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| Entered date | Event description | |
|---|---|---|
| ENS 52543 | 8 February 2017 17:31:00 | During a control room panel walk down by an on-shift Reactor Operator at approximately 1151 (EST) on 2/8/2017, Unit 1 High Pressure Coolant Injection (HPCI) suction and discharge pressure indicators were noted to be downscale. I & C investigated and found the output of 1E41K603, DC to AC inverter, degraded. This inverter also powers the HPCI flow controller. Without the flow controller HPCI would not auto-start to mitigate the consequences of an accident, thus HPCI was declared inoperable. All other emergency core cooling systems and the Reactor Core Isolation Cooling (RCIC) system remain operable. HPCI is a single train system with no redundant equipment in the same system, thus this failure is reportable as an event or condition that could have prevented fulfillment of a safety function needed to mitigate the consequences of an accident, 10CFR50.72(b)(3)(v)(D). Inverter 1E41K603 was replaced and functionally tested satisfactorily at 1630 on 2/8/2017, restoring HPCI to operable status. The NRC Resident Inspector was notified. |
| ENS 52531 | 3 February 2017 16:33:00 | In preparation for transitioning the Plant Hatch Fire Protection Licensing Basis from 10CFR50.48(b) (Appendix R) to 10CFR50.48(c) (NFPA 805), a weak-link and operator manual action (OMA) analysis for Information Notice (IN) 92-18 type hot shorts on motor-operated valves (MOVs) was performed to support the Plant Hatch Appendix R Safe Shutdown Analysis. As a result of the analysis, it was identified that cable impacts can bypass valve limit and torque switches, resulting in physical damage to valves required for Safe Shutdown. This would prevent the valves from being operated locally or being operated from the remote shutdown panel. These cable failures could also cause the valve motors to fail. This updated analysis has identified circuit configuration deficiencies in Fire Areas 0024 A & C (Main Control Room & Cable Spread Room), 1203F (U1 Reactor Building SE), 1205F (U1 Reactor Building NE), and 2203F (U2 Reactor Building NE). Therefore, due to the identified deficient conditions, it was determined that in the event of a postulated fire in the affected fire areas, the paths of safe shutdown on the affected unit(s) could be compromised and impact the ability to achieve safe shutdown conditions. Compensatory measures were already in place in accordance with the plant's Fire Hazard Analysis (FHA) as a result of previous conditions in these same fire areas. The presence of the compensatory measures in addition to automatic fire detection in these fire areas ensure that the safe shutdown paths are preserved until the degraded conditions can be repaired. CRs 10326399, 10326401, 10326402, 10326404 and 10326405 The licensee notified the NRC Resident Inspector. The unanalyzed condition is applicable to 10CFR50.48(b) Appendix R and not to 10CFR50.48(c) (NFPA 805). |