The inspectors identified that AmerGen performed an inadequate risk assessment for a planned, but not yet commenced, maintenance activity on the Bank 6 startup transformer in February 2008; which resulted in an under-estimation of the risk associated with performing the activity. This finding was determined not to be a violation of NRC requirements. AmerGens corrective actions for this issue included reassessing the risk for the activity and discussing this issue with work management personnel. The finding was more than minor because the risk assessment did not account for the unavailability of a single train of a system that provides a shutdown key safety function. This finding was also similar to more than minor example 7.e in NRC
Inspection Manual Chapter (IMC) 0612, Power Reactor Inspection Reports, Appendix E, Examples of Minor Issues, because when the activity was correctly assessed the plant would have been in a higher, licensee-established risk category. In accordance with
IMC 0609, Appendix K, Maintenance Risk Assessment and Risk Management
Significance Determination Process, the inspectors evaluated the significance of this issue and determined that the
incremental core damage probability deficit (
ICDPD) associated with this activity was less than 1.0 E-6 and noted that the incorrectly assessed maintenance activity did not occur. Therefore, in accordance with Appendix K this finding screened as very low safety significance. The performance deficiency had a cross-cutting aspect in the area of human performance because AmerGen did not plan a maintenance activity, consistent with nuclear safety because risk insights were not properly incorporated into the work planning
H.3(a). (Section 1R13)