Multi-scale thermal-hydraulic modelling for the Primary Heat Transfer System of a tokamak

During the pre-conceptual design stage, which the EU DEMO fusion reactor is currently facing, fast-running models can be very helpful by providing hints to support the designers, analysing several alternative scenarios. This paper presents the development of a code for this kind of analyses, called the GEneral Tokamak THErmal-hydraulic Model (GETTHEM). The code is developed to allow fast transient simulations of the tokamak primary cooling system, both under nominal conditions and off-normal transients; it has been benchmarked and validated in different scenarios which are presented here. So far, it has been successfully applied to the optimization of the coolant flow for two Breeding Blanket concepts, and it has also been used to analyse the effects of an accidental scenario on the primary confinement barrier.