P2. Overview of the IAEA s Project on Safety Goals

Transcription

1 P2. Overview of the IAEA s Project on Safety Goals Presented by: Irina Kuzmina, Safety Officer Safety Assessment Section/ Division of Nuclear Installation Safety/ Department of Nuclear Safety and Security i.kuzmina@iaea.org Technical Meeting on Development of a TECDOC on Development and Application of a Safety Goals Framework for Nuclear Installations Vienna, Austria July 8-12, 2013

2 Background IAEA Safety Standards INSAG report HIGHLIGHTS Overview of the developments under the IAEA project on Safety Goals TM in April 2011 CMs Outputs 2 of 26

3 RELEVANT STATEMENTS FROM THE SAFETY FUNDAMENTALS The fundamental safety objective is to protect people and the environment from harmful effects of ionizing radiation Principle 6: Limitation of risks to individuals Measures for controlling radiation risks must ensure that no individual bears an unacceptable risk of harm Implications: 1) Risk associated with nuclear installations needs to be assessed 2) Guidance (criteria) for unacceptable risk need to be established SAFETY GOALS 3) Relevant measures (design features and procedures) to be provided to control risk 3 of 26

4 SAFETY GOALS QUALITATIVE PROBABILISTIC QUANTITATIVE Safety Margins Defense-in-Depth Multiple barriers and levels of protection Diversity and redundancy within and between safety systems Single failure criterion Postulated initiating events, etc. 1.0E E E E E E E E E E E+00 Limits for respective RISK METRICS - frequencies of undesirable consequences (events/time unit) 4 of 26

5 1/y 1/y ILLUSTRATION OF THE CONCEPT OF NUMERICAL SAFETY GOALS CONSIDERED IN INSAG-12 & NS-G-1.2* Core Damage Frequency (CDF) Large Release Frequency (LRF) 1.0E E-05 CDF for operating NPPs 1.0E E-06 LRF for operating NPPs 8.0E E E E E E E E E E E E E E+00 CDF for new NPPs 3.0E E E E+00 Practical elimination of accident sequences that could lead to large early radioactive releases for new NPPs (NS-G-1.2)* * Comment: NS-G-1.2 is superseded by SSG-2, where such link is not included 5 of 26

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7 IAEA TECHNICAL MEETING ON SAFETY GOALS IN APPLICATION TO NUCLEAR INSTALLATIONS TM Objective Provide international forum for presentations and discussions on the current practices in establishing and use of Safety Goals for nuclear installations To contribute to outlining the way forward TM Summary Some 40 attendees from 23 countries and 5 international organizations - regulators, operators, designers, consultants, and TSOs 30 presentations and papers Two working groups: WG1: General Framework for Safety Goals and Methodologies/Processes for Compliance Assessment WG2: Process of Derivation of Low-Tier Quantitative Safety Goals and Qualitative and Quantitative Safety Goals Specification Questionnaire on national framework for Safety Goals with 20 responses 7 of 26

8 OUTPUT A formal TM report has been produced Outputs of WGs Questionnaires responded Papers Conclusions and recommendations for IAEA activities 8 of 26

9 OBSERVATIONS Surveys show that there is a variety of approaches relating to establishment and use of Safety Goals in Member States, which often include qualitative considerations and quantitative risk metrics Recent international projects on Safety Goals being pursued by different expert groups [e.g. MDEP, WENRA, Nordic PSA Group (NPSAG)] produced recommendations Growing importance of establishing a technically consistent holistic framework for Safety Goals for NPPs and other nuclear installations on the basis of synergetic consideration of qualitative concepts and quantitative risk metrics 9 of 26

10 RECOMMENDATIONS Five areas were recommended by the TM where IAEA should consider producing guidance (the formal TM report): 1. Develop a hierarchical approach for Safety Goals 2. Clarify interfaces between the Fundamental Safety Objectives, Safety Principles, Safety Requirements and the proposed framework for Safety Goals 3. Develop a methodology to derive lower-tier goals in a consistent and coherent manner 4. Develop guidance on methods and approaches to assess the degree of compliance with the full spectrum of Safety Goals and a comprehensive review methodology 5. Develop an approach to using Safety Goals 10 of 26

