ML21293A008

HEAF - NEI

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: ML21293A008
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 ZOI Illustration (NUREG/CR-6850 Appendix M, Figure M-1) due to the assumption that the fire will propagate and/or damage equipment within the zone of influence.

Does Al HEAF Require a Change to Modeled ZOI?

It is a safety concern warranting action It is not a safety concern

• OECD non-prototypic test but no ZOI

• Cables very robust measured * ~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