New approaches to the separation and concentration of americium in high oxidation forms for the fractionation of high-level waste

Abstract

The separation of americium during the fractionation of a highly active raffinate obtained in the extraction processing of spent nuclear fuel represents an urgent task of the contemporary nuclear fuel cycle. The article discusses new approaches to this task. It is shown that a sodium bismuthate powder (NaBiO₃), upon contact with a solution of Am (III) and Cm (III), oxidizes Am (III) to Am (VI) and sorbs actinides. The addition of a (NH4)₂CO₃ solution results in a content of up to 91% of americium and about 2% of curium in the solution after desorption. The behavior of americium and curium in acidic and alkaline solutions of potassium hexacyanoferrate (III) was studied. In acidic solutions of HNO₃, americium and curium are precipitated, while praseodymium, comprising a lanthanide simulator, remains quantified in the supernatant. In alkaline solutions of potassium hexacyanoferrate (III), ~50% of Am (III) is shown to oxidize to Am (V). The obtained results can be used as a basis for a new technology of separating americium from curium and lanthanides for the purposes of americium transmutation.