are touched by EPRI, US DoEprogramme and EU projects (for example FP7-HARMONICS).

Core management is divided into four distinctareas: core and fuel system design relatedcalculations and numerical modelling, evaluationof uncertainties, core reload optimisation and coremonitoring and instrumentation. Core designcovers neutron-physical design, thermal-hydraulicdesign and fuel rod and mechanical design. Inengineering practice these topics are yet treatedeither independently or with very simplifiedinterrelated feedbacks. The activities to beenvisaged here are similar to those described inTA1.2 and TA1.6.

The water chemistry topics were the subject of largebasic and applied research programmes in earlieryears. Recently, the most comprehensiveprogramme has been carried out by the EPRI(materialised mainly in the water chemistryguidelines). Radioactive waste managementtechnologies are subject of rather national andengineering companies’ effort than EU projects, thestate-of-the-art in this field is well documented bythe OECD NEA and IAEA. Innovative chemicalmethods and technologies usually used in otherindustries offer big potential for effective use innuclear power plants.

A strong focus put on radiation protection recentlyhas led to the establishment of the MultidisciplinaryEuropean Low Dose Initiative (MELODI) platform,

TECHNICA 28

with the overall aim of consolidating Europeaninitiatives on researching and better understandingthe health effects of man’s exposure to low doseradiation. New approach of ICRP, documented byICRP guidelines 103 and 109, started the new pointof view on designing and application of the limitsfor both personnel and population protection. A lotof activities worldwide (e.g. OECD-HRP) arefocused on virtualisation of real world with addedinformation (“Augmented Reality”) with the goal toserve as tool for optimisation of maintenance andrepairs of equipment in contaminated areas, fortraining of the personnel with the aim to reduceand/or eliminate human failures and, finally, foroptimisation of interventions and radiationmonitoring activities during emergencies.

III.3.4. Challenges

he TA3 encompasses quite variable spherescontributing to improvement of efficient,reliable also safe and secure operation of

nuclear reactors. The following six main challengesand subordinating research areas and topics wereidentified.

III.3.4.1. Improvement of the operation economics

Operators of NPPs are under strong pressure in thecurrent competitive market conditions withsignificant implications for plant operation. Theoptimisation of operation and maintenance costs isa key component of a broader integrated businessplanning process. Asset management and decisionmaking is integral part of the overall operationstrategy.

�

R&D topics

• Optimisation of outages.

• Advanced and integrated approachesto maintenance and lifetime managementof components and systems.

�

III.3.4.2. Human and Organisational Factors

The aspects which are considered as utmost priorityin this field are human reliability analysis,

operational culture and work practices. Importantchallenges are to strengthen the objectivity of safetyjudgments by using methods of risk-orienteddecision making in the human reliability area, toimprove the effectiveness of safety provisions, toharmonise operational principles across Europeand to minimise the negative impacts of complexityon operation and safety. Since organisational safetyculture and operating practices strongly influencethe safety level, new research should help indefining of the conditions required for ensuring therobustness of the organisations in charge ofoperating NPPs, based on a deep understanding ofwork practices and safety culture. It will beparticularly important to consider how individuals,teams and organisations function and interactwithin the plant under a specific safety culture, andhow they are supported by tools, artefacts,procedures, rules etc.

�

R&D topics

• Application of risk informed decisionmaking in human factor area.

• Improvement of safety culture andoperating practices for safety analysis.

• Development of socio-technicalapproach to improve management ofhuman resources under circumstanceswith dynamic features.

• Improvement of training based onsimulation of plant processes.

• Development of tools and methodsfrom collection, acquisition and analysisof human factors related data (plantevents, including low level events andnear misses; data from full scopesimulator exercises).

�

III.3.4.3. Implementation of advanced digital technologies and Cyber security management

Digital technologies are nowadays deployed in allmodern power generation plants and also in largeindustrial plants and devices characterised by anon-negligible risk level. The situation in the nuclearpower sector differs from the rest of the industry inthe following key aspects:

• Use of analogue systems is being extendedbeyond their expected service lifetime.

• Regulatory uncertainty and associatedbusiness risk concerns are delaying thedeployment of new technologies.

AL AREA 3 29


�

R&D topics

• Innovative I&C design andarchitecture.

• New technologies in I&C (smartinstrumentation, modern communicationmeans – wireless, field programmablegate arrays, irradiation resistance,electromagnetic compatibility etc.).

• Advanced diagnostics (equipmentcondition monitoring, reliability predictionetc.),

• Cyber security (policy, guidelines andtemplates for NPPs, etc.).

• Human performance support (highlyintegrated digitalised control rooms, fieldworkers support etc.).

• I&C life cycle management.

�

III.3.4.4. Improvement of core management modelling tools and core monitoring and instrumentation

The goal of the management of a LWR core withfuel assemblies and associated systems is tomaximise cycle energy production with minimal fuelcost while maintaining sufficient margins to relevantsafety criteria. It can be achieved throughimprovement of precision of core calculations andbetter estimation of their uncertainties.

Nuclear instrumentation is still mainly based on safebut conservative technologies. Present and futurelevel of competitiveness with the other powersources depends also upon accurate and predictiveknowledge of core behaviour. Advancedinstrumentation and measurement methods, andefficient signal analysis, can increase reliability,performance and competitiveness.

Figure 9: OSIRIS reactor at CEA Saclay (Source: CEA)

�

R&D topics

• Improvement of precision of corecalculation and numerical modelling.

• Improvement of core monitoring andinstrumentation.

• Improvement of robustness andprecision of uncertainty estimations.

• Multi-cycle core reload optimiation,combined optimisation of fresh fuelprofiling and fuel assembly emplacementin the core and improvement of reliabilityof the optimisation process.

�

III.3.4.5. Water Chemistry and LLW (Low Level Waste) Management

Water chemistry in primary circuit significantlyinfluences generation of radioactive waste andradiation fields and consequently personal dose. Inaddition, in all systems, it influences aging and life-time of components (due to corrosion, erosion) andperformance of components (for exampledecreased heat transfer due to depositions).

The pressure to reduce the radiation exposure ofthe workers as well as the radioactive release intothe environment requires constant improvement ofprocesses and technologies for LLW treatment andfor conditioning of liquid waste, potentially ablealso to reduce the costs. Priorities in the treatmentof liquid radioactive waste are to obtain higherdecontamination and volume reduction factors,lower on-site processing costs, reducing solidradioactive waste generation rates and minimisecorrosion.

�

R&D topics

• Purification and radiation reduction ofprimary water coolant.

• Crevice corrosion sampling andmeasurement.

• Boric acid purification and LLWreduction (advanced filtration andinnovative removal processes to monitor,control and limit activated corrosionproduct transport; tritium, carbon 14Cand boron management).

• Improvement of secondary waterchemistry and in auxiliary systems(prevention of deposition of scales, bio-fouling and bio-corrosion etc.).

�

TECHNICA 30

III.3.4.6. Radiation protection

Exposure to external and internal irradiationresulting in doses to personnel is an inevitableconsequence of the operation of NPPs, but it canbe minimised through various means, likeprocedures for maintenance, instructions formovement of personnel, etc. Cost effective solutionsand application of new tools are highly demandedincluding more accurate dosimetry. Risk remains inthe potential tightening of radiation limits forpersonnel and the environment leading to furthernew measures and requirements for newmeasurement tools. Large uncertainty in assessmentof risk also arises from the fact that co-exposurestypical of most real situations (radioactivity andother stressors such as chemicals and physicalstressors) have been very poorly considered so far.

Figure 10: Personal dose measurement (Source: IRSN)

Discharged radionuclides from NPPs during normalor abnormal operation (liquid and gaseous) maycause long-term impact to the general populationand the environment by various irradiationpathways and therefore it is a sensitive issue whichinfluences public opinion of the nuclear industry.

�

• Improvement of radiologicalprotection and reduction of occupationalexposures by application of new tools(real time monitoring of received dose,augmented reality tools, better dosimetricmeasurements (especially for actinides)and interpretation, etc.).

• Improvement of public andenvironmental radiological protection(improvement of organisational andtechnical issues for minimising the releaseof radioactive substances into theenvironment under normal operationalconditions from NPPs, improvement ofmodels and risk assessment methods forquantifying the impacts to the populationand the environment, including input data).

• Development of generic andharmonised process for data baseconstruction throughout Europe insupport to more robust and conclusiveepidemiologic studies based on smartlydesigned workers cohorts.

• Development of new concepts andsupporting strategies, methods and toolsallowing to take into account co-exposureto mixtures of stressors and their resultingimpact on populations of human beingsand other biota.

