ML22201A003
| ML22201A003 | |
| Person / Time | |
|---|---|
| Issue date: | 07/22/2022 |
| From: | Reinaldo Rodriguez, Sunil Weerakkody NRC/NRR/DRA, NRC/NRR/DRA/APOB |
| To: | Mike Franovich, Chris Miller NRC/NRR/DRA, NRC/NRR/DRO |
| Weerakkody S | |
| References | |
| Download: ML22201A003 (4) | |
Text
ENCLOSURE 3:
Summary of the Evaluation of Recommendations Table C-1 of LIC 504: Decision Options Criteria Used to Recommendations/Decision Options Evaluate Evaluation of Analysis Approach Considered by the LIC-504 Team Recommendations/Dec Recommendations/Decision Options ision Options 1 No actions needed.as a result of the LIC-504 Evaluate risk and regulatory LIC-504 guidance The team did not recommend this assessment. insights per LIC-504 process. option because high energy arcing fault (HEAF) events continue to occur.
Furthermore, some HEAF events have led to risk significant precursor events.
For example, since 2010, the NRCs Accident Sequence Precursor (ASP) program identified six precursor events associated with HEAFs. Additionally, based on the results of the analyses completed under LIC-504, the team concluded that there are important risk insights, best practices, and mitigative actions, etc., which, when shared with the industry, could lead to enhancements to public health and safety and reduce enterprise risk.
2 Issue plant-specific or generic orders to Information documented in NRC LIC-504 guidance on The team did not recommend this promptly implement corrective actions at memos (ML16064A250 and prompt regulatory option because (a) the first step of the nuclear power plants (NPPs) to address (ML21272A262) and results from actions LIC-504 evaluation confirmed that the increased estimate of risks when the new additional research about the new risk significance of HEAFs does not probabilistic risk assessment (PRA) method is HEAF PRA methodology exceed the LIC-504 guidelines for used. regarding potential changes to prompt regulatory action, and (b) there zones of influence (ZOIs) due to is no basis to conclude that licensees presence of aluminum. are not in compliance with NRC regulations, Orders, and NRC issued licenses.
3 Develop rulemaking plan to clarify and Determine if there is a safety Guidance provided in The team did not recommend this strengthen the requirements for Fire PRA issue based on the LIC-504 MD 6.3, Rulemaking action, since existing licensing configuration control, including the assessment and whether it can be Process basis/license conditions for TSTF-505 incorporation of new Fire PRA methods, for addressed via the rulemaking and NFPA-805 plants require licensees Commission review and approval. process. Team conducted to consider operating experience as quantitative and qualitative part of their performance monitoring assessments via the LIC-504 program (e.g., NFPA-805 Section 1
process. 2.4.3.3 and 2.6.2) and PRA results generated using information received from the two reference plants and insights from the ASP program relating to average HEAF risks are highly unlikely to justify rulemaking or backfitting.
4 Develop a document that identifies key Review of HEAF OpE Teaching element of the The team recommended developing a qualitative risk insights that plant operators documented in various reports Be RiskSMART document to identify the key qualitative may be able to use in a cost-effective manner and the ASP Database and framework risk insights and included it as an to reduce HEAFs to mitigate any potential information from reference plants enclosure to the LIC-504 enterprise risks and/or impacts to public health memorandum. Action complete. This and safety. qualitative assessment is provided in Enclosure 2 to the memo.
Recommendations Considered in Issuing a Generic Communication 5 Issue a Bulletin (BL). Evaluate information in staff MD 8.18 guidance, The team did not recommend this prompt action determination NRR/IOEB generic option, because, per MD 8.18, BLs are conclusion (ML21272A262), MD communication used to request actions from the 8.18 guidance, NRR/IOEB implementation licensee and/or information to address implementation guidance on BL guidance, LIC-504 significant issues that have great issuance, and LIC-504 guidance guidance (Figure 3) and urgency. Based on the staffs risk (Figure 3) information documented assessment, this issue does not in ML21272A262 require urgent information collection or licensee action.
6 Issue a Generic Letter (GL). MD 8.18 guidance, NRR/IOEB MD 8.18 guidance, The team did not recommend this implementation guidance on NRR/IOEB generic option because issue does not circumstances that should prompt communication constitute a risk-significant compliance issuance of generic letters and implementation matter that should be brought promptly LIC-504 guidance (Figure 3) guidance, and Figure 3 to the attention of licensee request, or of the LIC-504 document of sufficient safety significance to warrant information collection.
