Transcript OECD OPDE Project

International Workshop
On
Level 2 PSA and Severe Accident Management
Hosted by: Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbh, Köln, Germany
29th to the 31st of March 2004
Barry Kaufer, Deputy Head, Regulation
Nuclear Safety Division
Le Seine St.-Germain
12, boulevard des Iles
92130 Issy-les-Moulineaux, France
([email protected])
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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Table of contents
 Safety
and Regulation at OECD/NEA
 Committee on the Safety of Nuclear
Installations (CSNI)
 Working Group on Risk Assessment
(WGRisk) – Level 2 PSA
– 1997 State-of-the-Art Report
– 2004 Programme of Work
 Summary
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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COMMITTEE ON THE SAFETY OF NUCLEAR INSTALLATIONS (CSNI)
CHAIRMAN: A. THADANI - SECRETARY: J. REIG
BUREAU: G. LOWENHIELM, L. HAHN, K. ABE, J.C. NIEL, K. VALTONEN
January 2004
CSNI PROGRAMME REVIEW GROUP (PRG) CHAIRMAN: T. KING - SECRETARY: M. HREHOR
SPECIAL EXPERT GROUPS
WORKING GROUPS
RISK
ASSESSMENT
(WGRISK)
CHAIR: J. M. LANORE
SECRETARY: B. KAUFER
ANALYSIS AND
MANAGEMENT OF
ACCIDENTS
(GAMA)
INTEGRITY AND
AGEING OF
COMPONENTS AND
STRUCTURES
(IAGE)
OPERATING
EXPERIENCE
(WGOE)
CHAIR: M. DURIN
SECRETARY: J. ROYEN
CHAIR: N. CHOKSHI
SECRETARY: E. MATHET
CHAIR: A. VANDEWALLE
SECRETARY: P. PYY
CO-ORDINATED
PROGRAMME SERENA
INTEGRITY OF METAL
COMPONENTS &
STRUCTURES
FUEL CYCLE SAFETY
(FCS)
CONCRETE STRUCTURES
AGEING
JOINT CSNI/CNRA
TASK ON PLANT SAFETY
PERFORMANCE
INDICATORS
HUMAN &
ORGANISATIONAL
FACTORS
(SEGHOF)
FUEL SAFETY
MARGINS
(SEGFSM)
CHAIR: A. FRISCHKNECHT
SECRETARY: P. PYY
CHAIR: W. WIESENACK
SECRETARY: M. HREHOR
SESAR/SFEAR GROUP
SECRETARY: C. VITANZA
SAFETY MARGINS ACTION PLAN
CHAIR: O. SANDVERAG
SECRETARY: J. ROYEN
SEISMIC BEHAVIOUR OF
STRUCTURES
OECD PROJECTS
SECRETARIES: C. VITANZA
E.MATHET, P. PYY
HALDEN
SETH
CABRI WATER
LOOP
OPDE
OECD-FIRE
MASCA II
MCCI
PSB-VVER
ICDE
COMMITTEE ON NUCLEAR REGULATORY ACTIVITIES (CNRA)
January 2004
CHAIRMAN: J. LAAKSONEN - SECRETARY: J. REIG
CNRA BUREAU: S. COLLINS, C. VIKTORSSON, J. FURNESS/M. WEIGHTMAN, A. SCHMITT, K. ABE, J.J. VAN BINNEBEEK
WORKING GROUPS
JOINT ACTIVITIES
TASK GROUPS
WORKING GROUP ON
INSPECTION PRACTICES
(WGIP)
TASK GROUP ON
REGULATORY DECISION
MAKING
JOINT CSNI/CNRA
TASK ON PLANT SAFETY
PERFORMANCE INDICATORS
CHAIRMAN: H. KLONK
SECRETARY: B. KAUFER
CHAIRMAN: U. SCHMOCKER
SECRETARY: B. KAUFER
SECRETARY: P. PYY
WORKING GROUP ON PUBLIC
COMMUNICATION (WGPC)
NEA/WANO/IAEA
NUCLEAR EVENTS BASED WEB
SYSTEM (NEWS)
REGULATORY EFFECTIVENESS
INDICATOR INFORMATION EXCHANGE
(PILOT CONTINUATION)
SECRETARY: B. KAUFER
SECRETARY: B. KAUFER
CHAIRMAN: A JÖRLE
SECRETARY: J. ROYEN
NEA REGULATOR/INDUSTRY FORUM (RIF2004)
SECRETARY: B. KAUFER
RADIOACTIVE WASTE MANAGEMENT COMMITTEE
REGULATORS’ FORUM (RWMC-RF)
ANNUAL REPORT ON REGULATORY RELATED
ISSUES
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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WGRisk


