A finding of very low safety significance was self-revealed for the failure to implement procedures for using mobile cranes and the failure to use human error prevention tools. Consequently, a mobile crane boom contacted and severed the middle phase of an overhead 12 kilovolt line in the owner controlled area W yard. This caused a loss of power to the fire pump house, which rendered the electric fire pump
inoperable. This finding was entered into the licensees corrective action program as Action Request (
AR) 00860140. No violation of NRC requirements occurred. This finding was more than minor because it was related to the external factors attribute (fire) of the
Mitigating Systems cornerstone and adversely affected the cornerstone objective to ensure the availability of systems that respond to
initiating events. Specifically, the electric fire pump was rendered
inoperable and unavailable when power was lost to the fire pump house, which degraded the fire protection defense-in-depth strategies. The finding was of very low safety significance because the fire protection system performance was not affected in that both diesel-driven fire pumps were
operable. This finding was associated with a cross cutting aspect in the area of human performance work practices (
H.4(c))
