05000220/FIN-2013010-01
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Finding | |
|---|---|
| Title | Improper Bus Restoration Results in a Loss of Shutdown Cooling |
| Description | The inspectors documented a violation of Unit 1 Technical Specification (TS) 6.4.1, Procedures, because Constellation Energy Nuclear Group (CENG) failed to properly restore from a loss of a vital direct current (DC) bus in accordance with station off-normal procedures resulting in an unplanned loss of all shutdown cooling (SDC) when time to boil was less than 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. Specifically, operators failed to recognize a potential for loss of SDC during battery bus 12 restoration in accordance with N1-SOP- 47A.1, Loss of DC, Revision 00101, and N1-OP-47A, VDC Power System, Revision 02500. The inspectors determined that the failure of CENG to establish an adequate procedure for properly restoring the battery bus 12 was a performance deficiency that was reasonably within CENGs ability to foresee and correct and should have been prevented. The performance deficiency was determined to be more than minor because the inspectors determined it affected the configuration control aspect of the Initiating Events cornerstone and adversely affected the associated 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, CENG failed to specify the associated tripping circuits and tripping actions that could result from battery bus restoration in accordance with N1-SOP-47A.1, Loss of DC, Revision 00101, and N1- OP-47A, VDC Power System, Revision 02500. This performance deficiency resulted in loss of SDC during attempted restoration of the vital DC battery bus 12 on April 16, 2013. A phase III risk assessment was completed by NRC Senior Risk Analysts and .a preliminary greater than green finding and apparent violation letter, dated September 23, 2013, was issued (ML13266A237 AV 05000220/2013003-04). A Regulatory Conference was held in the NRC Region I office in King of Prussia, Pennsylvania, on November 1, 2013, during which CENG was given an opportunity to provide additional information to be considered prior to issuing the final significance determination. On November 5, 2013, and again on November 19, 2013, Significance and Enforcement Review Boards (SERPs) were conducted to discuss the information provided during the regulatory conference. The SERPs concluded that, based upon the information provided during the Regulatory Conference and as discussed in the cover letter of this report, this finding was of very low safety significance. The inspectors determined this finding had a cross-cutting aspect in the area of Human Performance, Resources, because CENG did not ensure that personnel, equipment, procedures, and other resources were available and adequate to assure nuclear safety - complete, accurate and up-to-date design documentation, procedures, and work packages, and correct labeling of components. Specifically, CENG procedures N1-SOP-47A.1 and N1-OP-47A did not contain adequate guidance to ensure recovery from a loss of a DC bus would not result in an unexpected plant transient Unit 1 TS 6.4.1, Procedures, requires, in part, that written procedures and administrative policies shall be established, implemented, and maintained that cover the applicable procedures recommended in Regulatory Guide 1.33, Quality Assurance Program Requirements (Operation), Appendix A, Typical Procedures for Pressurized- Water Reactors and Boiling-Water Reactors, dated November 3, 1972. Regulatory Guide 1.33, Appendix A, Section 4, Procedure for Startup, Operation, and Shutdown of Safety-Related BWR Systems, requires procedures for onsite DC system, and Section 6, Procedures for Combating Emergencies and Other Significant Events, requires, in part, procedures for including loss of electrical power (and/or degraded power sources). CENG procedures N1-OP-47A, 125 VDC Power System, Revision 02500, and N1- SOP-47A.1, Loss of DC, Revision 00101, implement this requirement. Contrary to the above, as of April 16, 2013, NMP did not establish adequate procedures for the onsite DC system to include a loss of electrical power. Specifically, following the loss of a vital DC battery bus 12, operators attempted to restore power using implementing procedures N1-OP-47A and N1-SOP-47A.1. While those procedures indicated tripping circuits and tripping actions may be carried out when power is reestablished, the procedures did not specify all of the affected components, including SDC pumps. As a result, when operators attempted to re-establish power, the site temporarily lost all SDC capability. Because this violation is of very low safety significance (Green) and CENG entered this issue into its corrective action program as CR-2013-002926 and CR-2013-002916, this violation is being treated as a non-cited violation (NCV) consistent with Section 2.3.2 of the NRC Enforcement Policy. |
| Site: | Nine Mile Point  |
|---|---|
| Report | IR 05000220/2013010 Section 4OA3 |
| Date counted | Sep 30, 2013 (2013Q3) |
| Type: | NCV: Green |
| cornerstone | Initiating Events |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71153 |
| Inspectors (proximate) | W Schmidt B Bickett D Roberts D Schroeder E Monteith R Lorson R Zimmerman W Dean |
| Violation of: | Technical Specification - Procedures Technical Specification |
| CCA | H.1, Resources |
| INPO aspect | LA.1 |
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Finding - Nine Mile Point - IR 05000220/2013010 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Nine Mile Point) @ 2013Q3
Self-Identified List (Nine Mile Point)
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