• Development of platforms, methods,guidelines and tools necessary forrealisation of credible and useful PSALevel-3 as an essential pillar ofemergency preparedness and response.

�

AL AREA 4 31


III.4. Technical Area 4 (TA4), Integrity assessment of Systems, Structures and Components

III.4.1. Scope

tructural assessments are an important part ofNPP management programs (e.g. ageingmanagement, maintenance and design

changes). These assessments are one requirementfor the effectiveness of periodic safety reviews.Aspects that need to be considered includedefinition of integrity assessment over the whole lifecycle, the various degradation mechanisms, ageingissues, safety margins and harmonisation issues.

The Structures, Systems and Components (SSC) thatneed to be considered are those important forsafety and availability, those that require high coststo replace and those that cannot be replacedwithout a significant long term refurbishmentprogram. Components like Instrumentation andControl (I&C) which are of high safety significancealso need to be addressed

III.4.2. Objectives

hile the assessment principles relating toSSC are generally comparable in Europe,the actual methodologies and codes are

different in the various European countries. With thelonger term objective of European harmonisationin mind, it is necessary for the differences to be fullyunderstood and for the lessons learned fromGeneration II nuclear power plants (NPPs) to betaken into account when developing and/orrevising best practice guidance for the safeoperation of SSC with sufficient, but not over-conservative safety margins. This is required toensure high integrity and high performance in thecase of internal and external loads. Post-Fukushimalessons imply that investigations of beyond designloads are also required to be considered.

This technical area is split into the six sub-technicalareas listed below:


ntegrity Assessment of SSC takes into accountmaterial properties, component geometry,loading and degradation mechanisms and

degradation effects. It mainly relies upon fracturemechanics methods, e.g., the integrity assessmentof the Reactor Pressure Vessel (RPV) under aPressurized Thermal Shock (PTS) loading, and theanalysis of Leak Before Break (LBB) in pipes ismandatory for the safe operation of nuclear powerplants. Codes, standards and procedures arecommonly used for integrity assessment. These aregenerally well founded and validated but in manycases they can have inherent levels of conservatism,particularly when considering plant life extension.

III.4.4. Challenges

III.4.4.1. Integrity Assessment

There is a need to properly quantify and understandthe levels of conservatism in the current integrityassessment methods with a view to revising theguidance and procedures. Such aspects as effectsof load history, crack arrest, treatment of thermaland weld residual stresses and warm pre-stressingeffects need to be considered with regards to thisaim. Lessons learnt from Generation II NPPs interms of integrity assessment validation should beconsidered and implemented.

The modelling of integrity assessment is importantin order to be able to translate the mechanisticunderstanding to simulation tools and assessmentprocedures to predict theoretical margins for thesafe operation of NPPs, taking into accountstructural features, real or postulated flaws, loadingconditions and relevant material characteristicsincluding ageing effects.

�

R&D topics:

Metallic components:

• Update of design curves includingfatigue and environmental effects,indicators and surveillance programs formaterials behaviour for long termoperation.

• Validated models for the assessmentof structural integrity of in-vesselcomponents under high doses ofirradiation, including integrity of RPV

TECHNICA 32

internals for long term operation.

• Assessing, optimising and developingthe use of advanced tools for thestructural integrity assessment of non RPVcomponents.

• Development of best practiceprocedures for assessing structuralperformance of multi-metal components,including cladded components.

• Development of a probabilisticapproach of RPV and other safety criticalsystems integrity assessment for long termoperation and harmonisation ofprobabilistic safety assessment to achieveimproved justification for safety factors (inclose link with TA1).

• Implementation of lessons learnt fromGeneration II NPPs in terms of integrityassessment validation.

• Benchmarking of safety assessmentmethodologies including comparison ofoutputs from deterministic versusprobabilistic methods and integration intothe safety assessment.

• Development of a probabilisticapproach of Leak Before Break (LBB)analyses for long term operation.

• Gaining an understanding of LBBprocedures and engineering assessmentprocedures employed in differentEuropean countries.

• Treatment of secondary and residualstresses (including crack closure and loadhistory effects).

• Developing and experimentallyvalidating warm pre-stressing assessmentand analytical tools for conditions beyondthe present experience & data.

• Fracture mechanics for thin sections.

• Treatment of non-crack like defects(corrosion, thinning, pitting, erosion, flowinduced corrosion, crevices).

• Development of a methodology toinclude high temperature ageing effectsin plant assessments.

Civil works:

• Gain understanding of modelingapproaches adopted in differentEuropean countries on life timeevaluation of civil structures.

• Modeling of cracks opening in pre-stressed concrete and air and air/steammixture flow rate through cracksaccording to different loads, includingsevere accidents loads.

• Develop probabilistic anddeterministic methodologies to evaluatethe impact of internal hazards (hydrogenexplosion, pipe whip impact) and externalhazards (seismic event, aircraft impactand explosion).

�

III.4.4.2. Description of Loads

Accurate knowledge of applied loads and resultingstresses (and strains) is needed for SSC’s reliability.Increased computing power over recent years,coupled with advanced modelling capabilities, hasresulted in enabling the accuracy to be evaluatedin greater detail. Examples of this include pipingsystem loads and stresses resulting from pressurizedthermal shock loading or fluid structure interaction.

�

R&D topics:


• Investigation of combined fatigue andtearing fracture resistance under highasymmetry cycles and random high cyclicloads.

• Improved methodologies for thermalstratification and mixing assessments(pipings and t-junctions).

• Harmonisation of load evaluationmethodologies.

• Development of guidance in order tomore accurately predict fluid tocomponent wall heat transfer (CFD,Computational Fluid Dynamics) forthermal fatigue analysis.

• Dynamic response of reactor internalsto Loss of Coolant Accidents (LOCAs).

• Methodologies for establishing thesignificance and ranking of external loadsfor deterministic and probabilisticassessments.

• Fluid structure interaction underturbulent flow conditions (resultingimpact force).

• Development of improved guidelinesfor lifetime extension of bolts and flanges(including defect tolerance).

�

III.4.4.3. Materials Performance and Ageing

The major challenge is to justify properly that allcomponents affected by an ageing mechanismremain within the design and safety criteria. Indeed,properly understanding the performance ofmaterials relevant to structural components and theeffect of ageing mechanisms on their performanceare key issues from the start to the end of life ofeach NPP. Basically, ageing management shouldfollow a well-defined procedure that consists offollowing key aspects:

AL AREA 4 33


• Identification of the SSCs that are subject toageing.

• Performing analysis, comprising theunderstanding and modelling of the mainrelevant ageing mechanisms concerningeach SSC (potential or encountered).

• Setting up of measures to justify the integrityof each SSC based on codes & standards,regulations, specifications & guidelines andscientific knowledge of the ageingmechanisms.

Figure 11: X-ray control of a tank welding (Source: IRSN)

III.4.4.3.1. Material Properties

Knowledge of many material properties is requiredin relation to SSC. Examples of material propertiesrequired for “start of life” assessments includetensile properties, fatigue stress versus number ofcycles (S-N) data and fracture toughness data fordefect tolerance evaluations. In addition, andparticularly for in-service evaluation of SSC,properties relating to aspects like irradiation creep(for high temperature operation), corrosion andenvironmentally assisted fatigue (EAF) may berequired. Data are fairly widely available on allthese materials properties for materials of interestbut there remains some concern and debateregarding e.g. the treatment of scatter, in corrosionand environmental fatigue data, to correctly applyin integrity assessments. Beyond that, operationaleffects potentially prolonging SSC’s lifetime are notconsidered in general. In addition, there is thecomplex issue of how manufacturing processes(including welding, thermal and mechanicaltreatments and coatings) may affect materials andmaterials' properties and how such processes maybe improved in the future.

�

R&D topics:


• Development and testing ofaccelerated (SCC) test methods for lifetime prediction.

• Establishing guidelines and rules forthe manufacturing conditions of crucialSSC’s (e.g. cold work, surface finish,welding procedures, metallurgicalheterogeneities, heat treatment, …) onmaterial performance.

• Further develop testing andqualification procedures for miniaturisedspecimens.

• Effect of dynamic strain ageing onfracture toughness of materials.

• Improve identification of radiation-resistant materials.

• Investigation of the fatigue enduranceroots.

• Development of characterisationmethodologies and qualificationprocedures for dissimilar metals welds(DMWs).

• Guidance for manufacturingprocesses based on material performancestudies.

• Creation of materials databaseincluding coolant (primary andsecondary), thermal, mechanical andirradiation effects (single and combinedeffect).

