05000280/FIN-2015003-01
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Finding | |
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| Title | Charging Pump Cubicle Floor Drain Backflow Preventer Failures during Unit 1 Safeguards Building Flooding |
| Description | A self-revealing, Green finding was identified because the instructions section of the procedure used to test floor drain back flow preventers (BFPs) did not include the instructions necessary to successfully fulfill the purpose of the procedure. A lack of testing methodology instructions allowed BFPs to be installed in the Unit 1 and Unit 2 charging (CH) pump cubicle floor drains that would not prevent backflow into the cubicles during low flow conditions. This was discovered when the Unit 1 and 2 CH pump cubicles filled with approximately two inches of water during the Unit 1 Safeguards building basement flooding event on May 20, 2015. This issue was documented in the licensees corrective action program (CAP) as condition reports (CRs) 580231 through 242. The inspectors concluded that the failure of the licensee to have the instructions necessary to successfully fulfill the purpose of 0-MPM-1900-02, Flood Protection Floor Drain Back Water Stop Valve Replacement as required by Dominion procedure SPAP-0504, Technical Procedure Writers Guide, and to correctly test the CH pump cubicle floor drain BFPs to prove functionality, was a performance deficiency (PD). Specifically, 0-MPM-1900-2 did not have instructions on the flow rate to fill the test stand and to observe that the BFP seats at a specified flow rate. Using IMC 0612, Appendix B, Issue Screening, dated September 7, 2012, the inspectors determined that the performance deficiency was more than minor because it was associated with the procedural quality attribute of the Mitigating Systems Cornerstone, and it adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the lack of complete testing instructions for BFPs allowed BFPs to be installed in the CH pump cubicle floor drains that would not seal during all flooding scenarios; and once cocked to the side during low flow, then had the potential to pass much higher flow rates into the CH pump cubicles. Using IMC 0609.04, Initial Characterization of Findings, Table 2, dated June 19, 2012, the finding was determined to affect the Mitigating Systems Cornerstone. The inspectors screened the finding using Manual Chapter 0609, Appendix A, Significance Determination Process (SDP) for Findings at-Power, dated June 19, 2012, and determined that it screened as Green because the deficiency involved the degradation of equipment specifically designed to mitigate a flooding initiating event, but did not involve the total loss of any safety function. This finding has a cross-cutting aspect in the documentation aspect of the human performance area, H.7, because the licensee did not have an adequate test procedure to ensure that the floor drain BFPs would seal during low flow backflow conditions. |
| Site: | Surry  |
|---|---|
| Report | IR 05000280/2015003 Section 1R12 |
| Date counted | Sep 30, 2015 (2015Q3) |
| Type: | Finding: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71111.12 |
| Inspectors (proximate) | A Masters C Jones E Stamm P Mckenna T Fanelli |
| CCA | H.7, Documentation |
| INPO aspect | WP.3 |
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Finding - Surry - IR 05000280/2015003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Surry) @ 2015Q3
Self-Identified List (Surry)
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