ENS 49389
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ENS Event | |
|---|---|
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 | |
|---|---|
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 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 569102023-12-28T16:29:00028 December 2023 16:29:00
[Table view]10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition ENS 565412023-05-25T17:45:00025 May 2023 17:45:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition of Emergency Diesel Generator ENS 538012018-12-20T05:00:00020 December 2018 05:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Containment Air Return Fan System Inoperable ENS 533492018-04-19T23:44:00019 April 2018 23:44:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Related to Emergency Core Cooling Gas Accumulation Acceptance Criteria ENS 528502017-07-12T16:38:00012 July 2017 16:38:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Related to Gdc-5 (General Design Criterion-5) for Dual Unit Operation ENS 519952016-06-08T19:26:0008 June 2016 19:26:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition That Could Potentially Degrade Plant Safety ENS 509602015-04-06T21:00:0006 April 2015 21:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Volume Control Tank Isolation Time Analysis Error ENS 508872015-03-13T15:00:00013 March 2015 15:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition ENS 505962014-11-05T18:10:0005 November 2014 18:10:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Regarding Appendix R Procedures ENS 505402014-10-15T21:00:00015 October 2014 21:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Appendix R Unanalyzed Condition Affecting the Turbine Driven Aux Feedwater Pump ENS 502452014-07-01T02:46:0001 July 2014 02:46:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition That Could Have Resulted in an Increased Maximum Flood Level ENS 498182014-02-11T23:00:00011 February 2014 23:00:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Nonconservative Operator Manual Actions Identified in Appendix R Analysis ENS 495412013-11-14T21:00:00014 November 2013 21:00:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Postulated Fire Induced Failure of Centrifugal Charging Pumps ENS 493892013-09-27T16:45:00027 September 2013 16:45:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Calculation Error Resulted in Unanalyzed Condition for Appendix R Event ENS 480562012-06-29T14:28:00029 June 2012 14:28:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition Due to Increase in Probable Maximum Flood Level ENS 487232009-07-28T05:00:00028 July 2009 05:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unanalyzed Condition That Could Have Resulted in an Increased Maximum Flood Level 2023-05-25T17:45:00 | |
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