Cartesian Meshing Impacts for PWR Assemblies in Multigroup Monte Carlo and Sn Transport
Cartesian Meshing Impacts for PWR Assemblies in Multigroup Monte Carlo and Sn Transport
复制标题
笛卡尔网格划分对多组蒙特卡罗和 Sn 输运中压水堆组件的影响
DOI：
10.1051/snamc/201405201
复制
发表时间：
2014
影响因子：
1.7
通讯作者：
and G. Sjoden
中科院分区：
文献类型：
--
作者：
K. Manalo;M. Chin;and G. Sjoden
混合的中子输运方法在应用中有了很大的增长，例如，在同时使用蒙特卡罗和确定性输运来计算感兴趣的量，如核反应堆中的通量和本征值方面。许多3D并行的SN代码应用笛卡尔网格，因此对于核反应堆，曲线燃料(圆柱体、球体等)的表示法。影响适当燃料库存的表示(包括质量偏差和精确的几何表示)。对于压水堆组件特征值问题，我们探索与该笛卡尔离散网格表示相关联的误差，并执行分析以计算将pcm与面积/体积偏差百分比(面积分别对应于2D和体积对应于3D)关联的斜率参数。我们的初步分析表明，在压水堆组件上使用多基团MCNP与参考精确的组合MCNP几何计算相比，pcm变化与面积/体积偏差之间存在线性关系。对于相同的多群问题，我们还打算在离散坐标(3D PENTRAN)中刻画这种线性关系，并讨论与传输交叉比较相关的问题。此外，我们使用我们的3D笛卡尔网格生成工具讨论了自动转换技术，以允许从基础PENTRAN SN模型完全生成MCNP5输入(笛卡尔网格和多组XS)。
Hybrid methods of neutron transport have increased greatly in use, for example, in applications of using both Monte Carlo and deterministic transport to calculate quantities of interest, such as flux and eigenvalue in a nuclear reactor. Many 3D parallel Sn codes apply a Cartesian mesh, and thus for nuclear reactors the representation of curved fuels (cylinder, sphere, etc.) are impacted in the representation of proper fuel inventory (both in deviation of mass and exact geometry representation). For a PWR assembly eigenvalue problem, we explore the errors associated with this Cartesian discrete mesh representation, and perform an analysis to calculate a slope parameter that relates the pcm to the percent areal/volumetric deviation (areal corresponds to 2D and volumetric to 3D, respectively). Our initial analysis demonstrates a linear relationship between pcm change and areal/volumetric deviation using Multigroup MCNP on a PWR assembly compared to a reference exact combinatorial MCNP geometry calculation. For the same multigroup problems, we also intend to characterize this linear relationship in discrete ordinates (3D PENTRAN) and discuss issues related to transport cross-comparison. In addition, we discuss auto-conversion techniques with our 3D Cartesian mesh generation tools to allow for full generation of MCNP5 inputs (Cartesian mesh and Multigroup XS) from a basis PENTRAN Sn model.