Radiation chemical behavior of aqueous butanal oxime solutions under alpha irradiation

Abstract : Context Hydrazinium nitrate is a compound used in industry to avoid nitrous acid accumulation during the liquid-liquid separation of uranium and plutonium (PUREX). Now, hydrazinium nitrate is a CMR (Carcinogenic, Mutagenic, or toxic to Reproduction) compound and its use has to be reduced according to the European REACH directive of 2007. Moreover, hydrazinium nitrate is not extracted in the organic phase. Then it induces an accumulation of nitrous acid in this medium due to its partition between the two phases. It leads to an over-consumption of the Pu reducer, U(IV), due to the reoxidation of plutonium (III) to plutonium (IV) by HNO$_2$ in the organic phase. Numerous substitutes to hydrazinium nitrate have then been considered to find a compound which quickly reacts with HNO$_2$ and which can be partly extracted by TBP. The aim of this study is actually to investigate the behavior of these potential substitutes under irradiation. As a result of previous investigations, butanal oxime has been selected as potential substitute to hydrazinium nitrate in the PUREX process.