A self-revealing finding was identified for an inadequate maintenance procedure regarding electrical connections associated with the Unit 2A
Main Transformer bushings. The procedure was not clear as to the appropriate method to prepare the surface for an aluminum
bushing terminal and did not provide adequate information on
torque requirements and the use of anti-oxidant grease. This resulted in the failure of the
bushing connection and a Unit 2 reactor
scram on February 1, 2008. Exelon entered this issue into the corrective action program (
CAP), performed repairs, and revised the procedure to reflect the appropriate information to successfully assemble the connection. The issue is more that minor because it is associated with procedure quality attribute of the
Initiating Events cornerstone and affected the objective to limit the likelihood of those events that upset plant stability and challenge critical safety functions during power operations. The inspectors evaluated the finding using Phase 1 of
IMC 0609, Appendix A, Significance Determination of Reactor Inspection Findings for At-Power Situations. This finding was determined to be of 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 be unavailable
