ENS 42978
ENS Event | |
|---|---|
12:44 Nov 9, 2006 | |
| Title | High Pressure Core Spray System Valve Inadvertently De-Energized |
| Event Description | At 0644 hours0.00745 days <br />0.179 hours <br />0.00106 weeks <br />2.45042e-4 months <br /> (CST), the Main Control Room (MCR) received an alarm that the Division 3 Shutdown Service Water (SX) system was not available. The MCR also received an indication that a Division 3 SX motor operated valve for the plant service water to the SX header isolation valve, 1SX014C, was not available and discovered that there was no light indication for this valve. This valve is required to reposition following a High Pressure Core Spray (HPCS) system initiation. With the loss of power to the valve, this resulted in the Division 3 SX and the HPCS systems being inoperable. Since the HPCS system is a single train safety system, this event is reportable under 10CFR50.72(b)(3)(v)(D). An investigation is underway to determine the cause of the loss of power to the 1SX014C valve, however, preliminary indications are that an individual may have inadvertently bumped the breaker to the 'off' position.
At 0742 hours0.00859 days <br />0.206 hours <br />0.00123 weeks <br />2.82331e-4 months <br />, the investigation of the 1SX014C breaker indicated that the breaker was in the 'off' position (i.e., not tripped). The cubicle door for the 1SX014C breaker was opened. There were no abnormal or unusual indications in the cubicle. The 1SX014C valve was verified open; then the 1SX014C breaker was closed. The breaker was taken directly to the close position and not reset first. The 1SX014C breaker closed, indication returned to the MCR, and the alarm cleared. The breaker remained closed and HPCS system was returned to an available status. At 1047 hours0.0121 days <br />0.291 hours <br />0.00173 weeks <br />3.983835e-4 months <br />, the Division 3 SX pump was started to confirm that operability of Division 3 SX and HPCS were restored by the actions taken to reclose the breaker at 0742 hours0.00859 days <br />0.206 hours <br />0.00123 weeks <br />2.82331e-4 months <br />. The 1SX014C valve operated normally and Division 3 SX and HPCS were declared operable. The NRC Resident has been notified. |
| Where | |
|---|---|
Clinton  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+0.63 h0.0263 days <br />0.00375 weeks <br />8.62974e-4 months <br />) | |
| Opened: | Jim Peterson 13:22 Nov 9, 2006 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Nov 9, 2006 |
| 42978 - 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 42978\u003C/a\u003E - \u003Ca href=\"/Clinton\" title=\"Clinton\"\u003EClinton\u003C/a\u003E\n\u003C/p\u003E\u003C/div\u003E\u003C/b\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003EHigh Pressure Core Spray System Valve Inadvertently De-Energized\n\u003C/p\u003E\u003C/div\u003E","title":"ENS 42978 - Clinton\n","link":"","lat":40.17286111111111,"lon":-88.8332,"icon":"/w/images/b/be/Constellation_icon.png"}],"imageoverlays":null} | |
Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (95 %) |
| After | Power Operation (95 %) |