CFD investigation of PWR channel shapes effects during rolling motion under normal and accident condition

Thermal-hydraulic parameters of the floating reactor fluctuate constantly, which can endanger the safety fea-tures and make challenges for safety systems. The rolling motion has more effect on the thermal-hydraulic of the floating reactor between other six motions. In this study, the effect of fuel shape and heated channel shape on thermal-hydraulic parameters were evaluated along with analysis of the parameter value changes during rolling motion under normal and LOCA accident. Also, simulation of the rolling motion with the oscillating velocity is done. The cylindrical and rectangular fuel shapes, as well as hexagonal and square channel shapes, were compared. For modeling the rolling motion, an UDF program is developed for solving the related equations in CFD code. The results indicated that the rectangular fuel with the square channel has lower changes during rolling motion than the other two models, which can be considered as the main reason for choosing the plate or rectangular fuel types in the new floating reactors.