05000400/FIN-2010002-02
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Finding | |
|---|---|
| Title | Failure to Promptly Evaluate Operating Experience and Identify Potential Steam Voiding as a Condition Adverse to Quality |
| Description | The inspectors identified a Green NCV of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, when the licensee failed to promptly evaluate operating experience (OE) received October 22, 2008 and identify potential steam voiding in the residual heat removal (RHR) system as a condition adverse to quality. During the evaluation, which was not completed until July 16, 2009, the licensee learned that the suction lines for the RHR pumps are susceptible to steam voiding at temperatures as low as 240F. If the steam void flowed to an RHR pump, that pump could fail causing the associated train of the Emergency Core Cooling System (ECCS) to fail. The delay in evaluating the OE resulted in a delay of determining and implementing appropriate corrective actions. Specifically, the failure to promptly evaluate this OE enabled the licensee to violate Technical Specification (TS) 3.0.4when the plant transitioned from Mode 4 to Mode 1 with only one operable train of ECCS after refueling outage (RFO) 15 on May 9, 2009. The licensee entered this issue into the CAP as AR #345425. The licensee took corrective action by changing procedures to avoid exposing the suction lines to excessive temperatures during Modes when it is required to be operable for ECCS, thereby preventing potential steam voiding. The inspectors determined that the failure to promptly evaluate OE received on October 22, 2008, and identify potential steam voiding as condition adverse to quality was a performance deficiency. The performance deficiency was more than minor because it was associated with the equipment performance attribute of the Mitigating Systems Cornerstone and it adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, it could have potentially caused one or more RHR pumps and associated ECCS trains to be inoperable due to steam voiding. Using Inspection Manual Chapter (IMC) 0609, Significance Determination Process, Phase 1 Worksheet, the inspectors concluded that a Phase 2 evaluation was required because this finding represented a potential loss of safety function of the RHR system. The inspectors performed a Phase 2 analysis using IMC 0609Appendix A, Determining the Safety Significance of Reactor Inspection Findings for At-Power Situations and the site specific risk informed inspection notebook. Due to the site specific risk informed inspection notebook not containing appropriate target sets to accurately estimate the risk input of the finding, it was determined that a Phase 3 analysis was required. A regional Senior Reactor Analyst performed the Phase 3 evaluation and concluded the finding was of very low safety significance (Green). The NRCs most current Standardized Plant Analysis Risk Model was used for the evaluation. The evaluation assumed that the B RHR Pump always failed to start for the exposure time of seventy hours. Also, there was a potential increase in the common cause failure of the RHR pumps. The dominant accident sequence was a postulated Small Break LOCA with initial success of the ECCS via High Pressure Injection, but the ECCS failed in the recirculation mode. The SDP performed for this violation considered the potential loss of safety function of the RHR system and therefore bounded all violations described in LER 05000400/2009-002 which is further discussed in Section 4OA3.2.This finding was determined to have a cross-cutting aspect in the OE component of the Problem Identification and Resolution area, in that the licensee failed to evaluate OE in a timely manne |
| Site: | Harris  |
|---|---|
| Report | IR 05000400/2010002 Section 4OA2 |
| Date counted | Mar 31, 2010 (2010Q1) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | A Nielsen J Austin L Miller R Musser P Lessard J Beavers |
| CCA | P.5, Operating Experience |
| INPO aspect | CL.1 |
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Finding - Harris - IR 05000400/2010002 | |||||||||||||||||||||||||||||||||||||||||
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Finding List (Harris) @ 2010Q1
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