Yuefeng Qiu

Global Flux Calculation for IFMIF-DONES Test Cell Using Advanced Variance Reduction Technique

Abstract Global neutron flux and dose maps for the test cell (TC) of the IFMIF-DONES (International Fusion Materials Irradiation Facility–DEMO Oriented NEutron Source) have been calculated applying the advanced variance reduction tool ADVANTG. The neutronics model of the TC has been updated to the current IFMIF-DONES design of the target assembly, the high flux test module, and the lithium quench tank as well as the TC surrounding rooms. A weight-window (WW) mesh has been produced using ADVANTG with the well-configured setups for IFMIF-DONES conditions. This WW mesh has been adjusted to achieve reasonably good statistics for the global flux mesh tally. It is concluded that the thickness of the beam upstream and lateral wall can be reduced by 0.5 m without strongly affecting the shielding performance. The neutron streaming through the gaps of the shielding plugs to the access cell above the TC requires local shielding to allow frequent access during operation.

A Fusion-Oriented Neutronics Modeling and Multiphysics Coupling System

A system has been developed to fulfill the entire coupled multiphysics analysis cycle for the design and analysis of complex fusion reactor components. It provides advanced modeling capability for converting computer-aided-design geometries to Monte Carlo (MC) geometries by employing constructive solid geometries and unstructured meshes. It also realizes the generic multiphysics coupling of the MC neutronics, computational fluid dynamics, and finite element thermal and structural analyses. This system is a seamless, extensible, and generic system that has been intensively verified for fusion applications.

A new Geant4 modeling solution based on CAD geometries

A new software system has been developed for converting CAD (Computer-Aided Design) models to Geant4 geometries. It converts CAD to two solids types — Constructive Solid Geometry (CSG) and tessellated solids. The CAD-to-CSG conversion is based on a newly developed half-space solid type, which represents exactly the CAD solids using analytical surfaces. The CAD conversion to the tessellated solids uses triangular facets to approximate the CAD solids. These two solid types can be hybrid used in one Geometry Description Mark-up Language (GDML) file. In addition, the system provides comprehensive CAD modeling capabilities, including CAD viewing, organizing, modification, etc. It has been verified using complex test cases, and has been distributed as an open source code.