ENS 49389
ENS Event | |
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16:45 Sep 27, 2013 | |
Title | Calculation Error Resulted in Unanalyzed Condition for Appendix R Event |
Event Description | On July 18, 2012, TVA identified that a calculation error resulted in the inability to establish Essential Raw Cooling Water (ERCW) supply to the Component Cooling System (CCS) heat exchanger within the required time to ensure cooling is available to Reactor Coolant System (RCS) seal injection water during an Appendix R event. TVA promptly established fire watches as a compensatory measure to prevent initiation of fires in the areas of concern. Subsequently, abnormal operating instructions were revised to take action to ensure that adequate time is available to establish ERCW cooling to CCS, and ensure cooling to [Reactor Coolant Pump] RCP seal injection water.
The calculation error was identified on July 18, 2012, however, it was not recognized at the time that an unanalyzed condition existed that was reportable under 10 CFR 50.72(b)(3)(ii)(B). This report documents that the condition that existed until fire watches were established is reportable under 10 CFR 50.72(b)(3)(ii)(B). The NRC Resident Inspector has been notified of this condition.
Watts Bar Nuclear Plant Unit 1 is retracting this 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> non-emergency notification made on September 27, 2013, at 1335 EDT (EN #49389). The notification on September 27, 2013, reported a calculation error which resulted in the inability to establish Essential Raw Cooling Water (ERCW) to supply the Component Cooing System (CCS) heat exchanger within the required time to ensure cooling is available to Reactor Coolant System (RCS) seal injection water during an Appendix R event. Subsequent analysis of actual plant data concluded that TVA could have established cooling to RCS seal injection during the subject Appendix R event, and achieved and maintained fire safe shutdown. Therefore, this event was not reportable under 10 CFR 50.72(b)(3)(ii)(B). The NRC Resident Inspector has been notified. R2DO (Bartley) notified. |
Where | |
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Watts Bar Tennessee (NRC Region 2) | |
Reporting | |
10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
Time - Person (Reporting Time:+-3.17 h-0.132 days <br />-0.0189 weeks <br />-0.00434 months <br />) | |
Opened: | Brian Mcilnay 13:35 Sep 27, 2013 |
NRC Officer: | Dong Park |
Last Updated: | Oct 29, 2013 |
49389 - NRC Website
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Unit 1 | |
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Reactor critical | Critical |
Scram | No |
Before | Power Operation (100 %) |
After | Power Operation (100 %) |
WEEKMONTHYEARENS 569102023-12-28T16:29:00028 December 2023 16:29:00
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