05000275/FIN-2011005-01
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Finding | |
|---|---|
| Title | Less than Adequate Evaluations of a Degreaded/Non-conforming Control Room Habitability Train |
| Description | The inspectors identified a non-cited violation of 10 CFR Part 50, Appendix B, Criteria V, Instructions, Procedures, and Drawings, after operations personnel failed to adequately evaluate the operability and extent of condition of a nonconforming control room habitability train. Beginning on August 30, 2011, the inspectors identified several nonconforming conditions associated with the habitability system, including disconnected ductwork, two 12-inch diameter openings in the control room envelope boundary, and less than adequate control room envelope pressurization and tracer gas surveillance tests. On November 7, 2011, the licensee re-performed the tracer gas test and observed significant unfiltered in-leakage into the control room envelope. Plant operators declared the habitability system inoperable. The licensee restored system operability after implementing compensatory measures. The licensee entered the finding into the corrective action program as Notification 50425114 and planned to restore the system to the current licensing basis condition. The inspectors concluded that the failure of plant operators to adequately evaluate the operability and extent of a nonconforming condition was a performance deficiency. This finding was more than minor because the licensees operability evaluation created a reasonable doubt that the system was capable of performing the specified safety function, similar to Example 3.k in Inspection Manual Chapter 0612, Appendix E, Examples of Minor Issues. The inspectors concluded that the finding was of very low safety significance because only the radiological barrier function of the control room was affected. This finding had a cross-cutting aspect in the area of problem identification and resolution, associated with the corrective action program component, because the licensee did not thoroughly evaluate the degraded control room ventilation train for operability and extent of condition P.1(c) |
| Site: | Diablo Canyon  |
|---|---|
| Report | IR 05000275/2011005 Section 1R15 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | NCV: Green |
| cornerstone | Barrier Integrity |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | E Ruesch D Reinert C Alldredge L Micewski N Makris L Ricketson G Guerra M Peck N O'Keefe M Young A Fairbanks |
| CCA | P.2, Evaluation |
| INPO aspect | PI.2 |
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Finding - Diablo Canyon - IR 05000275/2011005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Diablo Canyon) @ 2011Q4
Self-Identified List (Diablo Canyon)
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