CORRELATION BETWEEN ANNIHILATION OF RADIATION DEFECTS AND TRITIUM RELEASE IN NEUTRON-IRRADIATED LiAlO_2

摘要

The annihilation behaviors of radiation defects in neutron-irradiated LiAlO_2 were investigated by means of Electron Spin Resonance (ESR). It was found that the annihilation of radiation defects consisted of two processes, the fast and the slow processes. The activation energies of them were determined to be 0.14 ± 0.01 eV and 0.58 ± 0.01 eV, respectively. The F~+-center was found to act as a trapping site of tritium by comparing its annihilation behavior with that of tritium release. Taking the results obtained in the present and the previous works in consideration, it can be said that the annihilation process of oxygen vacancies is of very important because tritium release from the bulk of a breeder starts just after the slow annealing process becomes dominant. Therefore, to understand the slow annihilation process of radiation defects is an important key to clarify the mechanism of tritium release from ceramic breeder materials.