In-situ fabrication of dispersion nuclear fuel pellets with a core-shell structure

Highlights: • The fuel pellet with a core-shell structure was designed by an in-situ process. • The relationship between the shell thickness and mixing parameters were studied. • An empirical formula for the shell thickness and mixing parameters was established. - Abstract: Using the segregation phenomenon of different materials in the mixing process, the dispersion nuclear fuel pellet with a core-shell structure was firstly designed and fabricated by an in-situ preparation process. This core-shell structure could prevent the metal matrix from reacting with water to generate hydrogen, which improves the safety property of the pellet. Furthermore, it provides a perspective on integrated manufacture of pellets and claddings by one-step preparation. Effects of mixing process parameters on the shell thickness were investigated in detail. The results indicate that: a three-quarter cycle sinusoid could be used to describe the change in shell thickness with rotational speed; and there is a negative linear relationship between shell thickness and volume percentage of ZrO₂ microspheres; the shell thickness increases as the particle size difference of ZrO₂ microspheres/glass beads increases. What's more, an empirical formula describing the relationship between the shell thickness and these parameters has been established.