北京正负电子对撞机重大改造工程中超导四极磁体传热与流动计算

超导四极(SCQ)磁体是北京正负电子对撞机重大改造工程(BEPCⅡ)的关键设备之一。本文对SCQ磁体恒温器进行稳定运行状态下传热和流动计算。计算得到了磁体在低温下的热负荷以及磁体恒温器内各组成部分的温度分布，并在此基础上，提出减小SCQ磁体热负荷的方法。比较计算了SCQ磁体采用超临界和过冷液氦两种冷却方式对磁体稳定运行的影响。     

BEPCⅡ超导插入四极磁体冷却流程的数值分析

按北京正负电子对撞机重大改造工程（BEPCⅡ）计划，为压缩束团尺寸、提高探测器的分辨率以及粒子识别能力，在南对撞区分别安装1对强聚焦超导插入四极磁体（SCQ）和1台超导螺线管探测器磁体（SSM）。本文针对1对超导插入四极磁体的冷却，采用数值模拟的方法给出了SCQ磁体分别采用超临界氦流和过冷氦流两种冷却方式下冷却流程的热力参数，通过对模拟结果的分析，给出了适合该超导插入四极磁体的冷却方式和正常运行的热力参数。还给出了该低温系统关键设备之一的过冷器的设计方法以及设计参数。      

变负荷电流引线的设计

超导核聚变实验装置(EAST)的极向场超导磁体常常运行在空载、变电流条件下,将这种电流引线设计成过载电流引线可以进一步降低低温系统的热负荷。本文计算了不同材料制作的电流引线在额定电流和过载情况下的漏热、温度分布等参数,在分析计算的基础上给出了制造电流引线时的选材原则以及过载运行的条件。     

ADS注入器I超导短磁铁研制及测试

加速器驱动次临界系统(Accelerator Driven Sub-critical System,ADS)注入器I超导磁铁经过2012年模型磁铁(300 mm长磁铁)阶段后,因加速器物理设计需要,磁铁机械长度缩短到170 mm,截至到2014年共经过了三种结构类型的超导磁铁的研制。2014年7月在哈尔滨工业大学进行短磁铁的低温垂直测试,磁铁的各项性能指标都满足了设计要求,同时也验证了失超探测和磁场测量设备的可靠性。本文主要介绍170 mm长短磁铁的物理及结构、电流引线、失超保护以及超导磁铁裸磁铁的低温垂直测试情况。目前有两块超导短磁铁,两个超导腔已装入到测试恒温器中,并实现了2.1 K下的低温运行,超导磁铁的运行平稳,电流引线常温端也无结霜现象。     

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。     

C-ADS主加速器系统CM4低温恒温器的热负荷分析

为了优化CM4低温恒温器的结构型式,本文对低温恒温器热负荷来源进行了研究,包括低温绝热支撑(POST)、电流引线、高功率耦合器的热传导,80K冷屏的热辐射,超导腔、高功率耦合器的动态热负荷等。研究结果表明,CM4低温恒温器满足低热负荷的要求,为下一步低温恒温器的优化及运行调试提供了理论基础。     

ITER磁体过渡馈线的结构设计与优化

国际热核聚变实验堆ITER(Intemational Thermonuclear Experimental Reactor)是正在进行的一项大型国际合作项目.磁体过渡馈线是保证磁体正常工作的重要通道.本文对磁体过渡馈线系统各组件结构进行了设计,利用有限元软件对结构作了初步分析和结构优化.结果表明:现有结构完全满足设计要求;通过对现有结构进行优化,如增设横向筋板、L型加强板,简化超导电流传输线(Busbar)的弯曲结构等,可以达到降低成本、简化结构的目的.     

ITER10kA电流引线高温超导段研究

国际热核实验反应堆(ITER)高温超导电流引线（HTSCL）的特点是不仅电流容量大,且安全性要求非常高,高温超导段是HTSCL的关键部件。本文论述了ITER10kA电流引线高温超导叠和超导组件的真空钎焊工艺,分析了高温超导段漏热,并对高温超导段漏热和电流引线在10kA下的安全性参数进行了测试。结果表明,电流引线不仅漏热小,且安全裕度大,满足ITER设计要求。     

