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 (using expanding menus):
FY 2021
This guidance is being revised to enhance the risk informed, performance- based approach to the demonstration of compliance. The staff completed the development of responses to public comments. In addition, the staff updated the models and codes used for risk and dose assessment reviews in support of the risk-informed approach. The final NUREG-1757, Volume 2, Revision 2 is expected to be issued in the summer 2022 timeframe.
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Consideration of Safety Significance in Addressing NMSS Licensing Basis and Potential Violation Questions
Summary Description
The Office of Nuclear Material Safety and Safeguards (NMSS) regulates byproduct material use, fuel cycle facilities, storage and transport of spent fuel, decommissioning of nuclear facilities, and low-level waste disposal. NMSS is exploring how it can enhance existing processes and procedures to better focus regulatory attention on design and operational questions in all these areas commensurate with their importance to health and safety and common defense and security. This effort, which follows a similar activity in NRR, is sometimes referred to as the Low Safety Significance Issue Resolution process. It utilizes quantitative and qualitative risk insights; recognizing that most aspects of the materials arena do not fully use quantitative risk models. However, risk insights are derived by progressive screening questions up to, and including, qualitative-quantitative estimations based on operational experience and expert judgment using the risk triplet (i.e., What can go wrong? How likely is it? What are the consequences?). This ensures that questions and issues potentially impacting safety are promptly identified, evaluated, and promptly addressed, commensurate with their safety significance. However, the NRC does not always have clear guidance on evaluating significance prior to the expenditure of significant resources in evaluating an issue. For example, as a result of NRC an inspection, issues and conditions are identified that appear to be potential violations of governing requirements. Sometimes, there is a lack of clarity in the facility or activity licensing basis resulting in questions regarding whether the licensee is in compliance with its licensing basis. While these situations represent the exception, in practice, resolving these issues through the NRC's current processes can be resource intensive, inefficient, and untimely in many cases.
The Technical Assistance Request (TAR) process is often the means by which assistance in addressing the above type questions is provided and is routinely used to address unresolved questions from the NRC Regional Offices. For some licensing basis issues, past experience reveals an imbalanced expenditure of time, resources, and effort compared to the underlying issue's significance to health and safety, and common defense and security. In addition to improving the screening process within the inspection procedures to allow the consideration of safety significance in the light of a question on the licensing basis, the TAR process is currently being enhanced to include similar guidance.
Previous Fiscal Years
FY 2020
Work initially focused on enhancing the TAR process to identify and screen issues that are determined to be of very low safety significance using a progressive screening approach that relies on operating experience and expert judgment in addressing the risk triplet. In the second half of the fiscal year, the effort expanded to enhancing aspects of issue screening process within the inspection guidance. The draft TAR process has been internally reviewed within NMSS and the Regions and insights from those reviews indicated the need for additional clarity in the new risk-informed aspects of the procedure. The draft TAR is currently being revised. In addition, an NMSS working group has been formed to leverage the insights and approaches being pursued to ensure consistency and identify technical or regulatory reasons for differences based on the nuclear materials functional areas. External stakeholder engagement is planned for early FY 2021 to gain stakeholder feedback on this initiative.
FY 2021
During the past year the working group continued to refine the approach and an example past fuel cycle inspection issue was used to explore additional insights and improvements in the qualitative/semi-quantitative issue screening process. During the fall an additional issue was identified for low level waste that demonstrated how the risk triplet/BeRiskSMART approach could be used in identifying the appropriate options to consider when addressing an issue involving the interface between the inspection and licensing paradigms. As issues arise, the working group will continue to refine and further develop the approach and technical bases behind the process.
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Rulemaking Activities
For more information see existing public website.
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RG 1.200, Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities (LWRs)
Summary Description
Regulatory Guide (RG) 1.200 provides the staff position regarding what constitutes an acceptable PRA for a light-water reactor (LWR) and how the LWR 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 for LWRs 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 for LWRs, and documentation to support a regulatory submittal. RG 1.200 also provides the NRC endorsement of the published American Society of Mechanical Engineers/American Nuclear Society (ASME/ANS) LWR PRA standards and related industry guidance documents on PRA peer review.
