Development of a Thermal-Hydraulic Code for Chinese Helium-Cooled Ceramic Breeder TBM Cooling System

Helium was chosen as the coolant for divertor cooling loop, Korea helium cooled solid breeder TBM, European helium cooled pebble bed TBM and Chinese helium cooled ceramic breeder TBM. The thermal-hydraulic analysis for the divertor cooling loop and the TBM cooling systems were carried out by RELAP5 and MELOCR codes, which were developed for transient simulation of light water reactor coolant system during postulated accidents. In this study, a thermal-hydraulic and safety analysis code (TSACO) for helium cooling system was developed and calculation of the Chinese HCCB TBM cooling system was presented. Heat transfer and flow friction models for helium were added in the code. First, the code was verified by comparing with the RELAP5 code with the same initial and boundary conditions. The first wall temperature, pressure drop and inlet/outlet temperatures were studied and a good agreement was obtained, then ex-vessel loss of coolant accident for Chinese HCCB-TBM cooling system was investigated using TSACO. The results show that the TBM can be cooled efficiently and the TCWS pressure stays within the design limits with a large margin.