Radiochemical analysis of concrete samples from accelerator waste

For the decommissioning and disposal of shielding concrete from accelerator facilities, the Swiss Authorities require information on the radionuclide inventory. Besides the easy-to-measure gamma-emitters Eu-152, Co-60, Sc-44, Ba-133, Eu-154, Cs-134, Ce-144, Na-22, also long-lived radionuclides emitting alpha-or beta-radiation like I-129, Be-10, Cl-36, Pu-239/240 and U-238 have to be studied in order to obtain an overview to which extent they are produced and whether they represent a safety issue. In this study, we present the chemical separation and determination of selected radionuclides in shielding concrete from two different positions in the accelerator facilities at the Paul Scherrer Institute (PSI), the BX2 station, which was shut down in 1998, and the environment of the target M station, where the samples were taken in 1985 during reconstruction. The results of the measurements show that in no case the radionuclide content represents a safety risk. The components can be de-commissioned corresponding to the Swiss safety regulations.