Current European research on the separation of actinides from high-level radioactive wastes

Major part of the current European work on the development of a process for the separation of actinides from high-level radioactive wastes (HLLW) is performed within a European Community research programme. A flowsheet of such a process has been proposed, minimizing the amount of secondary wastes by using predominantly reagents composed only of carbon, hydrogen, oxygen and nitrogen. Actinides and fission lanthanides are to be extracted from the HLLW in the first cycle of the process by a completely incinerable N,N,N',N'-tetraalkylmalonamide extractant, such as N,N'dimethyl-N,N'-dibutyltetradecylmalonamide. In the second process cycle, Am(III) and Cm(III) are to be extracted selectively over fission lanthanides(III), using a soft-donor, i.e. a nitrogen or a sulfur donor extractant. Recent results of hot tests of malonamide extractants in counter-current experiments and achievements of the development of soft-donor extractants are described. (author)