05000387/FIN-2011003-06
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Finding | |
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| Title | Licensee-Identified Violation |
| Description | On May 4, a work activity to repair/replace the Open Indication on the 4kV alternate source breaker 2A2Arc9 was conducted from 12:00pm to 5:30pm. The work was originally scheduled to commence on May 6 at 9:00 a.m, The blocking required for the maintenance activity required the associated control power knife switch to be opened. This blocking rendered the alternate breaker unavailable to provide an alternate power source to the 24 bus. On the evening of May 4, the nightshift outage risk manager identified that Unit 2 had been in a Yellow risk period and that the outage control center and station management had been unaware. This issue was determined to be a violation of 10 CFR 50.65 (aX4), for failure to ensure work was properly modeled and evaluated for online plant risk. This finding is more than minor because it is similar to example 7.e. in NRC IMC 0612, Appendix E, Examples of Minor lssues. This example states, in part, that failure to perform an adequate risk assessment when required by 10 CFR 50.65 (aX4) is not minor if the overall elevated plant risk would put the plant into a higher licensee established risk category. The guidance of IMC 0612 Appendix K, Maintenance Risk Assessment and Risk Management Significance Determination Process, Flowchart 2 applies. Since the exposure time of the deficiency was limited to five and a half hours and other backup sources of electrical power remained available (i.e., the other offsite source and the onsite EDG\'s), incremental core damage probability (ICDP) and incremental large early release probability (ILERP) were determined not to be greater than 1E-6 and 1E-7 respectively. Therefore, this finding is determined to be of very low safety significance (Green). The issue was entered into PPL\'s CAP as CR 1401749. |
| Site: | Susquehanna  |
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| Report | IR 05000387/2011003 Section 4OA7 |
| Date counted | Jun 30, 2011 (2011Q2) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | P Kaufman J Furia A Rosebrook P Finney J Brand P Krohn E Torres J Greives |
| INPO aspect | |
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Finding - Susquehanna - IR 05000387/2011003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Susquehanna) @ 2011Q2
Self-Identified List (Susquehanna)
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