05000423/FIN-2016008-04
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Finding | |
|---|---|
| Title | Licensee-Identified Violation |
| Description | LER 05000423/2014-002-00 (Unit 3) describes an unanalyzed condition in which Dominion identified DC motor control circuits were unfused. Specifically, Dominion did not provide overcurrent protection for wiring associated with 125 V DC control circuits for non-safety related main turbine emergency lube oil and main generator emergency seal oil pumps to prevent wires from overheating due to fire induced faults and excessive currents flowing through the cable. With enough current flowing through the cable, the potential existed that the overloaded motor control wiring could damage adjacent control circuit wiring for components which are needed to achieve and maintain post-fire safe shutdown for a fire in several fire areas (turbine battery switchgear area, cable spreading room, instrument rack room, control room). This condition could result in a loss of the associated safe shutdown components or a secondary fire in another fire area. The failure to protect safe shutdown cables from the effect of postulated fires was a performance deficiency. This performance deficiency was a violation of Millstone Power Station, Unit 3, Renewed Facility Operating License Condition 2.H, which requires, in part, post-fire safe shutdown cables remain free of the effects of fire induced cable faults during postulated fires. Contrary to the above, Dominion identified they failed to meet this requirement and the condition existed since initial construction. The issue was more than minor because it was associated with the protection against external events (fire) attribute of the mitigating systems cornerstone and it adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The team determined that the finding was of very low safety significance (Green), based on IMC 0609, Appendix F, Fire Protection Significance Determination Process, Phase 2 screening criteria. The finding screened to Green based upon, task number 2.3.5, because the affected cables were routed in alternate shutdown fire areas that are continually manned or protected by detection and automatic suppression systems. Remaining fire areas are protected by detection systems, automatic suppression systems or rely on manual firefighting activities. Additionally, the cable construction is IEEE 383 (thermoset) which decreases the likelihood of inter-cable and intra-cable interactions. Based on a team walkdown, the team determined that the main turbine emergency lube oil and main generator emergency seal oil pump cable routing was not routed near a credible fire ignition source in the affected fire areas. Because this finding is of very low safety significance and had been entered into Dominions corrective action program (CR541983), this violation is being treated as a Green, licensee-identified NCV consistent with the NRCs Enforcement Policy. |
| Site: | Millstone  |
|---|---|
| Report | IR 05000423/2016008 Section 4OA7 |
| Date counted | Sep 30, 2016 (2016Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | C Cahill D Orr E Dipaolo J Patel J Rady K Young L Dumont S Freeman S Galbreath W Cook |
| Violation of: | License Condition - Fire Protection |
| INPO aspect | |
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Finding - Millstone - IR 05000423/2016008 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Millstone) @ 2016Q3
Self-Identified List (Millstone)
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