• Development of joining and weldingprocedures (including mixed welding,welding of thick components etc.).

Polymer materials:

• Development of acceptance criteriafor replacement taking into accountcorrelations of all properties (compositionversus performance).

• Irradiation ageing of polymers:Investigate the influence of dose rate andirradiation time when performingaccelerated irradiation.

• Synergistic effects of stressors atpolymers: Investigate synergistic effects ofirradiation, heat, moisture (water),vibration and other existing stressorsaffecting the environmental impact ofpolymers with special considerationstaken for elastomers. Establishment ofmethodologies for testing andcharacterising polymers used in nuclearpower plants.

�

III.4.4.3.2. Ageing and degradation mechanisms

Ageing management addresses physical ageingthat could result in degradation of SSC such that

TECHNICA 34

safety functionality could be impaired. Thus,degradation modes, including fatigue, irradiationembrittlement, stress corrosion cracking, irradiationassisted stress corrosion cracking, thermal ageing,general corrosion, erosion-corrosion, strain ageing,environmental fatigue, creep, creep-fatigue andthermal fatigue, need to be fully understood toensure a good SSC status. It is therefore veryimportant to be able to properly evaluate theirpositive or negative effect on “start of life”properties as they may become limiting factors forthe safe and reliable operation of NPPs. Importantas well is that the effects of the ageing anddegradation mechanisms should be considered forthe specific type of SSC material being assessed.Guidance and/or data are generally available forthe projected lifetime but very scarce for allowingbeyond design long term operation. There is clearlya need for further R&D to be undertaken in severalof the areas referred to in order for a betterfundamental understanding of the ageing anddegradation mechanism to be realised and to leadto realistic assessment guidance.

�

R&D topics:


• Investigation of micro-structural andmechanical effects in RPV steels caused bylong term irradiation leading to theimprovement of RPV safety assessment ofexisting European LWRs under long-termoperation and Generation-III reactorsunder construction (supporting RPVageing management and plant lifeextensions).

• Improving the knowledge regardingstress corrosion cracking (SCC) initiationwith respect to the field requirements,including experiments with relevantadvanced characterisation.

• Investigation of the fabricationprocess and initial surface condition of ametallic component on the SSC time-to-failure.

• Evaluation of methodologies todetermine and optimise fatigueendurance of safety critical componentswith the aim of gaining a betterknowledge of environmental fatigueeffects in PWRs.

• Investigation of crack initiation byirradiation assisted stress corrosioncracking (IASCC) and the creation of adatabase of experimental data.

• Investigation of corrosion andhydrogen embrittlement for structuralmaterials.

• Investigation of thermal ageing inaustenitic stainless steels.

• Investigation of irradiation in toughlow activation V alloyed steel for futureRPVs.

• Study of the crack morphology and itsinfluence on leak rates for provision ofdefined parameters and furtherimprovement in the accuracy of leak-rate/LBB models.

Polymer and Electrical Equipment:

• Irradiation ageing of polymers:Investigate the influence of dose rate andirradiation time when performingaccelerated irradiation.

• Synergistic effects of stressors atpolymers: Investigate synergistic effects ofirradiation, heat, moisture (water),vibration and other existing stressorsaffecting the environmental impact ofpolymers with special considerationstaken for elastomers.

�

III.4.4.3.3. Modelling of ageing

The high variability of ageing and degradationmechanisms necessitates predictive tools to allowtransferability and interoperability of the knowledgegained from limited experimental/empirical data(surveillance, in-field monitoring…). In this regard,one long term aim is to develop fully validatedmulti-scale based models that link the nano scalethrough to the macro (i.e. structural) scale basedon a multi-disciplinary approach. Betterunderstanding of the physical mechanisms affectingthe ageing of metallic materials combiningadvanced experimental investigations with the useof up-to-date modelling methods, such as thosedeveloped through the multi-scale approach.Important is to investigate in depth the localphenomena and their interaction by using powerfulnumerical tools allowing an accurate prediction ofageing, not only of the components that areaccessible for inspection, monitoring and repair butof all others that are not easy to reach. Thisextrapolation needs to be based on experimentallyvalidated models using data from both in-pile andout of pile experiments.

�

R&D topics:

• Better understanding of physicalmechanisms driving the ageing ofmaterials, by combining advancedexperimental characterisation of ageingmaterials with the use of atomistic andnanostructure evolution modelling tools,that should include the effect of localphenomena and the interaction betweenthem, by using powerful numerical tools,

AL AREA 4 35


including those required to homogenisein time and space.

• Development/improvement of modelsto predict crack initiation under variousageing mechanisms.

• Performance of representative in-pileexperiments and subsequent materialscharacterisation for the validation of themodelling tools.

• Investigation of ageing effects,especially irradiation hardening andsubsequent embrittlement, of reactorcomponents, especially the vessel, bymulti-scale modelling.

• Investigation of mechanismsdetermining irradiation creep andswelling in austenitic steels anddevelopment of relevant predictivephysical models, based on a multi-scalemodelling approach.

• Simulation of welding andmanufacturing processes with a view toevaluating ageing effects.

• Investigation of the correlationbetween microscopic properties andmacroscopic mechanical behaviour ofaged materials on the basis of combinedexperimental and theoretical analysis ofdislocation dynamics.

�

III.4.4.4. Ageing Monitoring, Prevention and Mitigation

SSC ageing needs to be monitored over thenominal and extended service life of SSC in orderto be able to correctly determine or anticipate therelevant ageing mechanisms and to evaluate theextent of degradation that may occur. In principle itis possible to monitor ageing effects (as flaws,thinning, material properties change etc.), functionperformance or its changes, operating conditions(including loading history) and efficiency ofpreventive measures applied to mitigate SSCageing. For particular monitoring measures it isnecessary to clearly state parameters to bemonitored and their acceptance criteria.

SSC ageing mitigation is aimed on replacement,maintenance, refurbishment, operational conditionchange and other measures, which can influencethe degradation rate.

R&D topics in this subchapter are focused to thedevelopment of effective and practical methods formonitoring and mitigating ageing of the SSC.

III.4.4.4.1. Ageing Monitoring

New operational experience and progress inunderstanding of material ageing phenomenaenables to develop new monitoring methods,diagnostics and monitoring simulation tools thatcan greatly increase the ageing managementefficiency.

�

R&D topics:

Concrete:

• Development of methods forassessing the current state of concretestructures by way for example ofretrofitting embedded humidity sensorsfor monitoring the quality of the concretewith respect to penetration of boric acid(and other liquids) in to the SSC.

Polymers and Electrical Equipment:

• Detection of local and globaldegradation of cables and establishing acorrelation for residual life estimation byusing in-situ non-destructive electricaltechniques for in-service full lengthmeasurements (for medium and lowvoltage cables.

�

III.4.4.4.2. Prevention and Mitigation of Ageing

Prevention and mitigation of both ageingmechanisms themselves and their resulting damageand failure has been a long term challenge forengineers and scientists in many industries.However, this is an area where further studies anddevelopments are required. The issue is associatedwith components that are usually very difficult andexpensive to replace and may not be readilyobservable.

Main challenges for this sub area coverdevelopment of efficient and applicable preventivemeasures and repair technologies. Other mitigatingmeasures are topics of the following sub areas.

�

R&D topics:

• Simulation of residual stresses anddevelopment of mitigation measuresincluding overlay welding.

• Investigation into annealing of RPVmaterials.

• Investigation of the effect of wateradditives on vessels, piping andcomponents in the primary loop of thereactor coolant systems in BWR, PWR andVVER plants.

• Development of improved mitigationtechniques for inter-granular stress

TECHNICA

corrosion cracking (IGSCC): e.g. modifiedwater chemistries or development ofother new techniques.

• Assessment of low temperature crackpropagation susceptibility for primarycircuit and core materials (welds, castmaterials: Inconel 182, alloy 690 coldworked etc.) in transient conditions withthe aim of optimising the water chemistry.

�

III.4.4.5. Equipment qualification

III.4.4.5.1. Equipment Reliability

The reliability of equipment turns out mandatoryeven if it has no direct impact on the system safetyas almost no SSC is operating in a stand-alonemanner. Thus, the incremental development ofeach NPP to implement the improvement of thesafety approaches necessitates a great R&D effortto establish if the SSC are able to perform theirintended function in a reliable and safe mannerthroughout the lifetime of their required use.

Figure 12: Arrival of EPR main vessel at Olkiluoto,Finland (Source: VTT)

�

R&D topics:

• Investigation of the reliability ofrelevant equipment for long termoperation.

