engleski

Fuel Handling Building Response to SFP Loss of Cooling

GOTHIC model of Fuel Handling Building (FHB) was developed for NPP Krsko. Simplified model of Spent Fuel Pool (SFP) is part of FHB model. SFP model includes control volumes with racks, transfer channel, and cask loading area. It is possible to plug more detailed SFP model (takes into account details of coolant natural circulation) into the same FHB model too, but that has negative influence on duration of calculation. SFP heat-up can be modeled with heaters having time-dependent forcing function to simulate decay heat, or heat source can be placed directly in fuel heat structure. In order to model response of FHB to loss of SFP cooling, up to the point when water level drops to top of active fuel, it is usually enough to use heater as a representation of decay heat. That way it is possible to calculate loss of water from the pool by evaporation and heat-up of FHB atmosphere. The temperature, pressure, and relative humidity are calculated in FHB rooms without and with depressurization panel that will be introduced as a part of plant’s safety upgrade project. Calculated thermal-hydraulic conditions in FHB rooms can be used in establishing environmental conditions for equipment qualification in the frame of equipment survivability program.

FHB, SFP heat-up, GOTHIC, equipment qualification

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