A self-revealing finding (
FIN) was identified for the licensees failure to implement adequate design control measures for the rod control power supply modification which resulted in the loss of 24VDC power in the 1AC rod control power cabinet. The inspectors determined that the licensees failure to implement adequate design control measures was more than minor because it affected the Design Control attribute of the
Initiating Events Cornerstone and adversely affected the cornerstone objective, in that, the insufficient margin in the rod control power supply OVP function caused a multiple drop rod event which resulted in a
reactor trip. This finding was determined to have very low safety significance (Green) because it did not contribute to both the likelihood of a
reactor trip and the likelihood that mitigation equipment or functions would not be available. A cross-cutting aspect was not assigned because the performance deficiency does not reflect current licensee performance.
