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On May 17, 2006, during the performance of an electrical engineering circuit evaluation of certain Appendix R fire scenarios, it was discovered that a previously unevaluated failure mode potentially existed for the Charging Pumps. Certain fire scenarios occurring in the Control Complex, Cable Tunnel, or Auxiliary Building, could result in the failure of specific under- voltage protection circuitry. The failed circuitry could trip the "A" Charging Pump breaker and hold it in a tripped condition. A similar condition existed for the "B" Charging Pump breaker, during certain fire scenarios in the "A" Battery Room. The safety significance of this event was reviewed and determined to be of low risk significance.

This report is being made under 10CFR50.73(a)(2)(ii)(B).

Corrective action to address the failure mode is outlined in Section V.