SEAFP Modeling of Accident Sequences, Source Terms, and Public Doses

Abstract

Within the European Safety and Environmental Assessment of Fusion Power (SEAFP), off-site public doses were assessed for representative hypothetical worst case fusion power station accident sequences driven by in-plant energies, without taking credit for any active safety measures. In this paper, in order to illustrate the calculations performed in SEAFP, the calculational sequence is described for one accident scenario. This is a major in-vessel LOCA. Several sources of active material are mobilized following the LOCA, and are transported across successive containment barriers as the accident evolves, with a small fraction of the source inventory eventually reaching the environment. Using conservative assumptions, modeling of thermo-fluid-mechanics, heat transfer, mobilization, transport, aerosol phenomena, and atmospheric dispersal and dilution, were used to determine several measures of public dose exposure. Calculations for other accident scenarios, performed within SEAFP, are not described in detail in this paper, but are commented on. The calculations indicate that maximum public doses would be well below levels at which emergency intervention would be required.