Absorption study of Am and Cm to TEVA, TRU and DGA resins

Full text: It has been generally assumed that Am and Cm retention behaviour on extraction chromatographic resins like TRU and DGA are sufficiently similar in order to allow the use of Am-243 as internal standard for Cm without additional yield correction. However recent results from intercomparison exercises (PROCORAD, NPL) showed that, depending on the separation method used, biases of up to 50% for the Cm results can be found. Unfortunately there is a distinct lack of data on the extraction behavior of Cm on TRU and DGA that might help identifying conditions under which Cm extraction behaviour significantly deviates from the behavior of Am. The aim of this study is the determination of the k' values of Am and Cm under varying conditions frequently found in separation methods used for the determination of Am and Cm. The evaluated conditions included, amongst others, various HCl and HNO3 concentrations, the presence of anions such as phosphate and cations like Al, Fe(II) and Fe(III). The results obtained will allow identifying conditions under which Am and Cm do not behave similarly and that are thus most probable to cause the bias between Am and Cm yields. This information will allow laboratories performing Am and Cm analysis to evaluate if their currently used protocol risks to result in biased Cm results and to indicate which step of the method might need to be changed in order to avoid these. (author)