Updated solution for stresses and displacements in TRISO-coated fuel particles

A closed-form solution for stresses and displacements in TRISO-coated fuel particles of a high temperature reactor has been updated to enhance its application in fuel particle analysis. The modified solution is applied incrementally through irradiation, which allows the material properties and irradiation temperature to change with time. It also removes the restriction in the original solution that Poisson’s ratio in creep for the pyrocarbon layers be set to 0.5. It is presented in a manner that would enable its application to a system of any number of coating layers, not just the three layers of a TRISO-coated particle. The solution has been implemented in the PARFUME fuel performance code, where it has been demonstrated to perform efficiently in particle failure probability determinations.