United States Nuclear Regulatory Commission - Protecting People and the Environment

Cross-Cutting Activities

This list shows the ongoing licensing initiatives, projects, and activities that the staff of the U.S. Nuclear Regulatory Commission (NRC) has targeted for greater use of risk information that substantially crosscut multiple subarenas:

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Rulemaking Activities

Summary Description

Risk insights are a fundamental consideration in the analyses supporting the U.S. Nuclear Regulatory Commission's (NRC's) rulemaking activities. Specific details on current rulemaking activities are provided in the NRC's centralized rulemaking tracking and reporting system at NRC Rules and Petitions.

The NRC has developed reference materials to support qualitative and quantitative assessment of costs and benefits (including risk) in rulemaking, including NUREG/BR-0058, "Regulatory Analysis Guidelines of the U.S. Nuclear Regulatory Commission." An effort was initiated in 2014 to restructure and consolidate the NRC cost benefit guidance into this NUREG. The update to NUREG/BR 0058 also incorporates improvements in methods for assessing factors that are difficult to quantify and includes relevant best practices identified in U.S. Government Accountability Office (GAO) guidance and in recommendations from GAO in GAO 15 98, "Nuclear Regulatory Commission: NRC Needs to Improve Its Cost Estimates by Incorporating More Best Practices," dated December 12, 2014. Finally, the update incorporates NRC experience and improvements in uncertainty analysis for use in cost benefit analysis.

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RG 1.200, An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities

Summary Description

Regulatory Guide (RG) 1.200 provides the staff position regarding what constitutes an acceptable PRA and how the PRA standards and peer review guidance are used to demonstrate conformance with the staff position. In this regard, RG 1.200 provides a definition for what constitutes a PRA and a staff position on PRA acceptability addressing the (1) scope of a PRA, (2) technical elements of a PRA, (3) level of detail of a PRA, and (4) plant representation in the PRA model. RG 1.200 also provides a staff position on consensus PRA standards and industry peer review PRA programs, demonstration of the acceptability of a PRA, and documentation to support a regulatory submittal. RG 1.200 also provides the NRC endorsement of the published ASME/ANS PRA standards and the NEI peer review guidance documents.

Associated Risk-Informed Activities below:

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PRA Standards Development

Summary Description

Staff participates with the ASME and ANS efforts to develop PRA Standards. ASME and ANS work together under the Joint Committee for Nuclear Risk Management (JCNRM). JCNRM is developing a suite of standards which (1) address operating LWRs, advanced LWRs in the design certification stage, and non-LWRs, (2) address all operating modes (at-power and low power and shutdown), (3) address both internal hazards (i.e., internal events, internal floods and internal fires) and external hazards (seismic, high winds, external floods and others), and (4) address all risk metrics (CDF, LERF/LRF, radiological release frequency, and consequences. These standards include:

  • Level 1 (CDF)/LERF PRA standard for at-power conditions, both internal (i.e., internal events, floods and fires) and external (i.e., fires, seismic, high winds, floods and others) hazards for operating LWRs. This standard was published as an ANSI standard in 2008, Addendum A in 2009 and Addendum B in 2013.
  • Level 2 (radiological release frequency) PRA standard for all operating modes and for both internal and external hazards for LWRs. This standard was published as an ASME/ANS Trial Use standard in 2015.
  • Level 3 (consequences) PRA standard for nuclear facilities and for all operating modes and both internal and external hazards. This standard has not been published.
  • LPSD PRA standard for Level 1/LERF for LWRs. This standard was published as an ASME/ANS Trial Use standard in 2015.
  • Advanced LWR PRA standard for new LWRs in the design certification phase addressing Level 1/LERF. This standard has not been published.
  • Non-LWR PRA standard for all three PRA Levels and all operating modes for both internal and external hazards and addressing multi-units at a single site. This standard was published as an ASME/ANS Trial Use standard in 2009.

To date, the staff has endorsed the Level 1/LERF PRA standard, specifically the 2009 addendum (i.e., ASME/ANS RA-Sb-2009).

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Industry Peer Review Guidance Development

Summary Description

Staff reviews and endorses the PRA peer review guidance issued by NEI in RG 1.200 for how to demonstrate conformance with the ASME/ANS PRA standards. RG 1.200 provides the staff position for what constitutes an acceptable peer review program. The NEI guidance documents include:

  • NEI 00-02 (published in 2000) provides the initial peer review guidance for internal events and internal floods Level 1 PRA. It also include a self-assessment to address the gap between the review criteria in NEI 00-02 and the ASME/ANS PRA standard. It is endorsed in RG 1.200.
  • NEI 05-04 (published in 2005) provides the updated guidance to NEI 00-02 to be commensurate the ASME/ANS PRA standard and addresses internal events and internal floods Level 1/LERF PRA. It is endorsed in RG 1.200.
  • NEI 07-12 (published in 2007) provides the peer review guidance for internal fire Level 1/LERF PRA. It is endorsed in RG 1.200.
  • NEI 12-13 (published in 2012) provides the peer review guidance for external hazards Level 1/LERF PRA. NRC issued a letter providing comments on the guidance, it has not been endorsed in RG 1.200.
  • NEI-17-07, "Performance of PRA Peer Reviews Using the ASME/ANS PRA Standard."

