ENS 41269
ENS Event | |
|---|---|
16:09 Dec 17, 2004 | |
| Title | Waterleg Pump Discharge Check Valve in Hpcs System Failed to Open |
| Event Description | During the performance of the High Pressure Core Spray system (HPCS) quarterly pump and valve operability test, the waterleg pump discharge low pressure alarm was unable to be cleared. It was determined that the waterleg pump discharge check valve had failed to open to provide keepfill flow.
The HPCS system had been declared [inoperable at 0818 for a planned surveillance activity. At 1109, the low pressure alarm came in as expected, but was not able to be cleared. Subsequent mechanical agitation of the waterleg pump discharge check valve caused the valve to open and the low pressure condition to clear. Tech Spec 3.5.1 is applicable. Entry time 0818 on 12/17/04. Action is to restore HPCS to Operable within 14 days. NRC Resident Inspector was notified.
An 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> notification was made on December 17, 2004, in accordance with 10CFR50.72(b)(3)(v)(C) and 10CFR50.72(b)(3)(v)(D). The report was made due to a potential loss of the High Pressure Core Spray (HPCS) system safety function as a result of the loss of keep-fill pressure. The water-leg pump discharge check valve was determined to be the most likely cause of the loss of keep-fill pressure and was replaced. A preliminary investigation has determined that the water-leg pump discharge check valve had sufficient corrosion products (on the rising stem) to cause the valve disk to stick. With the check valve not able to fully open, the system low pressure alarm was activated. The lowest system pressure, about 24 psig, was determined to be just below the alarm setpoint of 27 psig. The alarm setpoint includes a 10 psig margin between receipt of the alarm and the pressure at which the piping would start to void. The pressure, 24 psig, was equivalent to the static head provided by the Condensate Storage Tank (CST) to the HPCS system. This alignment is the method used to maintain the system filled when the water-leg pump is unavailable. The 24 psig system pressure was adequate to maintain the system full. Since the system pressure was adequate and the HPCS system was maintained full, the safety function of the system was not adversely affected. Since the safety function was not affected, there is no reportable condition and Event Notification 41269 is retracted. The NRC Resident Inspector was notified. |
| Where | |
|---|---|
Perry  Ohio (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+0.52 h0.0217 days <br />0.0031 weeks <br />7.12296e-4 months <br />) | |
| Opened: | Steven Benedict 16:40 Dec 17, 2004 |
| NRC Officer: | John Knoke |
| Last Updated: | Jan 5, 2005 |
| 41269 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (99 %) |
| After | Power Operation (99 %) |