11 CONTINUED WORK AFTER TM APRIL 2011 A series of consultant meetings ( ) to develop a draft TECDOC - Development and Application of a Safety Goals Framework for Nuclear Installations Overall Objective: to promote a greater harmonization of the use of Safety Goals in Member States Specific Objectives: to provide guidance for establishing a formal framework for Safety Goals and compliance assessment Drafting TECDOC - CM participants: Irina Kuzmina (IAEA) Andy Ashworth (AECL, Canada) Heinz Peter Berg (BfS, Germany) Nigel Buttery (EdF Energy, UK) Michael Knochenhauer (Lloyd s Register Scandpower, Sweden) Geoff Vaughan (ONR, UK) See-Meng Wong (NRC, USA) 11 of 26

12 OUTLINE 1. INTRODUCTION 2. DISCUSSION ON OBJECTIVES AND BENEFITS OF INTRODUCING A SAFETY GOALS FRAMEWORK 3. CONCEPTS RELATED TO THE SAFETY GOALS FRAMEWORK 4. A GENERAL FRAMEWORK FOR SAFETY GOALS 5. DERIVATION OF SAFETY GOALS WITHIN THE HIERARCHY 6. Section 6 APPLICATION OF THE SAFETY GOAL STRUCTURE AND COMPLIANCE ASSESSMENT 7. CONCLUSIONS APPENDIX 1 GLOSSARY APPENDIX 2 SPECIFIC EXAMPLES OF SAFETY GOALS FRAMEWORK APPENDIX 3 DEVELOPMENT OF USNRC SAFETY GOALS FOR LIGHT WATER REACTORS 12 of 26

13 DEVELOPMENT OF A SAFETY GOALS HIERARCHY Considers work within the CM teams as well as the hierarcies of Safety Goals suggested in the MDEP and NPSAG projects on safety goals 13 of 26

14 DEVELOPMENTS BY MULTINATIONAL DESIGN EVALUATION PROJECT - MDEP Within MDEP, a group was tasked with considering how to harmonise Safety Goals The MDEP work attempted to set out a hierarchical approach Top level = Fundamental Safety Objective of the IAEA of protecting people from radiation risks Second tier is based partly on the basic defence-in-depth approach, probably still to some extent technology independent From the upper levels the intention is to develop lower-level goals, eventually technology specific Top Level Safety Goal High Level Safety Goals (DiD and Risk Goals) Lower Level Safety Goals and Targets (Deterministic and probabilistic) Technology Specific Safety Targets 14 of 26

15 HIERARCHY SUGGESTED IN NORDIC PSA GROUP PROJECT - NPSAG As part of the NPSAG project on probabilistic Safety Goals, a hierarchy was suggested There are four levels : Society level (legislation expressing high-level requirements) Intermediate level (interpretation of legal requirements in a way that allows quantification) Technical level (quantitative requirements) High level (corresponding to PSA Level 1, 2 and 3) Low level (corresponding to safety systems and functions) 15 of 26

16 SUGGESTED HIERARCHY OF SAFETY GOALS (1/5) 16 of 26

17 SUGGESTED HIERARCHY OF SAFETY GOALS (2/5) Level Formulation Description Top Level Primary Safety Goal Protecting people and the environment from harmful effect of ionizing radiation Primary safety goal as set out in SF-1 and society level safety goals as defined in national legislation or regulations 17 of 26

18 SUGGESTED HIERARCHY OF SAFETY GOALS (3/5) Level Formulation Description Upper Level Adequate Protection Ensuring adequate protection in all operational modes of all facilities and installations at the site Interpretation of the top level safety goal in risk terms. This is often done by comparison with the levels of risks coming from other involuntary sources of risk 18 of 26

19 SUGGESTED HIERARCHY OF SAFETY GOALS (4/5) Level Formulation Description Intermediate Level General Safety Provisions Providing necessary safety provisions including technical and organizational measures based on proven approaches and good practices to ensure adequate protection Proven approaches and good practices to achieve the higher level safety goals as well as definition of general requirements on site level 19 of 26

20 SUGGESTED HIERARCHY OF SAFETY GOALS (5/5) Level Formulation Description Low Level Specific Safety Provisions Providing necessary specific safety provisions for all facilities and installations at the site Technology and facility specific safety goals aimed at assuring the nuclear installation meets the higher level safety goals 20 of 26

