ENS 42334: Difference between revisions
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| event date = 02/13/2006 09:33 EST | | event date = 02/13/2006 09:33 EST | ||
| last update date = 02/21/2006 | | last update date = 02/21/2006 | ||
| title = Loss | | title = Loss of Single Power Supply Could Result in Loss of Ventilation for Dc Subsystems in Both Units | ||
| event text = At 09:33 on February 13, 2006, a Susquehanna field operator inadvertently tripped an essential instrument AC panel breaker, while applying an energy control tag. He immediately communicated this condition to the control room, and then closed the breaker to restore power. During the subsequent investigation to determine applicable technical specifications, control room operators discovered that the tripped breaker resulted in a momentary loss of both battery room exhaust subsystems. To comply with the required actions for a loss of both battery room exhaust subsystems, Susquehanna declared all Unit 1 and Unit 2 DC subsystems inoperable, which resulted in LCO 3.0.3. | | event text = At 09:33 on February 13, 2006, a Susquehanna field operator inadvertently tripped an essential instrument AC panel breaker, while applying an energy control tag. He immediately communicated this condition to the control room, and then closed the breaker to restore power. During the subsequent investigation to determine applicable technical specifications, control room operators discovered that the tripped breaker resulted in a momentary loss of both battery room exhaust subsystems. To comply with the required actions for a loss of both battery room exhaust subsystems, Susquehanna declared all Unit 1 and Unit 2 DC subsystems inoperable, which resulted in LCO 3.0.3. | ||
Although the entry into LCO 3.0.3 is not reportable, Susquehanna did discover an unanalyzed condition on both units that significantly degrades plant safety, which is reportable in accordance with 10CFR50.72(b)(3)(ii). The loss of a single power supply could result in the loss of ventilation and cooling for all DC subsystems on both units, leading to degradation of essential DC power sources. This condition does not meet single failure criteria for safety-related equipment. | Although the entry into LCO 3.0.3 is not reportable, Susquehanna did discover an unanalyzed condition on both units that significantly degrades plant safety, which is reportable in accordance with 10CFR50.72(b)(3)(ii). The loss of a single power supply could result in the loss of ventilation and cooling for all DC subsystems on both units, leading to degradation of essential DC power sources. This condition does not meet single failure criteria for safety-related equipment. | ||
Latest revision as of 22:19, 1 March 2018
| Where | |
|---|---|
Susquehanna  Pennsylvania (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
| Time - Person (Reporting Time:+2.75 h0.115 days <br />0.0164 weeks <br />0.00377 months <br />) | |
| Opened: | Martin Lichtner 17:18 Feb 13, 2006 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Feb 21, 2006 |
| 42334 - NRC Website
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