Previous Fiscal Years
FY 2015
Staff and industry continue to use RG 1.200 in support of risk-informed activities.
FY 2016
Staff and industry continue to use RG 1.200 in support of risk-informed activities. Staff developed a draft position for a process for closure of peer review findings. This staff position has not yet been incorporated into RG 1.200.
FY 2017
Staff and industry continue to use RG 1.200 in support of risk-informed activities. Staff initiated efforts for Revision 3 of RG 1.200.
FY 2018
Staff and industry continue to use RG 1.200 in support of risk-informed activities. Staff continues to work on Rev 3 of RG 1.200 and has held public meetings to share information and receive stakeholder input. 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.
FY 2019
Staff continues to work on Rev. 3 of RG 1.200 and continues to hold public meetings to share information and receive stakeholder input. Staff continues to work with stakeholders to address consistency with RG 1.174 (e.g., defense-in-depth, use of the term PRA acceptability), newly developed methods and guidance on peer reviews, among other changes.
FY 2020
Staff continues work on Revision 3 of RG 1.200 and held public meetings to share information and receive stakeholder input. The staff had numerous interactions with external stakeholders to share information on industry documents being prepared for endorsement in RG 1.200, Revision 3, that relate to peer review of PRAs and newly developed methods. The staff published a proposed revision of RG 1.200, Revision 3, designated as draft guide (DG) DG-1362, for public review and comment. Final publication of RG 1.200, Revision 3, is anticipated in FY2021.
FY 2021
RG 1.200, Revision 3, was published in December 2020. RG 1.200, Revision 3, endorses NEI 17-07, Revision 2, “Performance of PRA Peer Reviews Using the ASME/ANS PRA Standard,” issued August 2019; ASME/ANS RA-S Case 1, “Case for ASME/ANS RA-Sb-2013 Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment of Nuclear Power Plant Applications,” dated November 22, 2017; and portions of PWROG-19027-NP, Revision 2, “Newly Developed Method Requirements and Peer Review,” issued July 2020
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PRA Standards Development
Summary Description
Staff participates with the ASME and ANS efforts to develop consensus PRA Standards. ASME and ANS work together under the Joint Committee for Nuclear Risk Management (JCNRM). The JCNRM is developing a suite of standards which (1) address operating LWRs, advanced LWRs in the pre-operational phases of design and licensing, and advanced non-LWRs, (2) address all operating modes (at-power and low power and shutdown (LPSD)), (3) address 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 LWR PRA standard for at-power conditions, for internal hazards (i.e., internal events, floods and fires) and external hazards (i.e., fires, seismic, high winds, floods and others). This ASME/ANS PRA standard was published as an American National Standards Institute (ANSI) standard in 2008, Addendum A in 2009 and Addendum B in 2013.
- Level 2 (radiological release frequency) LWR PRA standard for all operating modes and for internal and external hazards. This was published as an ASME/ANS trial use standard for pilot applications in 2015.
- Level 3 (consequences) PRA standard for nuclear facilities and for all operating modes and internal and external hazards. This was published as an ASME/ANS trial use standard for pilot applications in 2017.
- LPSD LWR PRA standard addressing Level 1/LERF. This was published as an ASME/ANS trial use standard for pilot applications in 2015.
- Advanced LWR PRA standard for LWRs in the pre-operational phases of design and licensing for addressing Level 1/LERF. This standard has not been published.
- Advanced non-LWR (ANLWR) PRA standard for a full initiator-to-consequence analysis addressing all operating modes, all hazards, and all sources of radioactivity at a single site. This was published as an ASME/ANS trial use standard for pilot applications in 2013.
- Multi-unit LWR PRA standard for nuclear installations with two or more reactor units on a site. This standard has not been published
To date, the staff has endorsed the ASME/ANS Level 1/LERF PRA standard, specifically the 2009 addendum to the 2008 standard (i.e., ASME/ANS RA-Sb-2009).
