Research And Implementation Of Geometric Model Transformation Method Based On The Reactor Monte Carlo Code

With the development of computer technology,Particle transport Monte Carlo simulation has been widely used in the field of nuclear engineering and nuclear technology.RMC(Reactor Monte Carlo code)is developed by the analytical laboratory of Tsinghua University Engineering Department of physics,nuclear science and Engineering Management Research Reactor Engineering(REAL team)for three-dimensional transport calculation and analysis of the reactor core of Monte Carlo program.In the aspect of geometric modeling,RMC forms a geometric entity(grid element)through a Boolean operation in a semi-space represented by a signed surface,and combines the hierarchical space and the repeated geometric description to construct a complete geometric object.RMC model is described by a specific format input file,it's a major app lication requirements on how to visualize the RMC file for intuitive troubleshooting and modification.In this paper,we first analyze the difference between CSG representation of RMC geometric model and BREP expression method of CAD Model,and the we put forward a method of RMC geometric model conversion to CAD geometric model conversion method on the necessity of engineering requirement.Then,this parper give a detailed analysis of modeling characteristics between RMC geometric model and CAD geometric model,and then we proposed a RMC-based geometric model conversion algorithm for specific engineering application requirements.The algorithm is divided into four subalgorithm module: RMC layer information module,basic grid element CSG to BREP expression module,RMC layer space building module,material fill rendering and CAD model output module.The algorithm first analyzes RMC geometry information,then transforms the CSG expression of the gate element into the BREP expression of the CAD model by analyzing the Futenma table calculation formula of the bottom floor Cell.Finally,Getting the position information of the “universe” by the geometric transformation and hierarchical relation.Transforming the RMC geometric model into CAD Model,the system realizes the visualization output of the RMC model through the filling of the material attributes and the model of the geometric modeling engine.And combined with the Visual Studio and Unigraphics NX(UG)platform,this paper complete the system development,and Given some kind of source code.Finally,this paper tests and validates the system.From the RMC basic geometric surface to the complex nuclear reactor model,a lot of testing work is carried out,and the practical value of the system is verified by the implementation of the system in the enterprise.