Abstract In this study, a hypothetical fast spectrum Liquid Fuel Molten Salt Reactor (LFMSR) core is modeled using the multiphysics C++ code GeN-Foam (General Nuclear Foam). GeN-Foam is based on OpenFOAM, a C++ open-source library for solution of continuum mechanics problems. The code utilizes a unified fine/coarse mesh approach, modeling different physics such as neutron kinetics, thermal-hydraulics based on porous fluid equations, and structural thermal-mechanics. A steady state analysis of a simplified two-dimensional (2D) LFMSR model has been performed assuming rotational symmetry to cross verify the code with the commercial ANSYS Computational Fluid Dynamics (CFD) code Fluent. The calculations showed very good agreement between the two codes allowing progression to a three-dimensional (3D) model simulation. A coupled neutron kinetics and CFD steady state analysis of a right-cylindrical 3D LFMSR core has been performed modeling one quarter of the core while using symmetry boundaries to reduce the computational time. Mixed uranium and plutonium chloride fuel has been selected in this preliminary study. Both 2D and 3D simulations showed appearance of recirculation zones within the right-cylinder core. These zones can be a challenge for LFMSR control and materials. A new hyperboloid design is proposed to remove recirculation zones, which is based on eight symmetrical loops. An Unprotected Loss of Flow accident (ULOF), in which the pump head is instantaneously reduced to zero, has been selected to demonstrate the safety characteristics of the reactor in one of the most challenging possible situations for LFMSR. The obtained results (e.g., reduced total precursors concentration at the core inlet and reduction of the core nominal power following the transient) confirm that GeN-Foam is capable of performing coupled LFMSR transient analysis and can be used for design analysis and optimization. Although the current design needs further assessment and development, it shows encouraging performance under ULOF conditions paving the way to the next step in the optimization process.

中文翻译：

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基于多物理场代码GeN-Foam的液体燃料熔盐反应器初步设计与分析

摘要 在本研究中，使用多物理场 C++ 代码 GeN-Foam（通用核泡沫）对假设的快速光谱液体燃料熔盐反应堆 (LFMSR) 堆芯进行建模。GeN-Foam 基于 OpenFOAM，这是一个用于解决连续介质力学问题的 C++ 开源库。该代码使用统一的细/粗网格方法，对不同的物理场进行建模，例如中子动力学、基于多孔流体方程的热力学和结构热力学。假设旋转对称，已对简化的二维 (2D) LFMSR 模型进行稳态分析，以使用商业 ANSYS 计算流体动力学 (CFD) 代码 Fluent 交叉验证代码。计算结果表明两个代码之间的一致性非常好，允许进行三维 (3D) 模型模拟。对一个右圆柱 3D LFMSR 核心进行了耦合中子动力学和 CFD 稳态分析，对四分之一的核心进行了建模，同时使用对称边界来减少计算时间。本初步研究选择了混合铀和氯化钚燃料。2D 和 3D 模拟均显示右圆柱芯内出现再循环区。这些区域对于 LFMSR 控制和材料来说可能是一个挑战。提出了一种新的双曲面设计，以消除基于八个对称环的再循环区。选择了泵压头瞬间降至零的无保护流量损失事故 (ULOF) 来证明反应堆在 LFMSR 最具挑战性的可能情况之一中的安全特性。获得的结果（例如，降低了堆芯入口处的总前体浓度并降低了瞬态后堆芯标称功率）证实 GeN-Foam 能够执行耦合 LFMSR 瞬态分析，并可用于设计分析和优化。虽然当前的设计需要进一步的评估和开发，但它在 ULOF 条件下显示出令人鼓舞的性能，为优化过程的下一步铺平了道路。