A self-revealing finding of very low safety significance was identified for the failure of
PSEG to resolve a long standing issue with the reliability of the Unit 1 main generator voltage regulator (VR). A failure in the Unit 1 main generator VR resulted in an
automatic reactor trip due to a
turbine trip above 50 percent power. Corrective actions include the planned replacement of the VR with a nuclear industry proven design during the October 2011 refueling outage.
PSEG entered this issue into their
CAP as notification 20481250. The performance deficiency was more than minor because it is associated with the equipment performance attribute of the
Initiating Events cornerstone and it adversely affected the cornerstone objective to limit the likelihood of those events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. The finding was evaluated under
IMC 0609, Attachment 4, Phase 1 - Initial Screening and Characterization of Findings. The inspectors determined that the finding is of very low safety significance (Green) because it does not contribute to both the likelihood of a
reactor trip and the likelihood that mitigation equipment or functions will not be available. The inspectors determined that this finding has a cross-cutting aspect in the area of human performance, because
PSEG affected long term plant safety by not minimizing long-standing equipment issues. Specifically, considering the increase in the number of Unit 1 main generator VR failures since 2007,
PSEG did not resolve the lack of vendor and part support for the Unit 1 main generator VR in a timely manner. (
H.2(a))
