钨铜偏滤器靶板疲劳损伤与寿命研究

发布时间：2018-09-19 12:23

【摘要】：随着聚变科学与技术的发展,各大托卡马克装置中的等离子体参数正一步一步提高,但是在通往商用聚变堆的道路上仍然有很多挑战。对于下一代托卡马克装置和未来聚变实验堆而言,长脉冲高约束运行模式被认为是获得高聚变能量增益的首选模式。在该模式运行下,由于磁流体不稳定性等,会周期性的出现大量粒子和能量进入刮削层,然后这些粒子和能量沿着磁力线输运到偏滤器区域,轰击到靶板上,形成极高的瞬态热负荷,对偏滤器造成损伤。偏滤器作为托卡马克装置中最重要的内部部件之一,在放电过程中不仅起着控制杂质的作用,而且是聚变反应中重要的能量和粒子排出通道。为了提高偏滤器的性能使得其满足高约束运行模式中排热或排出粒子的需求以及预研ITER偏滤器的性能和服役行为,EAST于2014年将上偏滤器升级成为类ITER结构的钨铜偏滤器。在高参数物理实验之前,开展偏滤器在高参数物理实验中的损伤与寿命研究是十分必要的内容,其结果可以为偏滤器的设计和制定偏滤器在聚变装置和反应堆服役中的维护方案提供指导意见,同时可以更好的从工程角度协助物理实验的进行和提高装置的运行效率。本论文基于EAST和世界上各大聚变装置在高约束模式实验中统计的沉积在偏滤器靶板上的热负荷特征,详细研究了 EAST钨铜偏滤器靶板在高约束模式运行中的温度和结构响应行为,并构建了可以由诊断得到的偏滤器靶板上的热负荷特征参数直接对应到靶板疲劳损伤的模型,从而可以实现对服役中偏滤器靶板的疲劳损伤进行实时评估和监测,判断其是否会发生疲劳失效。文中首先分析了偏滤器靶板在高约束模中由边界局域模(Edge localized modes)诱发的瞬态热负荷作用时的响应行为。为了更加直观的描述靶板在ELMs瞬态热负荷作用下的响应行为,本文建立了包含温度演化历程、热穿透深度和疲劳裂纹萌生寿命三个指标的体系来描述ELMs作用期间的靶板的温度宏观累积效应、表面层微观温度响应和微观结构响应,并分析了三个指标的主要影响因素以及它们与瞬态热负荷特征参数之间的关系。然后进一步开展了钨铜偏滤器靶板在长脉冲高约束运行模式中的响应行为研究。文中定义了完整放电过程中打击点处的热负荷随时间的演化历程,经过分析和讨论从中提取出了影响偏滤器靶板响应行为的稳态热负荷以及瞬态热负荷的峰值、上升时间、频率四个特征参数;接着根据偏滤器靶板的Monoblock结构在热负荷作用下的响应特性以及其结构特点,把Monoblock结构划分为四个关键部位,分别构建了它们在不同特征参数的热负荷下对应的温度与结构响应模型。最后,在上述分析结果的基础上,根据钨铜偏滤器靶板的面向等离子体面和铬锆铜水管的材料和功能特性,结合雨流计数法、Neuber法则和Miner损伤线性累积法则分别构建了与之对应的疲劳损伤和寿命预测模型。通过分析中构建的聚变堆疲劳寿命评判方法,能够合理的预测偏滤器靶板在服役中的疲劳损伤状况,然后针对性的制定维护方案。
[Abstract]:With the development of fusion science and technology, plasma parameters in major Tokamak devices are being improved step by step, but there are still many challenges on the way to commercial fusion reactors. In this mode, due to magnetohydrodynamic instability, a large number of particles and energy will appear periodically into the scraping layer, and then these particles and energy will be transported along the magnetic field line to the divertor area, bombarding the target plate, forming a very high transient heat load, causing damage to the divertor. The divertor as a Tokama. One of the most important internal components of the device, which not only controls impurities during discharge, but also is an important channel for energy and particle discharge in fusion reactions. In order to improve the performance of the divertor, the divertor can meet the requirements of discharging heat or particles in highly constrained operation mode, and the performance and service of the ITER divertor are studied in advance. EAST upgraded the upper divertor to an ITER-like tungsten-copper divertor in 2014. Before high-parameter physics experiments, it is necessary to study the damage and life of the divertor in high-parameter physics experiments. The results can be used to design the divertor and formulate the dimension of the divertor in fusion and reactor service. Based on the thermal load characteristics of EAST and other fusion devices deposited on the divertor target plate in the high confinement mode experiments, this paper studies the thermal load characteristics of EAST tungsten-copper divertor target plate in detail. The response behavior of temperature and structure under high restraint mode is studied. A model is constructed in which the characteristic parameters of thermal load on the divertor target can be directly corresponded to the fatigue damage of the target. Thus, the fatigue damage of the divertor target in service can be evaluated and monitored in real time and the fatigue loss can be judged. The response behavior of the divertor target plate under transient thermal loading induced by Edge localized modes in high confinement modes is analyzed. In order to describe the response behavior of the target plate under ELMs transient thermal loading more intuitively, the temperature evolution history, thermal penetration depth and fatigue cracks are established. The system of three indices of initiation life describes the macro-cumulative effect of temperature, the micro-temperature response and the micro-structure response of the surface layer of the target plate during ELMs. The main influencing factors of the three indices and the relationship between them and the characteristic parameters of transient thermal load are analyzed. Then the target plate length of tungsten-copper divertor is further developed. In this paper, the evolution process of heat load at the strike point during complete discharge is defined, and the steady-state heat load, the peak value of transient heat load, the rise time and the frequency are extracted from the analysis and discussion. According to the response characteristics of Monoblock structure of divertor target under thermal load and its structural characteristics, the Monoblock structure is divided into four key parts, and their corresponding temperature and structural response models under different characteristic parameters of thermal load are constructed. Finally, based on the above analysis results, the tungsten-copper divertor structure is divided into four key parts. Fatigue damage and life prediction models of the target plate for plasma surface and chromium-zirconium-copper pipe were constructed by rain-flow counting method, Neuber's law and Miner's damage linear cumulative law, respectively. The fatigue damage condition of the board in service is then formulated.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TL631.24

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