Graphical and experimental determination of uranium, nitric acid, plutonium and some fission products in an LMOM2 extractor in modified scheme of the first extraction in the Purex process

For the selective separation of uranium from plutonium and fission products, the low acid extraction flow sheet has been proposed which was then proved on a countercurrent 16-stage laboratory extractor of mixer-settler type. Experimentally obtained distribution of macrocomponent concentrations (U, HNO3) agreed well with the distribution predicted on the base of McCabe-Thiele diagrams. Above 99% of plutonium, reduced with the help of iron(2), was found in the raffinate. The decontamination of uranium from Zr, Nb and Ru was lower, compared with plutonium. The concentration of ruthenium and plutonium in the extractor was observed. Accumulation of plutonium is not dangerous as concerns criticality, for spent fuels from thermal reactors. (author)