At 1009 (all times MDT) today, 11/3/11, a Security Officer performing routine rounds noted 95-100% blockage on the inlet screens at the Fort St. Vrain Independent Spent Fuel Storage Installation (FSV
ISFSI). The FSV
ISFSI is located near Platteville,
Colorado. The FSV
ISFSI safely stores used fuel from the Fort St. Vrain Nuclear Generating Station (FSV NGS). The NGS has been decommissioned and released for unrestricted use. The fuel is stored at the
ISFSI under NRC license SNM-2504. The inlet screens are in place to provide a cooling path for the used fuel.
The Security Officer immediately notified the Emergency Coordinator, who directed the screens to be cleared of the blockage at 1010. The blockage was removed at 1021, at which time the event was terminated. The blockage was caused by frost, which built up due to dense fog, high humidity, and low temperatures. Removal was accomplished by lightly hitting the screens by hand. No further action is necessary.
Per FSV ISFSI Limiting Condition for Operation (LCO) 3.1, inlet screen blockage which equals or exceeds 95 percent must be cleared within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The blockage was cleared in 12 minutes. Thus the REQUIRED ACTION was satisfactorily completed, and the CONDITION was exited.
Per the FSV ISFSI Emergency Plan Implementing Procedure (EPI)-102, Emergency Action Level 1NE.6, 95% or greater blockage of the inlet screens constitutes a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> NON-EMERGENCY event. Required notifications were made by the Warning Communications Center (WCC) in Idaho.
There was no increase in building temperature during this event.