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Risk-Informed Steering Committee (RISC)

Summary Description

The NRC's RISC was established in 2014 to provide strategic direction to the NRC staff to advance the use of risk-informed decision making (RIDM) in various NRC activities, consistent with the Commission's Probabilistic Risk Assessment (PRA) Policy Statement. The NRC's RISC comprises of a senior management committee representing the NRC program offices (NRR, NRO, RES, NMSS, and NSIR as well as a senior executive from a regional office). The RISC is chaired by the NRR Office Director.

The objectives of the RISC include engaging the industry relative to the use of PRA to support regulatory decision-making, discussion of NRC driven initiatives that incentivize industry to continue to develop PRAs thereby providing a framework to make decisions in light of inherent uncertainty in PRA models, and discussion of industry actions necessary to achieve the vision of future use of PRA to support regulatory decisions. Recently, in response to comments from the Advisory Committee on Reactor Safety (ACRS) on SECY-15-0168, the NRC staff agreed with the ACRS's view that continued enhancements to the usage of risk-informed regulatory approaches should be pursued in future regulatory activities and stated that NRC activities in this and related areas will be overseen by NRC's RISC committee.

The NRC RISC regularly interfaces with its industry counterpart which comprises of licensee chief nuclear officers, senior level executives, and representation from the Nuclear Energy Institute (NEI). At the time NRC's RISC was formed in 2014, technical adequacy and uncertainties in risk-informed decision making were areas of focus. Technical adequacy was viewed as a solution to some of the PRA quality issues that arose in NFPA-805 reviews and the second issue stemmed from the aggregation of core damage frequency contributions from multiple initiators. Consequently, the NRC and industry each agreed to form two working groups; one focused on technical adequacy of PRAs and the other focused on treatment of uncertainty in RIDM. The NRC RISC, to address its objectives, has undertaken several activities in recent years under the auspices of these two working groups. Additional information is available.

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Regulatory Guide 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant Specific Changes to the Licensing Basis

Summary Description

As directed by the Commission in SRM SECY 11 0014, Regulatory Guide (RG) 1.174 was developed to assure consistent interpretation and implementation of the defense-in-depth philosophy. RG 1.174 provides guidance on the use of PRA findings and risk insights to support licensee requests for changes to a plant's licensing basis, as in requests for license amendments and technical specification changes under Title 10 of the Code of Federal Regulations (10 CFR) Sections 50.90, "Application for Amendment of License, Construction Permit, or Early Site Permit," and 50.92, "Issuance of Amendment."

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NUREG 1855, Guidance on the Treatment of Uncertainties Associated with PRAs in Risk-Informed Decisionmaking

Summary Description

This document provides guidance on how to treat uncertainties associated with PRA in risk-informed decision-making with regard to: 1) Identifying and characterizing the uncertainties associated with PRA in support of the PRA standard, 2) Performing uncertainty analyses to understand the impact of the uncertainties on the results of the PRA, and 3) Factoring the results of the uncertainty analyses into decision-making. This NUREG also provides guidance on how to meet the ASME/ANS PRA standard requirements for addressing uncertainties in the PRA model. NRC recognized that the Electric Power Research Institute (EPRI) also was performing work in this area with similar objectives. Both NRC and EPRI believed a collaborative effort to have technical agreement and to minimize duplication of effort would be more effective and efficient.

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Achieving the Vision of Becoming a Modern, Risk-Informed Regulator

Summary Description

In the Executive Director for Operations update of September 6, 2019, the EDO stated that we will know we have become a modern, risk-informed regulator when we've embraced improvements in our decision-making, adoption of technology, a culture of innovation, and a focus on recruiting, developing, and retaining a strong workforce. The update identified seven initiatives to address these focus areas in the near-term and stated that other initiatives would be launched in mid-2020. The initiatives will build upon and complement the important work going on throughout the agency.

The seven initiatives are:

  • Accepting risk in decision-making: This team will develop a common understanding of what it means to accept risk, how it connects to our transformation vision, and how risk insights should be applied in the NRC's work (corporate support, legal, or technical)
  • Agency desired culture: This team will build into the NRC's culture a mindset that welcomes change, while reinforcing the behaviors and outcomes described in the agency's Leadership Model
  • Career enhancement: This team will clarify and communicate opportunities to ensure that all staff understand available paths that will enable them to grow throughout their careers
  • Innovation: This team will finalize and implement the new "Innovate NRC" process and technology platform to create and sustain a culture of innovation
  • Process simplification: This team will be responsible for simplifying and reinforcing NRC's processes to achieve greater efficiency
  • Signposts and markers: This team will determine the key signposts and markers from those identified in the Futures Assessment Report and adapt NRC's decision-making process to incorporate these indicators, ensuring the agency is better prepared to, in turn, adapt to a changing external landscape
  • Technology services: This team will enable all staff to easily and efficiently complete their work with available technology and increase the use of new and existing technology across the agency

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Page Last Reviewed/Updated Wednesday, January 29, 2020