�

III.4.4.5.2. Industrial Obsolescence

NPPs are per definition designed to operate for along time period during which a substantialtechnological and societal changes occur.Obsolescence essentially refers to SSC that are nolonger manufactured or maintained properly during

the lifetime of an NPP. A common Europeanapproach should be developed with the help ofNUGENIA either to create versatile technologies,possibly with other industries, or to adapt nuclearprocedures to even faster evolving domains.

�

R&D topics:

• Establish a common position on therelevance of qualification tests and ontheir extension to cover longer-termoperation.

�

III.4.4.6. Qualification

The qualification of methods used for the integrityassessment of SSC is mandatory which necessitatesthe establishment of verification and validation ofstructural integrity assessment and lifetimeprocedures for SSC and the development of specificmaterials or component tests. Often an overallqualification approach for structural integrityassessment and lifetime procedures requires acombination of advanced analytical andexperimental qualification to comply with thefunctionality requirements for each component andsystem.

Qualification is inherent in performing R&D studieson the various issues relating to SSC.

�

R&D topics:

• Develop structural integrityassessment procedures for dissimilarmetal welds including numericalprediction methods for residual stressesand develop a test standard for toughnessmeasurement for multi-metallic specimenand components.

• Development of an accelerated testfor stress corrosion cracking initiation inLWR conditions.

• Assessment, optimisation and furtherdevelopments of advanced tools forstructural integrity assessment of pipingsystems.

• Understand and quantify constraintand bi-axial effects in metalliccomponents and investigate the effect ofwarm pre-stressing in combination withthe effect of crack tip constraint and bi-axiality.

• Comparison of existing codes andstandards for the estimation of K and Jvalues of various crack configurations in

36

AL AREA 4

pipes and other standard geometrycomponents to quantify the conservatismof the single methods.

• Development of a radiationembrittlement database and developmentof trend curves RPV life assessment basedon the collected data.

• Development of empirical/semi-empirical models for prediction of stresscorrosion cracking (SCC) initiation in LWRand super critical water conditions.

• Comparison of different numericalmethods on microstructure evolution ofirradiation creep and swelling.

• Upgrade and extend the existingVERLIFE Procedures (structural integrityand lifetime assessment procedures forVVER type reactors) with appendices onstructural integrity assessment for RPVinternals, LBB procedures for piping, NDEqualification.

�


37

TECHNICA 38

III.5. Technical Area 5 (TA5), Fuel Development, Waste and Spent Fuel Management and Decommissioning

III.5.1. Scope

echnical area 5 (TA5) covers development ofnuclear fuel for existing, advanced andinnovative core designs, aspects of fuel use in

reactors (nuclear fuel behaviour mechanisms) andthe fuel management steps – manipulation,transport and interim wet and dry storage. It alsoincludes factors relating to the generation andmanagement of radioactive waste, and thedismantling and decommissioning of nuclear powerplants. It includes the safety issues linked with: fuelbehaviour in normal operation and accidentconditions, and the safety of the fuel cycle,including the investigation of criticality accidentsand radioactive material dispersion.

TA5 has connections mainly with TA3 in parts ofcore optimisation and chemistry and to a lesserextent with TA6 regarding fuels for innovative LWRsand with TA1 for NPP safety and risk, includingcriticality. TA5 has an important interface with TA2,which deals with severe accident, while TA5 coversnormal and off normal behaviour, exclusive ofmajor core degradation.

Outside of the scope of TA5 is radioactive wastedisposal since IGD-TP is in charge of the researchagenda and deployment plan for this topic.

The scope also takes account of emerging lessonsfrom the Fukushima accident and proposesresearch, development and innovation to improvethe safety and resilience of the existing and newbuild LWR reactor fleet.

III.5.2. Objectives

he rationale of TA5 is to improve the safe,reliable and economic operation ofGeneration II and III NPPs (specifically in-

reactor and out-of-reactor nuclear fuelmanagement and radioactive waste management)and to maintain the sufficient level of safety definedby the regulatory bodies and reflecting therecommendations of the relevant internationalorganisations.

Nuclear fuel production and use have reached a

relatively mature state; nevertheless there ismotivation to improve existing fuel types and toestablish safety operating limits of developedinnovative fuel:

• To increase fuel safety margins and improvebehaviour under operation and accidentconditions,

• To reduce reactor operating costs (includingfuel costs),

• To reduce the amount and/or radio-toxicityof spent fuel,

• To recycle existing waste (uranium,plutonium) from reprocessing operations,

• To increase sustainability,• To improve the safety of fuel management

and decommissioning/dismantling andmore generally to the fuel cycle (such ascriticality and re-suspension and transfer ofradioactive materials),

• To improve proliferation resistance.

The general R&D needs for all fuel types are:• Development of manufacturing techniques,

improving safety as well as out of specmaterial.

• Collecting data on fuel and materialirradiation properties.

• Performing post-irradiation examination(PIE) and collection of in-pile data on fuelperformance (fuel thermo-mechanical andthermo-chemical behaviour underirradiation) and fuel resilience either duringnormal and accident conditions, and longterm storage.

• Understanding and modelling of fuelperformance and behaviour in accidentconditions.

• Providing data to evaluate criticality risk inthe fuel cycle, including the burn-up credit.

• Implementing source term determinationand mitigation strategies in case ofaccidental dispersion of radioactivematerials (re-suspension, filtering etc.).

Fuel behaviour in both normal operation, storageand accident conditions currently is, and willcontinue to be, a major issue for the safe, secureand economic operation of nuclear power plants.

Despite the considerable knowledge base, there arestill unknowns, necessitating dedicated fuel and

AL AREA 5 39


material property, separate effect and semi-integraland integral testing to provide experimental dataon fuel safety performance behaviour. These datacan then be used to inform fuel development andto improve understanding and simulation of fuelperformance and in parallel provide improved toolsfor regulatory bodies.

An understanding of fuel behaviour in normal andabnormal conditions is underpinned by fuel R&D,which must address new design and safetyrequirements, increases in uranium enrichment,uranium and plutonium recycling (and potentiallyin the future minor actinide recycling), power up-ratings, and increased cycle length and burn-upand post discharge storage timescales. It must alsoaddress differences in behaviour engendered byincremental changes in the fuel components: thatis, of the fuel pellets (composition / geometry),cladding and assembly structural components.

Both spent nuclear fuel management andradioactive waste management have achieved awidely agreed maturity, however lack of progresson a final disposal solution is leading to increasedstorage times and the need to relicense storagefacilities, that creates new needs, but there is still

room for progress, including the optimisation ofloading strategy and the introduction of moreefficient and reliable technologies leading to animprovement of the safety of processes, to areduction in cost and lower environmental impacts.

The number and variety of nuclear facilities in thedecommissioning stage will increase greatly in futureyears and therefore development of remotedismantling techniques and dose minimisationapproaches are needed along with more reliablemethods for the reuse and recycle of valuablematerials and the release of other materials to theenvironment.

Accordingly, the TA5 comprises the following fiveST-A’s:

Figure 13: Technology Readiness Levels (TRL) of Advanced Fuels (Source: NNL/DECC)

TECHNICA


O2 enriched up to 5% in the form of solidor annular pellets in zirconium alloycladding remains the most used fuel in

European reactors. The main nuclear fuel suppliersin Europe are currently Areva, Westinghouse, GNFand TVEL (LWR fuels). MOX fuel is used in limitedquantities mainly in France where processing isavailable. The existing expert and experimentalbase consists of vendors own R&D, and operationalexperience from utilities, research entities andinternational organisations (mainly IAEA, OECDNEA).

Figure 14: C5 cell of the LEFCA laboratory at CEA,Cadarache (Source: IRSN)

Burnable absorbers integrated into the fuel matrix(Gd and Er) are routinely used to control excessreactivity. Modifications to fuel microstructures havebeen recently introduced by incorporation ofadditives or by use of advanced manufacturingtechniques. Fuel behaviour mechanisms arecurrently well known for UO2 fuel in Zr claddingand AGR fuel for burn-ups up to 60 000 MWd/t.The fuel performance codes have been developedand validated (utilising data from operation anddedicated experimental programmes) and areroutinely used for simulation of normal operationand accident scenarios.

Experimental facilities (research reactors, hot cellsand laboratories) are still available for research andtesting, but this valuable infrastructure isdecreasing, driving the need for greatercooperation.

