Investigations on the separation of iodine-129 from filter material AC 6120 in view of future transmutation

Future transmutation of some selected long-lived radionuclides into short-lived and stable nuclides could drastically reduce the long-term radiotoxicity of radioactive waste. However, this will require further development of the reprocssing technology with the aim of a loss-free separation of the radionuclides to be transformed. In addition to several minor actinides the long-lived fission product I-129 is of the greatest relevance for future transmutation. This study first describes the behaviour and distribution of I-129 in the fuel cycle. According to the present state of the art in reprocessing technology, the I-129 contained in spent fuel elements can be completeley transferred into the dissolver off-gas and efficiently adsorbed on silver-nitrate-impregnated silica (AC 6120). For future transmutation, the I-129 should again be separated selectively and as completely as possible from the AC 6120 adsorption matrix. Experimental studies show that a quantitative recovery (>99%) of the iodine is possible by simple chemical processes. The resultant possibilities of producing a target for transmutation are being discussed. (orig.)