INFRA Risk informed decision making on nuclear power plant safety Technical Assistance Information Exchange Overview of the IAEA Activities in the Area of PSA and RIDM Presented by: Artur Lyubarskiy IAEA,NSNI/SAS, Instrument & State Nuclear Regulatory Committee of Ukraine 27 – 28 January 2011, Kyiv, Ukraine

2 OUTLINE IAEA Safety Publications on PSA and IRIDM Draft INSAG-25 “A Framework for Risk-Informed Decisions Making Process” Draft TECDOC “Integrated Risk Informed Decision Making Guidance ” Other related activities  Training in PSA and RIDM Safety Assessment Education and Training (SAET) Programme  IAEA TC Project RER9095 RIDM Workshops  PRIS Installation of IE module  SAN/CASAT Installation of Components Reliability Data Base (CRDB)  CRP “Development of Methodologies for the Assessment of Passive Safety System Performance in Advanced Reactors”  IPSART service

3 THE IAEA SAFETY GUIDES ON PSA, 2010 SSG-3: Development and Application of Level 1 SSG-4: Development and Application of Level 2

4 IAEA SAFETY STANDARDS (1/2) IAEA has statutory obligation to develop international standards of safety Safety Guides Requirements Safety Fundamentals Article III.A.6 of Statute: oTo establish or adopt standards of safety for the protection of health and minimization of danger to life and property oTo provide for the application of these standards IAEA SAFETY STANDARDS SERIES  Wide international consensus is achieved through a rigorous development process  134 publications planned, 101 published Global Reference Point for the High Level of Nuclear Safety

5 IAEA SAFETY STANDARDS (2/2) Safety Fundamentals (publication # SF-1) oPresents the fundamental safety objective and ten Fundamental Safety Principles of protection and safety and provides the basis for the safety requirements Safety Requirements oEstablish the requirements that must be met to ensure the protection of people and the environment, both now and in the future –Expressed as “shall” statements –Are governed by the objective and principles of the Safety Fundamentals If the requirements are not met, measures must be taken to reach or restore the required level of safety –Reflect an international consensus on what constitutes a high level of safety Safety Guides oProvide recommendations and guidance on how to comply with the safety requirements –Expressed as “should” statements –Reflect an international consensus on best practices STATUS OF SAFETY STANDARDS:  ARE NOT LEGALLY BINDING ON MSs  BINDING ON THE IAEA IN RELATION TO ASSUSTANCE PROVIDED TO MSs  INCREASIGNLY WIDER USE OF SAFETY STANDARDS BY MSs

6 IAEA SAFETY STANDARDS REVISION PROGRAMME In the new Safety Standards Series the documents which apply to NPP nuclear safety are : In the new Safety Standards Series the documents which apply to NPP nuclear safety are : - The Safety Fundamentals document, and - Three families of documents for:  Siting  Design  Operation The first document in each family is the Safety Requirements and the remaining documents are Safety Guides The first document in each family is the Safety Requirements and the remaining documents are Safety Guides

7 IAEA SAFETY STANDARDS RELATING TO SAFETY ASSESSMENT A need for safety assessment emphasized Comprehensive & detailed safety assessment using PSA & DSA is required for NPPs SAFETY FUNDAMENTALS SAFETY REQUIREMENTS SAFETY GUIDES New Safety Guides provide guidance on performance and application of DSA and PSA, and SAM programmes

SAFETY GUIDES ON PSA (SSG-3 & SSG-4) Objective: oTo provide recommendations for performing or managing a PSA project for an NPP and using it to support the safe plant design and operation –The recommendations aim to provide technical consistency of PSA studies to reliably support PSA applications and risk- informed decisions –An additional aim is to promote a standard framework that can facilitate a regulatory or external peer review of a PSA and its various applications Scope: oAll plant operational conditions oAll potential initiating events and hazards oRadioactivity source: reactor core

9 SAFETY GUIDE ON LEVEL 1 PSA (SSG-3) 1. INTRODUCTION 2. GENERAL CONSIDERATIONS RELATING TO THE PERFORMANCE AND USE OF PSA 3. PSA PROJECT MANAGEMENT AND ORGANIZATION 4. FAMILIARIZATION WITH THE PLANT 5. LEVEL 1 PSA FOR INTERNAL INITIATING EVENTS FOR FULL POWER CONDITIONS 6. GENERAL METHODOLOGY FOR INTERNAL AND EXTERNAL HAZARDS PSA 7. SPECIFICS OF INTERNAL HAZARDS PSA 8. SPECIFICS OF EXTERNAL HAZARDS PSA 9. LEVEL 1 PSA FOR LOW POWER AND SHUTDOWN MODES 10. USE AND APPLICATIONS OF THE PSA Three annexes: Three annexes: oAn example of a list of generic external and on-site hazards oAn example of a fire propagation event tree, and oSupporting information on PSA for low power and shutdown modes

10 SAFETY GUIDE ON LEVEL 2 PSA 1. INTRODUCTION 2. PSA PROJECT MANAGEMENT AND ORGANIZATION 3. FAMILIARIZATION WITH THE PLANT AND IDENTIFICATION OF DESIGN ASPECTS IMPORTANT TO SEVERE ACCIDENTS 4. INTERFACE WITH LEVEL 1 PSA: GROUPING OF SEQUENCES 5. ACCIDENT PROGRESSION AND CONTAINMENT ANALYSIS 6. SOURCE TERMS FOR SEVERE ACCIDENTS 7. DOCUMENTATION OF THE ANALYSIS 8.SPECIFIC NEEDS AND RECOMMENDATIONS FOR APPLICATIONS OF LEVEL 2 PSA Three annexes: Three annexes: oAn example of a typical schedule for a Level-2 PSA oInformation on computer codes for severe accidents, and oDetails of the severe accident phenomena

11 INTERFACE BETWEEN SGs ON PSA Safety Guide on Level 1 PSA and Applications Safety Guide on Level 2 PSA and Applications  Level-3 PSA will be covered later

12 PSA and RIDM in OTHER SAFETY-RELATED PUBLICATIONS

13 PSA IN OTHER SAFETY-RELATED PUBLICATIONS Informational publications May describe good practices and give practical examples and detailed methods that can be used to meet safety requirements Do not establish requirements or make recommendations INSAG IAEA-TECDOC Technical Reports Series Etc. Exchange information on good practices and new developments Safety Reports Series

14 INSAG … The overall risk would then be obtained by considering the entire set of potential events and summing the products of their respective probabilities and consequences… For future nuclear power plants, consideration of multiple failures and severe accidents will be achieved in a more systematic and complete way from the design stage… The target for existing nuclear power plants … is a frequency of occurrence of severe core damage that is below about 10 –4 events per plant operating year. Severe accident management and mitigation measures could reduce by a factor of at least ten the probability of large off-site releases requiring short term off-site response. Application of all safety principles and the objectives of para. 25 to future plants could lead to the achievement of an improved goal of not more than 10 –5 severe core damage events per plant operating year…

15 IAEA PROCEDURES ON PSA Procedures for Conducting Probabilistic Safety Assessments of Nuclear Power Plants (Level 1), Safety Series No. 50-P-4, IAEA, Vienna, 1992 Procedures for Conducting Probabilistic Safety Assessments of Nuclear Power Plants (Level 2): Accident Progression, Containment Analysis and Estimation of Accident Source Terms, Safety Series No. 50-P-8, IAEA, Vienna, 1995 Procedures for Conducting Probabilistic Safety Assessments of Nuclear Power Plants (Level 3), Safety Series No. 50-P-12, IAEA, Vienna, 1996 Treatment of External Hazards in Probabilistic Safety Assessments for Nuclear Power Plants, Safety Series No. 50-P-7, IAEA, Vienna, 1995

16 IAEA-TECDOC-1511 TECDOC-1511 ‘Determining the Quality of Probabilistic Safety Assessment (PSA) for Applications in Nuclear Power Plants’ oIssued in July 2006 oProvides an approach and detailed guidance for achieving the technical quality of PSA needed to support various PSA applications oCovers a Level-1 internal events at-power PSA for NPPs oUpdate of the TECDOC (TC RER9095) –External & Internal Hazards –Low power and shutdown PSA –CM will be organized in April-May 2011