Spent fuel management (with various nuclear fueltypes for both commercial and research reactors) isundertaken and has benefited from theaccumulated knowledge and experience of the past

decades. Nevertheless, there is significant room forimprovement and optimisation in various areaswhich would result in improved safety, security(proliferation resistance), and economic andenvironmental characteristics. The spent fuelmanagement chain is carefully regulated by rulesestablished by national regulators usually reflectingthe recommendations of international organisations(IAEA). Within the EU a range of spent fuel storagearrangements are employed, in some countries fuelis stored primarily at the reactor stations/site whereit is generated, whereas in other countriescentralised storage is used for interim/long termstorage after an initial cooling period at the reactorsite. Transport of spent fuel is a well-established andregulated operation. With increasing longer interimstorage periods, knowledge on the fuel andcladding behaviour needs commensurateadvancement.

Fuel recycling of UO2 and metallic fuels isgenerally well established within the EU,nevertheless development of knowledge is stillrequired at process level.

A number of decontamination, waste treatment andconditioning methods and technologies have beendeveloped and are used. The management ofspecial categories of waste has also beenaddressed (tritium and C-14 waste, Be, graphite,mixed radioactive and chemically toxic waste, etc.).Nevertheless, the potential for improvement toreduce costs, risks and impacts is still far fromexhausted. Methods of reuse and recycling ofvarious materials (metals, concrete) have also beenintroduced. Experience from decommissioning anddismantling of nuclear facilities is being continuallyaccumulated allowing drafting of guidelines andthe use of best practices.

This knowledge is shared under the umbrella ofinternational organisations (IAEA, OECD NEA –Working Party on Decommissioning andDismantling).

III.5.4. Challenges

everal key challenges remain for the shortterm such as the improvement of nuclear fuelallowing higher burn-ups and increased safety

margins, but also the development of accidentresistant fuels, innovative fuels and fuels allowingthe burning of Pu and minor actinides (includingnon-UO2 fuels). At the same time, improvement of

40

AL AREA 5

nuclear fuel reliability, improvement (reduction ofuncertainties) and extending experimental data onfuel behaviour at high burn-ups and in accidentconditions are vital.

To meet future requirements it is essential that thefuel performance codes are continuously improvedand validated. For this validation also the nuclearfacilities need to be maintained, and expanded. Itis therefore essential that support is provided toirradiation facilities, hot cell and laboratories, bothfor maintaining the current fleet and support forexpansion and new facilities.

�

R&D topics:

• Handling and storage of leaking fuelassemblies (spent fuel pool and interimwet and dry storage) and handling of fueland casks after longer term storageincluding the interface with a deepgeological repository.

• Improving understanding of ageingmechanisms, inspection requirementsand ageing management plans forinterim storage facilities, so as to avoidhidden legacies for future generations.

• Addressing the burn-up creditchallenges (code validation and licensingissues).

• Optimising the spent nuclear fuelcycle and reprocessing and recycling ofhigh burn-up and advanced fuels.

• Improving the fuel managementsafety (including long interim storageperiods), of dismantling operations and offuel cycle processes, regarding the risk ofre-criticality and of dispersion and releaseof nuclear materials particularly underbeyond design basis conditions.

• Using advanced I&C tools fordevelopment of integrated wastemanagement strategies.

• Minimising waste production bydesign and material selection andoperational measures as well asdevelopment of advanced wastetreatment and conditioning technologies.

• Developing efficient dismantlingtechnologies for structures andcomponents, including remotedismantling techniques.

• Elaborating and proposing wasteminimisation strategies fordecommissioning, including safe releaseof material to the environment (includingassay methods), recycle/reuse, disposal toLLW repositories along with reliable andcost effective activity measurementtechniques.

• Developing advanced radiation andtemperature tolerant adhesives andsealants.

• Developing improved filtrationmethods to reduce legacy radioactiveburden at end of life.

�


41

TECHNICA 42

III.6. Technical Area 6 (TA6), Innovative LWR design and technology

III.6.1. Scope

he deployment of advanced Light WaterReactors (LWR) for electricity production couldvaluably make the bridge throughout the 21st

century between the ageing nuclear installationscurrently in operation and/or the Generation III ones,now under construction, and the Generation IVreactors proposed by the GIF and promoted byESNII. For assessing and reinforcing theirattractiveness, there is a need to continuously improveperformance and safety, and to propose newtechnology and /or new concepts with new attributes.

Innovative technology will be developed along witha transverse view for fulfilling the needs andrequirements of the currently operated LWR, andnew designs as well. On the one hand, this willprovide new solutions and/or use of new methodsand techniques for addressing key issues pointedout in the other TAs which will be used as inputdata. On the other one, this will support thedevelopment of advanced light water reactorconcepts that would feature improved sustainabilitywith a better use of uranium resources andcapabilities of fissile materials multi recycling, or besized for smaller generated thermal power andmodular construction techniques, etc.

Both existing and new LWR designs will profit fromthe expected R&D programmes in TA6 through theprogress which should be achieved in the fields ofsafety & commissioning, operability, sustainability,economics and public acceptance, especiallyfollowing the Fukushima accident.

III.6.2. Objectives

nnovation is the key driver of the TA6 foraddressing technology, methods, testing andcomputation capacities, with the objective of

supporting the competitiveness of light waterreactors.

The development of new materials, manufacturingand assembly technology will result in thefabrication of high reliable components and forlong term operation. This will be applied to thereplacement of currently operated LWRcomponents, as well as to the fabrication of new

component which should comply with new LWRconcepts.

Other LWR concepts will be investigated forproposing new possibilities while benefiting fromthe experience gained in the field of LWRtechnology. High conversion ratio reactors offer abetter use of fissile material and in the same time,the possibility of Plutonium multi recycling insteadof storage in spent fuel. Small modular reactorsoffer lower initial capital investment and thepossibility to progressively increase electricitygeneration capacity through the addition ofelementary modules.

Whatever the LWR design is, inherent and passivesafety should be continuously assessed andimproved to the maximal possible extend. This is afirst step towards public acceptance. Lastly, in anevolving context regarding electricity productionsources and rationale for nuclear energy use in theEuropean countries, LWR integration in the energymix should be analysed for deriving new potentialrequirements. They will be used as input data forthe development of new material and componentfabrication technology.

Knowing that new technology deployment at theindustrial scale could be a long time durationprocess, the following time lines will be considered:

• Proposing evolutionary technology formid-term application.

• Supporting the development of new LWRdesigns such as with higher conversionratio or small modular reactors, expectedto be ready for commercial operation byfall of the next decade.

• Investigating breakthrough technology forpreparing the future.

Accordingly, the TA6 roadmap is organised in fivesub-areas corresponding to R&D challenges in linewith the objectives mentioned here above:

AL AREA 6 43



Synergies with all the other NUGENIA areas will beexploited for taking benefit from operating experiencefeedback from the current reactor fleet, prior todevelop innovative technology that will result inimproved performance. That will include enhancedrequirements for safety and performance, reducedmaintenance and long term operation, materialageing related issues, inspection, control and repair,operation, and plant power upgrade, as well.

The main material grades which are used in nuclearreactors components are mostly used as monolithicstructural materials, or may be coated. Recentstudies have shown evidence that combiningdifferent materials and manufacturing routes mayresult in multi-functional materials. Large powergeneration components are commonly fabricatedusing conventional methods, such as forging,casting and grinding as finishing operations. Recentstudies have highlighted the major attributes ofpowder metallurgy technology, especially highisostatic pressing, which can form near net shapecomponents with limited finishing operations.

The concept of a high conversion light water reactorhas gone on being studied over the 80’s in the aimat combining the advantages of LWR technologywith the use of uranium – plutonium fuel, theachievement of high burn up and low nuclear fuelconsumption.

Small modular reactors are expected to sharesimplicity of design and reduced sitting costcompared to a current LWR. This results in a revivalof interest worldwide.

The focus of the studies has to be placed on thesafety issues in light of the Fukushima event and ofthe “EU Stress Tests specifications”.

Innovative LWR designs requires furtherenhancement of inherent safety features andpassive safety on component and system levels.

The development of knowledge, safetyrequirements, criteria and rules for innovativetechnologies should facilitate and accelerate theirimplementation in the nuclear field.

III.6.4. Challenges

he main challenges for NUGENIA in the fieldof Innovative LWR design and technology canbe identified in the five sub areas which

address all the necessary stages of LWR technologyimplementation. The R&D projects proposed in TA6 will combine innovative technology and progressmade in any domain for reinforcing thecompetitiveness of LWR reactors.

III 6.4.1 Innovative Technology for Reactor Component Design & Technology

As a common theme for all LWR reactor concepts,advanced and breakthrough technologies forreactor component design and fabrication will beinvestigated. Synergies will be exploited tobenefitting from the more demanding requirementsand the progress made in basic technologies.Safety issues will be considered at the early stageof the design. Moreover, the overall performanceof the component will be assessed adopting newmethods.

