05000461/FIN-2012005-03
From kanterella
Jump to navigation
Jump to search
Finding | |
|---|---|
| Title | Failure to Complete an Adequate Extent Condition Review and to Correct a Previously Identified Design Problem Resulted in a Trip of the Emergency Reserve Auxiliary Transformer |
| Description | A finding of very low safety significance was self-revealed when the emergency reserve auxiliary transformer (ERAT) tripped during troubleshooting activities to isolate a direct current system ground following heavy rainfall. The ERAT trip occurred due to the presence of a latent design error identified on seal-in relays in the ERATs control circuitry and the licensees failure to adequately evaluate and correct it during its extent of condition review of the problem after it was identified in September 2002. The licensee restored the ERAT to service and implemented a modification to correct the latent design problem. Because the ERAT is not safety-related, no violation of regulatory requirements was identified. The finding was of more than minor safety significance because it was sufficiently similar to several examples in Inspection Manual Chapter 0612, Power Reactor Inspection Reports, Appendix E, Examples of Minor Issues, wherein licensees failed to adequately correct conditions adverse to quality and the consequences had some safety impact. The performance deficiency was also associated with the Equipment Performance attribute and adversely affected the Initiating Events Cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, when the ERAT tripped safety related 4160 volt bus 1A1, which had been powered by the ERAT, momentarily lost power. With the momentary loss of power several plant safety systems were affected including a loss of secondary containment differential pressure. The finding was a licensee performance deficiency of very low safety significance because it: (1) did not involve a loss-of-coolant accident initiator; (2) did not cause a reactor trip AND the loss of mitigation equipment; (3) did not involve the complete or partial loss of a support system that contributes to the likelihood of, or cause, an initiating event AND affect mitigation equipment; and (4) did not increase the frequency of a fire or internal flooding initiating event. While the finding did involve a partial loss of a support system (i.e., offsite power) that contributes to the likelihood of an initiating event, mitigation equipment was not adversely affected by the momentary loss of power. The inspectors concluded that because the licensees missed opportunity to correct the latent design error occurred in 2002 and no other more recent opportunities reasonably existed to identify and correct the problem, this issue would not be reflective of current licensee performance and no cross-cutting aspect was identified. |
| Site: | Clinton  |
|---|---|
| Report | IR 05000461/2012005 Section 4OA2 |
| Date counted | Dec 31, 2012 (2012Q4) |
| Type: | Finding: Green |
| cornerstone | Initiating Events |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | A Shaikh B Kemker B Orlikowski D Lords D Reeser J Draper J Laughlin S Mischke V Myers |
| INPO aspect | |
| ' | |
Finding - Clinton - IR 05000461/2012005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Finding List (Clinton) @ 2012Q4
Self-Identified List (Clinton)
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||