05000255/FIN-2012005-05
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Finding | |
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Title | Concerns with the Methodology Used to Determine Suction Side Void Acceptance Criteria |
Description | On January 11, 2008, the NRC requested each addressee of GL 2008-01 to evaluate its emergency core cooling, decay heat removal, and containment spray systems licensing basis, design, testing, and corrective actions to ensure gas accumulation was maintained less than the amount which would challenge the operability of these systems, and take appropriate actions when conditions adverse to quality were identified. In order to determine what amount of gas could challenge the operability of the subject systems, the licensee needed to develop appropriate acceptance criteria for evaluating identified voids. As part of this effort, the licensee developed acceptance criteria for evaluating voids identified in the suction side of the subject systems pumps. The suction side void acceptance criteria were based on an average over the transient duration time. This was inconsistent with the 0.5-second criterion recommended by NRR in TI 2515/177 Inspection Guidance (ML111660749). The NRR-recommended methodology was more conservative because it ensured there were no significant deviations exceeding the maximum recommended void fractions. However, because the licensees methodology averaged over the entire transient duration time, it allowed void volumes that could significantly exceed the recommended void fraction when the actual duration transient time was shorter than the maximum allowable duration time specified by the recommended void fraction acceptance criteria. The inspectors discussed this observation with NRR. This issue was captured in the licensees CAP as CR-HQN-2011-00853. Because the inspectors did not identify an existing void which would have exceeded the more conservative acceptance criteria, this issue does not involve current operability of any system. This issue is unresolved pending further evaluation of the licensees methodology |
Site: | Palisades |
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Report | IR 05000255/2012005 Section 4OA5 |
Date counted | Dec 31, 2012 (2012Q4) |
Type: | URI: |
cornerstone | Mitigating Systems |
Identified by: | NRC identified |
Inspection Procedure: | |
Inspectors (proximate) | T Taylor A Scarbeary J Corujo-Sandin J Beavers S Shah M Holmberg J Cassidy S Sheldon J Lennartz J Laughlin D Betancourta Stonec Baron C Brown C Zoia H Leake J Corujo-Sandin L Rodriguez S Sheldon |
INPO aspect | |
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Finding - Palisades - IR 05000255/2012005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Palisades) @ 2012Q4
Self-Identified List (Palisades)
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