Investigation of dog-boning & fishtailing defects in plate type dispersion fuel Rolling: Insights from finite element analysis and defect minimization techniques

In recent decades, there have been global efforts to replace high-enriched (>= 90 % 235U) low-density UAlx dispersion fuels with high-density, low-enrichment (<= 20 % 235U) alternatives. This transition is driven by initiatives such as the Reduced Enrichment for Research and Test Reactors (RERTR) program, which aims to develop low-enriched uranium fuels for research and test reactors. Notably, the successful implementation of this initiative globally involves the utilization of higher-density like U3Si2 dispersion fuels, which typically contain 40-55 % fuel in the fuel meat.However, the fabrication of these heavily loaded plates necessitates specific considerations to prevent the occurrence of defects such as dog-boning and fishtailing. In this regard, finite element analysis has been conducted to investigate the rolling process of these fuels and gain insights into these aspects. This article comprehensively explains the various elements of finite element analysis, including the FE model, material model, element type, FE solver, and analysis results. The simulations encompass both hot and cold rolling passes.Furthermore, the article elucidates the factors contributing to the formation of defects like dog-boning and fishtailing in the fuel. Based on the analysis, valuable suggestions are provided for structural design and manufacturing processes to mitigate these defects during fuel fabrication. By incorporating these recommenda-tions, the fuel design can be significantly improved, resulting in higher burnup potential.Overall, this study sheds light on the crucial role of finite element analysis in understanding the rolling process of U3Si2 dispersion fuels and offers practical insights for reducing manufacturing defects. Implementing the proposed suggestions will lead to the development of better-designed fuels with enhanced burnup capabilities.