A self-revealing apparent violation of
10 CFR 50, Appendix B, Criterion III, Design Control was identified following a review of the identified causes for the failure of the B
EDG jacket water cooling system on February 25, 2009. Specifically, NextEras failure to adequately control design changes implemented on the B
EDG jacket water cooling system in January 2009 led to the failure of the
gasket on
flange JTR005 in the B
EDG jacket water cooling system on February 25. The inspectors determined that this finding is more than minor because it is associated with the design control attribute of the
Mitigating Systems Cornerstone and affects the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to
initiating events to prevent undesirable consequences. Specifically, design modification 08MSE11, intended to address
flange JTR005 alignment and change the
flange gasket design was inadequate and resulted in inoperability of the B
EDG. In accordance with
IMC 0609,
Significance Determination Process, a Phase 3 risk analysis was performed and determined that the calculated delta
CDF for the finding was 2.27E-6, which represents a low to moderate safety significance or White finding. The cause of the finding is related to the corrective action component of the cross-cutting area of problem identification and resolution because NextEra did not thoroughly evaluate problems in a timely manner such that resolutions address causes (
P.1(c)). Specifically, NextEra did not adequately evaluate deficient conditions when addressing B
EDG cooling water
flange leaks, failed to adequately use readily available internal operating experience, and failed to adequately evaluate and correct the impact of engine vibrations on
flange JTR005 integrity, contributing to a subsequent failure of the
flange. (1R18
