LAUSR

Abstract The U3Si2-SiC system is one of the most promising accident tolerant fuel/clad systems. In this paper, the potentiality of thermal safety and economy of the U3Si2-SiC system was further exploited based on the constant fuel assembly structure of the PWR. Increasing fuel rod diameter from 8.5 to 10.5 mm with the consideration of the design constraint, assembly level analyses of thermal hydraulics and neutron physic were conducted to evaluate the variation of thermal safety and economy. The neutronic analysis result shows that the fuel rod design with smaller pellet diameter can prolong the reactor lifetime and increase k-infinity. The thermal hydraulic analysis result indicates that the fuel rod design with smaller fuel rod diameter can obtain high departure from nucleate boiling ratio (DNBR) with an acceptable fuel temperature during normal operation and reactivity initiated accident (RIA). The fuel rod design with smaller fuel rod diameter has better thermal safety and economy.