Säkerhetsmål för kärntekniska installationer Development and Application of a Safety Goals Framework for Nuclear Installations

Säkerhetsmål för kärntekniska installationer Development and Application of a Safety Goals Framework for Nuclear Installations Michael Knochenhauer Vice President, R&D Director Lloyd s Register Consulting SSM:s Forskningsdagar, Stockholm, 24-25 oktober 2013

Översikt Bakgrund nordiskt projekt The Validity of Safety Goals 2006-2010 Syfte och översikt Viktigaste resultat Struktur på föreslaget ramverk Status internationellt Pågående och nyligen genomförda aktiviteter Pågående IAEA-aktivitet Översikt Presentation av föreslaget ramverk

Nordiskt projekt The Validity of Safety Goals Finansierat av NKS (Nordisk kärnsäkerhetsforskning) NPSAG (Nordiska PSAgruppen) SAFIR (Finnish NPP safety research programme) Utfört av Lloyd s Register Consulting (Scandpower) VTT Samarbete med OECD/NEA WGRisk task 2006(2) 2006 2007 2008 2009

The Validity of Safety Goals - Viktigaste resultat Beskrivning av framväxten av säkerhetsmåltal i Sverige och Finland och erfarenheter av deras användning (Phase1 report) Baserad på omfattande intervjuer med centrala inblandade SKI Research Report 2007:06 (NKS-153, NPSAG 14-001:1) Aktivt deltagande i OECD/NEA WGRISK projekt om probabilistiska säkerhetsmåltal Beskrivning och analys av state-of-the-art internationellt Specifika delprojekt (phase 2-4 report) Jämförelse med kriterier i andra industrier (speciellt olja&gas, järnväg) Användning av kriterier ( Consistency in judgement ) Kriterier för PSA nivå 2 (koppling till nivå 3) Hierarkier av måltal (Subsidiary criteria) SSM Research Report 2010:35 (NKS-226, NPSAG 14-001:2) Vägledningsdokument Rekommendationer för hur numeriska kriterier skall definieras SSM Research Report 2010:36 (NKS-227, NPSAG 14-001:3)

The Validity of Safety Goals - Förslag till hierarki av säkerhetsmåltal Samhällsnivå (Society level) Lag/lagar som uttrycker högnivåkrav Mellannivå (Intermediate level) Tolkning av högnivåkrav på ett sätt som tillåter kvantifiering av risk Teknisk nivå (Technical level) Hög nivå Motsvarar PSA nivå 1, 2 och 3 Låg nivå Motsvarar säkerhetssystem och -funktioner

Internationell verksamhet Omfattande aktivitet på senare år, och säkerhetsmåltal och säkerhetskriterier har varit föremål för en hel del aktiviteter Några exempel på organisationer som arbetat med frågan NPSAG OECD/NEA MDEP WENRA Top Level Safety Goal High Level Safety Goals (DiD and Risk Goals) WENRAs förslag till hierarki av säkerhetsmål Lower Level Safety Goals and Targets (Deterministic and probabilistic) Technology Specific Safety Targets

IAEA 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 In order to control radiation risks: 1) Risk associated with nuclear installations needs to be assessed SAFETY GOALS 2) Guidance (criteria) for unacceptable risk need to be established 3) Relevant measures (design features and procedures) provided

IAEA TECHNICAL MEETING ON SAFETY GOALS IN APPLICATION TO NUCLEAR INSTALLATIONS 11-14 April 2011, Vienna, AUSTRIA IAEA Follow-up activities 2011-2013 TM recommendations addressed 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 TECDOC draft developed 2012-2013 and discussed at second TM July 2013

Outline of draft TECDOC Development and Application of a Safety Goals Framework for Nuclear Installations 1. INTRODUCTION 2. OBJECTIVES AND BENEFITS 3. RELATED CONCEPTS 4. GENERAL FRAMEWORK FOR SAFETY GOALS 5. DERIVATION OF SAFETY GOALS WITHIN THE HIERARCHY 6. APPLICATION AND COMPLIENCE ASSESSMENT 7. CONCLUSIONS ANNEX SPECIFIC EXAMPLES OF SAFETY GOALS FRAMEWORK A1. Developments by Western European Nuclear Regulators Association A2. Developments by Multinational Design Evaluation Project A3. Nordic PSA Group Project on Safety Goals for Nuclear Power Plants