7 Issue an Information Notice (IN) or Regulatory MD 8.18 guidance, NRR/IOEB MD 8.18 guidance, The team recommended a generic Issue Summary (RIS) as appropriate, and implementation guidance on NRR/IOEB generic communication to communicate, as consistent with the Generic Communication circumstances that should prompt communication appropriate, the LIC-504 quantitative process. The generic communication will issuance of an IN or RIS and LIC- implementation and qualitative assessments, related share information on (1) the operating 504 guidance (Figure 3) guidance, and Figure 3 operating experience, and the experience and risk insights from the LIC-504 of the LIC-504 document availability of the new HEAF PRA assessment; (2) regulatory framework/license methodology for licensee conditions and (3) the availability of the new consideration.
HEAF risk assessment methodology for For either the IN or RIS, the team licensee consideration (expected to be issued members recommend a for public comment in July 2022). comprehensive stakeholder engagement strategy to communicate 2
with external parties (see Recommendations 12, 13, and 14).
The qualitative risk insights shared using an IN or RIS could enable licensees to voluntarily adopt cost-effective changes to their programs such as to the preventative maintenance programs (e.g., to improve the reliability of feeder circuit breakers to improve the mitigation of HEAF events) and operational programs (e.g., housekeeping practices and enhancements to operator responses to HEAF events) to reduce HEAF-related risks.
Recommendation for Incorporating Risk Insights from LIC-504 Assessment to Ongoing PRA Configuration Control Program 8 Incorporate risk insights obtained from the 10 CFR 50.48(c) (NFPA 805) Goal of the PRA This recommendation is part of current LIC-504 assessment to inform NRRs ongoing requirements, TSTF-505 License configuration control efforts to address potential gaps with PRA configuration control initiative. Condition, pertinent license program is to ensure that NRCs oversight of PRA configuration conditions and PRA standards PRA analyses reflect the control programs, using a balanced as-built, as -designed, approached. No further action required.
and as -operated plant.
Recommendations Considered for Enhanced Inspection/Oversight 9 Communicate risk insights gleaned from the Conduct meetings to discuss with NRR/DRO/IOEB The team recommended this option HEAF-related risks/LIC-504 process with NRR Division of Reactor guidance on selecting because availability of risk insights will regional inspectors and Senior Reactor Oversight (DRO), Operating information that should enable regions to enhance use of Analysts using existing processes (KM-related Experience Branch (IOEB), to be shared with regional budgeted inspection resources in a risk meetings, Inspector Newsletters, periodic determine appropriate information staff informed manner to enhance plant meeting between APLB and fire protection to share with regional staff at safety.
inspectors, SRA counterpart meetings, etc.). opportune times.
10 Develop a Temporary Instruction to have IMC-0040, Preparing, Revising, Existence of clear The team did not recommend this regions inspect plants to collect additional and Issuing Documents for the regulatory requirements option. The best available information information and determine if HEAF events NRC Inspection Manual that the inspectors may does not justify an inspection focused have been adequately addressed. use to examine whether on HEAF and did not identify any non-there are potential compliances. Further, if the non--compliances or recommendation related to a generic potential performance communication is adopted, licensees deficiencies and/or the would be better informed of HEAF need for additional issues; thereby reducing the need for information to resolve additional inspections. Additionally, the issue(s). reference plant walkdowns and other aspects of the LIC-504 process (I.e.,
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assessment, of operating experience and accident sequence precursors etc.) have provided sufficient information to inform the decision process.
11 Consider incorporating risk insights obtained ROP change control process. Examine whether The team recommended this option from the LIC-504 assessment to inform NRRs inclusion of additional since the LIC-504 assessment has Reactor Oversight Process (ROP). guidance would support revealed insights that could enhance NRC efforts to enhance and better risk-inform the inspection further risk-informing the and oversight program.
inspection and oversight program.
Other Communications 12 Share risk insights gained from the HEAF LIC- Considered and identified benefits Teaching element of the The team recommended this option 504 analysis with external stakeholders via a gained by sharing risk insights Be RiskSMART because it would enhance the public meeting (e.g., workshop where a more with external stakeholders framework regulated communitys awareness of interactive format can be used to explain risk communities who could influence the importance of HEAF risks and insights and methodology enhancements, risk-informed decision-making in enable them to understand and further etc.). the regulated community. consider options available to them to reduce and/or mitigate risks associated with HEAFs at their facilities based on the best practices, etc.
13 Share insights gained from the HEAF LIC-504 Considered and identified benefits Teaching element of the The team recommended this option analysis with the PWR and BWR Owners by sharing risk insights with Be RiskSMART because it provides an opportunity to Group (OG) members. regulated communities who have framework leverage the OGs expertise to considerable knowledge in PRA consider implementing best practices and have the technical expertise and reduce/mitigate risks.
to offer technical solutions in this area.
14 Share insights gained from HEAF LIC-504 OIP guidance related information Teaching element of the The team recommended this option analysis with international community (e.g., exchanges. Be RiskSMART because it provides for an opportunity OECD HEAF project participants, OECD/NEA framework to enhance world-wide nuclear safety working group on risk assessment (WGRISK), with respect to HEAFs.
international conferences).
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