17 IAEA-TECDOC INTRODUCTION 1.1. Background 1.2. Scope of the report 1.3. Structure of the report 2. USE OF RISK IN REGULATORY DECISION MAKING 2.1. Deterministic approach 2.2. Probabilistic approach 2.3. Benefits of an integrated approach 3. INTEGRATED DECISION MAKING APPROACH 3.1. Introduction 3.2. Application of an integrated decision making process 3.3. Requirements of the regulatory body 4. INTEGRATED DECISION MAKING FOR PLANT SAFETY ISSUES 4.1. Overview 4.2. Description of the integrated decision making process as applied to plant safety 4.3. Examples of decisions made using an integrated decision making process 5. RISK INFORMING' REGULATORY ACTIVITIES 5.1. Overview 5.2. Using risk information to prioritize tasks within a regulatory activity 5.3.'Risk informing' the regulations 5.4 Risk informing other regulatory activity APPENDIX – NRC: Process for risk informing the regulation for combustible gas

18 PSA Level 1 SS No.50-P-4 PSA Level 2 SS No.50-P-8 Procedure guidance on PSA performance & review PSA specific tasks and applications under preparation published Safety Series, Safety Report TECDOC Treatment of internal fires, SSR No10 Quality of PSA for applications, TECDOC-1511 Framework of QA for PSA, TECDOC-1101 Review of PSA by Regulatory Body, SRS N025 Human reliability analysis SS No.50-P-10 PSA Level 3 SS No.50-P-12 PSA for low power and shutdown conditions, TECDOC IAEA DOCUMENTS ON PSA AND RIDM LEGEND: Applications of PSA for NPPs, TECDOC-1200 Living PSA, TECDOC-1106 Risk Monitors Use of plant specific data in PSA Risk informed regulation, TECDOC-1436 Interpretation of uncertainties in PSA Use of PSA for design evaluation PSA for Ext. Hazards SS No.50-P-7 Seismic PSA, TECDOC- 724 Precursor analysis, TECDOC-1417 IPSART guidelines, TECDOC-832 Treatment of CCF, TECDOC-648 Reg. Review PSA Level 2, TECDOC ‑ 1229 Reg. Review PSA Level 1, TECDOC ‑ 1135 IRIDM Guidance Level-2 PSA & Applications (SSG-4) Level-1 PSA & Applications (SSG-3) Safety Guide

DRAFT INSAG-25 A FRAMEWORK FOR AN INTEGRATED RISK- INFORMED DECISION MAKING PROCESS

20 IRIDM: The Promise and Reasons Integrated Risk-informed Decision-Making oConsiders all relevant, important factors in an appropriate way –to reach a balanced decision –taking account of all the risks and hazards posed by the facility Increasing interest in a structured framework for optimal decisions PSA is becoming increasingly mature and used widely oIAEA Fundamental Safety Principles and Requirements for Safety Assessment both encourage use of an integrated approach

21 INSAG 25: What is it Intended to Do? Identify the basic framework Set out the principles for application Define the key elements of IRIDM INSAG 25 – currently is being in publication

22 INSAG 25: Advantages of IRIDM  Transparency as the weightings of the elements and the way the resolution is reached are clear  Balanced if all elements are weighted properly  Logical if carried out in a structured way  Consistency if weightings developed appropriately  Accountable if documented properly so the process can be reconstructed The result is a good safety decision

23 INSAG 25: IRIDM Objectives  The main aim of IRiDM is to ensure that any decision affecting safety is optimised  The outcome should Maintain defence-in-Depth Maintain Safety Margins Take engineering and operational good practices into account Make use of relevant OEF, R&D and modern methodologies Establish adequate integration of safety and security, requirements, etc. Ensure relevant regulations are met

24 INSAG 25: The Basic Framework and Key Elements of IRiDM

25 Regulatory Considerations Existing and new regulations Inspection findings OEF Research Utility Considerations Improved performance Financial savings New knowledge Defined Options for maintaining/ improving safety Evaluation of Key Elements Outline process: Defining the Issue

26 Key Elements: Standards and Good Practices  Major considerations in IRIDM Standards and codes produced by a range of organisations  e.g. Government agencies, engineering organisations, QA bodies Good practices  e.g. IAEA Safety Standards, ASME/ANS Standards, IAEA Mission Reports

27 Key Elements: Deterministic Considerations  Basic deterministic safety principles are fundamental in IRIDM Defence-in-depth philosophy “ Adequate ” safety margins Fault tolerant design Emphasis on prevention Mitigation of accidents

