The team identified a violation of
10 CFR 50, Appendix R, Section III.G.2, for failure to physically protect or separate cables from fire damage and instead relying on an unapproved local
manual operator action. The unprotected cables were associated with a common electrical protection and metering circuit which was installed such that fire damage to a cable in or just above the 3A 4160V engineered safeguards (
ES) switchgear could result in tripping and locking out all feeder breakers to both 4160V
ES busses, resulting in a loss of all safetyrelated alternating current power. In addition, the local
manual operator action to reset the 3B
emergency diesel generator breaker lockout on the 3B 4160V
ES switchgear was determined to be non-feasible. During a severe fire in the adjacent 3A 4160V Switchgear Room the fire response activities would cause the location for the operator action (the 3B 4160V Switchgear Room) to be exposed to hot smoke, water mist, and water on the floor. This finding was an immediate safety concern and the licensee made modifications to correct the nonconforming condition before the inspection team left the site. This finding is unresolved pending the completion of a significance determination. The finding is greater than minor because it degraded the defense in depth for fire protection and also because it is associated with the protection against external factors attribute and degraded the reactor safety
mitigating systems cornerstone objective. The finding adversely affected the reliability and capability of equipment required to achieve and maintain a
safe shutdown condition following a severe fire in the 3A 4160V
ES Switchgear Room.
