ENS 49425
ENS Event | |
|---|---|
15:09 Oct 10, 2013 | |
| Title | Low Pressure Core Spray Declared Inoperable |
| Event Description | At 0809 PDT on 10/10/2013, after starting Standby Service Water (SW) pumps, Columbia Generating Station (Columbia) received a flow low alarm for the Low Pressure Containment Spray (LPCS) pump motor cooling water. The flow indicator SW-FIS-19 was reported too low to support pump function. The LPCS system was declared inoperable, and the appropriate Technical Specification action statement was entered. The cause of the low flow alarm has not been determined. This event is reportable under criterion 10 CFR 50.72(b)(3)(v)(D) 'Any Event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to (D) Mitigate the consequences of an accident.'
Columbia is continuing to troubleshoot and repair as appropriate to restore the SW flow to the LPCS pump. The licensee has notified the NRC Resident Inspector.
Subsequent to receipt of the low flow alarm, flushing of the flow indicating switch sensing lines was conducted. It has been determined that the instrument sensing lines are partially blocked providing a flow indication that is slow to respond to actual flow conditions. The flow is currently reading normally. The LPCS pump was declared operable on 10/10/13 at 1447 PDT. The initial notification incorrectly stated 'Low Pressure Containment Spray (LPCS)', the correct description is 'Low Pressure Core Spray (LPCS)'. The licensee has notified the NRC Resident Inspector. Notified R4DO (Hay).
Subsequent evaluation of this event found there was no actual low flow condition to the LPCS bearing cooler. A flow scan on the SW outlet line from the LPCS pump bearing cooler was conducted on 10/12/13 which confirmed the actual flow conditions were reading normally. The problem resides in the installed flow indication switch. Since there was no actual low flow condition to the LPCS bearing cooler, the LPCS pump could perform its safety function to mitigate an accident. Therefore, this event notification is being retracted. Notified R4DO (Azua). The licensee has notified the NRC Resident Inspector. |
| Where | |
|---|---|
Columbia  Washington (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+-1.02 h-0.0425 days <br />-0.00607 weeks <br />-0.0014 months <br />) | |
| Opened: | Matt Hummer 14:08 Oct 10, 2013 |
| NRC Officer: | Dong Park |
| Last Updated: | Oct 18, 2013 |
| 49425 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |