Development of flow regime maps for lead lithium eutectic–helium flows

Abstract Institute for Plasma Research (IPR), Gandhinagar (India) is currently involved in the design and development of its Lead-Lithium Ceramic Breeder (LLCB) module for testing in the International Thermo-nuclear Experimental Reactor (ITER). In order to fulfill the ITER safety requirements, some postulated events need to be analyzed. Among them, the internal loss of coolant accident is being studied using RELAP/SCDAPSIM/MOD4.0 code. To this aim, RELAP/SCDAPSIM/MOD4.0 capabilities of modeling lead lithium eutectic (LLE) and helium flows are being extended nowadays by a collaboration of three institutions, namely IPR, Innovative System Software (ISS) and UPC-BarcelonaTech. The current study is part of this effort and is focused on the adjustments of existing RELAP/SCAPSIM/MOD4.0 flow regime maps in order to deal with the LLE-helium pair. Due to the lack of experimental data, the current study is based on a numerical assessment of LLE-helium flows. The volume of fluid method implemented in OpenFOAM toolkit has been chosen to characterize the flow regime at different mixture velocities and helium fractions. The paper includes a description of the followed methodology and its validation. Results of the systematic simulations of both horizontal and vertical upward flows are shown and the proposed flow diagrams presented. It is worthwhile to mention that the numerically obtained flow regime maps must be validated by an experimental campaign. However, the current approach allows the use of RELAP/SCDAPSIM/MOD4.0 code to properly initiate the study of breeding blanket off-normal events postulated for Lead-Lithium Ceramic Breeder, Helium Cooled Lithium-Lead and Dual Coolant Lithium-Lead designs.