A Grouped ActiNide EXtraction (GANEX) process for the extraction of actinides from used nuclear fuel for transmutation purposes has been investigated. The studied solvent consists of phenyl trifluoromethyl sulfone (FS-13), CyMe 4-BTBP, and TBP, a combination that has previously shown promising results. The time to reach extraction equilibrium for the system has been found to be less than 20 min. A 2:1 complex has been found between CyMe 4-BTBP and americium (III) or curium(III), whereas plutonium(IV) and CyMe 4-BTBP create a 1:1 complex. The extraction of fission product is low in the system.

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Abstract. Several solvents for Grouped ActiNide EXtraction (GANEX) processes have been investigated at Chalmers University of Technology in recent years. Four different GANEX solvents; cyclo-GANEX (CyMe 4 --BTBP, 30 vol.% tri-butyl phosphate (TBP) and cyclohexanone), DEHBA-GANEX (CyMe 4 -BTBP, 20 vol.% N,N-di-2(ethylhexyl) butyramide (DEHBA) and cyclohexanone), hexanol-GANEX (CyMe 4 -BTBP, 30 vol.% TBP and hexanol) and FS-13-GANEX (CyMe 4 -BTBP, 30 vol.% TBP and phenyl trifl uoromethyl sulfone (FS-13)) have been studied and the results are discussed and compared in this work. The cyclohexanone based solvents show fast and high extraction of the actinides but a somewhat poor diluent stability in contact with the acidic aqueous phase. FS-13-GANEX display high separation factors between the actinides and lanthanides and a good radiolytic and hydrolytic stability. However, the distribution ratios of the actinides are lower, compared to the cyclohexanone based solvents. The hexanol-GANEX is a cheap solvent system using a rather stable diluent but the actinide extraction is, however, comparatively low.

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Astatine-211 is possibly the most promising radionuclide for targeted a-particle therapy when it comes to the treatment of occult disseminated cancer. Preclinical research has proven effective, and patient studies have been initiated based on these results. However, a lack of production capacity and the complex radiochemistry of 211 At are major obstacles for research and prospective clinical applications. In the present study, astatination of immunoconjugates, already prepared well in advance before radiolabeling, was performed to investigate the possibility of formulating a kit-like reagent for the production of 211 At radiopharmaceuticals. The shelf-life of e-lysyl-3-(trimethylstannyl)benzamide immunoconjugates was evaluated, that is, the effect of different storage times on the quality of the immunoconjugates. The quality being referred to is the capacity to maintain a good radiochemical yield and good cell-binding property after labeling with 211 At. The stability of the conjugates was found to be pH dependent with high stability at pH ‡ 7 and less stability at pH £ 5.5. The immunoconjugates (based on trastuzumab) could be kept for more than 3 months in a phosphate buffered saline solution (pH 7.4) at 4°C before labeling, without compromising the quality of the labeled product. The conjugates are also unaffected by storage at -20°C. Conjugates with a good shelf-life compatible with distant shipping as well as improved radiochemistry are important steps to facilitate further clinical progress with 211 At.

Studies have been performed with the purpose of determining the optimal solvent composition of a Chalmers grouped actinide extraction (CHALMEX) solvent for the selective coextraction of transuranic elements in a novel Grouped ActiNide EXtraction (GANEX) process. The solvent is composed of 6,6'-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzo-[1,2,4]triazin-3-yl)-[2,2']-bipyridine (CyMe 4-BTBP) and tri-n-butyl phosphate (TBP) in phenyl trifluoromethyl sulfone (FS-13). The performance of the system has been shown to significantly depend on the ratios of the two extracting agents and the diluent to one another. Furthermore, the performance of the determined optimal solvent (10 mM CyMe 4-BTBP in 30% v/v TBP and 70% v/v FS-13) on various simulated PUREX raffinate solutions was tested. It was found that the solvent extracts all transuranic elements with high efficiency and good selectivity with regard to most other elements (fission products/activation products) present in the simulated PUREX raffinate solutions. Moreover, the solvent was found to extract a significant amount of acid. Palladium, silver, and cadmium were co-extracted along with the TRUradionuclides, which has also been observed in other similar CHALMEX systems. The extraction of plutonium and uranium was preserved for all tested simulated PUREX raffinate solutions compared to experiments using trace amounts.