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The team identified a violation of 10 CFR The team identified a violation of 10 CFR 50 Appendix B Criteria III, Design Control. Specifically, the design modification package for the 480 VAC breaker replacements failed to ensure the breaker coordination for the 480 VAC electrical buses was maintained. As a result, feeder breaker 1B3A tripped unexpectedly during the fire event in the 1B4A switchgear. This performance deficiency also resulted in the loss of multiple buses on both trains of 480 VAC, including ECCS systems, from a single fault on a 480 VAC bus. This finding and its corrective actions will be managed by the NRCs Inspection Manual Chapter 0350 Oversight Panel. This finding is associated with Enforcement Action 12-121. The failure to ensure that the 480 VAC electrical power distribution system design requirements were maintained was a performance deficiency that was within OPPDs ability to foresee and prevent. The performance deficiency was reviewed using NRC Inspection Manual Chapter 0612, Appendix B, Issue Screening, and the issue was determined to be more than minor because it affected the Initiating Events Cornerstone attributes of protection against external events (i.e., fire) and design control. The issue adversely affected the associated cornerstone objective of limiting the likelihood of those events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. The significance of this finding is bounded by the significance of the Red finding documented in Inspection Report 05000285/2012010. The licensee entered this issue into its corrective action program as CR 2011-6621. The performance deficiency had a cross-cutting aspect in the area of human performance associated with resources because OPPD failed to ensure that station procedures for engineering changes, plant modifications, inspections, installations, and maintenance contained sufficient details. maintenance contained sufficient details.  +
23:59:59, 30 September 2012  +
05000285  +
23:59:59, 30 September 2012  +
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00:46:18, 21 February 2018  +
23:59:59, 30 September 2012  +
Failure to Ensure Breaker Coordination of 480 VAC Electrical Power Distribution System Was Maintained  +