XX09 an SFR Fuel Assembly
Pictures below describe the meshing of instrumented XX09 assembly used in Shutdown Heat Removal Tests (SHRT) that demonstrated passive safety features of the EBR-II Experimental Breeder Reactor. The specic test from which this problem is derived is SHRT17, which is a Loss of Flow with SCRAM experiment. This test conguration was selected for the multi-physics demonstration because of the availability of temperature and low validation data available from the experiment.
‘AssyGen’ a part of Reactor Geometry (and mesh) Generator (RGG) in MeshKit, and has been used to create the assembly geometry and meshing script for the reactor assemblies described below. Input files attached below are run using AssyGen program to create the geometry files. Mesh files for simulation codes UNIC and Nek5000 are generated by making small modifications to the CUBIT journal files automatically created by AssyGen .
For initial coupled simulations Nek5000 mesh has 356952 hex27 elements, whereas the UNIC mesh has 505815 hex8 elements.
A Coupled Thermal/Hydraulics – Neutronics – Fuel Performance Analysis of an SFR Fuel Assembly
Power (lower two parts) and the peak energy ux distribution (upper part) for the XX09 assembly.
Left: This figure shows XZ-plane section views of the entire assembly from Inlet-( i ) to Outlet ( iv ). Material coloring – pink:stainless steel, yellow:sodium, blue:clad, light blue:fuel, white:bond sodium and red:fission gas (i) Cylindrical inlet transitions to form a cone from left to right (ii) Interface of inlet sodium and pointed conical lower plug, also shows the fuel. (iii) Top of fuel surrounded by bond sodium and clad, filled on top with bond sodium and fission gas (iv) Upper plug and outlet sodium.Center: This is an oblique/closeup sectioned view showing the meshing complexities. It shows the conical fuel pin, bond sodium, clad and stainless steel outer ducts. Right: Shows a the sectioned top view of the 61 pin (Note: 59 fuel pins + 2 flowmeters) assembly.
XX09 assembly (i) Inlet region partitioned mesh (ii) Isometric view of 1024 partitions (iii) Top view of the outlet partition (iv) Top view of mesh showing 61 pins. Mesh is partitioned using the mbpart utility in MOAB.