Multinational Design Evaluation Programme (MDEP) The Structure and Application of High Level Safety Goals Geoff Vaughan Safety Goals Subcommittee Chair CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience Prague, Czech Republic 15-17 September 2010
Background - 1 MDEP Multinational Design Evaluation Programme An initiative taken by national safety authorities to leverage their resources and knowledge for new reactor design reviews Members are: Canada, China, Finland, France, Japan, Korea, Russia, South Africa, USA, UK plus IAEA Aims include: • To facilitate harmonisation of regulatory requirements • To facilitate licensing of future reactors, including Generation IV CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience 2 2 Prague, Czech Republic 15-17 September 2010
Background - 2 To achieve harmonisation there needs to be a convergence on the safety goals which must be met To regulate future reactors needs the development of consistent safety goals for different technologies This means there needs to be a comparison and understanding of the bases for the safety goals in each MDEP country and how they are expressed CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience 3 3 Prague, Czech Republic 15-17 September 2010
Definition of Safety Goals What is meant by safety goals in this work? All Health and Safety requirements covering radiation risks to workers, the public and the environment, whether due to normal operational exposures and discharges or accidental occurrences cf Basic Safety Objective in IAEA Safety Fundamentals CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience 4 4 Prague, Czech Republic 15-17 September 2010
What’s New? - 1 * Increasing interest in Risk-informed Decision Making combining probabilistic and deterministic considerations. * Many surveys have been done which have listed low level goals eg specific temperatures in reactor vessels of a specific type, or frequencies of specific events. * Differences arise due to different principles and assumptions in derivation and the detailed design considerations. * But without understanding these factors it is not possible to determine if the goals are consistent and coherent. CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience Prague, Czech Republic 5 15-17 September 2010
What’s New? - 2 We need to go back to basis of the safety goals. The approach we have taken is to: # start with the high level safety goals ie the requirements to protect people and the environment, # determine a structure for the safety goals that can be used for all types of nuclear technology, # develop a method to derive lower tier safety goals so they consistent for different technologies and are clearly related to the higher tier goals. CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience Prague, Czech Republic 6 15-17 September 2010
MDEP Subcommittee The MDEP Steering Technical Committee (STC) set up a subcommittee to pursue this work with the remit to initiate discussions with other bodies and recommend a way forward so that MDEP could complement their work. The subcommittee remit did not cover the development of a set of detailed safety goals. Participants: Canada, Finland, Japan, South Africa UK, USA, and IAEA CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience Prague, Czech Republic 7 7 15-17 September 2010
Work Undertaken Related activities • Identification and interaction with other groups • Survey of subcommittee members approaches and definition of high level safety goals • Determination of commonalities and a proposed coherent framework for all technologies • Procedure for developing lower tier safety goals in a consistent way • Application to specific reactor types ie proof of usefulness • Development of a report to MDEP ( in draft) • Drafting of MDEF Position Papers on Integrated Risk- informed Decision-Making and Safety Goals (awaiting approval from MDEP) CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience 8 8 Prague, Czech Republic 15-17 September 2010
Interactions with Other Groups IAEA/INSAG – IAEA were represented on subcommittee; two members on drafting group for INSAG-25 on Integrated Risk-informed Decision Making CSNI/WGRisk – members of WGRisk invited to subcommittee meeting to discuss work on probabilistic risks GIF/Reactor Safety WG – Representative of RSWG attended subcommittee meeting to discuss their work on future reactors WENRA/Reactor Harmonisation WG – chairman of RHWG attended two subcommittee meetings to discuss report on New Reactors; one member of subcommittee is member of RHWG CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience Prague, Czech Republic 9 9 15-17 September 2010
Other Groups: INSAG-25 - 1 INSAG -25 International Nuclear Safety Group group of experts providing authoritative on nuclear safety to IAEA INSAG 25 – Risk-Informed Decision Making (about to be published) Considers • Key elements that contribute to a risk-informed decision • Uses of RiDM • Managing the process • Training • Documentation But does not attempt to set criteria CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience Prague, Czech Republic 10 10 15-17 September 2010
Other Groups: INSAG-25 - 2 INSAG -25 Key Elements of RiDM CNRA International Workshop on 11 11 New Reactor Siting, Licensing and Construction Experience Prague, Czech Republic 15-17 September 2010
Other Groups: WENRA WENRA Western European Nuclear Regulators’ Association Reactor Harmonisation Working Group Draft of Safety Objectives for New Power Reactors - December 2009 • O1. Normal operation, abnormal events and prevention of accidents • O2. Accidents without core melt • O3. Accidents with core melt • O4. Independence between all levels of defence-in-depth • O5. Safety and security interfaces • O6. Radiation protection and waste management • O7. Management of safety The subcommittee sees some useful synergies between these objectives and the approach that it is pursuing CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience 12 12 Prague, Czech Republic 15-17 September 2010
Survey of High Level Safety Goals Survey Most countries require that NPP should add only insignificantly to risks to population: expressed in terms of deaths or cancer incidence. These cover workers, discharges to environment and accidents. Many goals relate to effects on individuals but all countries also recognise effects are wider such as use of land or food production. ~~~ The IAEA Basic safety Standard is the basis for occupational and public dose limits during normal operation. For new reactors, all countries propose offsite releases should be reduced to low level or “practically eliminated”. Major damage state frequency targets reduced by about an order of magnitude (WGRisk survey). CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience Prague, Czech Republic 13 13 15-17 September 2010
Defence-in-Depth -1 Din D • All countries use a form of Defence-in Depth concept in making decisions on nuclear safety • INSAG-12 provides good background • Enshrined in several IAEA Safety Standards from Safety Fundamentals down • Given wide usage and that philosophy has resulted in excellent safety record, subcommittee determined that a framework based on Defence-in-Depth should be used to define the structure of lower tier safety goals CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience 14 14 Prague, Czech Republic 15-17 September 2010
Defence-in-Depth -2 Din D Advantages: • Based on consensus IAEA Safety Standards • Well-known in nuclear industry • Simple, straightforward philosophy • Enables clarity of combining deterministic and probabilistic goals • Develops the INSAG-25 RiDM approach • Allows for a coherent and consistent development of lower tier goals from high level goals CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience 15 15 Prague, Czech Republic 15-17 September 2010
The Structure and Application of High Level Safety Goals (SAHLSG) - 1 The aim of the Subcommittee is to consider the framework within which potential goals can be included and be agreed upon as a move towards harmonisation. A draft paper reviews the high-level goals used in some MDEP countries and draws broad conclusions. We hope to include data from more [MDEP] countries in future drafts. From the survey results and other considerations, the Subcommittee has developed a set of possible safety goals and proposed a method of applying them within an extended DiD structure. MDEP are currently considering these proposals . CNRA International Workshop on New Reactor Siting, Licensing and Construction Experience 16 16 Prague, Czech Republic 15-17 September 2010
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