Previous Fiscal Years
FY 2015
Staff continues to support JCNRM efforts on the various standard activities:
- working on the new edition to the published Level 1 (CDF)/LERF PRA standard
- published trial use Level 2 PRA standard
- developing the Level 3 PRA standard for trial use
- piloting the published trial use LPSD PRA standard
- developing the Advanced LWR PRA standard for trial use
- piloting the published trial use non-LWR PRA standard
FY 2016
Staff continues to support JCNRM efforts on the various standard activities:
- working on the new edition to the published Level 1 (CDF)/LERF PRA standard
- piloting the published trial use Level 2 PRA standard
- developing the Level 3 PRA standard for trial use
- piloting the published trial use LPSD PRA standard
- developing the Advanced LWR PRA standard for trial use
- piloting the published trial use non-LWR PRA standard
FY 2017
Staff continues to support JCNRM efforts on the various standard activities:
- working on the new edition to the published Level 1 (CDF)/LERF PRA standard
- JCNRM published a Code Case which provides an alternate approach to Part 5 of the standard addressing seismic PRA
- NRC developed draft comments on the Code Case (for approval) and planned to request external stakeholder feedback
- piloting the published trial use Level 2 PRA standard
- developing the Level 3 PRA standard for trial use
- piloting the published trial use LPSD PRA standard
- developing the Advanced LWR PRA standard for trial use
- piloting the published trial use non-LWR PRA standard
FY 2018
Staff continues to support JCNRM efforts on the various standard activities:
- working on the new edition to the published Level 1 (CDF)/LERF PRA standard; provided extensive comments to JCNRM and participated in JCNRM working groups
- finalizing the published trial use Level 2 PRA standard
- published the Level 3 PRA standard for trial use
- finalizing the published trial use LPSD PRA standard
- developing the Advanced LWR PRA standard for trial use
- finalizing the published trial use non-LWR PRA standard
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.
FY 2019
Staff continues to support JCNRM efforts to revise the various PRA standards. Activities include:
- Support the development of the new edition of the Level 1 (CDF)/LERF PRA standard and preparing for ballot review in FY2020
- Support the development of the new edition of the Level 2 PRA standard and preparing for ballot review in FY2020
- Support the development of the non-LWR PRA standard and evaluate the endorsement of the trial use standard
- Support the development of the Level 3 and LPSD PRA standards
- Support the development of the Advance LWR trial use PRA standard
FY 2020
- Continued support for the development of the next edition of the ASME/ANS Level 1/LERF LWR PRA standard. The NRC voted on two ballot for this PRA standard and provided technical comments to the JCNRM in support of publishing the document.
- Continued support for the development of the Level 2 LWR PRA standard to prepare for subsequent ballot reviews for publication.
- Continued support for the development of the Level 3 LWR PRA standard to prepare for subsequent ballot reviews for publication.
- Continued support for the development of the LPSD LWR PRA standard to prepare for subsequent ballot reviews for publication.
- Continued support for the development of the ALWR PRA standard to prepare for subsequent ballot reviews for publication.
- Continued support for the development of the ANLWR PRA standard. The NRC voted on two ballot for this PRA standard and provided technical comments to the JCNRM in support of publishing the document. The staff are preparing for the review and endorsement of the ANLWR PRA standard after it is published as an ANSI standard.
- Supporting development of the multi-unit LWR PRA standard.
FY 2021
Continued support for the development of the next edition of the ASME/ANS Level 1/LERF LWR PRA standard. The NRC voted on two ballots for this PRA standard and provided technical comments to the JCNRM in support of publishing the document.
Continued support for the development of the Level 2 LWR PRA standard to prepare for subsequent ballot reviews for publication.
Continued support for the development of the Level 3 LWR PRA standard to prepare for subsequent ballot reviews for publication.
Continued support for the development of the LPSD LWR PRA standard to prepare for subsequent ballot reviews for publication.
Continued support for the development of the ALWR PRA standard to prepare for subsequent ballot reviews for publication.
Supported the development of the recently published NLWR PRA standard, ASME/ANS RA-S-1.4-2021. The NRC voted on two ballots for this PRA standard and provided technical comments to the JCNRM in support of publishing the document. The staff reviewed the NLWR PRA consensus standard and are in the process of completing the endorsing trial use regulatory guidance document, RG 1.247.
Continued support for the development of the multi-unit LWR PRA standard.
