ITER 10kA高温超导电流引线测试装置低温系统的研究

为ITER CC 10 kA高温超导电流引线服务的低温性能测试装置已研制完成,并成功运行。其低温系统主要由500W/4.5 K氦制冷机,真空杜瓦,低温组件(低温阀门,过冷槽,管道加热器,热防护层),汽化器及低温传输管线等部分组成。本文对真空杜瓦和过冷槽进行设计,并讨论该低温系统的冷却流程方案,最后通过电流引线10 kA稳态实验结果对低温系统的运行效果进行分析,结果表明该低温系统运行稳定,能满足ITER CC电流引线的测试需要。     

Preliminary Thermal Mechanical Analysis of the Equatorial Thermal Shield for ITER

Thermal analysis of the equatorial thermal shield for ITER is conducted in order to confirm that the cooling tube design was reasonable under both the plasma operational and the baking operational conditions. The structural performance was analyzed by means of the finite element software ANSYS. A comparison of the results with design requirements shows that the results of the simulation are within allowable design requirements, which indicates the feasibility and reliability of the equatorial thermal shield structure.     

Design of the Cryostat for HT—7U superconducting Tokamak

The cryostat of HT-7U tokamak is a large vacuum vessel surrounding the entire basic machine with a cylindrical shell,a dished top and a flat bottom.The main function of HT-7U cryostat is to provide a thermal barrier between an ambient temperature test hall and a liquid helium-cooled superconducting magnet.The loads applied to the cryostat are from sources of vacuum pressure,dead weight,seismic events and electromagnetic forces originated by eddy currents.It also provides feed-through penetrations for all the conecting elements inside and outside the cryostat.The main material selected for the cryostat is stainless steel 304L.The structural analyses including buckling for the cryostat vessel under the plasma operation condition have been carried out by using a finite element code.Stress analysis results show that the maximum stress intensity was below the allowable value.In this paper,the structural analyses and design of HT-7U cryostat are emphasized.     

CFETR VVPSS中爆破片优化设计与疲劳分析北大核心CSCD

为了应对泄漏事故下真空室内的过压情况,防止腔室内相关组件的过压损害,设计了真空室超压保护系统(VVPSS)。VVPSS是利用泄放装置(爆破片组件和泄压阀组件)泄放过压气体。考虑CFETR真空室内部布置的大量冷却管路,一旦发生严重的泄漏事故需要采用大直径爆破片在短时间内泄放大量过压气体。而国内的生产商无生产大尺寸爆破片的经验,所以大尺寸爆破片的研究工作迫切需要进行。本文简要描述了真空室超压保护系统的总体工程设计;为了方便快速拆装,满足遥操作的要求,开展了爆破片组件设计;利用有限元分析方法(FEM)研究了爆破片的厚度、圆角半径和缝宽对其爆破性能的影响,获得了符合设计要求的爆破片尺寸;同时针对使用寿命要求,对爆破片进行疲劳分析研究,获得目前爆破片结构使用寿命,分析结果满足设计要求。     

20 mm厚316LN不锈钢板的超高功率光纤激光自熔焊

采用20kW超高功率光纤激光器单道焊接了20mm厚316LN奥氏体不锈钢,研究了焊接工艺参数对焊缝成形及宏观形貌的影响,并对焊接接头的显微组织和力学性能进行了分析。结果表明,采用负离焦可以得到成形良好的焊缝;焊缝组织为单一的奥氏体组织,焊缝上部和底部中心区存在等轴晶粒,焊缝中部中心区为粗大的柱状晶。在优化的工艺参数下,焊接得到的接头抗拉强度为645 MPa,与母材相当。焊接接头断裂于熔合线边界处,为典型的韧性断裂。焊接接头热影响区的显微硬度略高于焊缝和母材。     

A Consideration on Increasing Current Density in Normal Conducting Toroidal Field Coil for Spherical Tokamak Power Plant

The center post is the most critical component as an inboard part of the toroidal field coil for the low aspect ratio tokamak. During the discharge it endures not only a tremendous ohmic heating owing to its carrying a rather high current but also a large nuclear heating and irradiation owing to the plasma operation. All the severe operating conditions, including the structure stress intensity and the stability of the structure, largely limit the maximum allowable current density. But in order to contain a very high dense plasma, it is hoped that the fusion power plant system can operate with a much high maximum magnetic field BT ≥12 T-15 T in the center post. A new method is presented in this paper to improve the maximum magnetic field up to 17 T and to investigate the possibility of the normal conducting center post to be used in the future fusion tokamak power plant.     

Conceptual Design and Analysis of Cold Mass Support of the CS3U Feeder for the ITER

In the International Thermonuclear Experimental Reactor(ITER) project,the feeders are one of the most important and critical systems.To convey the power supply and the coolant for the central solenoid(CS) magnet,6 sets of CS feeders are employed,which consist mainly of an in-cryostat feeder(ICF),a cryostat feed-through(CFT),an S-bend box(SBB),and a coil terminal box(CTB).To compensate the displacements of the internal components of the CS feeders during operation,sliding cold mass supports consisting of a sled plate,a cylindrical support,a thermal shield,and an external ring are developed.To check the strength of the developed cold mass supports of the CS3U feeder,electromagnetic analysis of the two superconducting busbars is performed by using the CATIA V5 and ANSYS codes based on parametric technology.Furthermore, the thermal-structural coupling analysis is performed based on the obtained results,except for the stress concentration,and the max.stress intensity is lower than the allowable stress of the selected material.It is found that the conceptual design of the cold mass support can satisfy the required functions under the worst case of normal working conditions.All these performed activities will provide a firm technical basis for the engineering design and development of cold mass supports.     

Numerical Simulation Approaches to Evaluating the Electromagnetic Loads on the EAST Vacuum Vessel

Numerical simulation approaches are developed to compute the electromagnetic forces on the EAST vacuum vessel during major disruptions and vertical displacement events, with the halo current also considered. The finite element model built with ANSYS includes the vacuum vessel, the plasma facing components and their support structure, and the toroidal and poloidal field coils. The numerical methods are explained to convince of its validity. The eddy current induced by the magnetic flux variation and the conducting current caused by the halo current are also presented for discussion. The electromagnetic forces resulting from the numerical simulation are proven to be useful for structure design optimization. Similar methods can be applied in the upgrades of the EAST device.     

一种应用于聚变堆的多层密封的设计与分析

遥操作系统的设计是中国聚变工程实验堆(CFETR)中的一个关键问题,其中遥操作车的密封结构设计在整个停堆维护过程中起着重要作用,它是保证操作者可以安全、可靠和可重复性执行针对不同维护对象的维护任务的前提。文中首先介绍了CFETR遥操作转运车以及双密封门的设计,针对多层密封的特点进行了优化改进;然后对密封圈的选材做了分析,并详细计算了所需密封力的大小,根据结果选择硬度50HS的氟橡胶作为密封圈材料;最后设计了检漏的方案,对泄露情形做了分析,计算了压降和随时间变化关系,结果满足操作时间要求和系统安全要求。     

国际热核聚变实验堆磁体线圈终端盒的设计

线圈终端盒（CTB）是国际热核聚变实验堆超导磁体系统的重要组成部分,其内部组件的漏热常常是整个磁体系统的主要漏热源之一,在很大程度上决定着低温系统的液氦消耗量。本文从降低热负荷的角度对CTB内部冷屏、超导电流传输线、电流引线、阀及冷却管路、外部盒体的设计进行了详细阐述,为最终结构的确定提供了理论依据。