ML23150A027
| ML23150A027 | |
| Person / Time | |
|---|---|
| Issue date: | 05/17/2023 |
| From: | Markhenry Salley NRC/RES/DRA/FXHAB |
| To: | |
| Hamburger K | |
| Shared Package | |
| ML23150A023 | List: |
| References | |
| Download: ML23150A027 (10) | |
Text
May 17, 2023 MarkHenry Salley P.E. Branch Chief Fire and External Hazards Analysis Branch (FXHAB)
Division of Risk Analysis Office of Nuclear Regulatory Research Rockville, MD.
High Energy Arching Faults PRA Methodology Workshop Application of the NRCs Be riskSMART Guidance to HEAFs
2 U.S. NRC: Protecting People and the Environment The NRC licenses and regulates the Nation's civilian use of radioactive materials, to provide reasonable assurance of adequate protection of public health and safety, to promote the common defense and security, and to protect the environment.
Becoming a Modern Risk-Informed Regulator Be riskSMART: combines traditional concepts, such as the risk triplet, risk management, the risk heat map and risk appetite, into a plain language framework that gives the staff confidence to apply and communicate risk-insights for all kinds of NRC decisions whether they are in the technical, corporate, or legal arena.
3 Be riskSMART: Guidance for Integrating Risk Insights into NRC Decisions (NUREG/KM-0016)
4 Applying Be riskSMART to HEAFs - Be Be clear about the problem:
NRCs Regulations are based on the 3 Ds Determinist Requirements, Design Basis Accidents,Defense-in-Depth 10CFR Part 50 Appendix A General Design Criteria for Nuclear Power Plants Criterion 3 Fire Protection Criterion 17 Electric Power Systems Review of Operating Experience (OpE)
HEAFs account for ~ 10% of significant NPP fires worldwide Review of US. NPP that transitioned to NFPA 805 identify HEAFs as the third highest fire risk driver NUREG/CR-6850 Appendix M (2005) first attempt to identify/quantify fire risk from HEAFs with a One-Size-Fits-All Zone of Influence (ZOI) approach Review of recent OpE suggests the Appendix M ZOI may be non-conservative.
More research is needed Is there an immediate safety concern?
Is there a potential Generic Issue (GI)?
5 Applying Be riskSMART to HEAFs -Spot Enter the Risk Triplet What can go wrong?
What are the consequences?
How likely is this to happen?
HEAFs are not unique to Nuclear Power Plants Atlanta Airport December 17, 2017 DC Metro System March 14, 2016 NFPA & IEEE large amount of research into Arc-Flash Commercial industry focuses primarily on personnel safety Risk to Nuclear Power Plant extends beyond personnel safety to Structures. Systems and Components (SSC) needed for Post-Fire Safe-Shutdown
6 Applying Be riskSMART to HEAFs - Manage Manage what you can:
Must first recognize there is a potential safety issue Goal is to reduce consequences and likelihood of event Tactics to Manage HEAF risk; Communicate to Licensee the potential problem Use of generic communications (Information Notices Presentations at Regulatory Information Conference (RIC) industry forums NEI Fire Protection Forum, Owners Groups Enlist a strong partner in the Electric Power Research Institute (EPRI) to advance/improve prevention measures (maintenance/inspection) of electrical power systems Strengthen the first echelon in Defence-in-Depth => Prevention Characterization of Testing and Event Experience for High-Energy Arcing Fault Events EPRI-3002011922 Nuclear Station Electrical Distribution Systems and High-Energy Arcing Fault Events EPRI-3002015992 Critical Maintenance Insights on Preventing High-Energy Arcing Faults EPRI-3002015459 Perform a Phenomena Identification and Ranking Table (PIRT) expert elicitation Better understanding of what we Know and Dont Know and focus on their importance
7 Applying Be riskSMART to HEAFs - Act Act on decision Evaluate what you have Spotted and Managed decide the next steps.
Enter HEAF into the Pre-Generic Issue (GI) Program Pre GI-018 => LIC 504 No Immediate Safety Issue Assemble group of experts Create a joint NRC /EPRI expert HEAF Working Group (WG)
National Institute Standards and Technology (NIST)
Sandia National Laboratories (SNL)
Reach out for international research partners Create an International Organization for Economic Co-operation and Development (OECD) Nuclear Energy Agency (NEA)
Ten member countries HEAF Working Group NRC as the operating agent Perform multiple series of small- & full-scale testing KEMA High Power Test Laboratories & BSI Electrical Contractor
8 Applying Be riskSMART to HEAFs - Realize Realize the Results and what they mean.
What did you learn?
Location and construction of switch gear and bus duct (EPRI Survey)
Aluminum/Copper question HEAF risk ranking with respect to other fire risk drivers (EPRI Presentation to ACRS)
Improved surveillance and maintenance research (EPRI Reports)
Improves 1st echelon Defence-In-Depth => Prevention NUREG/CR-6850 (EPRI1011989) Fire PRA Methodology for Nuclear Power Facilities, Appendix M, High Energy Arcing Faults (2005)
Realize the One Size Fits All approach was a good starting point, however, Using latest operating experience, test data, modeling and expert judgement, the HEAF WG developed more realistic PRA methods Recognized importance of physical parameters (e.g., fault clearance time, voltage, current, construction, etc.) and modeled accordingly Singular focus on HEAFs NRC/EPRI HEAF WG advanced the State-of-Practice for understanding and analyzing HEAF risk on NPP safety Publication of NUREG-2262 (EPRI 3002025942) High Energy Arcing Fault Frequency and Consequence Modeling (2023)
9 Applying Be riskSMART to HEAFs -Teach Teach others what you have learned:
Published test results, tool and methodology development for public comment as they were developed Incorporated/dispositioned public comments All reports (Research Information Letters, NUREGs) published in open literature Multiple presentations at the NRC annual Regulatory Information Conference (RIC)
Multiple public meetings/workshops during development Publishing the reports internationally thru OECD/NEA Professional outreach (e.g. seminar at University Maryland)
Public Web Page NRC High Energy Arc Fault (HEAF) Research https://www.nrc.gov/about-nrc/regulatory/research/fire-research/heaf-research.html NRC/EPRI final public workshop May 17 & 18, 2023 Hybrid, in-person & remote https://www.nrc.gov/pmns/mtg?do=details&Code=20230276
10 Safety is a Difficult Metric to Measure ~
What is Success?
Jack Ramsey noted that in his peregrinations around the globe promoting NRC safety methods and values, he was often asked to toast his hosts. He told them that if they did their job well, they will be forgotten by society, as history typically remembers nuclear safety failures not successes. He then raised his glass for the toast: In twenty years, I hope no one will remember us. Page 171