Decomposition of irradiated yttrium oxalate and CuO mixture

Influence of gamma -irradiation, (10-500KGy) on the thermal decomposition o f Y-2(C2O4)(3) + CuO (10 mol%) mixture has been studied in the temperature range, 603-643 K by gas evolution method. The alpha- t plots indicate that decomposition of unirradiated and irradiated mixture follows (i) initial ga s evolution, (ii) acceleratory period and (iii) decay stage. Irradiation pr omotes the initial gas evolution, alpha (i) and decreases the fractional de composition, alpha (i) at lower doses up to 50 KGy but the value increases at higher doses without affecting the nature of the isotherms. The data are analysed in the light of theories of various kinetic models and are found to be best fitted to Prout-Tompkins and Contracting Square mechanisms, sugg esting that nucleation takes place instantaneously in a chain branching man ner. The energy of activation of the acceleratory period is decreased but t hat of the decay stage is increased by irradiation. Plausible mechanism of decomposition and the effect of irradiation thereon has been discussed.