The Behavior of fission products in irradiated mixed oxide/nitride fuel under transitional heating conditions

Sato, Isamu

In the sphere of safety research of atomic power plants, it's of value to evaluate "source term" of radioactive species released into the environment during atomic reactor accidents. The high level accuracy is needed for the source term in points of safety and economic views. Especially, there are no experimental source term data for irradiated FR fuels under the temperature over the melting point of fuels and at rapid heating rate. Therefore, the experimental data for LWR fuels have been applied for the source term evaluation of FRs with some conservative assumptions. FP behavior in irradiated mixed nitride fuel with high FP gas entrapment function and high thermal conductivity and the material properties have been studied with the equivalent heating tests and a molecular orbital method, respectively. These results contributed to the source term evaluation and the swelling behavior related to the scenario during re-criticality of FRs.