Ricerc@Sapienza

In fusion reactor breeding blankets (BB), liquid metals (LM) are employed as working fluid due to their attractiveness as coolant, tritium carrier, and breeder. Their interaction with the strong magnetic field causes the onset of magnetohydrodynamic (MHD) phenomena within the fluid piping network. Compared with an ordinary hydrodynamic case, a MHD flow shows altered features, such as a significant flow redistribution, enhanced pressure losses and a rearrangement of turbulent structures. Therefore, it is well known that heat transfer in a LM BB must be evaluated considering all these phenomena. In this project, a correlations-based model able to predict the MHD heat transfer in the forced convection regime will be developed and it will be implemented in RELAP5/MOD3.3 system thermal-hydraulic code.
The reduced model will accurately predict the heat transfer coefficient (HTC) for forced convection regime in square/rectangular ducts and circular pipes. The range of application is foreseen to be from the purely electromagnetic laminar flow to the turbulence regime. The correlations will be derived for this purpose by an extensive assessment of literature regarding MHD heat transfer for fusion applications. At last, the verification and validation procedure of the software will be carried out to verify the reliability of the code.
The MHD heat transfer model, together with the MHD pressure drop model already implemented by the Sapienza DIAEE research team, is going to extend the applicability of the code to nonisothermal MHD flows. Those newly capabilities will make the enhanced RELAP5/MOD3.3 version (referred as RELAP5-FUSION) a fast and reliable numerical tool for supporting fusion reactor operational and safety design. It will stand as the first prototype of best-estimate thermal-hydraulic system codes that, as for fission reactors practice, could be employed for fusion rectors licensing procedure, which is mandatory to build and operate a nuclear power plant.