Title
10 CFR 50, Appendix B, Criterion III, Design Control, requires, in part, that measures shall be established to assure that applicable regulatory requirements and the design basis for those structures, systems, and components to which this appendix applies are correctly translated into specifications, drawings, procedures, and instructions. Contrary to this requirement, the licensees calculation of record for a
feedwater HELB break at the
feedwater pumps was not correctly translated into procedures to mitigate flooding. The lack of timeliness requirements in flood mitigation procedures would have resulted in potentially rendering the Division I
4kV switchgear
inoperable. This issue was documented in the licensees corrective action program as
CAP 01136111. The finding is of very low safety significance because the
HELB frequency for the Monticello plant is significantly below the level required to result in a
CDF increase of 1.00 E-06/year for the scenario of interest.
