中国聚变工程试验堆上的环形阿尔芬本征模线性稳定性及中子壁负载研究

发布时间：2018-08-13 09:02

【摘要】：随着传统能源的日益枯竭,对新能源的开发与利用是人类进步的必然选择。聚变能由于具有原材料储量丰富和安全无污染等诸多优点,被认为是解决人类能源危机的最佳方案。在磁约束聚变装置当中,托卡马克被认为是最有希望实现可控核聚变的实验装置。中国聚变工程试验反应堆(Chinese Fusion Engineering Test Reactor,CFETR)是正处于设计当中。CFETR的目标是为了获得长脉冲、氚自持的稳态运行,并且填补ITER和DEMO装置之间的空白,目前其初步的概念设计已经完成。在聚变反应堆中,氘氚聚变反应会产生3.5 MeV的高能α粒子。此外,中性束注入(NBI)和离子回旋波共振加热(ICRH)会产生高能离子以及低杂波(LHW)和电子回旋共振加热(ECRH)会产生高能电子。这些高能粒子具有内在自由能,并且高能粒子的速度和阿尔芬相速度接近,从而可以通过波粒共振来激发阿尔芬本征模不稳定性,反过来,这种不稳定的阿尔芬本征模能够造成高能粒子的重新分布或者损失,甚至有可能损坏约束壁。因此,对高能粒子与阿尔芬本征模相互作用的研究是托卡马克物理中一个重要的研究课题。其中典型的如环形阿尔芬本征模(TAE),它是由环向模数相同、极向模数相邻的波模耦合而成的。氘氚聚变还会产生中子。中子壁负载(NWL)表示聚变反应产生的中子打到第一壁的能量通量密度,它是决定包层材料和结构的一个重要参数。并且中子壁负载对聚变电站的经济、性能、设计、安全以及环境方面都有影响。本论文主要是在CFETR上研究被高能粒子驱动的TAE稳定性以及动理学参数对中子壁负载的影响。本论文一共分为6章,其中第1章为引言部分,第2章介绍了托卡马克等离子体中高能粒子与剪切阿尔芬波的相关物理研究背景,第3章,第4章和第5章是本论文研究的主要内容,第6章是工作总结以及展望。本论文的具体研究内容如下:在第3章中,在CFETR上使用NOVA/NOVA-K程序研究了环向模数n在1到12之间的TAE模的稳定性。我们是使用CORSICA程序来构造等离子体的平衡,安全因子选择为ITER方案中的三种典型剖面分布。对于这三种不同的安全因子分布,使用NOVA程序来计算它们的连续频谱和本征模结构,然后使用NOVA-K程序来计算对于不同环向模数下的驱动和各种阻尼。数值计算结果表明除了有一个不稳定的TAE模以外,在TAE频率间隙(gaps)中找到的所有TAEs都是稳定的。该不稳定的TAE是对应于安全因子正常剪切(normal shear)情况下的本征模,并且对应的环向模数是n = 4。这三种典型平衡剖面分布的主要差别是安全因子。如果安全因子剖面分布选择恰当,那么对应的所有TAEs都是稳定的。因此在CFETR上可以通过修改安全因子的剖面分布来减少TAE模的不稳定性。此外,通过扫描等离子体密度和温度分布来研究它们对TAE稳定性的影响。尽管等离子体剖面分布不是自洽的,但是扫描结果表明在很广的范围内CFETR上的TAE稳定性都是有效的。在第4章中,介绍了 M3D/M3D-K程序中的计算方法以及所使用的理论模型。M3D/M3D-K程序包含的理论模型主要有理想磁流体、电阻磁流体、双流体模型,以及动理学与磁流体混合模型。根据CFETR新尺寸下的参数,使用M3D/M3D-K程序对环形阿尔芬本征模进行了线性计算。在第5章中,我们计算了 CFETR上的中子壁负载分布,并且呈现了等离子体密度和温度剖面分布对中子壁负载分布的影响。计算结果表明:对于CFETR 200 MW的聚变功率,NWL的最大值是在外中平面附近,并且对应的NWL大约是0.4 MW/m2。等离子体密度和温度剖面分布对NWL的影响很小。因此,对于不同的运行方案,动理学参数对NWL的影响可以忽略。NWL的大小主要是由总聚变功率决定的。当对CFETR的包层结构进行设计时,如果总聚变功率保持不变,那么可以不考虑托卡马克的运行方案对包层的影响。
[Abstract]:With the depletion of traditional energy, the development and utilization of new energy is the inevitable choice of human progress. Fusion energy is considered the best solution to the human energy crisis because of its abundant reserves of raw materials, safety and non-pollution. Among the magnetic confinement fusion devices, Tokamak is considered the most promising one. The China Fusion Engineering Test Reactor (CFETR) is currently under design. The goal of CFETR is to obtain long pulse, tritium self-sustaining steady-state operation, and to fill the gap between ITER and DEMO. Its preliminary conceptual design has been completed. In addition, neutral beam implantation (NBI) and ion cyclotron resonance heating (ICRH) produce high-energy ions as well as low-energy clutters (LHW) and electron cyclotron resonance heating (ECRH) which produce high-energy electrons. These high-energy particles have intrinsic free energy and high-energy particle velocity and Al. In turn, the unstable eigenmode can cause redistribution or loss of high-energy particles, and may even damage the confinement wall. Therefore, the study of the interaction between high-energy particles and the eigenmode of Alphan is a Tokamak. One of the most important subjects in physics is the ring-shaped Alphan eigenmode (TAE), which is composed of the same ring-directional modulus and