Methods to Determine Equilibrium Core Models of Pebble-Bed Reactors

Different methods are discussed in the literature to determine approximations for zone-wise inventory in pebble-bed reactors. Various challenges exist including the consideration of a mixture of pebbles at different burnups, different travel paths of the individual pebbles through the core, traveling of the pebbles through zones of different temperatures/flux/powers/spectral conditions, and more. The panel is intended to cover the latest status of these methods, to discuss pros and cons of the different methods, to highlight where experience showed that phenomena need to be considered or that approximations are sufficient.