A self-revealing finding was identified for the failure to adequately maintain the E2
emergency diesel generator (
EDG) between July 1992 and September 2003. This finding involved two apparent violations. An apparent violation of Technical Specifications was identified for the failure to maintain the maintenance procedure for installation of
EDG adapter
gaskets. The procedure did not incorporate certain vendor recommendations intended to provide proper sealing of the
gaskets, leading to relaxation over several years that allowed combustion gases to enter the jacket coolant system. An apparent violation of
10 CFR 50 Appendix B, Criterion XVI, Corrective Actions was identified because Exelon did not correct a
condition adverse to quality following two instances of low jacket water pressure observed on the E2
emergency diesel generator (
EDG) in March and April 2003. Subsequently, the
EDG failed due to a low jacket water pressure condition. This finding is more than minor because it is associated with the equipment performance attribute of the
Mitigating Systems cornerstone and adversely affects the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to
initiating events. The finding was assessed using a Phase 3 evaluation. The finding is of low to moderate safety significance (WHITE) at Unit 2 based on delta core damage frequency (
CDF) and delta
large early release frequency (
LERF). The finding is of very low safety significance (GREEN) at Unit 3 based on
CDF and
LERF. The difference between the two units is attributable to differences in electrical bus loads. (Section 2.2)
