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 within the Reactor Safety Arena:
- Risk-Informed Steering Committee (RISC)
- Risk Management Regulatory Framework (RMRF)
- NRC "Grow Your Own" PRA Capability
- Update Regulatory Guide 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant Specific Changes to the Licensing Basis
- Update RG 1.200, An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities
- Update NUREG 1855, Guidance on the Treatment of Uncertainties Associated with PRAs in Risk-Informed Decisionmaking
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Risk-Informed Steering Committee (RISC)
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.
The NRC RISC held multiple public meetings with the industry RISC to receive updates on the working groups' status and to discuss other risk-informed initiatives. The industry working groups developed white papers outlining gaps in current processes and the actions to close those gaps. The NRC held public meetings to discuss the review of the white papers and provided comments to the industry. The NRC working groups will each issue a memorandum to the RISC with recommended actions to close gaps identified in the white papers. The actions will be completed by the appropriate line organization in accordance with normal work practices. The staff has developed plans and continued work on the related initiatives by scheduling a public workshop on NUREG-1855 and a public meeting to seek input on how to treat the industry developed, and NRC endorsed, Flex strategies and equipment in risk-informed decision-making. The NRC RISC will continue to hold public meetings with the industry RISC to discuss current and upcoming risk-informed initiatives of interest.
The NRC RISC held multiple public meetings with the industry RISC to receive updates on the working group's status and to discuss other risk informed initiatives. The NRC RISC working group held a public workshop to discuss draft guidance documents from the industry on the topic of a proposed approach to close out the comments generated by a peer-review of the licensee's PRA model. The NRC staff also observed an industry pilot project to implement the proposed approach and derive lessons learned for future discussions on the topic. NRC staff held a public meeting to discuss the new approach, termed the vetting panel process, proposed by the RISC's technical adequacy working group to determine the technical adequacy of a new PRA methods. The staff is currently developing internal guidance for the implementation of the proposed approach. These initiatives are expected to improve the staff's efficiency in the review of future risk-informed licensing actions.
The NRC RISC engaged the industry in activities related to crediting FLEX/mitigating strategies (MS) equipment in RIDM. The industry developed white papers and held a workshop with good participation from both industry and the NRC. The white papers were found to address a large number of issues that are important to the NRC staff in RIDM. The industry revised the white papers based on NRC staff comments. The staff plans to update internal guidance for considering credited FLEX/MS equipment during the review of risk-informed licensing applications.
In addition, NRC has held public meetings to seek stakeholder input on the update on NUREG-1855, "Guidance on the Treatment of Uncertainties Associated with PRAs in Risk-Informed Decision Making". As a result of the interaction at the public meetings, NRC is currently developing training related to the treatment of uncertainties in RIDM.
The NRC RISC directed the evaluation of the use of licensee PRA models in regulatory applications where SPAR models are currently being utilized. This evaluation was intended to evaluate the potential benefits, pitfalls, and cost of shifting to this approach. Ultimately, it was revealed that while there may have been some incremental cost savings after a full implementation period, the risk to the Agency of pursuing this initiative was too great to justify continued evaluation at this time.
The NRC RISC will continue to hold public meetings with the industry RISC to discuss current and upcoming risk-informed initiatives of interest.
The RISC engages the industry and addresses concerns relative to the use of PRA to support regulatory decision-making. The RISC provides strategic direction to the NRC staff by using a holistic, risk-informed, approach to decision making.
Risk Management Regulatory Framework (RMRF)
NUREG-2150, "A Proposed Risk Management Regulatory Framework," (RMRF) recommended that a risk management regulatory framework applicable to all NRC program areas be adopted by the NRC. The Chairman's tasking memorandum dated June 12, 2012, directed the staff to "Review NUREG-2150 and identify options and make recommendations, including the potential development of a Commission policy statement." The Commission's SRM dated May 19, 2014 on SECY-13-0132 directed that the staff's paper providing recommendations with respect to NUREG-2150 also include "a description of any interrelationships of ongoing risk-informed initiatives to ensure the activities are well coordinated, and effectively planned and implemented."
The NRC staff requested public comments on draft white papers addressing RMRF issues on November 25, 2013 (78 FR 70354) and May 12, 2015 (80 FR 27191). The staff held public meetings on June 5, 2013, January 30, 2014, May 27, 2015, and July 29, 2015. The staff also met with the Reliability and Probabilistic Risk Assessment subcommittee of the ACRS on September 4, 2013, and February 20, and June 8, 2015. The staff will meet with the ACRS full committee in early November 2015 and the staff will update the Commission in a SECY paper in December 2015.
