Journal of Nuclear Fuel Cycle and Waste Technology

The dynamic release behavior of Cs from high burn-up spent PWR fuel was experimentally performed under the conditions of a thermal treatment process such as voloxidation and sintering conditions. In voloxidation process, influence of the oxidation and reduction atmosphere on the Cs release characteristic using fragment type of spent fuel heated up to 1,500 ℃ was compared. In sintering process, temperature history effect on Cs release behavior was evaluated using green pellet under 4% H2/Ar environment. Temperature range for complete Cs release from spent fuel fragment under voloxidation condition was about 800℃ ~ 1,200℃, but that of green pellet under the reduction atmosphere was 1,100 ℃ ~ 1,400 ℃. Key parameters on Cs release behavior from spent fuel was powder formation as well as the diffusion rate of Cs compound to grain boundary and fuel surface.

Keywords

DUPIC,Spent fuel. Green pellet,Voloxidation,Sintering,Semi-volatile fission product,Cesium,Fractional release percent