The axial migration behavior of cesium was investigated in two kinds of axially heterogeneous (U, Pu)O2 fuel pins with different configurations of internal blanket position irradiated to $ ̃70 GWd/t. The axial distribution of cesium was measured nondestructively by a γ-ray intensity scanning and destructively by an electron probe microanalyzer. A reasonably good agreement between the experimental and analytical results was obtained by applying a model based on a two-stage process proposed by Adamson. The radial distribution could be explained by assuming a rapid migration down temperature gradient within the solid fuel. The evaporation-condensation process not only across the pellet-pellet interfaces, but also across cracks played an important role in the axial migration.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- Materials Science(all)
- Nuclear Energy and Engineering