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10 CFR 50.48(b)(2) requires, in part, that all nuclear power plants licensed to operate prior to January 1, 1979, must satisfy the applicable requirements of Appendix R to this part, including specifically the requirements of Sections
Section III.G, III.J, and III.0.
Section III.G.3 of 10 CFR, Part 50, Appendix R, requires, in part, that alternative of dedicated shutdown capability and its associated circuits, independent of cables, systems, or components in the area, room, or zone under consideration should be provided where the protection of systems whose function is required for hot shutdown does not satisfy the requirement of Paragraph G.2 of this section. Contrary to the above, prior to February 28, 2012, the licensee failed to ensure that alternative of dedicated shutdown capability and its associated circuits were independent of cables in the area. Specifically, the licensee failed to ensure that, in the event of a fire in the relay room or the 480V bus 51/52 area, fire damage to the cables and circuits for the
PORV valve PR-2B, pressurizer valve PR-33A, and reactor head vent valves RC-45A and RC-46 would not cause spurious operation of the valves. The performance deficiency was determined to be more than minor because it was associated with the
Mitigating Systems Cornerstone attribute of Protection Against External Factors (Fire) and affected the Cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to
initiating events to prevent undesirable consequences. The risk associated with this issue was determined to be of very low safety significance (Green) based on the initiating fire event frequencies and the probability of
hot shorts occurring for the valves affected. The licensee entered this issue into the
CAP as CR464393, Appendix R Fire Spurious Operation Concern for PR-33A, RC-45A, and RC-46, and expanded a roving
hourly fire watch to include the 480V bus 51/52 area.
