Development of passive direct reactor auxiliary cooling system model in Liquid Metal Fast Breeder Reactor

Passive safety is a design concept for fast reactors. An analysis code to perform thermal-hydraulic calculation in passive Direct Reactor Auxiliary Cooling System (DRACS) was developed through the coupling of thermal-hydraulic response in Direct Heat EXchanger (DHX) model, Air Heat EXchanger (AHX) and circuits of DRACS. After steady-state initialization, a transient starting from air damper opening at the instant of reactor scram was simulated. Key parameters, such as mass flow rate in intermediate loop under natural circulation, heat removed by DRACS, air temperature at AHX outlet, coolant temperature at both side of DHX, are calculated, which preliminary showed the effectiveness of the code. As part of the system analysis code development for the pool-type Liquid Metal Fast Breeder Reactor (LMFBR), the newly developed code is now ready to be incorporated into System Analysis Code for pool-type Fast Reactor (SAC-CFR) to perform the interactive response between the DRACS and the whole system after scram.