The staff submitted SECY-15-0168 in December 2015 to seek Commission direction on RMRF related issues. In response to the SECY, the Commission, via a SRM-SECY-15-0168, approved the staff's recommendations to: 1) maintain the existing regulatory framework for the nuclear power reactor safety program area, and 2) refrain from developing an overarching, agency-wide risk management policy statement. Additionally, the Commission also agreed with the staff's conclusions that a formal design-basis extension category of requirements should not be established, and a formal agency-wide definition and criteria for determining the adequacy of defense in depth should not be developed. Based on the Commission's directive in the SRM no further work is expected to be performed on the RMRF.
The Task Force was chartered "to develop a strategic vision and options for adopting a more comprehensive and holistic risk-informed, performance-based regulatory approach for reactors, materials, waste, fuel cycle, and transportation that would continue to ensure the safe and secure use of nuclear material." The resulting framework included the following objective: "Manage the risks from the use of byproduct, source and special nuclear material through appropriate performance-based regulatory controls and oversight" and a corresponding "Risk Management Goal."
NRC "Grow Your Own" PRA Capability
This NRC-wide PRA "Grow Your Own" (GYO) program was established to provide less experienced staff with high technical potential, the opportunity to have a focused, hands-on experience with risk-informed regulations, licensing actions, and decision-making. At the completion of the 3-year GYO program, those staff that pass their technical boards are recognized as reliability and risk analysts at the GG-14 level or promoted if at a lower grade.
FY 2015 Status
The initial two staff members in the program within the Office of New Reactors (NRO) and three staff members within the Office of Nuclear Reactor Regulation (NRR) completed all their required activities and passed their technical boards in the summer of 2015.
FY 2016 Status
The NRC continues to provide staff training on various aspects of PRA including use of the agency risk models/software and their application to analyze events and Licensee applications. The agency graduated 1 employees this year and currently has 8 program participants projected to graduate soon.
Enhancing the PRA knowledge and capability of NRC staff supports the application of risk-informed decision-making.
Update Regulatory Guide 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant Specific Changes to the Licensing Basis
Regulatory Guide (RG) 1.174 provides guidance on the use of PRA findings and risk insights to support licensee request 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," through 50.92, "Issuance of Amendment."
FY 2015 Status
The current status of this activity remains unchanged from the previous risk-informed activities update. Additional information is available.
FY 2016 Status
During this fiscal year, the staff continued to meet with internal and external stakeholders to solicit their input into the update of RG 1.174. The focus of this activity is a review and update of RG 1.174 and other related guidance documents (e.g., RGs 1.175, 1.177, and 1.178) to clarify the staff position on how the defense-in-depth principles of the integrated risk-informed decision-making process are addressed in the review of a licensee's request to change its licensing basis.
RG 1.174 describes an acceptable approach for assessing the nature and impact of proposed licensing basis changes by considering engineering issues and applying risk insights to demonstrate the licensing basis changes will only result in small increases in risk and when it is also reasonably assured that, among other things, sufficient defense-in-depth and sufficient safety margins are maintained.
Update RG 1.200, An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities
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 staff position (i.e., endorsement) of the published ASME/ANS PRA standards and the NEI peer review guidance documents.
Staff continued to work with standard developing organization (SDO) and industry to develop necessary PRA standards (specifically issuance of trial use PRA standards for a Level 2 and Low Power Shut Down (LPSD) standard for LWRs and a full-scope PRA standard for non-LWRs) and related peer review guidance for defining PRA acceptability in support of risk-informed activities.
Staff continues to work with SDO and industry to develop necessary PRA standards (new edition to the Level 1/LERF PRA standard for both internal and external hazards for at-power conditions and a code case for seismic PRA) and related peer review guidance for defining PRA acceptability in support of risk-informed activities. Specifically, staff developed a preliminary staff position on an acceptable process for closure of findings from the peer reviews and an acceptable process for addressing new PRA methods.
Under this activity the infrastructure is developed to support risk-informed decision-making. The purpose of this activity is to provide the agency position on an acceptable base PRA such that the results from the PRA can be used in risk-informed decision-making.
Update NUREG 1855, Guidance on the Treatment of Uncertainties Associated with PRAs in Risk-Informed Decisionmaking
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 reguirements 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.
Revision to the document is under review.
A public workshop was held to "pilot" the Revision 1 draft and finalize for publication.
NUREG-1855 helps the decision maker understand to what extent the risk results are impacted by the uncertainties, understand whether there are risk results that may challenge the risk acceptance guidelines, and to determine if the driver for the large uncertainties can be identified and remediated.