the adjacent polar-directional modes. Deuterium-tritium fusion also produces neutrons. Neutron wall load (NWL) represents the energy flux density of neutrons produced by fusion reaction hitting the first wall, which determines the cladding material. In this paper, the stability of TAE driven by high-energy particles and the influence of kinetic parameters on the neutron wall load are studied on CFETR. This paper is divided into six chapters. Chapter 1 is an introduction. Chapter 2 introduces the physical background of the high-energy particles and shear Alfven waves in Tokamak plasma. Chapter 3, 4 and 5 are the main contents of this paper. Chapter 6 is the summary and Prospect of the work. The specific research contents of this paper are as follows: In Chapter 3, the NOVA/NOVA-K program is used in CFETR. The stability of TAE modes with toroidal modulus n between 1 and 12. We use the CORSICA program to construct plasma equilibrium, and the safety factor is chosen as three typical profiles in the ITER scheme. For these three different safety factor distributions, the NOVA program is used to calculate their continuous spectrum and eigenmode structure, and then NOVA-K is used to calculate their eigenmode structures. Numerical results show that all TAEs found in the TAE frequency gap (gaps) are stable except for one unstable TAE mode. The unstable TAE is an eigenmode corresponding to the normal shear of the safety factor and corresponds to it. The circumferential modulus is n=4. The main difference between the three typical equilibrium profiles is the safety factor. If the safety factor profiles are properly chosen, all the corresponding TAEs are stable. Therefore, the instability of TAE modes can be reduced by modifying the safety factor profiles on CFETR. In addition, the plasma density can be scanned. In Chapter 4, the calculation method in M3D/M3D-K program and the theoretical model used are introduced. The M3D/M3D-K program contains Theoretical models include ideal magnetic fluid, resistive magnetic fluid, two-fluid model, and kinetic and magnetic fluid mixing model. According to the parameters of CFETR, the M3D/M3D-K program is used to calculate the linear eigenmodes of ring-shaped Alphan. In Chapter 5, the neutron wall load distribution on CFETR is calculated and the plasma is presented. The results show that the maximum value of NWL is near the outer-middle plane for the fusion power of CFETR 200 MW, and the corresponding NWL is about 0.4 MW/m2. The effect of plasma density and temperature profile distribution on the NWL is very small. Therefore, for different operation schemes, the kinetics of the NWL is studied. The influence of parameters on NWL can be neglected. The size of NWL is mainly determined by the total fusion power. When designing the cladding structure of CFTR, if the total fusion power remains unchanged, the influence of the operation scheme of Tokamak on the cladding can be ignored.
【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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