SEAFP MODELING OF ACCIDENT SEQUENCES, SOURCE TERMS, AND PUBLIC DOSES

Within the European Safety and Environmental Assessment of Fusion Powe r (SEAFP), off-site public doses were assessed for representative hypo thetical worst case fusion power station accident sequences driven by in-plant energies, without taking credit for any active safety measure s. In this paper, in order to illustrate the calculations performed in SEAFP, the calculational sequence is described for one accident scena rio. This is a major in-vessel LOCA. Several sources of active materia l are mobilized following the LOCA, and are transported across success ive containment barriers as the accident evolves, with a small fractio n of the source inventory eventually reaching the environment. Using c onservative assumptions, modeling of thermo-fluid-mechanics, heat tran sfer, mobilization, transport, aerosol phenomena, and atmospheric disp ersal and dilution, were used to determine several measures of public dose exposure. Calculations for other accident scenarios, performed wi thin SEAFP, are not described in detail in this paper, but are comment ed on. The calculations indicate that maximum public doses would be we ll below levels at which emergency intervention would be required.