Current status and future development of coated fuel particles for high temperature gas-cooled reactors

The coated particles were first invented by Roy Huddle in Harwell 1957. Through five decades of development, the German UO2 coated particle and US LEU UCO coated particle represent the highly successful coated particle designs up to now. In this paper, current status as well as the failure mechanisms of coated particle so far is reviewed and discussed. The challenges associated with high temperatures for coated particles applied in future VHTR are evaluated. And future development prospects of advanced coated particle suited for higher temperatures are presented. According to the past coated fuel particle development experience, it is unwise to make multiple simultaneous changes in the coated particle design. Two advanced designs which are modifications of standard German UO2 coated particle (UO2∗ herein) and US UCO coated particle (TRIZO) are promising and feasible under the world-wide cooperations and efforts.