Preparation Of UO₂/Mo Dispersed Nuclear Fuel

Dispersed nuclear fuel,as the most important type of fault-tolerant fuel,is a fuel obtained by uniformly dispersing fuel phase particles containing fissile materials in a non-fissile matrix phase with excellent performance.In particular,the performance of dispersive nuclear fuel using molybdenum as a dispersive medium is more excellent.Molybdenum has ultra-high thermal conductivity and high melting point,and is also an alternative material for accelerator subcritical systems(ADS).However,there are a series of challenges in the preparation of this kind of dispersed nuclear fuel,including the interfacial compatibility of nuclear fuel microspheres and the dispersion medium,and the fault tolerance of nuclear fuel pellets.The traditional preparation method of dispersed nuclear fuel is to directly disperse the nuclear fuel microspheres in an inert medium,but due to the difference between the physical properties of the two materials,the interface between the nuclear fuel microspheres and the dispersion medium is not very good during the high-temperature sintering process Ground fusion,gaps occur,so that the thermal conductivity of the entire pellet decreases.In this paper,the surface of the nuclear fuel microspheres is electrically modified so that the nanoparticles of the dispersion medium are adsorbed on the surface of the fuel microspheres under the action of electrical gravity,and then the nuclear fuel microspheres and the dispersion medium with the dispersion medium nanoparticles adsorbed on the surface The mixing has improved the compatibility of the interface between the nuclear fuel microspheres and the dispersion medium,and also improved the thermal conductivity of the nuclear fuel pellets.The dispersive nuclear fuel composed of a metal matrix such as molybdenum has the most excellent performance,but under accident conditions,the metal material will react with water vapor to generate hydrogen,which greatly reduces the safety of nuclear fuel pellets.In response to this problem,this paper discusses a new method to achieve the core(U3O8-Mo-SiC)-shell(SiC)structure by using the segregation phenomenon of particles with different densities and sizes mixed in a three-dimensional rotating mixer In-situ preparation of dispersed nuclear fuel pellets.This research helps to reduce the reactivity of dispersed nuclear fuel with metal as the dispersing medium to water vapor under accident conditions,and improve the fault tolerance of nuclear fuel.