The team identified a Green non-cited violation of
10 CFR Part 50, Appendix B, Criterion III, Design Control, consisting of two examples. In one example, the licensee failed to verify the adequacy of
GE model TED
molded case circuit breaker (
MCCB) design. In the second example, the licensee failed to verify the adequacy of Eaton model HFB
MCCB design. The licensee initiated Action Request (
AR) 01929605 and
AR 193674193674 which determined the systems were
operable because upstream protective devices provided protection from a failed HFB and/or TED
MCCBs, and that the HFB and TED
MCCBs would be replaced with
MCCBs that have adequate ratings. The licensees failure to design the Class 1E electric system
MCCBs in accordance with
IEEE 308-1971 Sections 4.1 and 5.3.5 was a performance deficiency. The team determined that the performance deficiency was more than minor because it was associated with the Design Control attribute of the
Mitigating Systems Cornerstone and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to
initiating events to prevent undesirable consequences. The finding was determined to be of very low safety significance (Green) because the deficiency affected the design or qualification of a mitigating structure, system, or component (
SSC), but the
SSC maintained its operability or functionality. No cross-cutting aspect was applicable because the finding was not indicative of current licensee performance.
