The inspectors identified a
Severity Level IV (
SL IV) non-cited violation (
NCV) of
10 CFR 50.59 requirements for the licensee's failure to fully evaluate a change to the plant which potentially involved an unreviewed safety question (
USQ). Specifically, the licensee implemented a plant change in 1992 which directed the discharge of safety injection system (
SIS) relief valve SI-857A to an open floor drain in the auxiliary building (contrary to the
Updated Final Safety Analysis Report), without evaluating the effects on dose consequences. The potential
USQ was related to an increase in the dose consequences, if valve SI-857A, which is located outside containment, were to lift (and potentially fail to reseat) during post-LOCA recirculation conditions. This finding was evaluated using traditional enforcement and is more than minor because it was a change to the facility which would require NRC review and approval prior to implementation. This finding affected the
mitigating systems cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to
initiating events to preclude undesirable consequences. However, the technical issue was determined to be of very low safety significance, given the low likelihood of a scenario involving a loss of coolant accident and actuation of SI-857A. The licensee entered this issue into the corrective action program as Action Request 151238.