28 Key Elements: Probabilistic Considerations Complements deterministic and other considerations o Aims to identify unanalysed failure sequences Probabilistic considerations can range from oEvaluation of data on simple events e.g. maintenance failures through analysis of system reliability, to complex analyses such as PSA Probabilistic Safety Analysis aims for “completeness” Both quantitative and qualitative outputs should be considered within IRIDM oInformation from the logic structure shows weaknesses and lack of balance in design or operation oQuantitative measures allow effects of changes to be evaluated and comparison with safety target In the IRIDM process it is important to consider the PSA quality

29 Key Elements: Organisational Considerations  Management for safety includes : Leadership Control Competence Communication, and co-operation between staff  IRIDM must give organisational and management issues adequate attention

30 Key Elements: Security Considerations  Security or physical protection of nuclear material are important issues which must be considered within the IRIDM process  IRIDM should provide a measured decision ensuring proper integration of safety and security requirements

31 Key Elements: Other Considerations The IRiDM process should consider all relevant factors that may affect risks to people and the environment oNormal operations pose risks to workers and the public from radiation doses due to exposures and discharges –Implementation of new safety measures may also pose risks to workers –The IRIDM process should consider the radiation effects of options on people and the environment and make efforts to reduce them Inspection Findings Research OEF Remaining Lifetime Costs Affects on operation and training

32 Corrective Action Back to “Defined Options ” Evaluated Options: What are the possible safety measures? Integrated Decision Which is the preferred safety measure(s)? Implementation Decisions need to be put into place! Performance Monitoring Has the level of safety desired been achieved? Evaluation of Key Elements NO NO A cceptable Options Outline process: Considering the Outcome

33 Integration of Deterministic and Probabilistic Elements The process of decision-making should be oLogical and made by a group of relevant experts oComprehensive –e.g. give explicit consideration to the possible adverse effects in other areas oTransparent –e.g. the weighting of elements is clear oReproducible in the form of adequate documentation oVerifiable by using a formal process The IRiDM process must be able to combine different forms of input from its various elements There is no single, simple IRIDM process oThe precise process and the relevant importance of each element depends on the issue under consideration

34 Other Features of INSAG 25 Training in IRIDM oSufficient budget and staff need to be allocated and staff need to be trained in the process so they can fulfil the IRIDM tasks oTraining on the IRIDM should be shared among all parties involved in the decision making process (e.g. operator, designer and regulator ) Documentation & Communication oIRIDM decisions should be documented, reviewed, approved, and communicated in a clear and consistent manner oThe methodology should be discussed among all parties involved in IRIDM –including the way the results of the process are obtained and presented

Draft TECDOC “IRIDM Guidance”

36 Objectives of the TECDOC To provide principles and suggest approaches to integrate the results of DSA and PSA as well as other important aspects to make sound, optimum, and safe decisions oFollows main principles listed in INSAG-25 report “A Framework for Integrated Risk-informed Decision Making Process” oProvides detailed information/guidance on the key elements of IRIDM oProvides examples illustrating how the decisions can be made or have been made using structured IRIDM process The first CS was held in Oct. 2009, the second in May 2010 oExperts from Armenia, Germany, Hungary, Korea Japan, UK, Ukraine, US NRS

37 IRIDM Process: Implementation Stages Performance is NOT satisfactory and other decision options are NOT available Performance is satisfactory STAGE 1: PREPARATORY PHASE  Taking a decision to establish IRIDM framework  Develop programme plan and analysis of potential obstacles in the implementation of IRIDM can be conducted to support the decision  Allocation of resources and definition of responsibilities STAGE 2: DEVELOPMENT OF GUIDELINES AND PROCEDURES STAGE 3: FORMATION OF THE ANALYSIS TEAM  Establishing of a multi-disciplinary team of specialists  Training for the IRIDM technique STAGE 4: CONDUCT OF THE ANALYSIS USING IRIDM TECHNIQUE 1) Definition of the issue 2) Identification of potential solution option(s) 3) Determination of technical inputs for IRIDM 4) Weighting the inputs 5) Integration of the inputs and making a decision  If a single solution option is available, the decision is of YES/NO type  If several solution options are available, the most efficient/effective option is chosen 6) Documentation of the analysis and results 7) Receiving a regulatory approval, where appropriate 8) Implement the decision STAGE 5: P ERFORMANCE MONITORING Selection of another option Performance is NOT satisfactory but other decision options are available Abandon the decision or provide corrective/ compensatory measures Continue with the decision Preparation for IRIDM

