Studies on the use of N,N,N′,N′-Tetra(2-Ethylhexyl) Diglycolamide (TEHDGA) for Actinide Partitioning II: Investigation on Radiolytic Stability

N,N,N',N'-tetra(2-ethylhexyl)diglycolamide (TEHDGA) was found to be a promising extractant for actinide partitioning from high-level waste (HLW) (Part I). In order to evaluate the applicability of TEHDGA to the HLW partitioning process, investigations on its radiolytic stability were carried out. The present work deals with the studies on the uptake of americium by -irradiated 0.2 M TEHDGA/n-dodecane in the absence and presence of phase modifiersdi(n-hexyl)octanamide (DHOA), isodecanol and n-decanolagainst the absorbed dose up to 1 x 106 Gy in the presence of nitric acid at varying concentrations. The addition of phase modifiers suppressed the radiolysis of TEHDGA in n-dodecane and DHOA was found to be the most effective radiolysis suppressor. Investigations were also carried out on the degradation of neat TEHDGA by -irradiation, and it was attempted to isolate and identify its degradation products by instrumental analysis. The radiolysis study showed that the degradation products were formed by the cleavage of the -C-N bond, to eliminate an ethylhexyl group, and the bond adjacent to the ether bond. The results obtained for TEHDGA radiolysis were compared with that of its straight-chain isomer TODGA, and TEHDGA was observed to be more resistant to radiation than TODGA. The changes in the physico-chemical properties of -irradiated TEHDGA against the absorbed dose were also investigated.