Hydrothermal synthesis of uranium dioxide and graphene composite and its application as an additive for uranium-dioxide-based accident tolerant fuel.

A novel kind of composite constructed by uranium dioxide and reduced graphene oxide (RGO) was developed via a one-step hydrothermal reduction method, named as UO 2 @G. The introduction of graphene oxide (GO) to the reaction system brought significant changes: in the control experiment without GO, the reductant of ethylenediamine itself could only reduce uranyl ions to mainly U 3 O 8 , and the final solid products appear in the form of flakes; by introducing GO to the system, the final products are pure UO 2 in homogenous nanospheres. By employing UO 2 @G as an additive in the UO 2 fuel pellet (the final volume ratio of graphene materials was controlled to be around 10%), the thermal conductivity is increased by 35.4%, which is significantly higher than that of the pellet prepared by simply mixing UO 2 powders and commercial graphene nanosheets. The simulation results show that the core temperature of the pellet containing the UO 2 @G composite additives is much lower than that of the one without UO 2 @G composite additives, showing the potential as novel kind of accident tolerant fuel. A novel composite constructed by UO 2 nanospheres and RGO sheets is prepared from uranyl and GO dispersion via a hydrothermal reaction. The two components distribute in each other homogenously. When using as additive in UO 2 ATF, the composite shows more obviously enhancing effect on the thermal conductivity by help RGO sheets distribute in the UO 2 ceramic matrix. [Display omitted] [ABSTRACT FROM AUTHOR]