Basic study of influence of radiation defects on tritium release processes from lithium silicates

The radiolysis of Li2SiO3 and Li4SiO4 was studied using the chemical scavengers method (CSM), thermoluminescence, lyoluminescence, electron spin resonance and spectrometric methods. The influence of the absorbed dose and many another parameters such as: irradiation conditions, sample preparation conditions and concentration of impurities on the accumulation rate of each type RD and RP were studied. Several possibilities for reducing the radiolysis of silicates were discussed. It has been found that tritium localization on the surface and in grains proceed by two different mechanisms. Tritium thermoextraction from the surface proceeds as chemidesorption of tritiated water, but from the bulk as diffusion. The tritium retention processes were studied. It has been found that tritium retention depends on irradiation conditions. Tritium retention is due to the formation of chemical bonds Li-T and thermal stable =Si-T bonds. The accumulation of colloidal silicon and lithium can increase the tritium retention up to 25-35%. (C) 1997 Elsevier Science B.V.