The inspectors identified a Green finding for the licensees failure to update calculations as required by procedure AD-EG-ALL-1117, Design Analyses and Calculations, Rev. 5. Specifically, the licensee revised calculation MCC-1381.05-00-0258, U1, 6.9kV,
4.16kV &
600V Auxiliary Power Systems Safety-Related Voltage Analysis, Rev. 6, to identify the effect of longer motor-driven
auxiliary feedwater pump (CA pump) acceleration times on the
switchyard voltage limits in place to ensure offsite power source operability. However, the licensee failed to update the previously analyzed condition of only one
offsite circuit in service from the
switchyard to the 4160V Class 1E buses via the unit step-up and unit auxiliary transformers (single busline alignment). As a result, there was no verification that the
offsite circuit operability limit was adequate during single busline alignment
