Computational thermofluid-dynamic analysis of DEMO divertor cassette body cooling circuit

Highlights: •The thermal-hydraulic performances of the DEMO divertor Cassette Body cooling circuit have been investigated. •A numerical approach based on the Finite Volume Method has been followed, adopting the ANSYS-CFX code. •Cooling circuit is generally able to provide a uniform cooling to steel structure with a total pressure drop of 0.1 MPa. •Limited hot spots have been found in the steel structure to be further investigated. -- Abstract: Within the framework of the Work Package Divertor, Subproject: Cassette Design and Integration (WPDIV-Cassette) of the EUROfusion action, a research campaign has been jointly carried out by ENEA and University of Palermo to investigate the thermal-hydraulic performances of the DEMO divertor cassette cooling system. The research activity has been carried out following a theoretical-computational approach based on the finite volume method and adopting a qualified Computational Fluid-Dynamic (CFD) code. Fully-coupled fluid-structure CFD analyses have been carried out for the recently-revised cassette body cooling circuit under nominal steady state conditions, imposing a non-uniform spatial distribution of nuclear-deposited heat power volumetric density drawn from the most recent neutron transport analysis. The pertaining thermal-hydraulic performances have been assessed in terms of coolant flow velocity and total pressure distributions as well as of coolant and structure temperature distributions to check whether they comply with the corresponding prescribed limits. Results obtained are reported and critically discussed.