Thermal and Hydrolytic Stability of Irradiated Tri- n -Butyl Phosphate

The dominant radiolytic transformation of tributyl phosphate is the elimination of butoxy and butyl groups with the formation of recombination (disproportionation and dimerization) products of the corresponding radicals. Radiolysis and post-radiation oxidation with nitric acid at temperatures up to 110°C make a comparable competitive contribution to the tributyl phosphate (TBP) degradation. Higher temperatures intensify the oxidation and degradation of radiolytic products with the formation of highly volatile compounds (up to 30 wt % at 150°C), which increases the fire and explosion hazard of irradiated TBP-based extraction mixture operations.