ENS 41344
ENS Event | |
|---|---|
07:37 Jan 19, 2005 | |
| Title | |
| Event Description | The environmental temperature of the tornado missile enclosure for the Emergency Diesel Generators during an accident condition when all three testable rupture disks open is expected to exceed the limiting temperature for the structural concrete. A detailed analysis of the capability of the tornado missile enclosure concrete to meet that standard cited in the USAR section 3.8.3.3.7 has not been located. At 0237 on 19 January 2005, Division 1,2 & 3 Diesel Generators were declared inoperable. Actions of Technical Specification 3.8.2 were directed and compliance verified.
NRC Resident Inspector was notified of this event by the licensee.
The following information was provided by the licensee by fax: An 8-hour notification was made on January 19, 2005, in accordance with 10CFR50.72(b)(3)(ii)(B), for an unanalyzed condition and 10CFR50.72(b)(3)(v)(D), for the loss of the accident mitigation safety function. This report was made after declaring division 1, 2, and 3 diesel generators inoperable because the tornado missile enclosure concrete analysis demonstrating compliance with USAR section 3.8.3.3.7 could not be located. Compensatory measures were taken to protect the concrete and vent lines in the area while an analysis was performed. The required analysis was performed by a contract engineering firm. On March 23, 2005, the analysis was owner accepted with comments for incorporation into the final report. None of the comments affected the conclusion of the analysis. This analysis confirmed that the concrete enclosure, as originally designed, supported operability of the diesel generators and their support subsystems. Modifications are being implemented to improve the design margin of the safety related enclosure under accident conditions with the testable rupture disks open. These design modifications are improvements and were not required for past diesel generator operability. Since the operability of the diesel generators and their support subsystems were not affected, there was no unanalyzed condition that significantly degraded plant safety, nor was there a loss of safety function. Since there was no reportable condition, ENF 41344 is retracted. The NRC Resident Inspector was notified. Notified RDO (Kozak) |
| Where | |
|---|---|
Perry  Ohio (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+-1.72 h-0.0717 days <br />-0.0102 weeks <br />-0.00236 months <br />) | |
| Opened: | Frederick Smith 05:54 Jan 19, 2005 |
| NRC Officer: | John Mackinnon |
| Last Updated: | Mar 23, 2005 |
| 41344 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |