OpenMC is a community-driven open-source Monte Carlo neutron and photon transport simulation code. It supports geometry modeling using constructive solid geometry, and is capable of performing fixed source particle transport simulation based on continuous-energy and group-wise nuclear cross-section data. The lack of variance reduction technique is one of the main drawbacks of this code, which prevent its use for deep penetration shielding calculations. In this work, a commonly used variance reduction technique – using the Weight Window Mesh (WWM) function has been developed and benchmarked for OpenMC. This enables OpenMC to use any WWM file produced for the MCNP code. For benchmarking, two deep penetration shielding cases, a sphere simulation model and the thickest shielding cases in the TIARA high energy neutron shielding experiment has been employed, using the WWM produced by the ADVANTG code. In addition, the OpenMC WWM function has also been applied on the IFMIF-DONES Test Cell global neutron flux distribution calculations. The successful benchmarking and application demonstrate ability of the newly developed OpenMC WWM function for applications in general purposes deep penetration shielding calculations.

OpenMC是社区驱动的开源蒙特卡洛中子和光子传输模拟代码。它支持使用构造实体几何的几何建模，并能够基于连续能量和逐组核横截面数据执行固定源粒子传输模拟。缺少方差降低技术是此代码的主要缺点之一，这妨碍了将其用于深度渗透屏蔽计算。在这项工作中，已经开发了一种常用的方差减少技术-使用权重窗口网格（WWM）功能，并已将其作为OpenMC的基准。这使OpenMC可以使用为MCNP代码生成的任何WWM文件。为了进行基准测试，使用了两个深层穿透防护罩 在TIARA高能中子屏蔽实验中使用了球形仿真模型和最厚的屏蔽层，并使用了ADVANTG代码生成的WWM。此外，OpenMC WWM功能也已应用于IFMIF-DONES测试室整体中子​​通量分布计算中。成功的基准测试和应用证明了新开发的OpenMC WWM功能在一般用途深穿透屏蔽计算中的应用能力。