Dynamic tests of cesium-137 recovery from the Mayak model alkaline HLW using <i>p</i>-isononylcalix[6]arene based extractant

The article presents the results of studies on composition optimization, properties, and laboratory dynamic tests of extraction mixtures based on p-isononylcalix[6]arene for the alkaline HLW purification to remove 137Cs. The distribution of 137Cs among the products of the technological scheme is presented and the coefficients of raffinate purification to remove 137Cs are determined. It was revealed that, in the case of using nitric acid as a stripping solution, nitrosation of p-isononylcalix[6]arene is possible in the technological process. The composition of the resulting product was determined. To prevent nitrosation of p-isononylcalix[6]arene, formic acid was used in the stripping stage, which ensured stable operation of the extraction stand for 48 h with 137Cs extraction from model alkaline HLW at a level of 99.7%.