38 IRIDM Process: Implementation Stages STAGE 1: PREPARATORY PHASE  Taking a decision to establish IRIDM framework  Develop programme plan  Analysis of potential obstacles in the implementation of IRIDM  Allocation of resources and definition of responsibilities

39 IRIDM Process: Implementation Stages STAGE 2: DEVELOPMENT OF GUIDELINES AND PROCEDURES  Setting probabilistic safety goals and establishing regulatory and/or utility policy in relation to IRiDM  The policy should clearly state that an IRiDM process is encouraged and decisions that are derived in accordance with this process will be considered and accepted if the IRiDM process is correctly applied  Establishing acceptance criteria

40 IRIDM Process: Implementation Stages STAGE 3: FORMATION OF THE ANALYSIS TEAM  Establishing of a multi-disciplinary team of specialists  Training for the IRIDM technique

41 IRIDM Process: Implementation Stages STAGE 4: CONDUCT OF THE ANALYSIS USING IRIDM TECHNIQUE 1) Definition of the issue 2) Identification of potential solution option(s) 3) Determination of technical inputs for IRIDM 4) Weighting the inputs 5) Integration of the inputs and making a decision  If a single solution option is available, the decision is of YES/NO type  If several solution options are available, the most efficient/effective option is chosen 6) Documentation of the analysis and results 7) Receiving a regulatory approval, where appropriate 8) Implement the decision

42 Documentation, Monitoring Programme and Feedback Documentation and Implementation of the Results oRisk-Informed decisions should be documented, reviewed, approved in a clear and consistent manner –Data, methods, and assessment criteria used to support the decision of the IRIDM in every step must be well documented Uncertainties associated with the analysis, assumptions made to deal with those uncertainties, degree of confidence in the conclusion of the analysis Factors not considered in the technical analysis of the issue, etc. Monitoring Programme oThe objectives are to verify that decisions –Are implemented as intended and assumptions used in the decision process remain valid –Are producing the intended results and are not producing adverse results oThe programme should be capable of trending performance after a decision has been implemented Feedback oFeedback of information and corrective actions need to be accomplished in a timely manner –That the performance is detected and corrected before safety can be compromised –The process for feedback and reporting should be clear

43 Example of an IRIDM Process Issue: 1) Increase the time between refueling outages from 12 to 18 months 2) Increase the maximum power to 104 % The list of factors and their weightsOption 1 To allow the change under the existing conditions Option 2 To allow the change with modified conditions Option 3 To postpone the change until the specified conditions are met Factor Weight (W)Impact (I)Weight (W)Impact (I)Weight (W)Impact (I) Mandatory requirements High (10)4 3 4 Defence-in-depth High (10)4 4 4 Safety Margins Medium (3)3 3 3 Risk changes Medium (3)5 6 6 Equipment qualification Medium (3)4 4 4 Electricity production. High (10)5 7 5 Maintenance costs Low (1)2 6 5 Radiation doses for workers Medium (3)3 6 5 Overall score = Sum (W*I) Normalized: 1.03 Normalized: 1.18 Normalized: 1.1 Note: Option 4 – to decline the change

44 Annex 1: Description of IRIDM Inputs 1 STANDARDS, BEST PRACTICES AND OPERATIONAL EXPERIENCE FEEDBACK 1.1Legally binding documents 1.2Specific regulations and guidelines 1.3Legally binding documents for licensee 1.4"Good practices" 1.5Operational experience 2DETERMINISTIC CONSIDERATIONS 2.1Safety Criteria 2.2Defence-in-depth 2.3Safety margins 2.4Other deterministic considerations 2.4.1Single Failure Criterion 2.4.2Fail-safe design 2.4.3Equipment qualification 2.4.4Preventing of common cause failure 2.4.5Limiting the claims made on the plant operators 3PROBABILISTIC CONSIDERATIONS 3.1Quantitative information 3.2Qualitative insights 4OTHER CONSIDERATIONS 4.1Security 4.2Radiation doses 4.3Economic benefits 4.5Results of research 4.6Remaining lifetime 4.7Waste Management 4.8 Decommissioning

