Abstract A new three-dimensional (3D) transport analysis method is developed and implemented in the light water reactor (LWR) whole-core analysis code STREAM. The method is named as 3D method of characteristics/Diamond-difference (MOC/DD). In this method, 3D variables such as flux and source are expressed as a combination of the two-dimensional (2D) radial component and the one-dimensional (1D) axial component. The 2D method of characteristics (MOC), which is widely used in 2D neutron transport analysis in reactor physics, is used to solve complicated radial geometries composed of fuel pin, burnable absorber, structural material, etc. The axial neutron source, which is discretized by the diamond-difference (DD) method, is merged into the 3D MOC source term. This paper presents a detailed derivation of the 3D MOC/DD method and a parallelization technique to apply the 3D MOC/DD method to a whole-core problem. The accuracy and performance are examined by solving the C5G7 benchmark and the BEAVRS whole-core benchmark problems

中文翻译：

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全芯中子输运计算的STREAM特征三维法/金刚石差输运分析法

摘要 开发了一种新的三维 (3D) 输运分析方法，并在轻水堆 (LWR) 全堆芯分析代码 STREAM 中实施。该方法被命名为3D特征法/钻石差法（MOC/DD）。在该方法中，通量和源等 3D 变量表示为二维 (2D) 径向分量和一维 (1D) 轴向分量的组合。二维特性法 (MOC) 广泛用于反应堆物理中的二维中子输运分析，用于求解由燃料棒、可燃吸收体、结构材料等组成的复杂径向几何结构。 离散化的轴向中子源通过菱形差 (DD) 方法，合并到 3D MOC 源项中。本文详细介绍了 3D MOC/DD 方法的推导以及将 3D MOC/DD 方法应用于整体核心问题的并行化技术。通过解决 C5G7 基准测试和 BEAVRS 全核基准测试问题来检查准确性和性能