Mobility of U, Np, Pu, Am and Cm from spent nuclear fuel into bentonite clay

The mobility of uranium, neptunium, plutonium, americium and curium from sp ent nuclear fuel (UO2) into Compacted bentonite was studied. Pieces of spen t BWR UO2 fuel was embedded in a compacted bentonite clay/low saline synthe tic groundwater system. After a contact time of six years the bentonite was sliced into 0.1 mm thick slices and analysed for its content of actinides. Radiometric as well as inductively coupled plasma mass spectrometry (ICP-M S) were used for the analysis. The influence on the mobility by the additio n of metallic iron, metallic copper and vivianite (Fe(II)-mineral) to the b entonite clay was investigated. The results show a low mobility of actinide s in bentonite clay. Except for uranium the mobility of the other actinides could, after six years of diffusion time, only be detected less than 1 mm from the spent fuel.