45 Annex 2: Examples of Decisions Made Using an Integrated Decision Making Process Examples of RI decisions made in oFinland, France, Hungary, Japan, UK, USA Examples of RI decisions made in several other MSs are also available and will be presented in Annex 2 o2 IRIDM workshops held in under TC Project RER9095 –More than 30 participants (Europe) –Experts (US, UK, Finland) oDetailed questionnaires have been completed by the participants from MSs –General information related to information on different PSA applications –Specific Risk-Informed Decisions More examples illustrating the suggested IRIDM process are needed oIn most cases only PSA information was used, but IRIDM process was not completely followed oAdditional efforts are needed: CS to finalize the TECDOC will be organized in April-May 2011

46 IAEA Training in PSA and RIDM

47 SAFETY ASSESSMENT EDUCATION AND TRAINING PROGRAMME (SAET)  Safety assessment competence is the key to making the right decisions in design, operation and licensing SAET: THREE STEP PROCESS Formulation of knowledge requirements Development of training programmes Knowledge and skills maintenance

48 SAET CURRICULUM STRUCTURE I. Fundamentals of Safety Assessment II. Deterministic Safety Assessment III. Probabilistic Safety Assessment Design Basis Analysis Level 1 PSA Beyond Design Basis Analysis Level 2 PSA Level 3 PSA Basic Nuclear Technology Courses 1. Reactor Physics 2. Thermal Hydraulics 3. Nuclear Power Reactor Designs Mandatory for all personnel involved in safety decision making Specialized knowledge aimed at analysts Practical applications skills Essential safety assessment knowledge IRIDM PSA Applications

49 A FLEXIBLE DISTANCE LEARNING PROGRAMME FOR Training in Safety Analysis via Online Learning Modules Using Interactive Analytical Simulators SAET: DEVELOPING ON – LINE TRAINING

50 The IAEA WSs on RIDM

IAEA TC Project RER9095: Workshops on RIDM (1/2) IAEA TC Project RER9095: Strengthening Safety Assessment Capabilities oSubject areas: –Harmonization of PSAs –RIDM The workshops “Framework and Techniques for PSA Applications and RIDM” o23 – 27 November, 2009, Nuclear Safety Research Institute (NUBIKI), Hungary oApril 19-23, 2010, Lithuanian Energy Institute (LEI), Kaunas, Lithuania oExtensive questionnaire (information on the status of PSA applications and RIDM in MSs) –Focus on actual decisions made with the use of risk information by both regulators and utilities –9 completed questionnaires were received from the participants  Information was used during the Working Groups (WGs) and compilation of the WS report  Was essential for preparation of the TECDOC on IRIDM

IAEA TC Project RER9095: Workshops on RIDM (2/2) Main topics for discussion oRole of safety margins and defence in depth in making risk-informed decisions oConservatisms in PSA –How the conservatism should be taken into account in the RIDM process? oUncertainties in PSA – How the uncertainties should be taken into account in the RIDM process? oProcedures/guidance to support RIDM oTraining for power plant staff in RIDM oRisk monitors application for regulators and utility oWeighting: what this means in the RIDM process? –Examples of different weights applied –Qualitative vs quantitative weighting oRegulatory legal framework for the implementation of RIDM system in its own activities

53 Components Reliability Data Base (CRDB)

CASAT & CRDB The Consultancy meeting “Installation of the Components Reliability Database (CRDB) in CASAT” oNovember 2009, Vienna oCASAT: Centre for Advanced Safety Assessment Tools –A knowledge and collaboration platform Follows recommendation of the TM “Development of Generic PSA Databases for WWER NPPs” (RER9/095) oThe CRDB database developed under IAEA TC project should be installed at IAEA in CASAT environment Major tasks (1) Installation of the CRDB in CASAT –The CRDB was successfully installed in the CASAT collaboration space (2) Modifications to the database structure –Reference tables have been compiled –Additional fields need to be added and structure of the “Queries” and ”Reports” were defined The overall goal is that after the component reliability database (CRDB) is installed it will be maintained by MSs operating WWER plants –Additional efforts are required to finalize CRDB

55 Power Reactor Information System (PRIS)

PRIS & IE frequencies (1/2) PRIS: Power Reactor Information System oReference database of authoritative information about NPPs PRIS covers oBasic and design information on nuclear power reactors oPerformance data oDecommissioning data Outage data oStart date/Duration oType code 1 - controlled shutdown until 4 weeks 2 - controlled shutdown within 24 hours 3 - extension of a planned outage 4 - reactor scram automatic 5 - reactor scram manual oDirect Cause code oOperational mode before outage oDescription PRIS is suitable for and is an ideal place for Initiating Event DB Implementation is relatively easy

