05000483/FIN-2011005-09
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Finding | |
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| Title | Licensee-Identified Violation |
| Description | Technical Specification 3.8.9, Distribution Systems Operating, required, in part, that any applicable inoperable distribution subsystem be restored within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. Technical Specification 3.8.9, Required Action D.1, required Mode 3 entry within 6 additional hours. Contrary to the above, in the three years prior to December 1, 2010, the licensee identified three failures to maintain the operability of equipment located in the electrical penetration room, train A, following a potential high-energy line break in nonnuclear, non-seismically analyzed auxiliary steam piping to the boric acid batching tank. Specifically, the harsh environment from a high-energy line break had the potential to impact safety related motor control center NG01B located in room 1410 for greater than the allowed 8 plus 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Additionally the licensee identified five areas with deficient high-energy line break barrier controls. The details of these deficient barrier controls were documented in License Event Report 05000483/2010-009-02. This finding is greater than minor because it was associated with the design control attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Using Manual Chapter 0609.04, Phase 1 - Initial Screening and Characterization of Findings, this finding required a Phase 3 significance determination to evaluate the cumulative risk of the multiple high-energy line break deficient barrier controls. The Region IV senior reactor analyst evaluated each case separately. For each area the approximate steam pipe break frequency was determined to be 2.5E-11/ft-hour. Each initiating event frequency was adjusted by the exposure period to obtain the initiating event frequency on a per year basis. Thus the event frequencies were 2.5E-11*Length*Exposure time/year. The analyst used the Callaway Standardized Plant Analysis Risk model to calculate the conditional core damage probabilities. The Standardized Plant Analysis Risk analysis assumed that the steam line break occurred and that the affected component failed and was not recoverable. The analyst determined that the five cases total change in core damage frequency was less than 2.3E-8/year. Because the delta core damage frequency was less than 1E-6 and the finding was not a significant contributor to the large early release frequency, the finding was of very low safety significance (Green). This finding was entered in the licensees corrective action program as Callaway Action Request 201102329. |
| Site: | Callaway  |
|---|---|
| Report | IR 05000483/2011005 Section 4OA7 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | S Hedger C Alldredge Z Hollcraft G Apgar L Ricketson K Clayton D Dumbacher L Willoughby N O'Keefe C Long A Fairbanks T Buchanan D Reinert |
| INPO aspect | |
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Finding - Callaway - IR 05000483/2011005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Callaway) @ 2011Q4
Self-Identified List (Callaway)
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