核反应堆系统多维度多物理场耦合有限元分析研究

Finite Element Based Multi-dimension and Multi-physics Coupling Analysis for Nuclear Reactor System

核反应堆系统庞杂且运行环境严苛,存在多物理场耦合的复杂现象。早期开发的多物理场耦合软件具有扩展性和通用性不足的缺点。因此,搭建多物理场耦合框架,针对耦合问题中的关键技术开展研究,对加快我国自主化多物理场耦合平台开发进程具有重要意义。本文介绍了西安交通大学核反应堆热工水力研究室开发的核反应堆多维度多物理场耦合有限元分析平台,主要包含热工流体计算模型的开发、燃料性能分析技术的研究以及多物理场耦合框架的建立等工作。在热工流体计算方面,开展了核反应堆系统两相流分析模型和液态金属快堆子通道分析模型研究,开发了系统分析程序NUSAC和子通道分析程序FLARE;在燃料性能分析技术方面,开展了包覆颗粒弥散燃料和板状燃料的性能分析研究,开发了针对多种燃料的燃料性能分析程序BEEs;在多物理场耦合分析方面,搭建了多物理场耦合框架,结合热工水力、中子物理和燃料性能分析程序,实现了核反应堆多物理场耦合的精细分析。本文搭建的核反应堆系统多维度多物理场耦合有限元分析平台可为核反应堆系统多维度多物理场耦合高保真数值模拟分析提供有力支持。

The nuclear reactor system is complex and the operating environment is harsh,resulting in the complex phenomena of multi-physics coupling.The multi-physics coupling codes developed in the early stage shows limitations on codes’scalability and generality.Therefore,it is of great significance to build a multi-physics coupling framework and conduct research on key technologies in coupling problems,which may accelerate the development process of autonomous multi-physics coupling platform in China.In this paper,the multi-dimensional and multi-physics coupling finite element analysis platform for nuclear reactor developed by XJTU-NuTHeL was introduced.The main work consisted of the development of thermal-hydraulic model,the research of fuel performance analysis technology and the establishment of multi-physics coupling framework.In terms of thermal-hydraulic calculation,XJTU-NuTHeL conducted a series of studies on pressurized water reactors and advanced reactors grounded in the advanced multi-physics coupling framework,and developed the nuclear reactor system safety analysis code,NUSAC.In addition,a subchannel analysis model tailored for liquid metal fast reactors was established,and the fully coupled subchannel transient analysis code,FLARE,was developed.NUSAC and FLARE were then verified against relevant codes and experimental data.In the realm of fuel performance analysis,considering the wide application of finite element method in solid mechanics and its versatile modeling capabilities,XJTU-NuTHeL developed a fuel performance analysis code,BEEs,based on finite element method.The code could not only conduct multi-physics coupling analysis for traditional rod fuels under steady and transient conditions,but also extends its applicability to accident tolerant fuels and other fuels with diverse geometric shapes.This paper focused on the study and analysis of coated particle dispersed fuel and plate type fuel.The multi-scale simulation results of coated particle dispersed fuels,as well as the thermomechanical and corrosion behavior of plate type fuels were shown.In the context of multi-physics coupling analysis,the efficiency and accuracy of different mesh grid mapping schemes were studied and a multi-physics coupling framework was established.An example of the framework was then presented,showcasing the integration of the fuel performance code BEEs,the Monte Carlo neutron physics code OpenMC,and reactor system safety analysis code NUSAC.The keys parameters of mechanics,thermal-hydraulic and neutronics were obtained and analyzed through the coupling different codes.The multi-dimensional and multi-physics coupling finite element analysis platform built in this paper can provide a strong support for the high-fidelity numerical simulation of nuclear reactor multi-scale and multi-physics coupling.