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Industry Peer Review Guidance Development
Summary Description
Staff reviews and endorses the PRA peer review guidance issued by NEI regarding how to demonstrate conformance with related requirements in the ASME/ANS consensus PRA standards. RG 1.200 provides the staff position for what constitutes an acceptable peer review program for LWR PRA. A new regulatory guidance document on ANLWR PRA acceptability will similarly provide the staff position for what constitutes an acceptable peer review program for ANLWR PRA. The related NEI guidance documents either in development or that have been published include:
- NEI 00-02 provides the initial peer review guidance for internal events and internal floods Level 1 LWR PRA. It also includes a self-assessment to address the gap between the review criteria in NEI 00-02 and the ASME/ANS PRA standard. This document was published in 2000 and is endorsed in RG 1.200.
- NEI 05-04 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 LWR PRA. This document was published in 2005 and is endorsed in RG 1.200.
- NEI 07-12 provides the peer review guidance for internal fire Level 1/LERF LWR PRA. This document was published in 2007 and is endorsed in RG 1.200.
- NEI 12-13 provides the peer review guidance for external hazards Level 1/LERF LWR PRA. This document was published in 2012 and the NRC issued a letter providing comments on the guidance, but it has not been endorsed in RG 1.200.
- NEI-17-07, provides peer review guidance for all hazards and can be used as an alternative to NEI 00-02, NEI 05-04, NEI 07-12, and NEI 12-13
- NEI 20-09, provides peer review guidance for all hazards, all modes, and all sources for an ANLWR PRA.
Previous Fiscal Years
FY 2015
NEI 00-02 – continues to be endorsed in RG 1.200
- NEI 05-04 – continues to be endorsed in RG 1.200
- NEI 07-12 – continues to be endorsed in RG 1.200
- NEI 12-13 – has not been endorsed in RG 1.200
FY 2016
NEI 00-02 – continues to be endorsed in RG 1.200
- NEI 05-04 – continues to be endorsed in RG 1.200
- NEI 07-12 – continues to be endorsed in RG 1.200
- NEI 12-13 – has not been endorsed in RG 1.200
FY 2017
NEI 00-02 – continues to be endorsed in RG 1.200
- NEI 05-04 – continues to be endorsed in RG 1.200
- NEI 07-12 – continues to be endorsed in RG 1.200
- NEI 12-13 – has not been endorsed in RG 1.200
- NRC developed draft comments on NEI 12-13 (for staff approval) and planned to request external stakeholder feedback
- Appendix "x" – The staff continued to observe uses of the appendix. The staff issued a letter providing interim approval of the process given certain staff comments were addressed. This appendix has not yet been endorsed in RG 1.200.
- NEI informed the staff of their intention to develop guidance, "Performance of PRA Peer Reviews Using the ASME/ANS PRA Standard." This guidance document is meant to replace the previous individual guidance documents.
FY 2018
NEI published NEI-17-07, "Performance of PRA Peer Reviews Using the ASME/ANS PRA Standard." This guidance document is meant to replace the previous individual guidance documents. The staff completed their initial review of this document.
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.
FY 2019
NRC staff continues to work towards developing a position for NEI 17-07 which is expected to be endorsed in a future revision to Regulatory Guide 1.200.
FY 2020
- NRC staff reviewed NEI 17-07, Revision 2, which will be endorsed in Regulatory Guide 1.200, Revision 3.
- NRC providing feedback on the development of NEI 20-09. The staff anticipate endorsing this document in new regulatory guidance on ANLWR PRA Acceptability.
FY 2021
The staff endorsed NEI 17-07, Revision 2, in Regulatory Guide 1.200, Revision 3.
The staff plan to endorse NEI 20-09, Revision 1, in the trial-use RG 1.247.
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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.
Previous Fiscal Years
FY 2015
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.
FY 2016
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.
