05000387/FIN-2011003-07
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Finding | |
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| Title | Unit 1 Secondary Containment Bypass Leakage Exceeded |
| Description | On March 15,2010, during a Unit 1 refueling outage, PPL determined that the as-found minimum pathway secondary containment bypass leakage (SCBL) TS limit had been exceeded during performance of local leak rate testing (LLRT). PPL attributed the cause of the event to the RHR drywell spray penetrations' isolation valve design and the difficulty of meeting the TS limit based on the number of penetrations and valve sizes. There were no actual consequences and analysis concluded that increases in doses would not have exceeded regulatory limits during a postulated accident. The as-found value for Unit 1 SCBL in 2008 was 3668 sccm when the TS requirement was less than 4247 sccm. The as-found value for Unit 1 SCBL in 2010 was 7977 sccm when the requirement was 7079 sccm. A TS amendment for both Unit 1 and Unit 2 licenses raised the TS SCBL limit from 9 scfh to 15 scfh between outages. Historic SCBL tests had met the TS requirement and there was no overall trend in SCBL results. The LER was reviewed for accuracy, the appropriateness of corrective actions, violations of requirements, and generic issues. Additionally, the inspectors reviewed the associated ACE, prior PPL LERs associated with SCBL, historic LLRTS, vendor manuals, the TS amendment to raise the SCBL limit, and the adequacy of corrective actions, Corrective actions included evaluating valve designs and configurations to determine methods to reduce leakage; performing a tra.ining needs analysis; and considering the need to adjust maintenance strategies based on the new as-found data. A subsequent review of corrective actions determined that the training needs analysis had identified no training gaps, that changing the SCBL TS limit was not feasible, and that eliminating RHR penetrations from SCBL was not feasible. PPL's open corrective action is to implement a design change to the ECCS keepfill system to incorporate it as part of the SCBL boundary. There was no performance deficiency as there were no prior trends to suggest the limit would be exceeded, there were no deficiencies related to maintenance practices identified by the inspectors, and the cause of exceeding the SCBL limit was not reasonably within PPL's ability to foresee and correct. In addition, PPL's analysis concluded that, during a postulated design basis accident, the increase in dose related to the elevated SCBL leak rate would not have exceeded regulatory limits. The overall failure to meet the SCBL requirement of SR 3.6.1.3.1 1, however, was a violation of TS 3.6.1.3. Because no performance deficiency was identified, no enforcement action is warranted for this violation of NRC requirements in accordance with the NRC's Enforcement Policy. Further, because PPL actions did not contribute to this violation, it will not be considered in the assessment process or the NRC's Action Matrix. PPL entered this issue in their CAP as CR 1243436. In addition, the inspectors reviewed PPL's evaluation and corrective actions subsequent to identifying the violation and made the following observations: . A correct-condition action from the ACE to perform a maintenance training needs analysis was closed without being performed; r Through inspectors questioning and a subsequent PPL engineering evaluation, it was determined that the boundary valve HV151F021A(B) actuators were not undersized as claimed in the ACE; and r NDAP-00-0752, "Cause Analysis," Revision 7, Step 8.1 requires an extent of condition for an ACE to consider the total population of items with the same undesired condition as the issue that was identified. The SCBL ACE, however, limited the extent of condition to the RHR drywell spray penetrations, For instance, the as-found 'A' feedwater penetration leakage, which was not considered in the extent of condition boundary, was 2050 sccm, I times the historical average of 256 sccm. PPL determined that the ACE conclusion would have been unchanged with inclusion of the feedwater penetration leakage. None of the above observations were determined to be more than minor since there was no actual safety consequences and reasonable assurance remained that physical design barriers would protect the public from radionuclide releases caused by accidents or events. PPL entered the issues into the CAP. This LER is closed. |
| Site: | Susquehanna  |
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| Report | IR 05000387/2011003 Section 4OA3 |
| Date counted | Jun 30, 2011 (2011Q2) |
| Type: | Violation: Severity level Enforcement Discretion |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | P Kaufman J Furia A Rosebrook P Finney J Brand P Krohn E Torres J Greives |
| INPO aspect | |
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Finding - Susquehanna - IR 05000387/2011003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Susquehanna) @ 2011Q2
Self-Identified List (Susquehanna)
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