Radiological characterization of large electromagnets in view of their elimination as very low-level wastes

The operation of particle accelerators at CERN requires the use of electromagnets, which are accelerator components used to guide and focus charged particles. In the framework of maintenance activities and machine upgrades or dismantling, a large number of magnets are removed from the accelerator complex and required characterization in view of their disposal as radioactive waste. The present document describes a new characterization methodology, which is applied to radioactive magnets with masses up to 25 tons and lengths up to 6 meters. The characterization of such large electromagnets is challenging due to their heterogeneous composition, variable radiological history, technical constraints related to handling, and the operational complexity of evaluating activity values with gamma spectroscopy . The innovative method proposed in this paper is based on the establishment of transfer functions which convert dose-rate to a radionuclide inventory. This method is validated by comparison with accurate gamma spectroscopy and benchmarking.