Thermal–hydraulic analyses and experimental modelling of MSFR

Highlights: • Summary, discussion of water based scaled experimental models of nuclear reactors. • CFD analyses of the MSFR concept to investigate thermal–hydraulics behaviour. • Discussion of feasibility and constraints of a segmented, scaled mock-up of MSFR. • Final design and the experimental model of MSFR for PIV measurements presented. • Measurement method, first measurement results are presented and discussed. - Abstract: Based on the MSFR (Molten Salt Fast Reactor) benchmark presented within the framework of the EVOL project (Evaluation and Viability of Liquid Fuel Fast Reactor System, EU FP7) preliminary three-dimensional thermal–hydraulic analyses will be presented and a scaled, segmented experimental mock-up of the MSFR will be introduced in this paper. The MSFR concept is a single region, homogeneous liquid fuelled fast reactor. The reactor concept uses fluoride-based molten salts with fissile uranium and/or thorium and other heavy nuclei content with the purpose of applying the thorium cycle and the burn-up of transuranic elements. The concept has a single region cylindrical core with sixteen radial inlet and outlet nozzles located at the bottom and the top of the core. The external circuit (internal heat exchanger, pump, pipes) is broken up into sixteen identical modules distributed around the core. The purpose of the presented three-dimensional Computational Fluid Dynamics (CFD) calculations is to study the possibility of experimental investigation of the fluid flow in the core of the proposed MSFR concept using a small, scaled plexiglas model and Particle Image Velocimetry (PIV) flow measurement technique under laboratory conditions. First the main properties of the proposed MSFR concept will be introduced, and the information on other experimental thermal–hydraulic modelling of different reactors, including MSRE will be summarised. Based on the CFD analyses and the discussion of scaling and segmenting the final design of the experimental system will be presented. Objectives of such experimental examination would be validation, benchmarking of CFD calculations and codes, application of CFD modelling experience in the detailed thermal–hydraulic design process of the MSFR core; possible measurements for the study of specific problems or phenomena (for example inlet geometry, optional internal structures, mixing)