21 BASIC TYPES OF SAFETY GOALS 21 of 26

22 An Example of Hierarchy of Safety Goals for Nuclear Installations O1 To protect workers, the public and the environment Qualitative O1-Q1 Management, leadership and safety culture Deterministic quantitative O1-D1 To meet ICRP criteria for workers by providing adequate radiation protection measures Operational states O2 To provide design features for security TOP LEVEL - PRIMARY SAFETY GOAL: To protect people and the environment from harmful effects of ionizing radiation UPPER LEVEL SAFETY GOALS: Ensuring adequate protection in all operational modes of all facilities and installations at the site O3 To minimize radioactive waste O4 To provide design features to facilitate decommissioning A1 Risk to life and health of people from the facilities and installations located at the site should be low comparing with risk from other sources to which an individual is generally exposed Accident conditions A2 Large off-site releases leading to land interdiction should be practically eliminated INTERMEDIATE LEVEL SAFETY GOALS: Providing necessary safety provisions including technical and organizational measures based on proven approaches and good practices to ensure adequate protection Qualitative A1-Q1 Maintaining effective defense-in-depth Deterministic quantitative A1-D1 Maintaining allowed doses for workers in DBAs Probabilistic quantitative A1-P1 Overall L(E)RF for the site for all events and hazards Qualitative A2-Q1 Providing effective SAM design features and SAMG at the site level Probabilistic quantitative A2-P1 Probabilistic interpretation of practically eliminated A3 Safety-security interface should be addressed A3-Q1 Vital area identification at the site level A4 Emergency response should be provided A4-Q1 Detailed emergency plan Society-wide Site-wide Technologyneutral Site-wide Technologyneutral O1-D2 To meet ICRP criteria for discharges to the environment by providing adequate measures for controlling the discharges A1-Q2 Maintaining sufficient safety margins A1-D2 Maintaining allowed discharges to the environment in DBAs A1-P2 Frequencies of external hazards/ magnitudes for design of site protective features A2-P2 Food ban radioactivity levels and accepted frequency A4-D1 Food ban levels A1-Q3 Providing sufficient redundancy and diversity to comply with single failure criterion A1-D3 Containment withstanding the crash of a specified size aircraft A2-P3 Habitation radioactivity levels and accepted frequency A4-D2 Habitation radioactivity levels LOW LEVEL SAFETY GOALS: Providing necessary specific safety provisions for all facilities and installations at the site Deterministic quantitative A1-Q2-INST1(D1) max fuel clad temp. for INST1 A1-Q2-INST1(D2) for INST A1-Q2-INST2(D1) max fuel clad temp. for INST2 A1-Q2-INST2(D2) for INST2 A1-Q3-INST1 - required three trains of safety systems Probabilistic quantitative LERF for each installation: A1-P1-INST1(LERF), A1-P1-INST2(LERF), Supplemental goals on CDF as applicable: A1-P1-INST1(CDF ), A1-P1-INST2(CDF), Instantaneous risk limit Qualitative A2-Q1- INST1(SAMG) A2-Q1- INST2(SAMG) Providing effective SAM design measures and SAMG at the facility level A3-Q1-INST1 A3-Q1-INST12 Vital area identification at facility level Technologyspecific Facility and installationspecific 22 of 26

23 ANTICIPATED REMAINING WORK TO DEVELOP TECDOC Second Technical Meeting to discuss draft TECDOC July 2013, Vienna, Austria CM July 15-19, 2013 Addressing recommendations of the 2d TM, finalization of the TECDOC 23 of 26

24 ISSUES NEEDING FURTHER CONSIDERATION Practically eliminated: The possibility of certain conditions occurring is considered to have been practically eliminated if it is physically impossible for the conditions to occur or if the conditions can be considered with a high level of confidence to be extremely unlikely to arise. Quantification is asked by Member States for the terms : Extremely unlikely High level of confidence What should be the basis for these? 24 of 26

25 SUMMARY Following the recommendations of Member States, the IAEA is developing a TECDOC aimed at: Suggesting an approach for establishing a robust framework for Safety Goals for nuclear installations, and Providing guidance on compliance assessment The TM will review and further develop the TECDOC High interest Important topic Publishing the TECDOC is anticipated end 2013 beginning of 26

26 THANK YOU FOR YOUR ATTENTION 26 of 26