Effect of flow distribution in reactor on thermal hydraulics of reactor

Coolant flow in the primary loop of reactor depends on the driving force, which is supplied by the density difference of coolant in primary loop for the reactor with natural circulation. Because of the limited driving force of the natural circulation loop in reactor, flow distribution in reactor core is closely related with thermal safety, and a good match between core flow distribution and power distribution in reactor core is helpful for the promotion of thermal-hydraulic design. The expected flow distribution can be contrived by the reasonable resistance arrangement of core inlet in reactor design. A core flow distribution optimization code coupled with the sub-channel analysis code was developed and introduced, and a case was selected to have an optimization analysis of core flow distribution with the code in this paper. The results show that the outlet coolant temperature difference of the assembly flow channels could be effectively reduced by the optimization of core flow distribution, the thermal safety margin is increased, which is helpful for the promotion of thermal-hydraulic safety in reactor design. (authors)