Tributyl phosphate irradiation

The effect of irradiation on the extractability of sulfoxides towards plutonium, uranium and some fission products were studied by Subramanian and coworkers . They studied mainly the effect of irradiation on dihexyl sulfoxide (DHSO) and found that irradiation did not change the distribution coefficient for Ru, Eu and Ce but increases the distribution coefficient for Zr and Pu. When comparing DHSO and tributyl phosphate (TBP), the usual solvent for the recovery and purification of plutonium and uranium from spent nuclear fuels, the effect of irradiation to deteriorate the extraction capability is much larger in TBP. Lan and coworkers studied diphenyl sulfoxides as protectors for the gamma radiolysis of TBP. It was found that diphenyl sulfoxide can accept energy from two different kinds of excited TBP and thus inhibits the decomposition of the latter. 

Fedosev, D.A., Artemova, L.A., Romanovskaya, I.A., Dunaeva, M.Y., Vladimirova, M.V. 1996. Radiation-chemical behavior of plutonium in the 30% tributyl phosphate + -do-decane system under conditions of repeated y-irradiation and regeneration of extractant. Radiochemistry 38(1) 78-80. (Translated from Radiokhimiya 38(1) 84—87.)... 

Wu, J.L., Fu, Y.X., Wang, W.Q. 1984. Energy transfer kinetics in irradiated tributyl phosphate to diphenyl sulfoxide and methyl isobutyl ketone. Radiat. Phys. Chem. 23(5) 601-606. 

The Acid-Thorex process has been used in recent years to recover 233U from neutron irradiated thoria targets. (] M This process uses n-tributyl-phosphate (TBP) in normal paraffin hydrocarbon (NPH) as the extractant and the relative uranium and thorium solubilities in each phase are adjusted by control of the nitric acid concentration. The Acid-Thorex process is the primary candidate for use in proposed aqueous thorium fuel cycles. In this process, uranium is separated from thorium through exploitation of the difference in equilibrium distributions since no usable valence change is available to aid in this separation. 

The principle of the Purex process, now commonly used for processing irradiated uranium by solvent extraction, is illustrated in Fig. 1.18. The solvent used in this process is a solution of tributyl phosphate (TBP) in a high-boiling hydrocarbon, frequently n-dodecane or a mixture of similar hydrocarbons. TBP forms complexes with uranyl nitrate [U0i(N03)2] and tetravalent plutonium nitrate [Pu(N03)4] whose concentration in the hydrocarbon phase is higher than in an aqueous solution of nitric acid in equilibrium with the hydrocarbon phase. On the other hand, TBP complexes of most fission products and trivalent plutonium nitrate have lower concentrations in the hydrocarbon phase than in the aqueous phase in equilibrium. 

Tributyl phosphate (C4H,)3P04 Uranium purification and irradiated fuel Purex... 

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