A numerical method for simulating the non-homogeneous irradiation effects in full-sized dispersion nuclear fuel plates

For full-sized dispersion nuclear fuel plates under heterogeneous irradiation conditions, the three-dimensional large deformation incremental constitutive relations and stress update algorithms are built for the homogenized fuel meat and cladding in the co-rotational coordinate frame with a location-dependent irradiation-hardening effect in the cladding involved. The user subroutines to define the location-dependent thermo-mechanical constitutive relations are correspondingly developed and validated. Numerical simulation of the thermo-mechanical behaviors in a non-uniformly irradiated fuel plate is correctly realized. The obtained results indicate that (1) both the volumetric swelling and temperature distributions show remarkable non-uniform characters; (2) the maximum thickness variation appears in the strongly irradiated location at lower burnup, and it is not the case at higher burnup; (3) at the initial stage a stress concentration area in the cladding exists in the constrained plate corner; and with increasing burnup the highest Mises stresses exist at the locations with an enhanced irradiation condition.