ML18331A373
| ML18331A373 | |
| Person / Time | |
|---|---|
| Site: | Nuclear Energy Institute |
| Issue date: | 11/28/2018 |
| From: | Ferrante F, Krueger G Electric Power Research Institute, Nuclear Energy Institute |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| Download: ML18331A373 (13) | |
Text
Facilitating Regulatory Change through an Understanding of the Current Levels of Safety November 28, 2018 Greg Krueger (NEI), Fernando Ferrante (EPRI)
©2018 Nuclear Energy Institute 2 Insights on Risk Margins The Nexus between Safety and Risk Application of Margin Regulatory Implications Next Steps Outline
©2018 Nuclear Energy Institute 3 Insights on Risk Margins
EPRI Product ID 3002012967 (May 2018)
Insights on Current Margins at Nuclear Power Plants: A Technical Evaluation of Margins in Relation to Quantitative Health Objectives and Subsidiary Risk Goals in the United States
Utilized previous NRC and EPRI work to provide a technical bases for how our understanding of margin to the regulatory Quantitative Health Objectives (QHOs) has evolved over time, and to estimate that margin
The EPRI white paper does not address how to apply the margin that exists
©2018 Nuclear Energy Institute 4 Change in Perceived Safety Margin Factor of 100 - 10,000 Factor of 2-5 Factor of 2-5
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Severe Accident Research - Improving State of Knowledge Margin to Safety Goal NRC Safety Goal QHOs 1985 1990 1995 2000 2005 2020 2015 2010 1995 NRC PRA Policy Statement
~1990 NUREG-1150 1986 NRC Safety Goal Policy 2007 NUREG-1860:
Regulatory Framework 2012 NUREG-1975:
SOARCA 2014 NUREG-2161:
Spent Fuel Pool Risks 2015 US NRC CPRR Regulatory Analysis CDF/LERF Objectives CDF/LERF Objectives CDF/LERF Objectives
©2018 Nuclear Energy Institute 5 Regulations based on deterministic requirements provide an important foundation for assuring safety Risk analyses assist in assessing the completeness and effectiveness of the deterministic framework Risk information is not intended to supplant deterministic requirements PRA tools assess and provide risk insights even when regulations are followed Measure or identify the residual risk Support a graded consideration of risk throughout the decision-making process The Nexus between Safety and Risk
©2018 Nuclear Energy Institute 6 A risk informed regulatory approach that complements deterministic regulations is the optimal means to make informed decisions on safety significance in an objective manner SECY-98-144 defines RIDM as a philosophy whereby risk insights are considered together with other factors to establish requirements that better focus licensee and regulatory attention on design and operational issues commensurate with their importance to health and safety Risk Informed Decision Making (RIDM)
©2018 Nuclear Energy Institute 7 Application of margin for general decision-making Use the appropriate level of resources to investigate an issue commensurate with safety
Improve timely disposition of safety significance conclusions
Disposition low safety significance conclusions quickly Prioritize regulatory issues Reassess impact and use of regulatory quantitative risk thresholds Application of margin in support of specific decision-making Increase in margin driven by plant design and operational changes should allow flexibility in response, scope, and depth of review of regulatory initiatives Margin in the Context of RIDM
©2018 Nuclear Energy Institute 8 Licensing and Oversight of Operating Reactors Focus resources on safety significant issues and apply the appropriate (limited) review for low risk regulatory decisions Align regulatory response commensurate with the understanding of margin and low safety significance of issues within the ROP Do not expend resources on inspections of low safety significant components within 10 CFR 50.69 Take full advantage of inherent plant features and operator response to optimize security Regulatory Implications
©2018 Nuclear Energy Institute 9 Risk-inform Reasonable Assurance RISK INSIGHTS REGULATORY DECISION LOW SAFETY SIGNIFICANCE Reduced Scrutiny & Touchpoints HIGH SAFETY SIGNIFICANCE Increased Confidence & Focus Qualitative &
Quantitative
©2018 Nuclear Energy Institute 10
Purpose:
Identify LSS issues early to avoid resource expenditures Applicability:
Licensing Oversight Inspections Non-concurrences Low Safety Significance Off-Ramps LSS Exit
©2018 Nuclear Energy Institute 11 Licensing and Oversight of Advanced Reactors Streamline and focus the licensing process of advanced reactor designs due to their enhanced safety Regulatory Implications
©2018 Nuclear Energy Institute 12 Application of PRA Insights and Metrics Limit the need to quantify all risk contributors with detailed PRAs if they can be shown to be of low risk Apply PRA insights to enable a reconsideration of past practices and conventions Improve application of quantitative regulatory guidelines (RG 1.174) to preclude the use of hard limits Understand the implications bounding new methods cause on risk insights and metrics Regulatory Implications
©2018 Nuclear Energy Institute 13 Acknowledge the implications of the increased margin between surrogate risk metrics and the QHOs Apply the understanding of the margin to the QHOs, in conjunction with the extensive accumulated operating and regulatory experience, into an integrated risk informed decision-making framework (IRIDM)
A framework for decision-making can consist of a qualitative, consequence-biased framework that incorporates insights from quantitative PRA tools, as appropriate, to a spectrum of regulatory decisions Incorporate concepts from the soon-to-be-published EPRI Report (3002014783) - A Framework for Using Risk Insights in Integrated Risk-Informed Decision-Making Next Steps