The effects of manufacturing uncertainties on the stresses in the TRISO-coated fuel particle

Tristructural-isotropic (TRISO) coated fuel particles are key components in the high-temperature gas-cooled reactor (HTGR) fuel elements, and their integrity is potentially important for the nuclear reactor safety. Many fuel performance models were established concerning the stress calculations of TRISO particles, however, some gaps remain in what specific role the particle geometry plays in the stress calculations. Therefore, analytic solution calculations were employed in the paper to evaluate the tangential and radial particle stresses under various cases. Eleven cases were studied accounting for the different dimensions of the kernel, buffer and the IPyC/SiC/OPyC coating layers as well as the variation of PyC density and anisotropy during the manufacturing processes. Subsequently, the geometry statistics was introduced in the pressure vessel model and the PyC-involved stress model to update the calculated stresses of TRISO particles. The present work determined an important role of the particle dimension variations in the stress calculations, which potentially provided a path to the optimization of the design and manufacturing processes of TRISO particles. (author)