ENS 43801: Difference between revisions
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| event date = 11/20/2007 20:28 CST | | event date = 11/20/2007 20:28 CST | ||
| last update date = 11/21/2007 | | last update date = 11/21/2007 | ||
| title = Failure | | title = Failure of Uf6 Release Detection System | ||
| event text = At 2028 CDST, on 11-20-07 the Plant Shift Superintendent (PSS) was notified that the C-333 Unit 6 Cell 7 UF6 Release Detection (PGLD) System failed to function when performing the twice per shift test firing. The test firing of the PGLD detector heads is required per TSR-SR 2.4.4.1-1. This PGLD System contains detectors that cover C-333 Unit 6 Cell 7, Section 3, and Section 4 of the cell bypass piping. At the time of this failure, unit 6 cell 7 and some areas of Section 3 and Section 4 of the cell bypass were operating above atmospheric pressure. TSR 2.4.4.1 requires that at least the minimum number of detector heads in the cell and in each defined section of the cell bypass are operable during steady state operations above atmospheric pressure. With the Unit 6 Cell 7 PGLD system inoperable, none of the required cell heads and only 2 of the required 3 heads in Section 3 and Section 4 of the cell bypass were operable. This PGLD System was declared inoperable, TSR LCO 2.4.4.1.B.1 and 2.4.4.1.C.1 was entered and a continuous smoke watch was put in place within one hour. Troubleshooting indicated the failure was not similar to writing failures recently experienced on other PGLD systems. The two components most susceptible to failure have been replaced and investigations continue into root cause. The system had functioned correctly when the previous test firing was performed at 1430 hours on 11-20-07. However, since the failure potentially occurred prior to the test firing at 2028 hours the event is being reported as a 24 hour event in accordance with 10 CFR 76.120(c)(2)(i). This is an event in which equipment is disabled or fails to function as designed when (a) the equipment is required by a TSR to prevent releases, prevent exposures to radiation and radioactive materials exceeding specified limits, mitigate the consequences of an accident, or restore this facility to a pre-established safe condition after an accident; (b) the equipment is required by a TSR to be available and operable and either should have been operating or should have operated on demand, and (c) no redundant equipment is available and operable to perform the required safety function." | | event text = At 2028 CDST, on 11-20-07 the Plant Shift Superintendent (PSS) was notified that the C-333 Unit 6 Cell 7 UF6 Release Detection (PGLD) System failed to function when performing the twice per shift test firing. The test firing of the PGLD detector heads is required per TSR-SR 2.4.4.1-1. This PGLD System contains detectors that cover C-333 Unit 6 Cell 7, Section 3, and Section 4 of the cell bypass piping. At the time of this failure, unit 6 cell 7 and some areas of Section 3 and Section 4 of the cell bypass were operating above atmospheric pressure. TSR 2.4.4.1 requires that at least the minimum number of detector heads in the cell and in each defined section of the cell bypass are operable during steady state operations above atmospheric pressure. With the Unit 6 Cell 7 PGLD system inoperable, none of the required cell heads and only 2 of the required 3 heads in Section 3 and Section 4 of the cell bypass were operable. This PGLD System was declared inoperable, TSR LCO 2.4.4.1.B.1 and 2.4.4.1.C.1 was entered and a continuous smoke watch was put in place within one hour. Troubleshooting indicated the failure was not similar to writing failures recently experienced on other PGLD systems. The two components most susceptible to failure have been replaced and investigations continue into root cause. The system had functioned correctly when the previous test firing was performed at 1430 hours on 11-20-07. However, since the failure potentially occurred prior to the test firing at 2028 hours the event is being reported as a 24 hour event in accordance with 10 CFR 76.120(c)(2)(i). This is an event in which equipment is disabled or fails to function as designed when (a) the equipment is required by a TSR to prevent releases, prevent exposures to radiation and radioactive materials exceeding specified limits, mitigate the consequences of an accident, or restore this facility to a pre-established safe condition after an accident; (b) the equipment is required by a TSR to be available and operable and either should have been operating or should have operated on demand, and (c) no redundant equipment is available and operable to perform the required safety function." | ||
The NRC Resident Inspector has been notified of this event. | The NRC Resident Inspector has been notified of this event. | ||
Revision as of 21:15, 1 March 2018
| Where | |
|---|---|
| Paducah Gaseous Diffusion Plant Paducah, Kentucky (NRC Region 2) | |
| License number: | Gdp-1 |
| Reporting | |
| 10 CFR 76.120(c)(2) | |
| Time - Person (Reporting Time:+15.23 h0.635 days <br />0.0907 weeks <br />0.0209 months <br />) | |
| Opened: | Calvin Pittman 17:42 Nov 21, 2007 |
| NRC Officer: | John Mackinnon |
| Last Updated: | Nov 21, 2007 |
| 43801 - NRC Website
| |