Solvent extraction behaviour of some fission product elements with N,N-dihexyl octanamide and tri-n-butyl phosphate under simulated PUREX process conditions

Summary

Extraction behaviour of some fission product contaminants like Zr(IV), RuNO(III), La(III), Ce(III) and Nd(III) with 1.1 M solutions of N,N-dihexyl octanamide (DHOA) and tri-n-butyl phosphate (TBP) in n-dodecane from nitric acid medium has been investigated under conditions prevailing in the PUREX process. Results of the study reveal that the extraction of Zr(IV), La(III), Ce(III) and Nd(III) with 1.1 M DHOA is significantly lower than that of TBP. However, the extraction of RuNO(III) with DHOA is of the same order as that with TBP. The influence of uranium(VI) saturation of the organic phase on the extraction of Zr(IV) and RuNO(III) is evaluated. The effect of degradation products of DHOA (caprylic acid/n-dihexylamine) and TBP (di-n-butyl phosphoric acid) on the extraction of Zr(IV) is also examined. The study indicates the innocuous nature of the degradation products of DHOA towards the extraction of Zr(IV) under the PUREX process conditions. This is unlike the degradation products of TBP, the presence of which produce noticeable increase in the extraction of Zr(IV).