Formation and properties of radiation-induced defects and radiolysis products in lithium orthosilicate

Abstract

Formation and properties of radiation-induced defects and radiolysis products in polycrystalline powders and ceramic pellets of Li 4SiO 4 were studied under the effect of various types of ionizing irradiation (γ quants, accelerated electrons, reactor irradiation), humidity, temperature, impurities in the samples, etc. The content of radiation defects and radiolysis products poorly depends on irradiation type, dose rate, admixture elements. The concentration of defects highly depends on the temperature of irradiation, humidity, granural size. Empirical dependence of radiolysis degree α on the dose was found: α = 5 × 10 −2 × D 0.5 for γ and electron irradiation ( T rad = 300−350 K) and α = 5 × 10 −3 × D 0.5 for reactor radiation ( T rad = 700–800 K); α - matrix dissociation degree (in %); D - dose (in MGy). Colloidal litium and silicon, lithium and silicon oxides, and O 2 are the final products of radiolysis. Radiation-induced defects change tritium thermo-extraction parameters, deteriorate mechanical, thermo-physical and electric properties of ceramics.