Fundamental investigation of extraction properties of actinides elements with tetramethylmalonamide resin

Shimada, Asako ; Nash, K.*; Alexandratos, S.*; Yang, Y.*

For the disposal of low-level radioactive waste (LLW) in a near surface repository, evaluation of its radioactive inventory is required. Since the amount of alpha-emitting nuclides is much lower than the matrix elements in LLW, chemical separation is necessary for analysis of alpha emitting nuclides. In this study, the extraction properties of tetramethylmalonamide (TMMA) resin for alpha-emitting nuclides are reported. TMMA resin strongly extracts tracer amount of Th and U from HNO and HCl solutions in the concentration range from 0.01 to 10 mol/dm with the extraction equilibrium being reached within 1 hour. The extraction of Am with TMMA is lower than those of U and Th, and it takes approximately 3 hour to reach equilibrium. The effect of co-existing nuclides on Am extraction with TMMA is also studied. At [Fe] above 0.01 mol/dm, the extraction of Am was decreased. In contrast, Am extraction is slightly increased in the presence of Ni.