05000219/FIN-2007005-04
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Finding | |
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| Description | On December 19, 2007, a reactor power reduction to approximately 50% was commenced to perform planned maintenance on the reactor recirculation pump MG sets and to find and repair condenser tube leaks in the A north water box. Shortly after reducing power to 55%, the plant experienced a loss of vacuum in the A condenser and a trip of the A reactor feedpump due to low suction pressure. Operations personnel responded in accordance with abnormal operating procedures ABN-14,Loss of Condenser Vacuum, and ABN-17, Feedwater System Abnormal Conditions; and performed a manual reactor scram (shutdown) due to the plant conditions. Specifically, the B reactor feedwater pump was removed from service during the power reduction per operating procedures; and with only the C reactor feedwater pump in service, operators performed a manual scram per abnormal operating procedure ABN-17 guidance. Operators mitigated the reactor scram and stabilized the plant in accordance with abnormal operating procedure ABN-1, Reactor Scram and emergency operating procedure (EOP) EMG-3200.01A, RPV Control - No ATWS. Operations personnel and equipment responded as expected during the event. The plant was maintained in hot shutdown while investigation into the cause of the event was determined. At the time of the event, Oyster Creek was operating with two of its four circulating water pumps in-service. In accordance with AmerGens environmental plan and work management schedule for the downpower, the circulating water system was reduced to two pump operation to maximize discharge water temperatures and to minimize the thermal shock impact to aquatic life in the discharge canal during winter conditions. AmerGens preliminary investigation (IR 713652) into the cause of the event determined that two circulating water pump operation, combined with draining of the A north water box, resulted in degraded condenser vacuum, reduced performance of the A condensate pump, and the subsequent trip of the A reactor feedwater pump on low suction pressure. AmerGen reported this event to the NRC in Event Notification 43854, Manual Reactor Scram Due to Lowering Reactor Level. The inspectors responded to the control room following site announcement of a loss of condenser vacuum and observed the response of AmerGen personnel to the event, including operator actions in the control room. At the time of the event, the inspectors verified that conditions did not meet the entry criteria for an emergency action level (EAL) as described in the Oyster Creek EAL matrix. In addition, the inspectors reviewed 10 CFR 50.72, Immediate Notification Requirements for Operating Nuclear Power Reactors, to verify that AmerGen properly notified the NRC during the event. The inspectors also reviewed technical specification requirements to ensure that Oyster Creek operated in accordance with its operating license. This also included a review of Oyster Creeks environmental technical specifications and AmerGens environmental discharge permit NJ0005550 (issued by New Jersey Department of Environmental Protection) due to the impact on the aquatic life (fish) due to the unplanned shutdown. The inspectors reviewed PPC data, control room logs, and discussed the event with AmerGen personnel to gain an understanding of how operations personnel and plant equipment responded during the event. The inspectors evaluated AmerGens program and process associated with event response to ensure they adequately implemented station procedures OP-AA-108-114, Post Transient Review and OP-AA-106-101-1001, Event Response Guidelines. The inspectors also observed the PORC meeting prior to plant startup to evaluate whether AmerGen understood the cause of the event and appropriately resolved issues identified during the event. The inspectors reviewed AmerGens post-trip review report (IR 713652) to gain additional information pertaining to the event, and ensure that human performance and equipment issues were properly evaluated and understood prior to plant startup. No findings of significance were identified. An unresolved item (URI) was identified to review AmerGens corrective action program root cause evaluation (IR 714203) regarding the manual reactor scram on December 19, 2007. The inspectors plan to review this evaluation after it is completed, which had not occurred by the end of this inspection period. (URI 05000219/2007005-04, Loss of A Condenser Vacuum and Trip of A Feedwater Pump Results in a Reactor Scram) |
| Site: | Oyster Creek |
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| Report | IR 05000219/2007005 Section 4OA3 |
| Date counted | Dec 31, 2007 (2007Q4) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | R Nimitz J Tifft R Treadway J Schoppy M Ferdas A Rosebrookr Treadways Pindale M Ferdas A Rosebrook A Patel R Nimitz L Casey R Bellamy O Ayegbiso |
| INPO aspect | |
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Finding - Oyster Creek - IR 05000219/2007005 | |||||||||||||
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Finding List (Oyster Creek) @ 2007Q4
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