ML18331A373

Industry Presentation of Margins to QHOs Final - November 28 2018

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 Greg Krueger (NEI), Fernando Ferrante (EPRI)

November 28, 2018

Outline Insights on Risk Margins The Nexus between Safety and Risk Application of Margin Regulatory Implications Next Steps

©2018 Nuclear Energy Institute 2

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 3

Change in Perceived Safety Margin NRC Safety Goal QHOs

? Factor of 2-5 Factor of 2-5 Factor Margin to of 100 - 10,000 CDF/LERF CDF/LERF Safety Goal Objectives Objectives CDF/LERF Objectives 2014 NUREG-2161:

Spent Fuel Pool Risks 2007 2015 1986 1995 2012

~1990 NUREG- US NRC NRC NRC PRA NUREG-NUREG- 1860: CPRR Safety Policy 1975:

1150 Regulatory Regulatory Goal Policy Statement SOARCA Framework Analysis 1985 1990 1995 2000 2005 2010 2015 2020 Severe Accident Research - Improving State of Knowledge

©2018 Nuclear Energy Institute 4

The Nexus between Safety and Risk 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

©2018 Nuclear Energy Institute 5

Risk Informed Decision Making (RIDM)

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

©2018 Nuclear Energy Institute 6

Margin in the Context of RIDM 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

©2018 Nuclear Energy Institute 7

Regulatory Implications 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

©2018 Nuclear Energy Institute 8

Risk-inform Reasonable Assurance REGULATORY DECISION HIGH SAFETY SIGNIFICANCE Increased Confidence & Focus LOW SAFETY SIGNIFICANCE RISK Reduced Scrutiny & Touchpoints INSIGHTS Qualitative &

Quantitative

©2018 Nuclear Energy Institute 9

Low Safety Significance Off-Ramps

Purpose:

Identify LSS issues early to avoid resource expenditures LSS Exit Applicability:

Licensing Oversight Inspections Non-concurrences

©2018 Nuclear Energy Institute 10

Regulatory Implications Licensing and Oversight of Advanced Reactors

• Streamline and focus the licensing process of advanced reactor designs due to their enhanced safety

©2018 Nuclear Energy Institute 11

Regulatory Implications 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

©2018 Nuclear Energy Institute 12

Next Steps 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 ©2018 Nuclear Energy Institute 13