Finding | |
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| Title | |
| Description | On October 24, 2010, control rod 10-35 failed to insert upon actuation of an automatic reactor scram caused by loss of condenser vacuum (CARD10-29509). An emergent issue team was formed to investigate this event. The apparent cause was determined to be a hydraulic lock caused by blockage in the flow path between the control rod drive mechanism and the scram discharge volume. The investigation never found any foreign material, but postulated that the likely foreign material was discharged into the scram discharge volume, ultimately ending up in the torus room sump. As a corrective action, for cycle 15 the licensee increased the frequency of performing TS surveillance SR 3.1.4.2 scram time testing to every 100 days, adjusted the representative sample size to assure all rods would be tested during cycle 15, and included control rod 10-35 in each quarterly scram time testing sample. On November 18, 2011, the control rod failed to fully insert during scram time testing. The rod was fully inserted and remained there for the rest of the cycle. The inspectors are waiting for the licensees evaluation of this event, specifically their conclusions regarding the foreign material found, and their evaluation of how the foreign material could have been present, causing the first event, but migrated to allow successful scram time testing on November 11, 2010, and the first three quarters of 2011 before finally causing the failure identified on November 18, 2011. Because the licensee had not completed their evaluation, this issue is being treated as an unresolved (URI) item. |
| Site: | Fermi  |
|---|---|
| Report | IR 05000341/2012003 Section 4OA2 |
| Date counted | Jun 30, 2012 (2012Q2) |
| Type: | URI: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | M Phalen J Rutkowski R Morris D Kimble R Jones J Bozga J Cameron P Smagacz T Brileyj Cassidyd Jones R Morris A Wilson R Jones J Cameron P Smagacz T Briley J Steffes S Bell |
| INPO aspect | |
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Finding - Fermi - IR 05000341/2012003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Fermi) @ 2012Q2
Self-Identified List (Fermi)
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