ML23150A041
| ML23150A041 | |
| Person / Time | |
|---|---|
| Issue date: | 05/17/2023 |
| From: | Markhenry Salley NRC/RES/DRA/FXHAB |
| To: | |
| Hamburger K | |
| Shared Package | |
| ML23150A023 | List: |
| References | |
| Download: ML23150A041 (9) | |
Text
May 18, 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 Arcing Fault PRA Methodology Workshop Use of NRC HEAF Research and NRC/EPRI HEAF Working Group Information in Non-PRA Applications
2 The focus of the NRC Research and Working Group was the impact of HEAFs on Structurers, Systems, and Components (SSC) important to nuclear safety.
Personnel Safety was outside the Scope of this project For guidance on personnel safety (arc-flash) please see:
OSHA's general industry electrical safety standards published in Title 29 Code of Federal Regulations (CFR), Part 1910.302 through 1910.308 Design Safety Standards for Electrical Systems, and 1910.331 through 1910.335 Electrical Safety-Related Work Practices Standards.
NFPA 70E Standard for Electrical Safety in the Workplace Personnel Safety is Outside the Scope of this project
3 Are HEAF unique to only Nuclear Power Plants with a Fire PRA?
No. The potential for HEAF events have and will continue to occur in all electrical power generating facilities/industrial facilities due to multiple common root causes such as (see Information Notice 89-64 for examples):
Inadequate Maintenance Improper Foreign Material Exclusion Aging Insulation Degradation Human Error Water Intrusion Apply principles of Defense In Depth See Chuck Fishers presentation on the 2020 Harris HEAF
4 Useful Information from the NRC HEAF Research and NRC/EPRI Working Group for Non-PRA applications for Fire Protection Engineers (FPE) performing/updating NPPs Fire Hazard Analysis (FHA)
NPP that do not have Fire PRA Utilities that have other large Non-Nuclear generation Fossil Fuels (coal, natural gas)
Hydroelectric Renewable (solar, wind)
Members of the public in other applications Use the NUREG-2262 Zone of Influence (ZOI) tools See Ashleys presentation on ZOIs for detailed discussion Bounding ZOI (Fault Clearing Unknown)
Refined ZOI (If you know the fault clearing time)
Assumption ZOIs are based on defined target fragilities (15 & 30 MJ/m2)
5 Screening (Bounding) ZOI Approximations-Load Centers Circuit Breaker HEAF Location 2.5ft 2ft
6 Screening (Bounding) ZOI approximations-MV switchgear 15MJ/m2
7 Screening (Bounding) ZOI Approximations-Bus Ducts UAT Steel Aluminum
8 Screening (Bounding) ZOI Approximations-Bus Ducts SAT Steel Aluminum
9 Use screening (bounding) ZOI for HEAF source equipment NUREG-2262 (EPRI 3002025942) provide extensive refinements to these bounding values All ZOIs are based off the linked target fragility of 15MJ/m2 and 30MJ/m2 for further fragility information see Appendix F of the PRA report and RIL202201-Target Fragilities for Equipment Vulnerable to High Energy Arcing Faults Model thermal fires - NUREG-2178 Refining and Characterizing Heat Release Rates from Electrical Enclosures during Fire (RACHELLE-FIRE)
- New guidance in NUREG-2262 (EPRI 3002025942)
HEAF + ensuing fire See Ashleys presentation on post-HEAF ensuing fires Additional Information