All the necessary stages for reactor componentdesign and fabrication will be addressed, whileseeking for innovation. Safety issues will beconsidered at the early stage of the design. Finally,the overall performance of the component for therelated reactor concept will be assessed using newmethods benefiting from the recent progress intesting capacities, physical modelling andnumerical simulation.

�

R&D topics:

• Development of new materials andprocessing methods for reaching tailoredproperties:

- multi-layer material e.g. with highresistance to corrosion and enhancedelasticity,

- surface engineering e.g. for stresscorrosion cracking, nano-materials,

- composite materials and hybridse.g. combining high mechanical stressand other functionality, to achieveproperties suitable for high-performance nuclear components.

- multi scale modelling will provideguidance for the evaluation of newalloyed materials e.g. resistanceagainst irradiation damage, swelling,creep

• Development of new manufacturingand assembly process, such as usingpowder metallurgy and predictivemodelling on the resulting materialmicrostructure, metallurgical properties,and macroscopic behavior of thecomponent; application to existing

TECHNICA 44

component for coating, dissimilar metalassembly, near net shape fabrication, andfocus on compact heat exchanger forSmall Modular Reactors.

• As a transverse approach for allreactor concepts, the development ofengineering simulator tools will beconsidered to assess the overall reactorsystem performance, including theenvironmental impact. This will firstrequire the development of in-depthknowledge of local phenomena leadingto degradation mechanisms

�

III 6.4.2 Innovative LWR Concepts including : High Conversion LWRs, Small Modular Reactors, etc.

The development of new concepts which couldbroaden the functionalities of Light Water Reactorand be ready for commercial operations for the nextdecade will arise new requirements and provideguidance for implementing R&D work in manyfields.

�

R&D topics:

• Concept screening: High conversionratio, small modular reactors etc. foridentifying the main requirements intechnology development

• Material and component withenhanced properties as required by therelated concepts, such as compact heatexchanger fabrication for small modularreactor, performance of heat removalsystems

• Core design based on availableconcepts: reactor physics, robust nucleardata, heterogeneous core,

• Reactor core cooling: The tight latticecore of high conversion core makes thecooling very specific and raises newchallenges in thermal hydraulicevaluation

• Investigation on various separatethermal hydraulics phenomena, specificto the reactor technology: natural andmixed convection conditions, boiling heattransfer of Steam generator as plate ortube, flow induced vibration in compactSMR

• Analysis of modular constructiontechniques

• Assessment of overall reactor systemperformance, in operating and accidentalconditions.

�

Figure 15: Plate heat exchanger to be fabricated forSmall Modular Reactor

III 6.4.3 Innovative LWR-specific safety issues & approach

The development of innovative materials,component fabrication processes, as well as theevaluation of new reactor concepts, could requirespecific safety approaches and the incorporation ofpassive system which should be integrated at theearly stage of design. Harmonisation with EUDirectives establishing a common framework for thenuclear safety of nuclear installations, likewise toWestern European Nuclear Regulators Association(WENRA) statements and to IAEA safety publicationsis to be achieved.

�

R&D topics:

• Exploitation of pre-normativeresearch results to implement the safetyrequirements, including site selection andevaluation.

• Development of more sophisticatedinstrumentation and control systems forsafety applications.

• Integration of the safety issueshighlighted after the Fukushima Daiichiaccident and by the EU stress testsspecifications.

�

III.6.4.4 Key success factors for innovative LWR deployment

Key success factors for the deployment of newand/or innovative LWR reactors must beinvestigated vs. the deployment strategy of

AL AREA 6 45


Generation IV systems and to the growingcontribution from the renewable energy sources.Flexible fuel cycle scenarios will be evaluated usinga wide range of combinations of electricity sourcesfor a transition period: current and innovative LWRtechnologies, thorium cycle, fast reactors, and windenergy which are intermittent and should becomplemented.

Enhanced operability of LWRs will be consideredalong with two objectives that could be separate orcomplementary:

Innovative solutions for minimising theenvironmental impact of LWRs will be evaluated.

�

R&D topics:

• Evaluation of flexible fuel cyclescenarios relying on a wide range ofcombinations of electricity sources for apostulated transition period, such ascurrent and innovative LWR technologies,thorium cycle, Sodium fast reactors, andrenewable energy sources. Establishmentof criteria for scenario analysis (massinventory, radiotoxicity, ultimate waste,etc.). The outcome from ENEF analysis willbe used as an input.

• Search for the enhanced operability ofLWRs, including potential benefit foreither load following or combined mode,and innovative technology for plantoperation simplification.

• Evaluation of innovative solutions forminimising the environmental impact ofLWRs.

�

III.6.4.5 Public acceptance drivers for new builds

In this subarea, it is proposed to address therationale behind nuclear energy acceptance by thepublic, notably for new build. European policy is toprovide with key elements for guidance.

�

R&D topics:

• Identification of the main driverstowards public acceptance for new builds,taking into account the specificrequirements of different countries.

• Harmonisation of the communicationpolicies, taking into account thedifferences in the public awareness andacceptance, which exist among theEuropean countries.

• Organisation of the informationdissemination.

�.

TECHNICA 46

III.7. Technical Area 7 (TA7), Harmonisation

III.7.1. Scope

armonisation, and standardisation, itssubsidiary, are crucial cross-cuttingobjectives within the NUGENIA technical

scope. Interest for standardisation andharmonisation - shared by designers, operatorsR&D organisation and TSOs - is growing every day.

Despite its cross-cutting nature, harmonisation hasbeen identified within NUGENIA as a full-scope TA to:

• Emphasize the needs for a progress in thefield within Europe,

• Support and supply help to valorisingprojects from different technical areas thatcontribute to harmonisation issues,

• Drive attention to the R&D programs andactivity underway which can contribute tothe improvement of rules, codes, standardsand practices.

III.7.2. Objectives

he objectives of harmonisation inNUGENIA include three different fields ofendeavour:

• Supporting the competitiveness of Europeannuclear energy through setting-up thetechnical basis for an effective standardisationof reactor systems and components.

• Improving the safety level of the nuclearinstallation through shared designapproaches and common safety assessmentmethodologies.

• Benefiting in the public acceptance throughits better information and involvement.

Figure 16: Increasing research domain covered by allstakeholders enlarges the field of technical consensus

(Source: IRSN)

The process of harmonisation in the nuclearindustry at European - and international - level issupported by several professional or internationalorganisations; some of them gather the operators(FORATOM, WANO), others illustrate the safetyefforts (WENRA, AEN/CSNI, ETSON), but few ofthem gather similarly nearly all stakeholders in thenuclear industry as NUGENIA does. OrientingNUGENIA’s research towards selected issues, maycontribute sensibly to improve harmonisation. TheNUGENIA technical area 7 will therefore supportactivities in four complementary fields:


any projects and industrial initiatives Manyprojects and industrial initiativesconcerning more or less directly

harmonisation are already going on, mainly in thefields of pre-normative research (even if theoutcomes of such programs are not fully fed-backto practices and rules), design and assessmentmethodologies (fields in which a wide effort iscurrently done to harmonise practices for newreactors), and codes and standards, mainly fordigital systems and components.

Several national nuclear codes are also availablein Europe (like RCC-M and RCC-MRx in France,KTA in Germany) and should be used as input forEuropean codes.

TA7 is intended to support initiatives alreadyunderway, emphasizing their potential contributionto the improvement of rules, practices andmethodologies. It also aims at stimulating initiativesand proposing cross-cutting projects and coachingprojects within other technical areas which presentside interest and can be valorised for harmonisationpurposes.

AL AREA 7 47


III.7.4. Challenges

he main challenges for NUGENIA in theharmonisation field can be identified along itsfour main fields of endeavour:

III.7.4.1. Pre-normative research

The pre-normative research can be defined as both:

• The preliminary phase of an experimentalresearch aimed at better characterising newtechnologies and the related safety aspectsby applying well established procedures andmethodologies.

• A research the results of which are to beused to develop guidelines, standards andtechnical codes.

Therefore, any technical domain and anyNUGENIA project may provide data for pre-normative activities, data that can also be useful forother standardisation organisations.

The pre-normative approach can also apply to safetycriteria that were defined once to comply with a givenlist of transients and for specific types of reactors. Itcould appear useful to generalise these criteria toseveral kind of design and to express them in generalterms such as control of the thermal power, coolingof heated parts of the plant, and keeping thestructural integrity of the different barriers betweenthe fission products and the environment.