Over the past 24 years, PWG5 and now WGRisk have looked at the technology
and methods used for identifying contributors to risk and assessing their
importance. Work during the early part of this period was concentrated on
Level 1 PSA methodology, but in recent years, the focus has shifted into
specific PSA methodologies modelling issues and risk informed applications.
During this long period WGRisk has produced over 40 technical reports, held
over 25 international workshops and has issued several important consensus
statements and opinion papers on specific aspects of PSA.
The main mission of the Working Group on Risk Assessment (WGRisk) is to
advance the understanding and utilisation of Probabilistic Safety Assessment
(PSA) in ensuring continued safety of nuclear installations and in improving the
effectiveness of regulatory practices in Member countries. In pursuing this
goal, the Working Group shall recognise the different methodologies for
identifying contributors to risk and assessing their importance. While the
Working Group shall continue to focus on the more mature PSA methodologies
for Level 1, Level 2, internal, external, shutdown, etc. It shall also consider the
applicability and maturity of PSA methods for considering evolving issues such
as human reliability, software reliability, ageing issues, etc., as appropriate.
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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WGRisk Classification of Probabilistic Safety Assessment Topics
Risk Informed Regulation and Safety Management
Level 2 PSA and Severe
Accident Management
Level 1 PSA
Integrated Methods for PSA
Methodologies
Non-reactor nuclear facilities
Human Reliability
PSA Topic Specific Methods
Development
Exchange of Information
Seismic Risk
Modelling Ageing Issues in
PSA
Level 3 PSA
Fire Assessment
Software Reliability
Living PSA
PSA Standards
Other External
Events
Reliability of Passive
Systems
Low Power &
Shutdown Events
Uncertainty Analysis
PSA Applications
Risk Monitors
Event Analysis
(PSAEA)
Plant Modifications
PSA for Operation
(Tech. Specs., ISI,
IST, etc.)
PSA for Power
Upgrades, Life
Extensions, etc.
PSA Related Information
Collection
Common Cause
Failures (ICDE)
Software (COMPSIS)
Piping (OPDE)
Fire (OECD-FIRE)
Human Reliability
Other PSA Issues
Alternative
approaches
Dynamic PSA
PSA Comparison
PSA for Advanced
Reactors
Public Perception of
Risks
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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High
Figure 1
Exchange of Information
Human Reliability
Fire Assessment
Level 2 PSA
Low Power/Shutdown
Event Analysis
ICDE
OECD-FIRE
HRAD
Prioritisation of PSA Topics
Medium
PSA Standards
Other External Events
Ageing Issues
Software Reliability
COMPSIS
PSA for Power Upgrades,
Life Extension, etc.
Living PSA
Seismic Risk
PSA for Operation
OPDE
Uncertainty Analysis,
Plant Modifications
Passive Systems
Public Perception
Low
Priority
Risk Monitors
Alternative
Approaches
Dynamic PSA
Low
Level 3 PSA
Non-reactor Nuclear
Facilities
PSA Comparison
Advanced Reactors
Level 1 PSA
Medium
High
Importance
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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WGRisk – Level 2 PSA Discussion Outcomes

[1996]
– In the early 1990’s, with the advent of increasing use of PSAs, a proposal was made
at the 1993 PWG5 Annual meeting for future work in the area of Level 2 PSA. The
main objective of the proposed task was to perform a state-of-the-art review of the
methods available for performing level 2 PSAs and severe accident/source term
uncertainty analyses for use in the regulatory process and the
evaluation/implementation of severe accident management strategies.

[2002]
– The reports from the experts and discussions within WGRisk show it is clear that if
one were to use NUREG 1150 as a basis, experimental evidence over the past 10
years or more indicates that the perceptions of risk in Level 2 PSA has changed what
may be considered significant. While it is not clear how the results would specifically
change, the body of information that has been compiled would change the
distributions that were used in NUREG 1150. Additionally, based on the national
reports presented at WGRisk meetings many countries (Germany, Korea, Finland,
France, Hungary, Czech Republic, Switzerland and Japan) are actively working on
Level 2 PSA. Therefore the proposed workshop is considered is seen as beneficial to
getting a better understanding of the current state-of-the-art.
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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WGRisk State-of-the-Art Report, 1997

The report (Level 2 PSA Methodology and Severe Accident Management
NEA/CSNI/R(1997)11) reviews and evaluates Level 2 PSA results and
methodologies with respect to plant type specific and general insights

The report also looks at approaches and practices for using PSA results in
the regulatory context and for supporting severe accident management
programmes by input from Level 2 PSAs are examined.
– The report is based on information contained in:


PSA procedure guides, PSA review guides and regulatory guides for the use of PSA
results in risk-informed decision making, and

