Abstract Ensuring the integrity of the reactor pressure vessel (RPV) during the operating life of nuclear reactors is of paramount importance, and hence the harmful effects of irradiation on the steels of the RPVs have been extensively studied especially the irradiation embrittlement effects. However, improvements in the calculation methods are still necessary to further reduce the discrepancy between calculations and experiments. This study was performed to examine the neutron fluence and respective rate of displacement per atom (DPA), an important parameter describing the irradiation-induced damage, in the VVER-1000 RPV steel based on the criticality calculation, instead of the common fixed source approach, with the MCNP6 Monte Carlo code, and identify the most sensitive locations in the VVER-1000 RPV. The MCNP6 modeling of the VVER-1000 reactor was verified against the OpenMC calculations in addition to the confirmation of the convergence of the effective neutron multiplication factor and the Shannon entropy of the fission source distribution in the MCNP6 criticality calculations to ensure reliable tally results of the neutron fluence. Consequently, the maximum neutron fluence in the VVER-1000 RPV was found at the positions adjacent to the peripheral fuel assemblies, and the respective DPA rate was analyzed in correlation with the neutron fluence and energy spectrum.

中文翻译：

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使用 MCNP6 研究 VVER-1000 反应堆压力容器中子注量和每个原子的位移

摘要 在核反应堆运行寿命期间确保反应堆压力容器（RPV）的完整性至关重要，因此辐照对RPV钢的有害影响特别是辐照脆化效应得到了广泛的研究。但是，仍然需要改进计算方法以进一步减少计算与实验之间的差异。进行这项研究是为了检查 VVER-1000 RPV 钢中基于临界计算的中子注量和每个原子的位移率 (DPA)，这是一个描述辐照诱导损伤的重要参数，而不是常见的固定源方法，使用 MCNP6 蒙特卡罗代码，并识别 VVER-1000 RPV 中最敏感的位置。除了在 MCNP6 临界计算中确认有效中子倍增因子和裂变源分布的香农熵的收敛性之外，VVER-1000 反应堆的 MCNP6 建模还针对 OpenMC 计算进行了验证，以确保可靠的计数结果中子注量。因此，在与外围燃料组件相邻的位置发现了 VVER-1000 RPV 中的最大中子注量，并结合中子注量和能谱分析了各自的 DPA 率。