ENS 45104
ENS Event | |
|---|---|
02:40 May 29, 2009 | |
| Title | Loss of Control Power to Eccs Valves |
| Event Description | At 2140 on 5/28/09 Braidwood Station identified a loss of control power for a Safety Related MCC (Motor Control Center) which provided power to SVAG (Single Valve Actuation Group) valves associated with both trains of the ECCS system. The MCC is normally de-energized to maintain the valve power removed in accordance with Tech Specs for ECCS. Loss of the control power for the associated MCC would prevent operation of these valves, which would prevent realignment of components required for transfer to cold leg recirculation and hot leg recirculation for long term core cooling.
Entry was made into LCO 3.5.2, ECCS Operating, and LCO 3.0.3 due to inoperability of both trains of ECCS based on the inability to realign portions of both trains of the ECCS system from injection to cold leg recirculation and subsequent hot leg recirculation. At 2230 on 5/28/09 preparations had been completed for ramp off line per LCO 3.0.3. Troubleshooting was performed and a blown control power fuse was identified and replaced at 2319 on 5/28/09. No Unit ramp was initiated. The NRC Resident Inspector was notified.
The purpose of this report is to retract the ENS report made on May 29, 2009 at 04:49 EDT (ENS #45104) under 10CFR50.72(b)(3)(v)(B), a condition that could have prevented fulfillment of a safety function. The initial report was made based on identification of a loss of control power for a Safety Related MCC (Motor Control Center), which provided power to SVAG (Single Valve Actuation Group) valves associated with both trains of the ECCS system. The MCC is normally de-energized to maintain the valve power removed in accordance with Technical Specifications. The loss of the control power for the associated MCC would prevent operation of these valves. It was initially concluded that this condition would prevent realignment of components required for transfer to cold leg recirculation and hot leg recirculation for long term core cooling. Therefore, the referenced ENS report was made for a loss of safety function. Subsequent review of UFSAR information and previously developed analytical data determined that the safety function for ECCS was not lost due to the event. The failure of the MCC to energize would have NOT affected the ability of the 1B ECCS train to perform its design function of cold and hot leg recirculation. A blown control power fuse, the cause of the event, was identified and replaced on May 28, 2009 at 23:19 hours. The NRC Senior Resident Inspector has been notified of this retraction. R3DO(Pelke) notified. |
| Where | |
|---|---|
Braidwood  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat | |
| Time - Person (Reporting Time:+2.15 h0.0896 days <br />0.0128 weeks <br />0.00295 months <br />) | |
| Opened: | James Smit 04:49 May 29, 2009 |
| NRC Officer: | Mark Abramovitz |
| Last Updated: | Jun 8, 2009 |
| 45104 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 533532018-04-20T15:42:00020 April 2018 15:42:00
[Table view]10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Both Diesel Generators Inoperable ENS 467072011-03-30T01:00:00030 March 2011 01:00:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Potential Voiding in Auxiliary Feedwater Alternate Suction Line ENS 451042009-05-29T02:40:00029 May 2009 02:40:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Loss of Control Power to Eccs Valves 2018-04-20T15:42:00 | |