Plant specific PSAs and PSA related literature exemplifying specific procedures,
methods analytical models, relevant input data and important results, use of
computer codes and results of code calculations. The PSAs are evaluated with
respect to results and insights.
Review of Report was performed in 2002 (next presentation)
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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Chapter 1
1. TASK DESCRIPTION AND WORKING
METHODOLOGY
–
–
–
–
–
–
1.1 Background
1.2 Objective and Scope
1.3 Level 2 PSA methodologies
1.4 Accident management
1.5 OECD/NEA activities on accident management
1.6 OECD/NEA activities on severe accident
phenomena
– 1.7 Structure of the report.
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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Chapter 2
2 RESULTS AND INSIGHTS FROM RECENT
LEVEL 2 PSA
– 2.1 Examined PSAs and considered aspects
– 2.2 Objectives and scope of recent level-2 PSAs.
– 2.3 Plant characteristics influencing severe accident
progression
– 2.4 Level 2 methodology and codes
– 2.5 Principal results, insights on containment failure
modes and releases.
– 2.6 References
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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Chapter 3
3 KEY SEVERE ACCIDENT ISSUES
– 3.1 Key Severe Accident Phenomena.
– 3.2 Review of severe accident computer codes
– 3.3 Documentation of the Use of Severe
Accident Computer Codes in Selected Level 2
PSAs for Nuclear
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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Chapter 4
4
SEVERE ACCIDENT MANAGEMENT
–
–
–
–
4.1 Background and Objectives
4.2 Evolution of an accident from the operators perspective
4.3 Safety objectives for the development of SAM Guidance
4.4 Examples of implemented provisions for mitigative SAM
(level 2) and of their effectiveness
– 4.5 Identification of Recovery and SAM Actions in the Level
1 Domain that can influence SAM in the Level 2 Domain.
Some Examples
– 4.6 References
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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Chapters 5 and 6
5 AVAILABLE METHODOLOGY FOR QUALITATIVE
LEVEL 2 ANALYSIS
– 5.1 Level 1/2 Interface
– 5.2 Accident progression Event Trees
– 5.3 Modelling of human intervention
6 EVALUATION OF LEVEL 2 PSA MODELS AND
QUANTIFICATION
– 6.1 Brief description of Methods
– 6.2 Use of Expert Judgement
– 6.3 Uncertainty Issue Quantification Technique
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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Chapter 7
7
INTEGRATED AND PSA INFORMED APPROACH
TO DECISION MAKING
– 7.1 Introduction
– 7.2 Recent activities and publications related to risk informed
decision making
– 7.3 Quality requirements for PSAs
– 7.4 National Positions on risk informed decision making.
– 7.5 Treatment of Uncertainties
– 7.6 Examples of risk informed decisions in the level 2 domain
– 7.7 Conclusions
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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Appendices
APPENDIX A: SEVERE ACCIDENT COMPUTER
CODES
– A.1 Fully Integrated Plant Simulation Codes
– A.2 Separate Phenomena Codes
– A.3 Parametric Codes
APPENDIX B:
–
–
–
–
B.1 EVNTRE
B.2 SOLOMON
B.3 RISKMAN
B.4 SPSA
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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2004 WGRisk Programme of Work (1)
 International
Workshop on Level 2 PSA and Severe
Accident Management.
– The main objectives are:
To provide a forum to discuss recent developments in the state-ofthe-art of Level 2 PSA and Severe Accident Management.
 The information gathered will be used to produce an addendum to
the 1997 WGRisk report,
 Will provide input into the joint workshop planned by WGAMA,
IAGE and WGRisk on Evaluation of Uncertainties in relation to
Severe Accident and Level 2 Probabilistic Safety Analysis (to be
held in the Fall of 2004), and
 Will be used to develop future tasks by WGRisk.

(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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2004 WGRisk Programme of Work (2)

The Use and Development of PSA in NEA Member
Countries [NEA/CSNI/R(2002)18]
– This report provides descriptions of the current status of PSA
programmes in 17 Member countries including basic background
information, guidelines, various PSA applications, major results in recent
studies, PSA based plant modifications and research and development
topics. While the compilation is a not complete compilation it provides a
“snapshot” of the current situation in the Member countries and hence it
provides reference information and various insights to both the PSA
practicien and others involved in the nuclear industry.
– The report forms the basis for a yearly round table discussion at WGRisk
meetings and will be updated every 3 to 4 years.
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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2004 WGRisk Programme of Work (3)
 Use
of PSA in Emergency Planning [Task
2004-3]
– The aim is to identify the approaches being used in the
member countries to define the emergency planning zones
round nuclear facilities and how this relates to the
information provided by the Level 2 PSA. The various
approaches would be compared to identify similarities and
differences. Consideration would also be given on whether
it would be possible to define a common approach to using
the Level 2 PSA information for this purpose.
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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2004 WGRisk Programme of Work (4)
 GAMA/WGRISK/IAGE
Workshop on Evaluation
of Uncertainties in Relation to Severe Accidents and
Level 2 PSA
– The objectives are:
To transfer information among Working Groups on an important crosscutting issue.
 To develop a coherent approach/understanding regarding uncertainties.
 The product will be proceedings, and conclusions/recommendations
addressed to CSNI and the Working Groups.

– Tentative Date: Spring 2005
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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Summary
 WGRisk
State-of-the-Art report provided first
in-depth look at Level 2 PSA Methodology in
the Member Countries
 WGRisk has an active programme in the area of
Level 2 PSA and Severe Accident Management
 WGRisk works (and will continue to work) with
other working groups (e.g., GAMA) and other
organisations (e.g., IAEA) to co-ordinate it work
on this issue.
(Workshop on Level 2 PSA and Severe Accident Management, March 2004 )
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