Development of a complex method for the determination of actinoides

A combined radiochemical separation method has been developed that enables the simultaneous determination of ²³⁴U, ²³⁵U, ²³⁸U, ²³⁷Np, ^239,240Pu, ²³⁸Pu, ²⁴¹Am, ²⁴²Cm, and ²⁴⁴Cm in medium and low level liquid radioactive wastes. The main steps of the method are sample destruction, co-precipitation on iron(II)-hydroxide and calcium-oxalate, separation by extraction chromatography using supported dipentyl-pentyl phosphonate (UTEVA) and supported N,N-octylphenyl-di-i-butylcarbamoylmethyl phosphine oxide with tributyl phosphate (TRU), and α source preparation. The key parameter of the method is the adjustment of the oxidation states of the actinoides before adding the sample onto the UTEVA column. It has been determined that (NH₄)₂S₂O₈ can be used for oxidation state adjustment resulting sufficient chemical yields.