Abstract

New multiphysics coupling capabilities for molten salt reactor (MSR) analysis have been developed in the Virtual Environment for Reactor Applications (VERA). This development consisted of two main efforts. First, a generic species transport module was added in the CTF code, which is the thermal-hydraulics (TH) code for VERA. This module uses the velocity fields for which CTF solves during the TH calculation to transport species through the core and around the primary loop. Additionally, a gas sparging model has been added to CTF to model the movement of certain species, namely, fission products such as xenon gas, to transport between the molten salt and gas bubbles present in the salt. The second effort in this development was coupling this capability to VERA’s neutron transport code MPACT. This effort focused on coupling the detailed TH transport models in CTF to MPACT to account for feedback effects in the neutron transport calculations. Finally, the thermochemistry code Thermochimica has also been coupled to VERA. Thermochimica performs pointwise calculations for chemical potential and Gibbs free energy and determines what phases are produced by the temperature, pressure, and elemental concentrations at different locations in the primary loop.

These capabilities are demonstrated using a model of the Molten Salt Reactor Experiment (MSRE). This reactor operated at Oak Ridge National Laboratory in the 1960s, providing sources of experimental data that were used to develop the model. Various combinations of species were modeled using VERA’s new multiphysics coupling capabilities. Species distributions and reactivity effects behaved as expected for the MSRE model, demonstrating that the coupling is behaving correctly and causing appropriate feedback. The results of these calculations show the potential for VERA to be used for a wide variety of MSR analyses.

摘要

已在反应堆应用虚拟环境 (VERA) 中开发了用于熔盐反应堆 (MSR) 分析的新多物理场耦合功能。这一发展包括两个主要努力。首先，在 CTF 代码中添加了一个通用的物种传输模块，即 VERA 的热工水力 (TH) 代码。该模块使用 CTF 在 TH 计算期间求解的速度场，通过核心和初级回路传输物质。此外，CTF 中还添加了气体喷射模型，以模拟某些物质（即氙气等裂变产物）在熔盐和盐中存在的气泡之间传输的运动。这项开发的第二项努力是将此功能与 VERA 的中子传输代码 MPACT 相结合。这项工作的重点是将 CTF 中详细的 TH 输运模型与 MPACT 耦合，以解决中子输运计算中的反馈效应。最后，热化学代码 Thermochimica 也已耦合到 VERA。Thermochimica 对化学势和吉布斯自由能进行逐点计算，并确定主回路中不同位置的温度、压力和元素浓度会产生哪些相。

使用熔盐反应器实验 (MSRE) 模型演示了这些功能。该反应堆于 1960 年代在橡树岭国家实验室运行，提供了用于开发模型的实验数据来源。使用 VERA 新的多物理场耦合功能对各种物种组合进行建模。物种分布和反应性效应的表现符合 MSRE 模型的预期，表明耦合行为正确并引起适当的反馈。这些计算结果显示了 VERA 可用于各种 MSR 分析的潜力。