PRIS & IE frequencies (2/2) It was agreed to extend the existing outage coding system in PRIS by an Initiating Event code oThe extended PRIS would effectively identify initiating events for calculating realistic IE frequencies from the worldwide shared data IAEA Consultancy Meeting (CM) o2-4 November 2009, Vienna Results ( during and after the CM) –IE lists for particular reactor types and models for implementation into PRIS have been finalized –Concept for implementation of IE data items into the PRIS-WEDAS application has been agreed –Guideline on how to assign an IE code to a scram record has been drafted –The requirements to output reports which will support IE data utilisation for PSA studies were specified It is expected that the new extension to PRIS will be available in 2011 oContact person: Mr. Mandula, Jiri; J.

58 Coordination Research Project (CRP)

CRP: “Development of Methodologies for the Assessment of Passive Safety System Performance in Advanced Reactors” oObjective –To determine a common method for reliability assessment of passive safety system performance Method would facilitate application of risk-informed approaches oThe key specific research objectives –Identify requirements for a method of reliability assessment of passive safety systems –Identify a benchmark problem for comparison and validation of methodologies for reliability assessment of passive safety system performance –Select reliability assessment methodologies and perform trial applications, including evaluation of the uncertainties, for a selected benchmark problem –Compare the results and prepare recommendations for a common analysis-and-test based unified approach oTwo Research Coordination Meeting already have held – March 2009, 2010, Vienna oProgress is observed

60 IPSART Service

IPSART SERVICE I I n t e r n a t i o n a l P P r o b a b i l i s t i c S S a f e t y A A s s e s s m e n t R R e v i e w T T e a m  Established in 1988  Conducted in accordance with dedicated Guidelines

Review duration:  1 to 2 weeks Review Team composition:  IAEA Team Leader, assisted, if required, by other IAEA staff  Four to seven international independent experts PSA models, e.g. accident sequences and system analysis IPSART Surface check of methodological aspects, completeness, consistency, coherence, etc. Detailed spot checks PSA objectives, purpose, scope, project plan, work and team organization Database, methodology, parameters, human reliability analysis PSA documentation, information, results, applications, LPSA aspects QA, internal review IPSART REVIEW APPROACH

IPSART MISSION REPORT – MAIN RESULT review findings, Describes the review performed, the review findings, the technical aspects of the PSA study, strengths, and limitations improvement of the PSA quality Provides suggestions and recommendations for improvement of the PSA quality and its sound use for enhancing plant safety and risk management applications IPSART service helps to achieve high quality of PSA and therefore assists in further enhancing the nuclear safety IPSART service helps to achieve high quality of PSA and therefore assists in further enhancing the nuclear safety

CONCLUDING REMARKS Integrated Risk-informed Decision-making is a process oBut not a constraining process oCan be performed in a structured formal manner where major decisions are required such as for new installations or significant modifications but oThe concept of balancing the key elements should be the basis of sound decision INSAG-25 and TECDOC on IRIDM will facilitate development of the IRIDM framework in MSs PSA guides and standards exist to support development of good quality PSA models oPlatform for consistent development, application, and review of PSA studies IAEA continuously provides support to Member States in the area of PSA and RIDM oTraining, Projects, Review Missions, etc. oThe IAEA publications available at:

65 REFERENCES (1/4) IAEA, Safety Assessment for Facilities and Activities, IAEA Safety Standards Series, IAEA, Vienna, GSR-part 4 (2010). IAEA, Safety of Nuclear Power Plants: Design, IAEA Safety Standards Series No. NS-R-1, IAEA, Vienna (2000) IAEA, Safety of Nuclear Power Plants: Operation, IAEA Safety Standards Series No. NS-R-2, IAEA, Vienna (2000) IAEA, SSG-3 “Development and Application of Level-1 PSA”, 2010 IAEA, SSG-4 “Development and Application of Level-2 PSA”, 2010 Basic Safety Principles for Nuclear Power Plants, 75-INSAG-3 Rev. 1, INSAG-12, IAEA, Vienna (1999) IAEA-Safety Report Series No. 10, Treatment of Internal Fires in Probabilistic Safety Assessment for Nuclear Power Plants, (1998). IAEA-SAFETY SERIES No. 50-P-4, IAEA, Procedures for Conducting Probabilistic Safety Assessments of Nuclear Power Plants (Level 1), (1992). IAEA-SAFETY SERIES No. 50-P-8, Procedures for Conducting Probabilistic Safety Assessments of Nuclear Power Plants (Level 2), (1995). IAEA-SAFETY SERIES 50-P-12, Procedures for Conducting Probabilistic Safety Assessments of Nuclear Power Plants (Level 3), (1996). IAEA-SAFETY SERIES No. 106, The Role of Probabilistic Safety Assessment and Probabilistic Safety Criteria in Nuclear Power Plant Safety, (1992).

