05000389/LER-2013-002
| St. Lucie Unit 2 | |
| Event date: | 06-03-2013 |
|---|---|
| Report date: | 07-29-2013 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3892013002R00 - NRC Website | |
Description of the Event
On June 3, 2013 at approximately 2000, Instrumentation and Controls (I&C) personnel were given permission by operations to begin the performance of the monthly functional test on the 2A hydrogen analyzer (EIIS: BB). Unit 2 was in Mode 1 at 8 percent power in the process of raising power following a forced outage. Upon completion of the functional test on the hydrogen analyzer at 2112, the containment upper dome sample valve (EIIS: BB) did not close when the sample point selector switch (EIIS: BB) was taken to "OFF". When informed by I&C of the condition, the Unit Supervisor (US) did not recognize the valve as a containment isolation valve, and consequently did not enter the associated technical specification (TS) action statement and complete the required action to de-energize a downstream isolation valve within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. The downstream valve was however, in its normally closed position. The dayshift operations crew recognized the condition and at approximately 0936 on June 4, 2013 the TS action statement was met by de-energizing the downstream valve by opening its breaker.
Cause
An apparent cause analysis identified that the cause was a human error in evaluating the impact to plant operation caused by the failure of the hydrogen analyzer containment isolation valve. Contributing causes included: 1) an inadequate procedure, and 2) ineffective hydrogen analyzer labeling.
Analysis of Safety Significance The containment upper dome hydrogen sample valve is a containment isolation valve (CIV) designated as a Class E piping penetration, which is designed to be open during a design basis event. Thus by design this valve does not provide a barrier against the release of radioactivity during engineered safety feature system operation. CIVs Probabilistic Risk Assessment (PRA) and therefore, this event had no risk impact and no significant safety consequence. This containment isolation valve event is reportable pursuant 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by Technical Specifications.
Immediate Corrective Actions
1. Failure of the containment upper dome hydrogen sample valve was re-evaluated and it was determined that Technical Specification 3.6.3 was applicable.
At approximately 0936 on June 4, 2013 the TS action statement was complied with by de-energizing the inline hydrogen sample valve by opening its breaker. (COMPLETE) 2. Operations held a briefing for the department to document and share human performance lessons learned for the event. (COMPLETE) Additional Corrective Actions The corrective actions listed below are entered into the site corrective action program. Any changes to the actions will be managed under the corrective action program.
1) The hydrogen analyzer procedure will be revised to include information about containment, isolation valves and TS implications concerning hydrogen analyzer maintenance.
2) The hydrogen analyzer valves will be re-labeled to clearly demonstrate that the valves on the hydrogen analyzer are containment isolation valves.
Similar Events A search and review of data in the St. Lucie Corrective Action Database addressing the past two years revealed no previous occurrences or similar events.
Failed Component(s) ISOL VLV (PENETR P-48A) FOR CNTMT DOME AREA HYDROGEN SAMPLING IEEE Class lE 3/8" solenoid valve Model V52600-515(3/8") Manufacture Valcor Engineering Company