Actinide Partitioning with a Modified TODGA Solvent: Counter-Current Extraction Studies with Simulated High Level Waste

Abstract

Actinide partitioning studies with improved N,N,N',N'-tetraoctyl diglycolamide (TODGA) solvent (0.05 M TODGA + 5% iso-decanol in n-dodecane) has been explored in order to achieve better decontamination from fission products. The distribution behavior of various metal ions, viz. Am, Pu, U, Eu, Sr, Pd, Cs, Tc, Fe, and Mo with improved TODGA solvent was investigated. Lower concentration of TODGA (0.05 M as compared to previously proposed 0.1 M or 0.2 M) exhibited required extraction properties for actinide partitioning from pressurized heavy water reactor high level waste (PHWR-HLW). Counter-current extraction studies with simulated PHWR-HLW spiked with different radio-tracers (viz. 241 Am, 152 Eu, 137 Cs, 85,89 Sr, 59 Fe, 106 Ru, 109 Pd, 95 Zr, and 99 Mo) suggested that > 99.9% of the trivalent actinides and lanthanides could be extracted in six stages and stripped in four stages. The decontamination factor for various fission products with respect to Am was: 3918 (Cs), 2990 (Sr), 1150 (Zr), 1407 (Ru), 1185 (Pd), and 3250 (Mo). The counter-current extraction studies with the irradiated solvent (500 kGy) reflected a significant amount of Mo extraction.

Benzene-centered tripodal diglycolamides: synthesis, metal ion extraction, luminescence spectroscopy, and DFT studies

“…n-Dodecane was used as the diluent in view of its process compatibility and 5% iso-decanol was used as the phase modifier. 8 Apart from the extraction of actinide ions such as Am 3+ , UO2 2+ , Pu 4+ , and PuO2 2+ , the extraction of fission product ions such as Eu 3+ , Sr 2+ , and Cs + was also studied to understand their decontamination behaviour. An attempt was made to understand the nature of the extracted species by luminescence spectroscopy and bonding of the metal ligand complexes by DFT calculations.…”

“…Et2O was bought from VWR and distilled before use. 4-Nitrophenyl 2-(2-(dioctylamino)-2oxoethoxy)acetate, 8 1,3,5-tris(2-aminoethyl)-2,4,6-triethylbenzene, 7 and 1,3,5-tris(3-aminopropoxy)benzene tristrifluoroacetate, 20 were prepared according to reported procedures. 241 Am, 233 U, and Pu (mainly 239 Pu) were taken from the laboratory stocks after suitable purification of the radiotracers.…”

Diglycolamide-Based Solvent Systems in Room Temperature Ionic Liquids for Actinide Ion Extraction: A Review

“…For radioactive waste management of high-level waste containing the hazardous minor actinides such as Am and Cm, TBP is not suitable and extractants such as CMPO, malonamides and DGAs have been successfully employed in laboratory-scale runs [23][24][25]. Out of these extractants DGA extractants such as TODGA (N, N, N′, N′-tetra-n-octyl DGA) have been found to be most efficient ( Figure 2) and several hot counter-current extraction runs have been reported with highly encouraging results [26][27][28].…”

Effect of irradiation on some actinide and fission product ions' extraction using several tetraalkyl diglycolamides

“…Moreover, it was interesting to note that with the exception of T2EHDGA, all the diglycolamide extractants showed reasonably high Am values (>10) even after exposing to 1000 kGy dose suggesting that the extractants have a good potential for process application and recycling possibilities are fairly good. We have recently reported the flow sheet for the counter-current extraction of actinide ions from tracer spiked simulated high level waste solution [28,29]. In those studies, 0.2 M HNO 3 was used as the strippant.…”