ENS 45855: Difference between revisions
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| event date = 04/18/2010 22:25 CDT | | event date = 04/18/2010 22:25 CDT | ||
| last update date = 04/22/2010 | | last update date = 04/22/2010 | ||
| title = Lco 3.0.3 Entry | | title = Lco 3.0.3 Entry and Loss of Safety Function Due to Loss of Turbine Building High Energy Line Break Compensatory Measure | ||
| event text = At 2225 CDT on 4/18/2010, Operations discovered that the Unit 1 Turbine Building Truck Aisle Rollup Door Security Fence was closed. This fence was to be maintained open as the truck aisle is a required drainage path from the Unit 1 Turbine Building to outside in the event of flooding resulting from a High Energy Line Break (HELB). With the expanded metal mesh door [fence] closed, turbine building debris could clog the drainage path and result in a higher than calculated water level being reached for this event. As the final water level cannot be predicted, this represented an unanalyzed condition. The higher water levels would be reached at least one hour after the postulated turbine building HELB event. High water levels could result in a Loss of Safety Function for Unit 1 Emergency Diesel Generators. Auxiliary Feedwater (both units) and DC Electrical Power (both units) if water levels exceed critical heights in the associated rooms. | | event text = At 2225 CDT on 4/18/2010, Operations discovered that the Unit 1 Turbine Building Truck Aisle Rollup Door Security Fence was closed. This fence was to be maintained open as the truck aisle is a required drainage path from the Unit 1 Turbine Building to outside in the event of flooding resulting from a High Energy Line Break (HELB). With the expanded metal mesh door [fence] closed, turbine building debris could clog the drainage path and result in a higher than calculated water level being reached for this event. As the final water level cannot be predicted, this represented an unanalyzed condition. The higher water levels would be reached at least one hour after the postulated turbine building HELB event. High water levels could result in a Loss of Safety Function for Unit 1 Emergency Diesel Generators. Auxiliary Feedwater (both units) and DC Electrical Power (both units) if water levels exceed critical heights in the associated rooms. | ||
The doors [fence] were reopened at 2227 CDT. Unit 1 entered LCO 3.0.3 for this two minute period. With the doors [fence] opened, Unit 1 and 2 LCO conditions were again satisfied. | The doors [fence] were reopened at 2227 CDT. Unit 1 entered LCO 3.0.3 for this two minute period. With the doors [fence] opened, Unit 1 and 2 LCO conditions were again satisfied. | ||
Latest revision as of 22:09, 1 March 2018
| Where | |
|---|---|
Prairie Island  Minnesota (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 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 | |
| Time - Person (Reporting Time:+-0.22 h-0.00917 days <br />-0.00131 weeks <br />-3.01356e-4 months <br />) | |
| Opened: | John Kempkes 03:12 Apr 19, 2010 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Apr 22, 2010 |
| 45855 - NRC Website
| |
Prairie Island with 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 | |