An investigation of the Pu migration phenomena during irradiation in fast reactor

The phenomenon of radial plutonium migration in fast reactor MOX fuel is on e of the important performance issues. In this study, mechanisms of this ph enomenon were modeled for vapor transport concurrently occurring with therm al diffusion. Further improvement was modeled by accounting for the effects of the oxygen to metal ratio. Additionally, to evaluate more precisely the fuel temperature history during irradiation, the thermal conductivity in t he fuel-cladding gap was evaluated by including the thermal effects of fiss ion-product (FP) compounds. The calculated plutonium distribution in MOX fu el irradiation tests, with the linear heat rate (LHR) gradually decreasing with irradiation, agreed well with the measured data. improvement by consid ering the effect of the oxygen to metal ratio was considered to be effectiv e and indispensable for the evaluation of plutonium migration in the MOX fu el. (C) 2001 Elsevier Science B.V. All rights reserved.