05000416/FIN-2015007-02
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Finding | |
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Title | Failure to Ensure that Electrical Interrupting Devices are Rated for Available Fault Current Levels |
Description | The team identified a Green, non-cited violation of 10 CFR Part 50, Appendix B, Criterion III, Design Control, which states, in part, design control measures shall provide for verifying or checking the adequacy of design, such as by the performance of design reviews, by the use of alternate or simplified calculational methods, or by the performance of a suitable testing program. Specifically, from January 20, 2010, to August 26, 2015, the licensee issued Calculation EC-Q1111-90028, AC Power Systems, Revision 6, but failed to verify that the calculated fault current levels were within the ratings of the installed Division III circuit breakers. In response to this issue, the licensee performed an operability evaluation to support an operable but degraded/nonconforming condition, recommending an action to perform a detailed fault current study, and reviewing fault current levels at maximum switchyard voltage of 105 percent to verify that they do not create additional concerns. This finding was entered into the licensees corrective action program as Condition Reports CR-GGN-2015-4607, CR-GGN-2015-4934, and CR-GGN-2015-5112. The team determined that failure to ensure that electrical interrupting devices are rated for available fault current levels was a performance deficiency. This performance deficiency was more than minor, and therefore a finding, because it was associated with the equipment performance 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. Specifically, the licensees failure to verify the design adequacy of the interrupting equipment would operate with a fault resulted in a reasonable doubt with the operability of Division III motor control center 17B01. In accordance with Inspection Manual Chapter 0609, Appendix A, The Significance Determination Process (SDP) for Findings At-Power, dated June 19, 2012, Exhibit 2, Mitigating Systems Screening Questions, the finding was determined to have very low safety significance (Green) because it was a design or qualification deficiency that did not represent a loss of operability or functionality; did not represent an actual loss of safety function of the system or train; did not result in the loss of one or more trains of nontechnical specification equipment; and did not screen as potentially risk significant due to seismic, flooding, or severe weather. This finding had a human performance crosscutting aspect associated with design margins, because the licensee failed to operate and maintain equipment within design margins. |
Site: | Grand Gulf |
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Report | IR 05000416/2015007 Section 1R21 |
Date counted | Dec 31, 2015 (2015Q4) |
Type: | NCV: Green |
cornerstone | Mitigating Systems |
Identified by: | NRC identified |
Inspection Procedure: | IP 71111.21 |
Inspectors (proximate) | D Loveless H Leake J Watkins L Brandt R Latta T Farnholtz W Sherbin J Mchugh |
Violation of: | 10 CFR 50 Appendix B Criterion III, Design Control |
CCA | H.6, Design Margins |
INPO aspect | WP.2 |
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Finding - Grand Gulf - IR 05000416/2015007 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Grand Gulf) @ 2015Q4
Self-Identified List (Grand Gulf)
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