Improved containment transport modelling for hypothetical accidents in fusion power plants

We report here improvements to a code, FUSCON, developed for the SEAFP-2 (Safety and Environmental Aspects of Fusion Power) study to model containment transport and release to the environment. The previous version of FUSCON did not include heat transfer to the wall, accounted for condensation for only a limited set of conditions, and hence placed restrictions on some of the containment parameters investigated. The improvements described involve modelling of post-accident convective transport in the containment system. This is a good basis for enhancement of the model to include mass transfer effects associated with condensation. Three-dimensional, computational-fluid-dynamics, finite-element calculations have guided the derivation of a computationally economic model of convective containment transport. The efficiency of the model will ensure that FUSCON is still sufficiently fast-running to be used to study confinement system optimisation and selection.