The preparation and performance of graphene oxide-doped UO2 pellets

Subjects: Nuclear Science and Technology >> Nuclear Materials and Techniques submitted time 2024-03-25

WEN Feng DU Jiangping ZHAO Yumeng YANG Ning SHAO Zongyi LIU Wei CAI Zhenfang

Abstract： Background : Uranium dioxide (UO₂) has been broadly employed as nuclear fuel in nuclear reactors. The poor thermal conductivity of UO₂, however, reduces the safety of the reactor due to possible sharp temperature gradients. Graphene oxide (GO) is a kind of promising additive to improve the thermal conductivity of UO₂ for its excellent thermal performance. Purpose : This work aimed at achieving uniform distribution of GO in UO₂ pellets, effectively controlling the doping amounts, and finally enhancing the thermal conductivity of UO₂ pellets. Methods : GO-doped UO₂ powders with different doping amounts were prepared by solid-liquid mixing method and ammonium diuranate (ADU) co-precipitation method. After selecting the optimized powdering process, the UO₂-GO composite fuel pellets were prepared by spark plasma sintering (SPS). The properties of the UO₂-GO composite fuel pellets, such as density, grain size, physical phase, thermal conductivity, etc., were examined and compared with that of the conventional pure UO₂ pellets. Results : The results showed that the density of UO₂-GO pellets could reach up to 97.6% T.D. The thermal conductivity of UO₂-GO pellets with 1.5 wt. % doped GO was 85.9% higher than that of conventional UO₂ pellets at 1000 ℃. The grain size of the UO₂-GO pellets was uniform, and the GO was homogeneously distributed at the grain boundary to form a bridging thermal conduction network. Conclusions : The thermal conductivity of the UO₂ pellets was successfully improved through GO doping.

Peer Review Status:Awaiting Review

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