Influence of irradiation and metal nitrates on the reactive thermal hazards of tributyl phosphate

Abstract

Tributyl Phosphate TBP is widely used as a solvent for the extraction of uranium and plutonium from the irradiated spent fuel solution in fuel recycling Presence of TBP in aqueous streams poses problems when subjected to evaporation in fuel recycling in the presence of nitric acid and metal nitrates It was reported that an organic layer called Red oil formed as a result of the reactions at elevated temperatures between TBP diluent and radiolytic degradation products Tributyl phosphate and its degradation products at temperatures above 130 oC lead to runaway reaction associated with the formation of red oil followed by rapid pressurization and violent explosion Gordon et al 1994 Accidents in recycling plants are reported to be associated with the formation of red oil Incidents caused by red oil phenomena in semi scale and industrial radiochemical units were analyzed to ascertain the causes and simulate the consequences Since 1957 several accidents involving TBP have been reported Among those reported incidents Savannah River 1953 and Tomsk newline1993 were the major accidents In many of them TBP with its degradation products metal nitrates from nitric acid and heavy metals were involved It was reported in the past that acid strength concentration of metal nitrates irradiation dose and temperature were the factors for red oil formation newline newline