The inspectors identified the
URI during a routine Maintenance Rule inspection on the gas turbine system. Gas turbines 1 and 3 (GT-1 and GT-3) are credited in Entergy's analysis to cope with station blackout and Appendix R fire scenarios to ensure
safe shutdown of the reactor. The system is classified as risksignificant in accordance with Entergys
Maintenance Rule program. This system has been in a category (a)(1) monitoring status since the inception of the Maintenance Rule in 1996. An (a)(1) action plan was established to improve overall system performance. However, Entergy may not have provided justifiable (a)(1) goals for maintenance preventable functional failures (
MPFFs) and Entergy may not have appropriately classified repeat maintenance preventable functional failures (RMPFFs). Specific to reliability, the goal was set as less than or equal to five
MPFFs and no RMPFFs in a 24 month rolling cycle. The number of allowable
MPFFs was calculated under the assumption that there would be, on average, 82 start demands during the 24 month cycle. The inspectors reviewed the operating history over the last three years and determined that the number of start demands averaged 38 during the 24 month cycle. The inspectors need more information to evaluate Entergy's goals for
MPFFs to determine their adequacy. Additional information is required to evaluate Entergy's implementation of the Maintenance Rule as it pertains to the gas turbine system. Actual unavailability and reliability information is needed to evaluate the gas turbine system performance and to assess whether performance of the system is bounded by the Station Blackout / Appendix R commitments, and assumptions in the design basis. This issue will be treated as a
URI pending additional licensee input and inspector evaluation of gas turbine system performance.
