05000237/FIN-2011003-08
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Finding | |
|---|---|
| Title | Failure to Place One Channel of the Rod Block Monitor Into Trip |
| Description | The inspectors identified a finding of very low safety significance and NCV of Technical Specification 3.3.2.1.1, Required Action B.1, for the licensees failure to place one Rod Block Monitor (RBM) channel on Unit 3 in trip within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> as required upon meeting Condition B, Two RBM channels inoperable. The licensee performed troubleshooting on the issue and declared the RBM inoperable to repair the failed component. The finding was determined to be more than minor because, if left uncorrected, if could lead to a more significant safety concern. Specifically, if a RBM channel had fewer than three real inputs, but was counting false inputs due to the shorted diode, it would be unable to fulfill its Inop function, and would not insert a rod block to prevent a rod withdrawal error. The inspectors performed a Phase 1 Significance Determination in accordance with IMC 0609, Attachment 4. The inspectors concluded that this finding affected the Mitigating Systems Cornerstone since it was a degradation of reactivity control. The finding screened as Green, or very low safety significance, in Table 4a of Attachment 4, since it is not a design or qualification deficiency and did not represent an actual loss of safety system function. This is because the RBM maintained a sufficient number of real inputs and because the licensees Rod Withdrawal Error analysis does not assume the RBM function. The inspectors determined that this finding has a cross-cutting aspect in the area of Problem Identification and Resolution in the component of Corrective Action Program, since it involved the licensees failure to thoroughly evaluate problems. |
| Site: | Dresden  |
|---|---|
| Report | IR 05000237/2011003 Section 4OA3 |
| Date counted | Jun 30, 2011 (2011Q2) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | M Bielby M Ring T Go J Draper C Tilton J Corujo-Sandin M Munir R Winter A Dahbur D Melendez-Colon C Phillips C Moore |
| CCA | P.2, Evaluation |
| INPO aspect | PI.2 |
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Finding - Dresden - IR 05000237/2011003 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Dresden) @ 2011Q2
Self-Identified List (Dresden)
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