FY 2017
The NRC and industry RISCs held multiple public meetings to discuss a number of activities important to NRC's RISC or industry's RISC. The key issues discussed at the FY 2017 meetings were Technical Specification (TS) Initiative 4B, the peer review Facts and Observations (F&O) closure process, risk-informed categorization and treatment of SSCs for nuclear power reactors (10 CFR 50.69), diverse and flexible coping strategies (FLEX) in risk-informed decision making (RIDM), Fire PRA realism, PRA methods vetting process, realism in the reactor oversight process (ROP), and Risk Aggregation. Some highlights of these risk informed initiates are provided below:
- TS Initiative 4B: The NRC staff issued its amendment to implement TS Initiative 4B for the pilot plant in August 2017. The NRC is developing a revised version of TSTF-505 which the licensee will use in support of Tech Spec 4B. The revised TSTF-505 is less complex but more restrictive than the approved pilot's TS Initiative 4B program.
- Facts and Observations (F&O) closure process: The NRC staff provided a letter dated May 3, 2017, accepting industry's guidance on the F&O independent assessment process (ADAMS Accession No. ML1707A427). The staff plans to incorporate its expectations for closure of F&Os as a staff regulatory position in the next update to RG 1.200, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities." The staff regulatory position will be used as the basis for endorsement of NEI's guidance for the F&O independent assessment process.
- 10 CFR 50.69: The NRC informed industry that it has resources to review 10 license amendment applications per year. The staff believes that the facts and observations (F&O) closure process will result in more efficient licensing reviews. The NRC completed the pilot license amendment request (LAR) for this initiative.
- FLEX in RIDM: FLEX is currently being credited in multiple-risk applications. The NRC staff has developed several guidance documents to promote consistency and efficiency in applications in these areas. The staff is continuing to monitor the licensees' use of FLEX and is evaluating the need for additional guidance changes.
- Fire PRA Realism: The NRC's Office of Nuclear Regulatory Research (RES) is working closely with EPRI to address a number of areas to improve the level of realism in fire PRA. This effort encompasses topics such as main control room abandonment, heat release rates, fire ignition frequencies, fire growth rate assumptions, and the potential influence of aluminum in high-energy arcing faults. Industry and the NRC are discussing the most effective means to update the NUREG/CR-6850 methodology.
- PRA Methods Vetting process: In April 2017, the staff approved a fee waiver to industry to permit the piloting of three new PRA methods through the vetting panel process. In June 2017, the staff and industry discussed and agreed on changes to draft NEI 16-04 that would guide the pilot actions for the vetting panel process.
- Realism in the ROP: On March 21, 2017 NRC transmitted their plan to address industry concerns for the treatment of Common Cause Failures (CCF), the treatment of dependency between human errors in accident sequences, and the methods used to model various performance deficiencies. Several public meetings have been held to move forward on these topics. The industry has proposed that pursuing the CCF issue is the highest priority.
- Risk Aggregation: The staff has prepared training material for NUREG 1855, Revision 1 that will discuss uncertainty and decision-making in risk-informed applications. The upcoming revision to RG 1.174 in March 2018 will expand the explanations and definitions of deterministic consideration, which will help when making risk-informed licensing decisions. EPRI has published a report that provides its approach for addressing risk aggregation (EPRI Report 3002003116). At this time, the Pressurized-Water Reactor Owners Group is in the process of piloting this framework.
The RISC will be continuing to meet and discuss the current and upcoming risk-informed initiatives to provide the strategic direction to advance the risk-informed decision making in NRC activities.
FY 2018
The NRC and industry RISCs held multiple public meetings to discuss a number of activities important to NRC's RISC or industry's RISC as well as to discuss the charter to provide a better focus on strategic issues that should require the purview of senior management as opposed to number of lower-tier implementation items. The key issues discussed at the FY 2018 meetings were Technical Specification (TS) Initiative 4B, the peer review Facts and Observations (F&O) closure process, risk-informed categorization and treatment of SSCs for nuclear power reactors (10 CFR 50.69), diverse and flexible coping strategies (FLEX) in risk-informed decision making (RIDM), Fire PRA realism, PRA methods vetting process, and realism in the reactor oversight process (ROP). Some highlights of these risk informed initiates are provided below:
- TS Initiative 4B: The NRC staff issued its amendment to implement TS Initiative 4B for the pilot plant in August 2017. The NRC is developing a revised version of TSTF-505 which the licensee will use in support of Tech Spec 4B. The revised TSTF-505 is less complex but more restrictive than the approved pilot's TS Initiative 4B program. The NRC staff is reviewing for additional license amendment requests
- Facts and Observations (F&O) closure process: The NRC staff provided a letter dated May 3, 2017, accepting industry's guidance on the F&O independent assessment process (ADAMS Accession No. ML1707A427). In 2018, the staff conducted a number of audits to ensure that licensees appropriately followed the independent assessment process. The staff plans to incorporate its expectations for closure of F&Os as a staff regulatory position in the next update to RG 1.200, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities." The staff regulatory position will be used as the basis for endorsement of NEI's guidance for the F&O independent assessment process.
