Neutronic thermal-hydraulic coupling analysis for PT-SCWR-reactor core

According to the pressure tube supercritical water reactor (PT-SCWR) new 62-element design, the power density and the fuel temperature, coolant density/temperature are coupled. Neutron physics analysis code (WIMS-AECL) and sub-channel analysis code (ATHAS) are used to optimize the design. The results show that the coupling method is effective. The results indicate that the maximum cladding surface temperature of the bundle and the coolant outlet temperature are lower than the design limits. So the scheme meets the design objectives. We can adjust the fuel enrichment from 5% to 5.5% and 4.6%, adjust the fuel assembly pitch circle of the inner bundle from 5.30 cm to 5.175 cm to obtain a uniformity temperature distribution. By comparing the moderator temperature coefficient and void coefficient under different pitch, we obtained an optimum pitch of 21 cm. (authors)