III.7.4.2. Design and assessment methodologies and practices

Several plant performance evaluationmethodologies have been developed and are stillunder continuous improvement:

• The defence-in-depth approach, declined inthe INSAG 10, provides a functionalanalysis through identification of systemsand components, their failure modes andthe mitigation needs. It allows assessing therobustness of the plant design against therisk of dispersion of nuclear materials in theenvironment and contamination of thehuman being.

• The risk-informed methodology allowsincreasing the robustness of design throughfeed-backing the estimated contribution of the

accidental sequences to the risk. It applies inparticular to in-service-inspection andmaintenance optimisation, and in assessmentof plant risk and benefits of plant modifications.

• More recently, studies have been engagedon the safety margins approach, which isintended to account for all major potentialcontributions to the risk, independently fromtheir ranking and expected issues. The safetymargins evaluation approach is the subjectof a common challenge.

Several projects in NUGENIA should help clarifyingand improving those methodologies.

III.7.4.3. Codes & Standards

Many organisations are editing standards relevantto nuclear industry: ISO and IAEA for example. Atthe European level three standardisationorganisations are active: the European Committeefor Standardisation, the European committee for thestandardisation of the electro-technical domain andthe European Telecommunication Standard Institute.

Gathering and synthesising the already existingknowledge to single-out the methodologies andpractices that need to be harmonised is a preliminaryexercise in NUGENIA. The prerequisite to participatein codes and standards development consist inestablishing liaisons with the main harmonisationorganisations in order to offer them technical supportto back up the standardisation process.

III.7.4.4. Harmonisation strategy

The valorisation of the NUGENIA projects willinclude exploitation of results in terms ofstandardisation and preparation of formatted datafor standardisation activities.

Sharing projects in the field of methodologies,design, technology and systems will be a source ofbetter harmonisation orientation for all participants;NUGENIA should propose and realise researchprojects to bring technical basis to all stakeholdersin other standardisation organisations.

In the field of safety, NUGENIA efforts will rely on asystematic and continuous dialogue among thestakeholders and should lead those developingpractical ways to reach the objectives settled by thesafety authorities.

TECHNICA 48

III.8. Technical Area 8 (TA8), In-service Inspection and Non Destructive Examination

III.8.1. Scope

he European Network for Inspection andQualification (ENIQ) deals with the reliabilityand effectiveness of non-destructive testing

(NDT) for nuclear power plants (NPP) and is anetwork driven by European nuclear utilitiesworking mainly in the areas of qualification of NDTsystems and risk-informed in-service inspection (RI-ISI). Since its establishment in 1992 ENIQ hasperformed two benchmark studies and has issuednearly 50 documents. Among them arerecommended practices, technical reports,discussion documents and the two ENIQ frameworkdocuments, the “European Methodology forQualification of Non-Destructive Testing,EUR22906EN” and the “European FrameworkDocument for Risk-Informed In-Service-Inspection,EUR21581EN”. ENIQ is recognised as one of themain contributors to today’s global qualificationguidelines for ISI.

ENIQ has three task groups in which the technicalwork is performed, the Task Group for Qualification(TGQ), the Task Group for Risk (TGR) and the TaskGroup for inspection qualification Bodies (TGIQB).Their members come from utilities, ISI vendors,IQBs or research organisations in Europe withadditional members from Canada and the USA.Beside the task groups ENIQ has a steeringcommittee (SC), which is the decision making bodyof ENIQ. The SC has twelve voting members, onefor each EU member country (with operating NPPs)and Switzerland. SC members come entirely fromEuropean utilities. Beside the voting members theSC has non-voting members (observers) fromCanada, USA, the chairpersons of the three taskgroups and additional representatives of Europeanutilities, ISI vendors, IQBs or research organisations.In 2010, the ENIQ SC recognised that theEuropean nuclear industry was entering a period ofsignificant change and thus initiated an internaldiscussion to determine its vision and objectivesregarding ENIQ's future role and activities. Thisexercise resulted in the issuing of a strategydocument, entitled the "ENIQ 2020 Roadmap" andthe decision of ENIQ voting members to integrateENIQ into NUGENIA, making ENIQ the8thTechnical Area of NUGENIA.

III.8.2. Objectives

y coordinating expertise and resources, ENIQaims at supporting licensees (utilities) andstakeholders in:

• Addressing issues where the practice andimplementation of NDT will ensure the safeand reliable operation of NPPs throughinspection qualification, the application ofrisk-informed approaches, and otherprocesses.

• Providing recommendations and guidanceto optimise and harmonise processes.

• Continually improving the processes forinspection qualification and RI-ISI forincreased effectiveness and efficiency.

• Responding to the new challenges resultingfrom plant life extension (PLEX) and newbuild.

• Promoting ENIQ approaches outsideEurope and in non-nuclear industries.

Accordingly, the technical content of TA8 issubdivided into four ST-A, as follows:


III.8.3.1. NDT Qualification

The ENIQ Methodology is established as one of themain contributors to providing assurance that NDTof nuclear safety critical components is fit forpurpose. This approach assembles theoretical andexperimental evidence and combines this withformal practical demonstrations to ensure thatspecific performance objectives are met. As such,ENIQ has always been playing a first order role onqualification state-of-the-art, creating the firstqualification methodology based on technicaljustifications, issuing recommended practices (RP)and carrying out pilot studies.

The ENIQ TGQ is responsible for having developedthe inspection qualification methodology that is nowbeing used as a basis for all Europeanmethodologies and for CANDU type reactors. TheENIQ inspection qualification methodology is alsoaccepted by the IAEA as recommended practice to

AL AREA 8 49


be followed for nuclear inspection qualification allover the world. After publishing the third issue of theEuropean Qualification Methodology Document in2007, TGQ has recently issued a recommendedpractice on personnel qualification and a documentgiving an overview of inspection qualification for thenon-specialist. Currently TGQ is involved in anumber of projects and preparing new ones.

III.8.3.2. Risk-Informed In-Service Inspection

ENIQ TGR published the "European FrameworkDocument on RI-ISI, EUR21581EN" in 2005 andsince then has been developing a series ofsupporting Recommended Practices (RPs) andinitiating a number of other work-streams toadvance the principles of RI-ISI and maximise theoverall risk benefit. Amongst these are RPs on theverification and validation of structural reliabilitymodels and guidance on the use of expert panelstogether with discussion documents on theapplication of RI-ISI to the inspection of reactorpressure vessels and updating of RI-ISIprogrammes. Also ENIQ TGR members wereheavily involved in the RISMET benchmark projecton RI-ISI that was organised by OECD-NEA.Currently TGR is drafting a technical report on thelessons learned from the application of RI-ISI toEuropean NPP.

III.8.3.3. Inspection Qualification Bodies

Structural Integrity claims for safety critical NPPsoften depend upon having a high level ofconfidence in NDT results, performed either duringmanufacturing of NPP components or ISI of theoperating NPP. The inspection qualification processthat provides this confidence requires thefunctioning of the IQB as a recognised assessmentorganisation (second or third party assessmentorganisation in accordance with ISO 17020). Assuch IQBs that are established by each country arein the best place to provide advice to licensees onthe processes and application of inspectionqualification. Consequently, the licenseesrepresented in ENIQ have decided in 2012 to setup a separate task group for IQB to improvequalification practice and to provide a consensusview to licensees. The role of TGIQB is to providea forum for the free exchange of informationbetween qualification bodies and to identify and

conduct R&D and harmonisation activities that aretargeted at improving the efficiency andeffectiveness of approaches for establishingconfidence in NDT.

Figure 17: Instruments for inspection of the BoronInjection nozzles (Source: EdF)

III.8.4. Challenges

III.8.4.1. NDT Qualification

At present, the main challenges for qualification aremutual recognition of qualification approachesbetween countries and the qualification of new NDTsystems such as those based on phased arrayultrasonic testing, time of flight diffraction ultrasonictesting and computed radiography. This alsoincludes the qualification of NDT techniques formaterials and plant items that have hitherto notbeen considered in any great depth such asconcrete and high density polyethylene. Theaccuracy and validity of NDT inspection simulationsoftware will continue to be an important area ofactivity due to its increasing role in NDT design andqualification.

�

R&D and harmonisation topics:

• A comprehensive investigation intothe performance of computedradiography (CR) aimed to identify theessential parameters that affect theperformance of CR thereby providing aconsistent approach to inspection designand the production of technicaljustifications.

• Develop a recommended practice forcomputed radiography qualification and

50

Phased Array qualification under ENIQtype Methodologies.

• An independent assessment of theaccuracy of guided waves ultrasonictesting (GWUT) for NDT inspections.

