[en] CEA has determined reference zones for the radioactive waste arising from the decommissioning of a linear particle accelerator (700 MeV, electrons) and a synchrotron (3 GeV, protons). The analytical approach adopted makes allowance for the design and history of the installations and the corresponding operating rules. The methodology used consisted in: Identifying those areas and materials where interactions could occur between the beam and the material; Characterising the radiation fields and determining which radioactive elements were representative of the potential activation of the materials; Estimating the activity per unit mass by means of semi-empirical calculations or Monte Carlo type simulations; Checking the radiological state of the zones by measuring the radioactivity of samples and mapping absorbed dose rates. That process has been ratified by the safety authorities and has allowed increasing the value of 85 per cent of materials (about 3.10⁷ kg), so that the production of final radioactive waste has been very limited. (author)