66 REFERENCES (2/4) IAEA-SAFETY SERIES No. 50-P-10, Human Reliability Analysis in Probabilistic Safety Assessment for Nuclear Power Plants, (1995). IAEA-SAFETY SERIES No. 50-P-7, Treatment of External Hazards in Probabilistic Safety Assessment for Nuclear Power Plants, (1998). IAEA, OECD NEA, Risk Monitors: The State of the Art in their Development and Use at Nuclear Power Plants, WGGRisk, NEA/CSNI/R(2004)20, OECD/NEA, Paris, (2004) IAEA, TECDOC-1200, Applications of Probabilistic Safety Assessment (PSA) for Nuclear Power Plants, Vienna (2001) IAEA, TECDOC-1436 “Risk informed regulation of nuclear facilities: Overview of the current status” (2005) IAEA, TECDOC-1511 “Determining PSA Quality for Various Applications”, 2006 IAEA, The Role of Probabilistic Safety Assessment and Probabilistic Safety Criteria in Nuclear Power Plant Safety, Safety Series No. 106, IAEA, Vienna (1992) IAEA-TECDOC-1411, Procedures for performance of low power and shutdown probabilistic safety assessment, (1999) IAEA-TECDOC-1200, PSA Applications, (1999) IAEA-TECDOC-1002, Use of PSA Level 2 analysis for improving containment performance, (1998). IAEA-TECDOC-1101, Framework for a Quality Assurance Programme for PSA, (1999).

REFERENCES (3/4) IAEA-TECDOC-1106, Living probabilistic safety assessment (LPSA), (1999). IAEA-TECDOC-1135 “Regulatory review of probabilistic safety assessment (PSA) Level 1”, (2000) IAEA-TECDOC-1229 “Regulatory review of probabilistic safety assessment (PSA) Level 2”, (2001) IAEA-TECDOC-478, Component Reliability Data for Use in Probabilistic Safety Assessment, (1988). IAEA-TECDOC-508, Survey of ranges of Component reliability data for use in probabilistic safety assessment, (1989). IAEA-TECDOC-611, Use of Plant Specific PSA to Evaluate Incidents at Nuclear Power Plants, (1991). IAEA-TECDOC-636, Manual on reliability data collection for research reactors, (1992). IAEA-TECDOC-648, Procedures for Conducting Common Cause Failure Analysis in Probabilistic Safety Assessment, (1992). IAEA-TECDOC-711, Use of Probabilistic Safety Assessment for nuclear installations with large inventory of radioactive material, (1993). IAEA-TECDOC-719, Defining Initiating Events for the Purposes of Probabilistic Safety Assessment, (1993). IAEA-TECDOC-724, Probabilistic Safety Assessment for Seismic Events, (1993).

REFERENCES (4/4) IAEA-TECDOC-729, Risk Based Optimization of Technical Specifications for Operation 0f Nuclear Power Plants, (1993). IAEA-TECDOC-737, Advances is reliability analysis and probabilistic safety assessment for nuclear power reactors", (1994). IAEA-TECDOC-740, Modelling and data prerequisites for specific applications of PSA in the management of nuclear plant safety, (1994). IAEA-TECDOC-749, Generic Initiating Events for PSA for WWER Reactors, (1994). IAEA-TECDOC-751, PSA for the shutdown mode for nuclear power plants, (1994). IAEA-TECDOC-832, IPERS Guidelines for the International Peer Review Service, (1995). IAEA-TECDOC-873, Application and development of probabilistic safety assessment for nuclear power plant operation, (1996). IAEA-TECDOC-930, Generic component reliability data for research reactors, (1997) The vast majority of documents is available free of charge in PDF-form at the IAEA publications WEB-page: ohttp://www-pub.iaea.org/MTCD/publications/publications.asp

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