• Understand the technical barriers thatpreclude the transport of qualificationsbetween countries and find methods orprocedures on how to overcome these.

• Improve the consistency in inspectionspecifications between countries includingformat, content type and technical details.

• An independent assessment to verifythe accuracy of NDT inspection simulationsoftware,

• Develop accurate and reliableinspection methods for high-densitypolyethylene (HDPE) piping.

• Develop a process for evaluating thereliability of commercially availableinspection techniques and to implement aqualification process for these techniquesfor concrete components.

�

III.8.4.2. Risk-Informed In-Service Inspection

The present challenges on the RI-ISI field are RI pre-service inspection (PSI) for new build and RI-ISI fornew build in general, the development ofprobability of detection (PoD) methodologies andrisk reduction quantification and optimisation of ISIintervals.

�

R&D topics:

• Producing specifications for the use ofprobability of detection (PoD) curves,performance of a pilot study on theapplication of the Monte-Carlo approachfor producing PoD and define the role ofquantified PoD in risk reduction.

• Analysing the role of RI-ISI fordefence in-depth and to assess theachievable level of risk reduction with RI-ISI.

• To review RI pre-service inspection(PSI) for new build.

�

III.8.4.3. Inspection Qualification Bodies

The main challenges for TGIQB are the mutualrecognition of qualified inspections and theimprovement of inspection qualification practices.

�

Harmonisation topics:

• Development of a consensus on thedesign of practical trials and production oftest pieces for qualification of ISIprocedures and personnel.

• Investigate the wider aspects of NDTmodel validation.

• Establish consistent approaches forthe re-qualification of NDT personnel.

• Provide a consistent approach to theassessment of NDT simulation.

�

PRIORITISATION51


Prioritisation is an important exercise in theNUGENIA roadmap because:

• All identified projects cannot be launchedsimultaneously,

• Consistency between the different TAsshould be ensured through a global vision,

• Some of the usual financers of the projects(European Commission, Larger industrycompanies, TSOs) ask for identification ofthe most important subjects to besupported.

The prioritisation will be regularly updated aftertaking into account the progress of the R&D.

Using the process described in chapter II.6, 15objectives appear to be correlated with a highernumber of challenges than the others; thereforethese objectives can be considered as cross cuttingthe technical areas. In other words, the technicalexperts identified challenges that contribute to fulfilthe high level objectives, but some objectives couldrequire more research topics to be defined in thefuture.

As a consequence, the prioritisation processrealised through the correlation of high levelobjectives with the identified challenges allowsdrawing several conclusions:

• The existing roadmaps challenges and topics fitglobally with the high level objectives,

• Some objectives deserve to be further developedin the roadmaps,

• Cross-cutting objectives can be identified tocover several challenges and might be consideredas the main objectives presently covered by theNUGENIA roadmaps.

IV.1. Main initial objectives

The comparison of high level objectives withsub-area topics shows that, the main prioritiescovered by the technical experts include:

• Improve safety in operation and by designfor existing plant through safety andreliability assessment based on lessonslearnt, as well as for new builds throughimproved diversity of systems andindependence of defence in depth levels.

• Assess the performance and ageing of NPPsfor long term operation, by investigation theageing degradation and conditions for longterm operation, demonstrating structuralintegrity of NPP components continuously,and optimising equipment qualification,functionality and maintenance by ageingmanagement.

• Reach the highest reliability and optimisedfunctionality of systems, including I§C, andimprove resilience of systems toaggressions, up to strong aggressions, aswell as their capacity to mitigate severeaccidents, This will only be reached if theboundary conditions for each componentare better understood.

• Increase the reliability of componentsthrough development of new materials,manufacturing and fabrication processes,better reliability of fuel, and increased safetyand reliability predictability as well ascontrol efficiency,-develop better conditionmonitoring methods.

• Improve modelling of phenomena in NPPsin order to reduce uncertainties in themodels and increase their predictability,obtain appropriate validation of the tools,

IV. Prioritisationof area

challenges along main objectives

52

and develop fast running tools to supportreal time action.

• Develop coupled computational tools foradvanced prediction of phenomena(neutronics-thermalhydraulics, fluid-structure interactions by coupling classicalthermal-hydraulic approaches withindustrial fluid dynamics calculations,resolve structure issues while using localapproaches) and for multi-scaleapproaches.

• Increase public involvement in the researchin order to increase public awareness andcontribute to public acceptance.

• Realise an efficient integration of NPPs inthe energy mix, in particular consideringcombinations of different electricity sourcesthat may modify NPP operations and affectthe usage factor for materials, and mode ofdisturbances.

• Prepare the future for avoiding technologyobsolescence and in developing innovation,prepare for integration of new technologiesin existing plants.

Realising all these technical objectives shouldfavour long term operation of existing NPPs,considering also their permanent upgrading forcompensating possible degradations andimproving the global safety level.

This initial list of research objectives for NUGENIAcommunity does not prevent identification of newobjectives in the future, in particular when thecorresponding projects have been performed andexploited.

IV.2. Limitations of theprioritisation exercise andfuture directions

Doing the prioritisation exercise, the timescale assigned to the challenges and topicsin the areas and sub-areas was difficult to

maintain because different time scale challengeswere contributing to the same objective. As aconsequence, it can be understood that thosechallenges are intended to be realised in the shortor in the medium term.

Considering now the completeness of the exercise,and considering that all the objectives have to beachieved up to the same level, NUGENIA intend tomonitor the progress towards each of theseobjectives.

Therefore, to avoid disparity and confusion amongthe different project proposals, an open knowledgeplatform will be developed to help establishing acommon background and initiating challengingprojects of benefit to all members.

In conclusion, in order to improve and confirm theresults of the first prioritisation exercise, whilemeeting the high objectives and challenges ofNUGENIA overall program, it appears useful toexchange first more knowledge between members,and second to carry out in depth discussion toimprove convergence on common technicalpriorities, deploy the necessary effort for education,training and dissemination of new knowledge thatresults from R&D projects.

The Table 1 is the result of the first prioritisationexercise identifying the scientific and technicalobjectives (second column of the table) needed forthe accomplishment of the high level objectivesdefined by the NUGENIA ExCom, TALs and SALs(first column of the table). The numbers in the thirdcolumn are relative to the subareas described indetail in the chapter III of this publication, where theobjective will be considered for initiating,monitoring and valorizing R&D efforts.

53


Table 1: Relations between objectives and challenges.

55


List of contributors

List of acronymsAcronym Definition

BWR Boiling Water Reactor

CFD Computational Fluid Dynamics

EIA Environmental Impact Assessment

ENSREG European Nuclear Safety Regulators Group

FP Framework Programme for Research and Development of European Commission

GRS Gesellschaft für Reaktor Sicherheit

IFE-Halden Institute For Energy - Halden (Norway)

IRSN Institut de Radioprotection et de Sûreté Nucléaire

ISTP International Science Technology Programme

MCCI Molten-Core-Concrete-Interaction

NEA Nuclear Energy Agency

NERISEuropean Platform on Preparedness for Nuclear and Radiological Emergency Response and Recovery

NOIP NUGENIA Open Innovation Platform

NPP Nuclear Power Plant

OECD Organisation for Economic Cooperation and Development

PSA Probabilistic Safety Analysis

PWR Pressurised Water Reactor

RCS Reactor Cooling System

RPV Reactor Pressure Vessel

SA Severe Accidents

SAL Sub-Area Leader

SAMG Severe Accident Management Guidelines

SNETP Sustainable Nuclear Energy Technology Platform

SRIA Strategic Research and Innovation Agenda (SNETP)

SSC Systems, Structures and Components

ST-A Sub-technical area

TAL Technical Area Leader

� Abderrahim Al Mazouzi (EDF )

� Didier Banner (EDF)

� Karim Ben Ouaghrem (IRSN)

� Giovanni Bruna (IRSN)

� Marilyse Caron Charles (AREVA ANP)

� Gorän Hulqovist (Vattenfall)

� Petr Kadecka (UJV)

� Elisabeth Keim (AREVA GmbH)

� Ales Laciok (CEZ)

� Etienne Martin (EDF)

� Oliver Martin (JRC)

� Steve Napier (NNL)

� Martin Pecanka (LGI)

� Sven Reese (E.ON Kernkraft GmbH)

� Edouard Scott de Martinville (IRSN)

� John Sharples (AMEC)

� Jean Pierre Van Dorsselaere (IRSN)

ROADM NUGENAIA Roadmap P2013 - SNETP

Documents

Transcript of ROADM NUGENAIA Roadmap P2013 - SNETP