Dynamic Optimization of the Thermal Hydraulic Parameters for the DEMO's CS Magnet

The DEMO project is a magnetic-confinement fusion reactor conceived as a technology demonstrator for a fusion power plant. In order to search for a cryogenic and magnetic optimal design such a large and complex project requires dynamic mutli-parameters studies. Thus, regarding a magnet design [1], using Simcryogenics, 0D cryogenic components in the forced-flow cooling loop and 1D Cable-In-Conduct-Conductors (CICC) and pipes are modeled. This code is particularly efficient in performing thermal-hydraulic parametric calculations with pulsed heat loads. This paper presents the exploration study of the Central Solenoid (CS), using the CEA 2022 magnet design [1]. Thermal-hydraulic calculations are performed under pulsed magnetic field operation and variable cryogenic operating conditions keeping constant temperature margin. The 1.5 K temperature margin requirement is obtained by adjusting the inlet temperature for a given pressure head at constant inlet pressure. The resulting data are analyzed through the lens of the global cryogenic cost, considering the expected operating cost of exergy at 4.5 K and the expected cryogenic capital cost. It then allows to estimate the optimal region in term of cryogenic operating parameters.