ML21293A008
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| ML21293A008 | |
| Person / Time | |
|---|---|
| Site: | Nuclear Energy Institute |
| Issue date: | 10/20/2021 |
| From: | Nuclear Energy Institute |
| To: | Lingham S NRC/NRR/DORL/LPL4 |
| Lingham S | |
| Shared Package | |
| ML21293A007, ML21291A179 | List: |
| References | |
| EPID L-2021-NFO-0007 | |
| Download: ML21293A008 (2) | |
Text
Zone of Influence (ZOI)
- NUREG/CR-6850 Definition (generic): A volume surrounding an ignition source where all intervening combustibles and targets may be adversely affected by a fire initiated by the ignition source.
- NUREG/CR-6850 (HEAF-specific severity factors): High-energy arcing faults are modeled assuming damage to a predefined zone of influence. The severity factor is 1.0 due to the assumption that the fire will propagate and/or damage equipment within the zone of influence.
ZOI Illustration (NUREG/CR-6850 Appendix M, Figure M-1)
Does Al HEAF Require a Change to Modeled ZOI?
It is a safety concern warranting action
- OECD non-prototypic test but no ZOI measured It is not a safety concern
- Cables very robust
- ~100,000 of component operating years with Al widespread
- No op ex shows an increased ZOI
- Harris HEAF with Al
- Actual ZOI bounded by currently modeled ZOI
- Cables within ZOI functional
- Robinson within modeled ZOI
- Appendix R separation - change in ZOI would have to be very large