Evaluation of EBR-II Driver-Fuel Elements Following an Unprotected Station Blackout Accident

摘要

One of the current design objectives for a liquid metal reactor (LMR) is the inherent shutdown-cooling capability of the reactor, such that the reactor itself can safely reduce power following a total loss of pump power without activating the reactor shutdown system (RSS). Following a loss-of-flow (LOF) accident and a failure of RSS, in EBR-II, reactor core damage and plant restartability is of considerable interest. In the LOF event, high temperature in the reactor causes negative reactivity feedback that reduces reactor power. After an accident, reactor fuel performance is one of the factors used to assess the restartability of the plant. A thermal-hydraulic-neutronic analysis was performed to determine the response of the plant and the temperature of individual subassemblies. These temperatures were then used to assess the damage to driver fuel elements caused by the station blackout accident. The maximum depth of cladding wastage from molten eutectic at temperatures >715 deg C was found to be 0.0053 mm for the hottest subassembly; this value is considerably less than the 0.28 mm cladding thickness. 12 refs. (ERA citation 11:019957)