10 CFR 50.65 (a)(4) requires in part before performing maintenance activities, the licensee shall assess and manage the increase in risk that may result from the proposed maintenance activities. Contrary to this, on January 26, 2009, the licensee underestimated the Unit 1 maintenance risk category when it failed to update its maintenance risk assessment upon discovery on January 24, 2009 when the 1-2A
EDG automatic fuel oil transfer pump would not automatically start in response to a low fuel oil day tank level. The licensee evaluated the Unit 1 risk category on January 26, 2009 as Green when the actual risk category was Yellow for performed work activities concurrent with the 1-2A
EDG automatic transfer pump unavailable to perform its automatic function. This was identified in the licensees
CAP as CR 2009100820. This finding is of very low safety significance because the
incremental core damage probability deficit as a result of the flawed risk assessment was less than
1E-6 and the incremental large early release probability deficit was less than
1E-7 when assessed by Appendix K, Maintenance Risk Assessment and Risk Management
Significance Determination Process of
Inspection Manual Chapter 0609,
Significance Determination Process 