05000219/FIN-2011003-02
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Finding | |
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| Title | Difficulty in drawing a main condenser vacuum during plant startup due to water in 48 inch holdup line |
| Description | An unresolved item (URI) was identified to review the results of Exelon\\\'s investigation to identify the source of water that builds up in the 48 inch offgas header following a plant shutdown, an evaluation of the effect of that water on the inability to draw a vacuum in the turbine condenser on the subsequent startup, and to evaluate the effectiveness of the corrective actions taken following a similar event in 2006 to determine if a performance deficiency existed. The inspectors will review the results of Exelon\\\'s evaluation after it is completed, which had not occurred by the end of this inspection period. During the startup from the 1M26 outage in December 2010, Oyster Creek experienced a full reactor scram due to a main condenser low vacuum trip. Exelon performed a root cause evaluation, which was centered on operator performance issues, and documented the results in IR 1 155520. NRC inspectors reviewed the root cause report (RCR) in March 2011 and identified that the root cause evaluation did not address the issue of the difficulty of drawing a vacuum in the main condenser using the mechanical vacuum pump and three sets of air ejectors. Exelon generated IR 1 1931 10 to document the inspectors\\\' observation. During resident inspector follow-up of the issue, the inspectors identified that a similar event had taken place during the startup following the 1R21 outage in November 2006 and evaluated in an equipment apparent cause evaluation (EACE) documented in IR 556890. The inspectors identified that the source of the excess water found in the 48 inch hold up line was not identified in either the 2006 EACE or the 2010 RCR. Additionally, the inspectors questioned effectiveness of the corrective actions identified in the 2006 EACE due to the recurrence of the issue in 2010 which resulted in a reactor scram. The licensee documented the inspectors\\\' concerns in IR 1227974, which is currently being evaluated. |
| Site: | Oyster Creek |
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| Report | IR 05000219/2011003 Section 4OA2 |
| Date counted | Jun 30, 2011 (2011Q2) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | J Caruso J Kulp S Barr A Patel J Tomlinson R Bellamy J Ambrosini T Hedigan E Keighley C Cowdrey M Catts L Doerflein O Ayegbusic Newgentg Hunegs J Amberosini J Kulp J White M Modes N Lafferty R Montgomery R Nimitz S Barr |
| INPO aspect | |
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Finding - Oyster Creek - IR 05000219/2011003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Oyster Creek) @ 2011Q2
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