ENS 43436
ENS Event | |
|---|---|
07:15 Jun 21, 2007 | |
| Title | Hpci Inoperable Due to Quarterly Valve Stroke Test Failure |
| Event Description | During performance of the quarterly HPCI valve stroke test the HV-55-2F006, HPCI pump discharge isolation valve to Core Spray failed to open within the maximum allowed time. The HV-55-2F006 valve is a motor operated valve and the maximum allowed opening time is 17.25 seconds. The valve was given an open signal via the hand switch as required by the test but did not initially respond. Several minutes later the valve went full open. HPCI was declared inoperable at 0315 on 6/21/2007. Cause for valve stroke time failure is not known at this time.
As a result, the licensee is in a 14 day shutdown LCO. The licensee notified the NRC Resident Inspector.
This is a retraction of the event notification made on 6/21/07 at 04:05 hours EDT. This event (#43436) was initially reported as a condition that at the time of discovery could have prevented the fulfillment of the High Pressure Coolant Injection (HPCI) system safety function under the requirement of 10CFR50.72(b)(3)(v)(D). The Unit 2 HPCI system was declared inoperable due to failure of the HPCI pump discharge isolation valve to Core Spray to open within the maximum allowed time during surveillance testing. The valve was required to open within 17.25 seconds but opened several minutes after the open signal was initiated. The open contactor was replaced and the valve was successfully tested. The affected valve was declared operable on 6/22/07 at 04:07 hours. The HPCI system was restored to operable on 6/23/07 at 04:07 hours following completion of maintenance and testing activities. An evaluation determined that HPCI was capable of injecting sufficient flow to complete its safety function through the unaffected operable injection flow path to the feedwater header. The achievable flow rate would have exceeded the leakage from a one-inch liquid line break. Also, HPCI operation remained capable of being terminated by operator action during an ATWS event. Therefore, HPCI remained capable of fulfilling its safety function while the injection flow path to Core Spray was unavailable. A condition did not exist at the time of discovery that could have prevented the fulfillment of the HPCI safety function. The licensee notified the NRC Resident Inspector. R1DO (White) notified. |
| Where | |
|---|---|
Limerick  Pennsylvania (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+-3.17 h-0.132 days <br />-0.0189 weeks <br />-0.00434 months <br />) | |
| Opened: | Ned Dennin 04:05 Jun 21, 2007 |
| NRC Officer: | Joe O'Hara |
| Last Updated: | Aug 1, 2007 |
| 43436 - NRC Website
Loading map... {"minzoom":false,"maxzoom":false,"mappingservice":"leaflet","width":"350px","height":"250px","centre":false,"title":"","label":"","icon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"zoom":6,"defzoom":14,"layers":["OpenStreetMap"],"image layers":[],"overlays":[],"resizable":false,"fullscreen":false,"scrollwheelzoom":true,"cluster":false,"clustermaxzoom":20,"clusterzoomonclick":true,"clustermaxradius":80,"clusterspiderfy":true,"geojson":"","clicktarget":"","imageLayers":[],"locations":[{"text":"\u003Cb\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003E\u003Ca class=\"mw-selflink selflink\"\u003EENS 43436\u003C/a\u003E - \u003Ca href=\"/Limerick\" title=\"Limerick\"\u003ELimerick\u003C/a\u003E\n\u003C/p\u003E\u003C/div\u003E\u003C/b\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003EHpci Inoperable Due to Quarterly Valve Stroke Test Failure\n\u003C/p\u003E\u003C/div\u003E","title":"ENS 43436 - Limerick\n","link":"","lat":40.22646666666667,"lon":-75.58323333333334,"icon":"/w/images/b/be/Constellation_icon.png"}],"imageoverlays":null} | |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |