05000289/FIN-2010009-04
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Finding | |
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| Title | Potential Concern Regarding TMI\'s Internal and External Flood Protection Barriers and Mitigation Strategies |
| Description | The team identified that Exelon was not meeting the requirements of USFSAR Section 2.6.5 and of 10 CFR 50.65 because TMI did not have an effective program to monitor the condition of flood seal penetrations into safety-related structures. This has been a long-standing issue for several years. However, a formal penetration seal inspection and evaluation program was only established in October 2009 and the initial round of seal inspections had not been completed. Considering the age of the flood seal components could be beyond the qualified lifetime, this program may not be adequately identifying degrading and non-conforming conditions which could impact the operability of safety-related equipment during a design basis flooding event. As a result, the NRC has opened an UnreSOlved Item (URI) related to this concern. The inspectors identified a potential concern regarding TMl\'s internal and externai flood protection barriers and mitigation strategies. Specificaily, TMI has not implemented an effective program for identifying, maintaining, inspecting, or repairing flood barriers to ensure that internal and external flooding risks are effectively managed and to verify that safe shutdown equipment is not subjected to damage from internal and external flood events. Monitoring of safety-related SSCs, as weil as non-safety-related components whose failure could prevent a SSC from fulfiiling their safety function, is required by 10 CFR 50.65. The inspectors questioned Exelon about the controls in place to verify, inspect and maintain ail openings below probable main flood elevation (309 foot level) that are potential leak paths (ducts, pipes, conduits, cable trays, seismic gaps, flood seals, non return flood protection check valves, watertight seismic gaps, etc.) in order to meet the commitments detailed in TMI UFASAR Section 2.6.5. However, Exelon was not able to demonstrate which barriers are credited as flood barriers, what the design and specified materials are, what the expected qualified life of the barriers is, nor the condition of ail the credited barriers. The team concluded that not having an effective program to monitor the condition of flood penetration seals for safety-related structures was a performance deficiency that was reasonably with in Exelon\'s ability to foresee and prevent. Since Exelon has not yet completed their initial evaluation of the flood seals at TMI, the team was unable to evaluate the potential impacts of this issue. Exelon intends to complete the initial inspections and report the results to the NRC by October 31, 2010. Subsequent to the completion of the PI&R inspection, Exelon issued Event Notification (EN) 46194 on August 23, 2010, describing that flood barriers needed to protect safety-related equipment in the TMI Auxiliary Building were identified to be missing or never instailed. The inspectors determined that issues concerning the internal and external flood programs at TMI, including flood barriers design, inspections, maintenance, and repairs, is an unresolved item pending further NRC review of Exelon\'s initial inspection and safety assessment. |
| Site: | Three Mile Island  |
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| Report | IR 05000289/2010009 Section 4OA2 |
| Date counted | Sep 30, 2010 (2010Q3) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | F Arner R Nimitz D Kem J Brand R Bellamy J Heinlyd Orrj Brand R Bellamy A Rao |
| INPO aspect | |
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Finding - Three Mile Island - IR 05000289/2010009 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Three Mile Island) @ 2010Q3
Self-Identified List (Three Mile Island)
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