A Decay Heat Removal System Design of the Prototype Sodium-cooled Fast Reactor

The decay heat exchangers (DHXs) are located in the cold pool and 4MWt (1% of the rated core thermal power) has been decided as the decay heat removal capacity. There are 4 DHRS loops composed of 2 Active DHRS (ADHRS) loops and 2 Passive DHRS (PDHRS) loops. Each loop has 1MWt heat removal capacity. There are three heat transport paths in the DHRS, i. e., a Primary Heat Transport System (PHTS) path including the DHX shell-side sodium flow, a DHRS sodium loop path through the piping, an air flow path through the sodium-to-air heat exchanger shell-side. To design the components of the DHRS and to determine its arrangement, key design parameters such as mass flow rates of the three paths, inlet/outlet temperatures of primary and secondary flow sides of each heat exchanger have to be determined reflecting the coupled heat transfer mechanism over the heat transfer paths. As a preliminary design work, design parameters of the DHRS have been calculated and thermal sizing of the DHRS components has been conducted. A design point has been calculated for the DHRS design of 150MWe prototype SFR. Based on the design point, thermal sizing of the DHRS components and the DHRS arrangement has been carried out