MCNP辅助建模工具中的关键问题研究

大型通用中性粒子计算程序MCNP的输入文件包含三维几何模型．研究了B-Rep到CSG的自动转换算法．该算法是开发MCNP辅助建模工具的基础．在Shapiro等工作的基础上，结合MCNP几何模型的特点，对算法中的“构造‘充分曲面集’”和“分解‘栅元’”两点进行了改进，降低了问题的复杂度，减少了冗余分解；并在此基础上，开发了MCAM（MCNP Automatic Modeling）软件，该软件已在国内外多家单位进行了测试和应用，取得了满意的效果．

Research on Key Problems of Aided Modeling Tool of MCNP

MCNP(Monte Carlo N-Particle Transport Code) is a general purpose N-particle transport code, and its input file contains 3-D geometry model. The paper studies the algorithm of automatic conversion from B-Rep to CSG. The algorithm is the basis of developing MCNP aided modeling tool. Based on SHAPIRO's work, and taking into consideration of the features of MCNP geometry model, the paper improves the algorithm on two aspects, constructing sufficient surface set and decomposing cell. The improvement reduces the algorithm's complexity, and removes some redundant decomposition. Based on the algorithm, the software package Mcam(MCNP Automatic Modeling) is developed. It has been used & tested by many users at home and abroad, and the test result is satisfactory.