Bitte wählen Sie ihr Lieferland und ihre Kundengruppe
Two dimensional (r-theta) finite element analysis is used to calculate the thermal stress in complete fast reactor fuel pellets, completely cracked pellet segments and partially cracked pellet segments. The residual stress levels are used to assess whether further cracking is probable and linear-elastic fracture mechanics used to study crack propagation. The results of the analyses show that propagation of cracks with a circumferential component becomes increasingly probable as the pellet cracks into segments with smaller angles. By making simplifying assumptions for the degree of relaxation of stress and crack healing in pellets after prolonged irradiation, the number and orientation of cooling cracks is predicted. Included are cross sections of irradiated hollow and solid fuel pellets, subjected to different rating levels. (ERA citation 03:030839)