AbstractWithin the context of the Safety and Environmental Assessment of Fusion Power (SEAFP), a sequence of calculational methods has been set up to study the potential consequences of hypothetical upper-bound accident scenarios in a tokamak fusion power plant. This paper outlines the methods used within the United Kingdom Atomic Energy Authority (UKAEA) to select a postulated accident sequence to be analysed, for which the nuclide inventories due to neutron activation, temperature histories via thermal modelling, activation product mobilization rates, aerosol behaviour within the containment, atmospheric dispersion and potential doses are calculated. These techniques together represent a complete consequence modelling capability for the selected postulated accident scenario. Only preliminary results are presented in order to illustrate the use of the models.