- 10 CFR 50.69: The NRC issues the safety evaluation for Limerick Generating station. Staff is reviewing 12 additional license amendment requests.
- FLEX in RIDM: FLEX is currently being credited in multiple-risk applications. The NRC staff has developed several guidance documents to promote consistency and efficiency in applications in these areas. The staff is continuing to monitor the licensees' use of FLEX and is evaluating the need for additional guidance changes. The staff emphasized the need to receive operational experience on FLEX strategies and enhanced HRA methods to support various applications that can be credited with FLEX strategies.
- Fire PRA Realism: The NRC's Office of Nuclear Regulatory Research (RES) is working closely with EPRI to address a number of areas to improve the level of realism in fire PRA. This effort encompasses topics such as main control room abandonment, heat release rates, fire ignition frequencies, fire growth rate assumptions, and the potential influence of aluminum in high-energy arcing faults. Industry and the NRC are discussing the most effective means to update the NUREG/CR-6850 methodology.
- PRA Methods Vetting process: In April 2017, the staff approved a fee waiver to industry to permit the piloting of three new PRA methods through the vetting panel process. In June 2017, the staff and industry discussed and agreed on changes to draft NEI 16-04 that would guide the pilot actions for the vetting panel process. In June 2018, NEI formally informed that they are no longer interested in vetting panel process and provided an alternative for staff consideration.
- Realism in the ROP: On March 21, 2017 NRC transmitted their plan to address industry concerns for the treatment of Common Cause Failures (CCF), the treatment of dependency between human errors in accident sequences, and the methods used to model various performance deficiencies. Several public meetings have been held to move forward on these topics. The industry has proposed that pursuing the CCF issue is the highest priority.
The RISC will be continuing to meet and discuss the current and upcoming risk-informed initiatives to provide the strategic direction to advance the risk-informed decision making in NRC activities. 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.
FY 2019
The NRC and industry RISCs held multiple public meetings to discuss a number of activities important to NRC's RISC or industry's RISC. The key issues discussed at the FY 2019 meetings were Technical Specification (TS) Initiative 4B, risk-informed categorization and treatment of SSCs for nuclear power reactors (10 CFR 50.69), diverse and flexible coping strategies (FLEX) in risk-informed decision making (RIDM), Fire PRA realism, issues relating to High Energy Arcing Faults (HEAF), and the new PRA methods approval process. In each of these areas, senior managers of the industry and NRC discussed status of key projects, challenges, and strategies to overcome those challenges. Consequently, in each of these areas the NRC staff made significant progress while appropriately considering industry concern.
FY 2020
The NRC and industry RISCs held multiple public meetings to discuss a number of activities important to NRC's RISC or industry's RISC. The key issues discussed at the FY 2020 meetings were Technical Specification (TS) Initiative 4B, risk-informed categorization and treatment of SSCs for nuclear power reactors (10 CFR 50.69), diverse and flexible coping strategies (FLEX) in risk-informed decision making (RIDM), Fire PRA realism, issues relating to High Energy Arcing Faults (HEAF), the new PRA methods approval process, and the Risk-Informed Process for Evaluations as part of LSSIR. In each of these areas, senior managers of the industry and NRC discussed status of key projects, challenges, and strategies to overcome those challenges. Consequently, in each of these areas the NRC staff made significant progress while appropriately considering industry concerns.
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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-15-0168, Regulatory Guide (RG) 1.174, Revision 3 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."
Previous Fiscal Years
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.