Basic types of Safety Goals

Hierarchical Approach to Safety Goals - preconditions Applicable to all types of nuclear installations. Applicable to all relevant lifetime stages. Cover both operational states and accident conditions. Complement and in agreement with the IAEA Safety Fundamentals and the associated IAEA Safety Standards structure. Consistent with the structure and intents of defence-in-depth and support its implementation. Shall include qualitative as well as quantitative safety goals. Top level shall express overall requirements on society level Lower levels will successively detail the top level goals. Safety goals on different levels shall be consistent and traceable It shall be possible to derive lower level goals from higher level ones. Higher level safety goals shall as far as possible be technology neutral Lower level goals are expected to be increasingly technology specific. The structure shall be clearly and unambiguously defined.

Application of TECDOC Hierarchy of Safety Goals

Example matrix (from TECDOC)

Top Level Primary Safety Goal Level Top Level Primary Safety Goal Description Primary safety goal as set out in SF-1 and society level safety goals as defined in national legislation or regulations.

The example matrix (from TECDOC)

Upper Level Adequate Protection Level Upper Level Adequate Protection Description 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.

Intermediate Level General Safety Provisions Level Intermediate Level General Safety Provisions Description Proven approaches and good practices to achieve the higher level safety goals as well as definition of general requirements on site level.

Intermediate Level some important Regulations from the Radiation Safety Authority SSM FS 2008:1 Regulations concerning Safety in Nuclear Facilities SSM FS 2008:12 Regulations concerning Security in Nuclear Facilities SSM FS 2008:13 Regulations concerning Mechanical Equipment at Certain Nuclear Facilities SSM FS 2008:15 Regulations concerning Emergency Preparedness at Certain Nuclear Facilities SSM FS 2008:17 Regulations and General Advice concerning the Design and Construction of Nuclear Power Reactors SSM FS 2008:23 Regulations on Protection of Human Health and the Environment in connection with Discharges of Radioactive Substances from certain Nuclear Facilities SSM FS 2008:26 Regulations on Radiation Protection of Individuals Exposed to Ionizing Radiation at Nuclear Facilities

Low Level Specific Safety Provisions Level Low Level Specific Safety Provisions Description Technology and facility specific safety goals aimed at assuring the nuclear installation meets the higher level safety goals.

Low Level Safety Goals Säkerhetsmåltal i Sverige Authorities Vattenfall EON (Sydkraft) 1985 Core damage - Release Extremely unlikely release of more than 0,1 % of the inventory of the caesium isotopes Cs-134 and Cs-137 in a core of 1800 MWt. (No frequency defined, but interpreted as < 10-7 /year) 1990 Core damage 10-5 /year with a high degree of confidence Release 10-7 /year for a release involving more than 0,1% of the core inventory of substances causing ground contamination. 2006 Core damage 10-5 /year for core damage Release 10-7 /year for a release involving more than 0,1% of the core inventory of substances causing ground contamination 1995 Core damage 10-5 /year Release 10-7 /year for release involving more than 0,1% of the core inventory excluding noble gases. 2006 Core damage 10-5 /year for severe core damage Release Frequency of release involving more than 0,05-0,1% (depending on thermal effect) of the core inventory excluding noble gases shall be considerably lower than 10-5 /year.

Några slutsatser Det av IAEA utvecklade ramverket för säkerhetsmål har bedömts som relevant och användbart (TM juli 2013) Triangeln ger en god bild av ramverkets och målhierarkins konceptuella aspekter. Matrisen ger specifika exempel. (Skall dock inte ses som en checklista!) Ramverk och matris fungerar också som en fullständighetskontroll indikerar områden som saknas eller är oklart definierade. TECDOC kommer att avslutas i december 2013. Ramverket är tillämpligt över hela livscykeln och har visats fungera för olika typer av kärntekniska installationer. Ramverket har varit ganska enkelt att tillämpa på svenska förhållanden Observera dock att kartläggningen är både preliminär och inkomplett!. Det nordiska projektet om säkerhetsmåltal låg väl i tid och har varit värdefullt som underlag för IAEA:s projekt Har tillhandahållit konkret och detaljerat underlag

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