On August 21, 2010 an inspection of the Air Intake Tunnel (
AIT)
sump identified missing flood barriers needed to protect safety related equipment in the plant. If enough flood water had entered into the
AIT, water could have entered into the Auxiliary Building (
AB) through the ventilation ductwork that connects the
AIT and the
AB. If flood water continued to enter the
AB, then safety related equipment in the
AB could have been affected.
This condition could have resulted in the unavailability of equipment in the Auxiliary Building including the 1A and 1B Decay Heat pumps, the 1A and 1B Building Spray pumps and 1A, 1B and 1C Make-up Pumps. This is reportable as an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> ENS notification under 10CFR50.72(b)(3)(v)(B) and 10CFR50.72(a)(1)(ii) as a condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to remove residual heat.
Flood protection barriers have been established for the affected penetrations. Inspections of the flood protection barriers are ongoing. Further engineering review is being performed to determine the impact of the potential water intrusion into the AIT and AB.
The licensee notified the NRC Resident Inspector. The licensee will notify the Pennsylvania Bureau of Radiation Protection.
- * * RETRACTION FROM MICHAEL FITZWATER TO JOHN SHOEMAKER AT 1437 EDT ON 10/19/10 * * *
EN# 46194 made on August 21, 2010 at 1100 EDT is being retracted. Upon further Engineering review it was determined that the external flood barrier design deficiency in the Air Intake Tunnel (AIT) did not result in a condition that could have prevented the fulfillment of the safety function needed to remove residual heat. The AIT sump pump is in the cavity that had the degraded barrier where the in leakage of concern enters through conduits from yard electrical vaults. This pump starts automatically and has capacity in excess of the in leakage during the Probable Maximum Flood (PMF). The AIT sump pump's functional capability was confirmed to be available over the past three years. Therefore the ability to prevent flood water from the AIT reaching and impacting safety related equipment needed to remove residual heat was maintained. The event is therefore NOT reportable.
The Licensee has notified the Resident Inspector.
Notified R1DO.