FY 2017 Status
During this fiscal year, the staff continued revising the defense-in-depth guidance and soliciting input from internal and external stakeholders, including feedback from the Advisory Committee on Reactor Safeguards (ACRS) Subcommittee on Reliability and PRA. The staff published for public review and comment an update of the draft regulatory guide for Revision 3 of RG 1.174 (i.e., DG 1285). The staff resolved all internal and external stakeholder comments on DG-1285 and prepared to meet with and receive feedback from the ACRS Full Committee on the final draft of the revised RG.
FY 2018
Staff finalized Revision 3 to RG 1.174 which was published in January 2018. The primary revisions involved updating the guidance on defense-in-depth.
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. The intent of the assessment is to demonstrate the proposed licensing basis changes will only result in small increases in risk and only when it is also reasonably assured that, among other things, consistency with the defense-in-depth philosophy and sufficient safety margins are maintained.
FY 2019
Staff and industry continue to use RG 1.174 in support of risk-informed activities.
FY 2020
Staff and industry continue to use RG 1.174 in support of risk-informed activities.
FY 2021
Staff and industry continue to use RG 1.174 in support of risk-informed activities
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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.
Previous Fiscal Years
FY 2015
Revision to the document is under review.
FY 2016
A public workshop was held to "pilot" the Revision 1 draft and finalize for publication.
FY 2017
The staff published Revision 1 to the NUREG. The revision provided additional text to further clarify the guidance and the relationship to the associated EPRI documents. In addition, the staff developed a Web-based training course for both internal and external stakeholders. The course is designed for both staff and management. It teaches the concepts used in the guidance for treating PRA uncertainties in risk-informed decisionmaking. The course has options that allows the user to take a shorter version of the course or go into more detail.
FY 2018
The staff continues to work on developing a training handbook to NUREG-1855. The handbook is meant to provide examples to illustrate how to implement the guidance in the NUREG.
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.
FY 2019
The staff continues to work on developing a training handbook to NUREG-1855. The handbook is meant to provide examples to illustrate how to implement the guidance in the NUREG.
FY 2020
The staff continue to work on developing a training handbook to NUREG-1855, which is intended to provide examples illustrating how to implement the guidance in the NUREG. The staff are also preparing for a new revision to NUREG-1855 to make it current with respect to the next edition of the Level 1/LERF LWR PRA standard and in consideration of other potential enhancements.
FY 2020
Staff and industry continue to use NUREG-1855 in support of risk-informed activities. The staff continue preparations for the next revision of NUREG-1855 to align with the next edition of the ASME/ANS Level 1/LERF LWR PRA standard and to consider other potential enhancements such as expanded guidance on the treatment of uncertainties in PRA for advanced LWRs.
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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
Previous Fiscal Years
FY 2019
Each of these initiatives will be implemented by an initiative team and supported by one or more executive sponsors. Each of these initiatives will have its own timeline – some shorter, some longer-term. Future Agency-Wide Risk-Informed Activities Updates will address these initiatives, separately as appropriate.
FY 2020
The Office of the Executive Director for Operations’ Be riskSMART initiative team is developing a holistic, high-level framework that gives staff confidence to consistently apply and communicate risk insights for all NRC decisions (including technical, corporate, and legal decisions) without compromising our mission. The framework includes guidance and steps for identifying and managing risk (for issues where there is no pre-determined answer in a law, policy, or standard); performance metrics for how well we are considering risk; and training to ensure a common understanding of risk.
Figure: Summary of the Be riskSMART risk-informed decision-making framework.
The figure above summarizes the key steps of the Be riskSMART framework: Be… clear about the problem; Spot… what can go wrong or right?, what are the consequences?, and how likely is it?; Manage… what you can; Act… on a decision; Realize… the result, and Teach… others what you learned.
The arrow illustrated under the Be riskSMART logo represents the prompt re-evaluation of a decision to determine if conditions have changed or new information is available.
A diagnostic tool was developed to measure NRC staff’s current state in evaluating the agency’s effectiveness for applying risk-insights. This tool can be used to identify who owns or implements the use of risk-insights in decision-making.
Training is being developed for the staff to overcome any challenges and barriers with applying risk insights in decision-making. The purpose of the training is to ensure that the staff shares a common understanding of risk and how it can be used in decision-making across the agency.
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Regulatory Improvements for Production and Utilization Facilities Transitioning to Decommissioning Rulemaking
For more information see existing public website.
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