ENS 43324
ENS Event | |
|---|---|
20:26 Apr 29, 2007 | |
| Title | Technical Specification Shutdown Due to Both Emergency Diesels Declared Inoperable |
| Event Description | At 1453, [the licensee] declared D/G [Emergency Diesel Generator] - A inoperable due to outside air temperature exceeding 78.2 degrees Fahrenheit and entered Technical Specification 3.7.b.2 [which has a] 7-day LCO. At 1526, outside air temperature increased to greater than 81.4 degrees Fahrenheit and D/G - B was declared inoperable. With both D/Gs declared inoperable, Technical Specification 3.0.c , Standard Shutdown Sequence was entered. No other safety related components are inoperable at this time. Plant shutdown was initiated at 1624 on 4/29/07.
Based on recent findings by the licensee, the EDGs may not be capable of generating the minimum electrical power output needed to support a safety bus when outside air temperature exceeds certain limits (Operability Determination 151 dated April 26, 2007) The licensee is in the process of making ventilation modifications that will correct this condition. The licensee expects that the temperatures will drop below the EDG inoperability limits before the plant actually shuts down. The licensee notified the NRC Resident Inspector.
EN 43324 provided notification of initiation of a unit shutdown due to both emergency diesel generators (EDGs) being declared inoperable due to outside air temperature exceeding allowable limits. Unit shutdown had been initiated per Technical Specification (TS) 3.0.c, Standard Shutdown Sequence, due to TS 3.7 not being met. A subsequent engineering evaluation allowed for increasing the allowable limit for outside ambient air temperature at which the EDGs are operable. The highest outside ambient air temperature recorded on 04/29/2007 (83.5 F) did not exceed the new allowable limit. Therefore, based on the new evaluation, both EDGs remained operable. TS 3.7 remained met and no TS shutdown was required. Consequently, this condition did not meet any reportability criteria in 10 CFR 50.72. As a result, the notification made on 4/29/07 (EN 43324) is hereby retracted." NRC R3DO (Patrick Louden) notified. The NRC Resident Inspector was notified of this retraction by the licensee. |
| Where | |
|---|---|
Kewaunee  Wisconsin (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
| Time - Person (Reporting Time:+-2.63 h-0.11 days <br />-0.0157 weeks <br />-0.0036 months <br />) | |
| Opened: | Dave Karst 17:48 Apr 29, 2007 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Jun 19, 2007 |
| 43324 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (89 %) |