Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 50772 | 28 January 2015 08:56:00 | At 0535 CST on 1/28/15, control room staff identified that valve EJHV8716A, RHR A To SIS (Safety Injection System) Hot Leg Recirc Loops 2&3 (isolation valve), had been closed per clearance order C20-D-EJ-A-005 to support maintenance on the A RHR system. Closing valve EJHV8716A placed Wolf Creek in TS 3.0.3. At 0550 CST on 1/28/15, power was restored to valve EJHV8716A and the valve was opened, allowing the unit to exit from TS 3.0.3. Subsequent reviews of clearance order C20-D-EJ-A-005 identified that valve EJHV8809A had been energized and closed per direction of the clearance order. TS 3.0.3 was reentered at 0635 CST due to discovery of this condition. At 0650 CST, valve EJHV8809A was opened and deenergized allowing exit from TS 3.0.3. The licensee notified the NRC Resident Inspector. |
| ENS 46196 | 22 August 2010 00:15:00 | On 8/21/10 at 1700 (CDT) with the Unit in Mode 1, 100% power, Engineering personnel provided information to the Control Room that a known void in the 'A' Residual Heat Removal (RHR) heat exchanger could move from the heat exchanger to other locations in the Emergency Core Cooling System (ECCS). The analysis provided by a vendor indicates that during a specific RCS leak scenario with a failure of the A' RHR Pump, our (Unit 1) piping configuration could potentially allow the void to be swept from the 'A' RHR heat exchanger and be transported to the 'A' Centrifugal Charging Pump (CCP) and 'A' Safety Injection Pump (SIP) while in the cold leg recirculation mode of operation. This condition results in one train of ECCS being inoperable. The ECCS safety function is maintained due to redundant and interconnecting piping, in both injection and recirculation phases of operation. The NRC Resident has been informed. The licensee declared one train of ECCS inoperable placing Unit 1 in the 72-hour Technical Specification (TS) 3.5.2, Condition A, Action A.1. Corrective actions are on going to remove the void and exit the TS Action Statement.
Additional information has been obtained by Engineering. The largest void identified in the 'A' RHR heat exchanger would not prevent the RHR system from performing its safety function. Hydraulic analysis models of this void moving through the system have shown that no pressure pulses will occur that could challenge the structural integrity of the system. The model results also show that ingestion of the void by the higher head ECCS pumps during the ECCS recirculation mode has no adverse affect on the ECCS high head pumps and they would remain capable of performing their safety function. As a result, this event is not reportable per 50.72(b)(3)(ii)(B). This event is being retracted. The licensee notified the NRC Resident Inspector. R4DO (Lantz) has been notified. |