The effects of nuclear fusion plasma excursions on the performance of Eurofer-97 components

核聚变等离子体偏移对 Eurofer-97 组件性能的影响

• 批准号: 2279877
• 金额: --
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2279877
• 关键词: effects; nuclear; fusion; plasma; excursions

The high operating temperatures and nuclear radiation within a fusion reactor can significantly change the microstructure of its components, which in turn can change the material properties and mechanical behaviour . The materials chosen for fusion reactors have been specifically engineered to reduce the amount of induced radiation, but it is also important to understand how such materials will behave when exposed to the high temperatures of the fusion plasma.Eurofer-97 is a reduced-activation ferritic-martensitic steel that is proposed for many of the structural and cooling components within the ITER and DEMO fusion reactors, including the cladding material and coolant pipes in the water-cooled lithium-lead breeder blanket, one of four cooling mechanisms being trialled at ITER. Generating power using a cooling system is a key step in achieving commercialisation of nuclear fusion power generation. The plasma at DEMO is expected to be around 100 million C, using focused magnetic fields for containment. However, in the event of a loss of this containment it is possible for the plasma to contact with wall, leading to dramatic increases in temperature over short timeframes.Preliminary work in the Interface Analysis Centre (IAC), has shown that even a few hours of high temperature (- 1s 0 C) exposure can cause significant microstructural degradation of the Eurofer-97 stainless steel material used for structural support and cooling pipes. This could affect mechanical properties and corrosion resistance, in turn leading to a shortening of component life. This PhD project will study the effect of very short-term thermal excursions and assess their effect on the microstructure and corrosion behaviour of the material.The student will use advanced computational modelling using the software package Comsol to explore the effect of thermal transients due to plasma excursions on the temperatures of components within the reactor. This temperature behaviour will then be input into Abaqus to investigate the structural integrity implications of repeated thermal cycling on component stress. Meanwhile, the impact of repeated thermal excursions on the microstructure will be explored using phase chemistry software such as Matcalc. The student will use a combination of these simulations results to predict the resistance of components to degradation mechanisms such as creep and corrosion as a factor of their proximity to thermal excursion locations.In parallel with the computational work, the student will build on existing experimental research at Bristol studying the behaviour of Eurofer-97 after repeated short-term thermal exposure. This will include design of experiments for short-term thermal treatments. Exposed specimens will then be characterised using scanning and transmission electron microscopy, x-ray diffraction and tomography to observe the change in the steel's structure with increasing heat exposure and determine if any embrittlement or change in mechanical properties occur that might cause problems if used in a fusion reactor. There may also be opportunities to combine this work with the effects of irradiation and/or corrosion.This project is a multi-technique approach to understand the structural integrity of an importar:,t material for fusion power. The student will have the opportunity to learn how to use advanced simulation packages and characterisation techniques, and will work closely with industry partners at the UKAEA and NNL.

核聚变反应堆内的高温和核辐射会显著改变其部件的微观结构，从而改变材料的性能和机械行为。为聚变反应堆选择的材料经过专门设计，以减少诱导辐射的数量，但了解这些材料在暴露于聚变等离子体的高温下的表现也很重要。Eurofer-97是一种低活化铁素体-马氏体钢，被提议用于ITER和DEMO聚变反应堆的许多结构和冷却部件，包括水冷锂-铅增殖包层中的包层材料和冷却剂管道，这是ITER正在试验的四种冷却机制之一。利用冷却系统发电是实现核聚变发电商业化的关键一步。DEMO的等离子体温度预计在1亿摄氏度左右，使用聚焦磁场进行密封。然而，在这种容器失去的情况下，等离子体有可能与壁接触，导致温度在短时间内急剧升高。界面分析中心（IAC）的初步工作表明，即使几个小时的高温（- 15 - 0℃）暴露也会导致用于结构支撑和冷却管道的Eurofer-97不锈钢材料的显著微观结构降解。这可能会影响机械性能和耐腐蚀性，进而导致组件寿命缩短。该博士项目将研究极短期热漂移的影响，并评估其对材料微观结构和腐蚀行为的影响。该学生将使用Comsol软件包进行高级计算建模，以探索由于等离子体漂移对反应堆内组件温度的热瞬变的影响。然后将这种温度行为输入到Abaqus中，以研究反复热循环对构件应力的结构完整性影响。同时，利用相化学软件（如Matcalc）研究重复热漂移对微观结构的影响。学生将使用这些模拟结果的组合来预测组件对降解机制（如蠕变和腐蚀）的抵抗力，作为它们接近热偏移位置的一个因素。与计算工作并行，该学生将在布里斯托尔现有的实验研究的基础上，研究Eurofer-97在反复短期热暴露后的行为。这将包括设计短期热处理的实验。然后，将使用扫描和透射电子显微镜、x射线衍射和断层扫描对暴露的试样进行表征，以观察钢的结构随着热暴露的增加而发生的变化，并确定是否发生任何脆化或机械性能的变化，这些变化如果用于聚变反应堆可能会导致问题。也可能有机会将这项工作与辐照和/或腐蚀的影响结合起来。这个项目是一个多技术的方法来了解一个重要的核聚变能源材料的结构完整性。学生将有机会学习如何使用先进的模拟软件包和表征技术，并将与UKAEA和NNL的行业合作伙伴密切合作。