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Development of the Diamex Process for Treating PHWR High-Level Liquid Waste

Journal Article · · Nuclear Technology
OSTI ID:20826786

The extraction behavior of actinides like U(VI), Pu(IV), and Am(III) as well as of fission products like Tc(VII), Zr(IV), Eu(III), and structural material Fe(III) using nitric acid/simulated pressurized heavy water reactor-high-level waste solution as aqueous phase and N,N'-dimethyl-N,N'dibutyl tetra decyl malonamide (DMDBTDMA) in n-dodecane as solvent was investigated. The present work contributes significantly toward the development of nonphosphorous (environmentally friendly) extractant capable of partitioning long-lived actinides and fission products like {sup 99}Tc from relatively short lived fission products like {sup 90}Sr and {sup 137}Cs as well as inactive components present in high-level waste. The D{sub Am} values determined in the temperature range between 15 and 45 deg. C showed a gradual decrease with increase in temperature throughout the acidity range. The effect of N,N di-2-ethylhexyl acetamide (D2EHAA) as phase modifier on the physicochemical properties of DMDBTDMA/n-dodecane solvent was investigated and could be correlated with parameters like the limiting organic concentration value of HNO{sub 3}, D{sub Am}, or phase disengagement time. Overall comparison of diamide extraction (Diamex) and transuranium extraction (Truex) solvents has been made.

OSTI ID:
20826786
Journal Information:
Nuclear Technology, Journal Name: Nuclear Technology Journal Issue: 3 Vol. 139; ISSN 0029-5450; ISSN NUTYBB
Country of Publication:
United States
Language:
English