[en] The research on partitioning and transmutation at the Department of Nuclear Chemistry, Chalmers, is focused on the separation using solvent extraction. For an efficient transmutation process it is essential that the nuclides intended for transmutation (i.e. the actinides and selected fission products) be separated from the rest of the fission products or else too many neutrons will be lost transmuting nuclides that are already short-lived or stable. In the proposed process the separation is accomplished in at least two steps. First actinides and lanthanides are co-extracted from high concentration nitric acid and then the trivalent actinides and the lanthanides are back-extracted into a nitric acid solution of lower concentration. These are then separated from each other in a second step. All reagents used in this future process should follow the so-called CHON-principle, i.e. consist of only carbon, hydrogen, oxygen and nitrogen atoms, to be completely incinerable and thereby minimising the secondary waste produced. The main part of the studies at the Department of Nuclear Chemistry, Chalmers, during this year has concerned the latter part of the separation process, i.e. the separation of trivalent actinides from lanthanides