ENS 45460: Difference between revisions
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| event date = 10/23/2009 16:34 EDT | | event date = 10/23/2009 16:34 EDT | ||
| last update date = 10/23/2009 | | last update date = 10/23/2009 | ||
| title = Plant Shutdown Due | | title = Plant Shutdown Due to Excess Letdown Heat Exchanger Tube Leak and After-The-Fact Unusual Event | ||
| event text = On 10/23/09 at 1633, North Anna Unit 1 was placing Excess Letdown in service per 1-OP-8.5 due to a small unquantifiable throughwall leak on 1-CH-TV-1204B. At 1634 [the licensee] entered action of TS 3.4.13 due to what appears to be an Excess Letdown Heat Exchanger tube leak. The Component Cooling Water Head Tank [level] increased from 59% to 79% and the VCT [Volume Control Tank] level dropped 20 % indicating approximately 260 gallons of RCS had flowed into the Component Cooling Water System. At 1638 Excess Letdown was removed from service and the leak was terminated. At 1718 [the licensee] commenced ramping Unit 1 from service [TS Required Shutdown] to comply with TS 3.6.1, 'Containment Integrity' due to the throughwall leak on 1-CH-TV-1204B. | | event text = On 10/23/09 at 1633, North Anna Unit 1 was placing Excess Letdown in service per 1-OP-8.5 due to a small unquantifiable throughwall leak on 1-CH-TV-1204B. At 1634 [the licensee] entered action of TS 3.4.13 due to what appears to be an Excess Letdown Heat Exchanger tube leak. The Component Cooling Water Head Tank [level] increased from 59% to 79% and the VCT [Volume Control Tank] level dropped 20 % indicating approximately 260 gallons of RCS had flowed into the Component Cooling Water System. At 1638 Excess Letdown was removed from service and the leak was terminated. At 1718 [the licensee] commenced ramping Unit 1 from service [TS Required Shutdown] to comply with TS 3.6.1, 'Containment Integrity' due to the throughwall leak on 1-CH-TV-1204B. | ||
The licensee has placed the normal letdown system back in service while the plant is being shut down. The throughwall leak on 1-CH-TV-1204B is relatively small and unquantifiable compare to the tube leak on the excess letdown heat exchanger. The licensee plans to proceed to Mode 5 to repair both the Letdown valve and the Excess Letdown Heat Exchanger tube leak. | The licensee has placed the normal letdown system back in service while the plant is being shut down. The throughwall leak on 1-CH-TV-1204B is relatively small and unquantifiable compare to the tube leak on the excess letdown heat exchanger. The licensee plans to proceed to Mode 5 to repair both the Letdown valve and the Excess Letdown Heat Exchanger tube leak. | ||
Latest revision as of 22:10, 1 March 2018
| Where | |
|---|---|
North Anna  Virginia (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Other Unspec Reqmnt | |
| Time - Person (Reporting Time:+-3 h-0.125 days <br />-0.0179 weeks <br />-0.00411 months <br />) | |
| Opened: | Robert Counts 17:34 Oct 23, 2009 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Oct 23, 2009 |
| 45460 - NRC Website
| |