Canadian Regulatory Perspective on Safety Challenges for New NPP A. Viktorov, Canadian Nuclear Safety Commission IAEA Technical Meeting June 22-26, 2015 1
How this presentation works.. 1. CNSC outline 2. Preparation for new build in Canada 3. Canadian requirements related to the TM scope 4. Special case – small reactors 2
1. Canadian Nuclear Safety Commission • Established May 2000, under the Nuclear Safety and Control Act • Replaced the AECB, established in 1946, under the Atomic Energy Control Act • The CNSC regulates all nuclear- related facilities and activities 3
1. Our Mission To protect the health, safety and security of persons and the environment; and to implement Canada’s international commitments on the peaceful use of nuclear energy To disseminate objective scientific, technical and regulatory information to the public concerning the activities of the Commission and the effects on the environment and on the health and safety of persons 4
1. CNSC Core Activities • Develop regulatory framework • Carry out licensing and certification • Assess baseline compliance • Support Canada's international obligations • Engage stakeholders through public hearings and consultations Commitment to continuous improvement 5
2. Preparation for New Build • Site preparation licence issued in August 2012 for Darlington B • Technology not specified – But several specific reactor designs considered • Decision is contested in courts 6
2. Mature regulatory framework for new NPP Enabling Legislation • Most of regulatory Act documents for nuclear power reactors Regulations Requirements “ must meet” updated recently Licences, Certificates, Licence Conditions and Orders • Coherent approach for Requirements all nuclear facilities Guidance 7
2. CNSC Licensing Process Five stages in the lifecycle of a nuclear facility Site preparation Construction Operation Decommissioning Release from under under under under licensing under Licence to Licence to Licence to Licence to Licence to Prepare Site Construct Operate Decommission Abandon 8 8
2. Licensing process independent of reactor technology or size • Estimated licensing time ~ 9 years from the initial trigger to the operating licence • In addition to design and operational requirements, guides explain the licensing process in Canada 9 Page - 9
2. Vendor Design Review - test of readiness • VDR is a high level review of design to evaluate whether there are fundamental barriers to licensing in Canada – Tool to determine whether the vendor is ready for potential deployment in Canada – Standardized process – Requires design to be essentially complete • Outcomes help the vendor have discussions with potential customers and the regulator on the path forward • Vendor Design Review is optional and not part of licensing 10
2. Vendor Design Review outcomes • Several designs have gone through the all or some stages of review – ACR, EC6, AP1000, EPR, ATMEA • No fundamental barriers for licensing of considered designs in Canada – That is, no safety challenges that could not be resolved based on the current knowledge and technology 11
2. VDR – examples of potential challenges • Reflection of lessons learned from the Fukushima Daiichi accident • Beyond Design Basis Accidents (BDBA) and Severe Accidents (SA) prevention and mitigation • Classification of Structures, Systems and Components • Application of Single Failure Criteria • Containment Leak Rate and Filtered Venting provisions • Robustness against malevolent acts, physical and cyber security • Digital control systems, sharing of instrumentation and measurements 12
2. Being prepared for safety challenges • New reactors would not be licensed for construction with any substantive safety issues outstanding • Substantive issues – are those which may require multi-year effort to achieve satisfactory resolution • Regulatory requirements and acceptance criteria should be developed in anticipation of substantive issues or safety challenges • Need to identify potential safety challenges 13 13
2. Where challenges lie • The reactors in Canada are re-licensed every 5 years based on the outcomes of regulatory assessments – Reactors are safe to operate – safety challenges are understood • Safety requirements are in place for new NPP – at least, for the traditional technologies • Largest challenges for new NPP are not related to safety but – Economics – Public acceptance – Regulatory readiness, for novel technologies 14
3. Emerging safety challenges • Some safety challenges are relatively novel – Malevolent acts – Cyber security – Counterfeit, fraudulent or suspect items – Digitalization of plant control – Loss of know-how in countries with established programs – Acquiring expertise, in countries starting to develop nuclear energy • Not the focus of this discussion 15
3. Focus on Defence in Depth • CNSC perspective on Principle of DiD and – Assessment of DiD – Design Extension Conditions – Emergency Mitigating Equipment – Engagement with IAEA 16
IAEA Summary Report on Fukushima Daiichi Accident • “The defence in depth concept remains valid, but implementation of the concept needs to be strengthened at all levels by adequate independence, redundancy, diversity and protection against internal and external hazards. There is a need to focus not only on accident prevention, but also on improving mitigation measures.” 17
3. Three key messages CNSC takes away • Re-balancing capability for prevention and for mitigation – Design features to deal with DEC – SAMG – Increased understanding of safety margins in DEC • Attention to external hazards – Quantification of site specific hazards – PSA • Refinement of regulatory requirements 18
3. CNSC requirements for DiD • REGDOC-2.5.2, Design of Reactor Facilities: Nuclear Power Plants – This documents sets requirements for New NPP – Used as guidance in conduct of Periodic Safety Reviews • Based on IAEA NS-R-2 and SSR-2/1 and reflects Canadian best practices The concept of defence in depth shall be applied to all organizational, behavioural, and design-related safety and security activities to ensure they are subject to overlapping provisions. The levels of defence in depth shall be independent to the extent practicable. 19
3. Assessment of DiD • Guidance on performing a systematic assessment of DiD is given in IAEA safety reports series No. 46, Assessment of Defence in Depth for Nuclear Power Plants – Logical and comprehensive approach – Very cumbersome in application • Effort to strengthen DiD principle should be accompanied by effort to develop an approach for evaluation • CNSC currently undertakes a project to develop a simplified assessment approach 20
3. Design Extension Conditions • High level requirements in REGDOC-2.5.2, Design of Reactor Facilities: Nuclear Power Plants – The design authority shall identify the set of design-extension conditions (DECs) ... These DECs shall be used to further improve the safety of the NPP by enhancing the plant's capabilities to withstand accidents that are … more severe than DBAs … • Standard CSA N290.16 will provide more specific requirements related to BDBA 21
3. Canadian standard N290.16 (in development) • Sets Canadian requirements for both existing and new reactors • Clarifies terminology (for example “BDBA” versus “DEC”) – Based on the Plant State diagram – next slide • Describes functional requirements for different types of systems used in BDBA • Defines objectives and requirements for analysis and management of BDBA 22
3. Plant states, according to CNSC 23
3. Design principles for DEC • Design basis not to be compromised • Features necessary for accident management to be provided • Containment performance requirements to be specified for DEC • Complementary design features, fixed and portable 24
3. Design principles for DEC • Interfaces / connection points to be designed to the highest safety class of interfacing systems • Portable SSC shall have an approved design process and specific criteria – Includes inspection, testing and maintenance requirements • DEC SSC to be assessed for survivability and habitability – Reasonable confidence in functionality of SSC under harsh conditions 25
3. Assessment principles for DEC and BDBA • Objective – evaluate design ability to withstand challenges posed by DEC, to reasonable degree of confidence • Use of best estimate method and integration with PSA • PSA – main, but not the only, source for identification of DEC • Uncertainties to be considered • Ongoing hazard assessment, recognizing that site hazard change over time, especially man-made 26
3. Emergency mitigating (portable) equipment • Additional features to supplement fixed SSC if needed • EME is currently provided at, or close to, NPP sites 27
3. Emergency Mitigating Equipment • Design requirements for EME to be developed, supported and documented – Could be commercial grade • New NPP could employ the concept of additional mobile equipment to strengthen independence of safety provisions 28
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