On March 22, 2012, McGuire Nuclear Station notified the NRC of a condition which could result in fire induced spurious operation of the block valves for the Unit 2
Steam Generator (
SG) Power Operated Relief Valves (
PORVs). This potential condition could adversely affect the ability to achieve and maintain a cold shutdown of Unit 2. This represented a condition reportable as per the requirements of
10 CFR 50.72(b)(3)(ii)(B). Reference Event #47764 [for Unit-2].
In accordance with 10 CFR 50.72(c)(2)(i), McGuire is reporting results of ensuing cause and extent of condition evaluation of Event #47764, which has identified a similar condition on McGuire Unit 1. This condition could result in a fire induced spurious operation of the block valves for the Unit 1 SG PORVs. This spurious operation could potentially damage these valves and render them inoperable. Since these valves are unisolable, they could not be repaired to allow the Unit 1 SGs to be used for Unit cool down if needed. This potential condition could adversely affect the ability of the plant to achieve and maintain a cold shutdown of Unit 1. This represents a condition reportable as per the requirements of 10 CFR 50.72(b)(3)(ii)(B). This potential condition is mitigated by existing compensatory measures (i.e. fire watches) which have been in place as part of McGuire's transition to NFPA 805.
The licensee notified the NRC Resident Inspector.
