05000315/FIN-2014005-01
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Finding | |
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| Title | Failure to Identify Conditions Adverse to Quality associated with the Unit 1 TDAFW Pump Turbine Oil System |
| Description | A finding of very low safety significance, with an associated non-cited violation of 10 CFR Part 50, Appendix B, Criterion 16, Corrective Actions, was identified by the inspectors for the licensees failure to promptly identify and correct a condition adverse to quality (CAQ) associated with Unit 1 Turbine-Driven Auxiliary Feedwater (TDAFW) pump turbine bearing oil. Specifically, the licensee failed to identify that water was entering the oil system after leakage had been identified directly above one of the TDAFW pump turbine bearings. On April 7, 2014, a cooling water leak was identified above the outboard turbine bearing. The leak was classified as about 1 drop-per-minute (dpm). On April 11, 2014, the licensee discovered the turbine bearing oil level was above the maximum mark on an attached sight glass. Several possible reasons were postulated for the high level (which had been steady in-band for over a year), such as rising turbine building temperatures and the fact that it was not uncommon for personnel to do unnecessary oil adds to the machine. Oil was drained out until level returned to the maximum mark. On May 22, 2014, the licensee again noted oil level to be above the maximum mark. Oil was drained again, and similar reasons provided for the level increase. Further, a statement was made that oil level had been steady for the past month, neglecting the previous high level condition. In parallel, NRC inspectors had questioned why level was being maintained at the maximum mark when the operator logs and a sign stated level should be kept at the minimum mark. On May 23, the licensee decided to drain the oil system; 620 ml of water was found. New oil was added, and a temporary modification was installed which directed leakage away from the bearing. The issue was entered into the Corrective Action Program (CAP), and an apparent cause evaluation later determined the leakage to be the primary intrusion pathway for the water. The issue was more-than-minor because it adversely affected the Configuration Control attribute of the Mitigating Systems Cornerstone, whose objective is to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Additionally, if left uncorrected, the issue could lead to a more significant safety concern. The inspectors assessed the finding for significance using IMC 0609, Significance Determination Process. Per Appendix A, the finding screened as Green, or very low safety significance, in Exhibit 2. Specifically, all questions were answered no under Section A for findings related to Mitigating Structures, Systems and Components (SSCs) and Functionality. The inspectors reviewed the licensees past operability evaluation and concluded that given the projected amount of water that could be entrained in the oil during operation, along with the duration of operation assumed in the safety analyses, that operability of the pump would be maintained. The finding had an associated cross-cutting aspect in the Human Performance area, specifically, H.11, Challenge the Unknown. Regarding the TDAFW oil system, the licensee rationalized why the level was increasing without sufficient investigation given the significance of the system, and did not seek further information that was readily available regarding appropriate oil levels. |
| Site: | Cook  |
|---|---|
| Report | IR 05000315/2014005 Section 1R15 |
| Date counted | Dec 31, 2014 (2014Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | E Sanchez J Cassidy J Ellegood J Lennartz K Riemer M Garza M Mitchell M Phalen T Go T Taylor |
| Violation of: | 10 CFR 50 Appendix B Criterion XVI |
| CCA | H.11, Challenge the Unknown |
| INPO aspect | QA.2 |
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Finding - Cook - IR 05000315/2014005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Cook) @ 2014Q4
Self-Identified List (Cook)
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