液氮温度下高T_C超导材料电阻率及零场电流密度测量装置

介绍了测量液氮温度下高T_c超导材料电阻率及零场下电流密度装置的原理及结构。装置适用于测量电阻小于10~(-9)Ω临界电流大于600A的超导材料。由于采用了衰减法,所以精度较高。在液氮温度下,探头的线性度优于1％,放大器的漂移约为±1μV/h(折合到输入端),感应变压器可在超导环内产生1000A的感应电流。     

托卡马克HT-7U低温超导磁体的绝缘系统

主要介绍低温超导托卡马克HT-7U中磁体的绝缘结构,绝缘材料的特性,绝缘结构形成的工艺,绝缘层的电性能和力学性能等。     

旋转线圈测量法测量BEPCⅡ对撞区超导磁铁磁场

北京正负电子对撞机二期工程(BEPCⅡ)中的超导磁铁用来提高BEPCⅡ的对撞亮度,并对闭轨和耦合进行校正。超导磁铁要尽可能靠近对撞点(IP),并浸泡在1.0T的探测器BESⅢ螺线管磁场中。对撞点两侧各有1块超导磁铁,每块都包含有聚焦磁铁SCQ、水平偏转磁铁SCB/HDC、垂直校正子VDC、斜四极子SKQ及反螺线管AS等功能磁铁。利用旋转线圈的测量方法对SCQ、SCB/HDC、VDC、SKQ等进行测量,了解其积分场、高次谐波及沿束流运行方向的局部磁场。通过与BNL在垂直杜瓦中的测量结果进行的比较可知,高次谐波测量结果差别不大;与张力线的比较可知,SCQ及SCB的主极矩偏差小于3×10-3。表明提出的计算方法可进行磁场的绝对测量。     

R＆D on Resistive Heat Exchangers for HTS High Rated Current Leads

The HTS current leads of superconducting magnets for large scale fusion devices and high energy particle colliders can reduce the power consumption for cooling ...     

超导磁体气冷电流引线的优化设计

从超导磁体气冷电流引线的经典微分方程出发,将电流引线分为很少的几段,提出了一种较为精确计算电流引线长横比及由电流引线末端流入低温容器热量的计算方法。并以黄铜为例计算了电流引线的长横比和流入低温容器的热量。     

EAST安全联锁监管系统设计

全超导托卡马克装置(FullSuperconductingTokamak,FST)所有主要磁体均为超导磁体,其运行风险大大高于现有的其它超导托卡马克。EAST(ExperimentalAdvancedSuperconductingTokamak)是一个全超导托卡马克装置,为了避免人员和装置出现意外事故,建立了联锁系统与安全系统。安全联锁监管系统位于EAST联锁系统与安全系统的顶层,协调各分控系统的安全运行。根据EAST安全联锁系统的需求,采用可编程逻辑控制器、联锁信号光纤网和光电转换设备,建立了安全联锁监管系统,实现了事件收集、信号循环扫描、保护动作输出、系统状态和故障日志信息记录和实时监控等功能。该系统实际扫描周期平均值约0.7ms,最大值约3ms,达到了EAST安全联锁系统的要求。     

Experimental Study on Paschen Discharge in Helium for High Voltage Cryogenic Insulation Material

According to the requirements of large superconducting components, all the solid superconducting insulation of current leads, magnets, cooling and measurement pipeline at high potential should withstand 80–300 K thermal cycles. If helium leak or pipe leak taken place, and insulation has been formed some flaws, Paschen discharge would be occur. The experimental program aimed at analyzing the low-temperature electro-physical performance of solid superconducting insulation, which was designed with different configuration such as thickness, material structure and so on. The dielectric performance of both pre-preg cryogenic insulation and the wet wrap cryogenic insulation were studied. Both of the dielectric strength of the two type insulation is in the range from 11 to 23 kV/mm at 80 K helium condition. Besides, both of the two type insulation samples of 3 and 5 mm thickness can withstand 30 kV under various helium pressures at 80 K.     

The structural design of superconducting magnets for the large coil program

Fusion reactor designs based on magnetic confinement will require the use of superconducting magnets to make them economically viable. For a tokamak fusion reactor; large magnetic field coils are required to produce a toroidal magnetic confinement volume. Although superconductors have been used for approximately 20 years, several requirements for their application in fusion reactors are beyond demonstrated technology in existing magnets. The Large Coil Program (LCP) is a research, development, and demonstration effort specifically for the advancement of the technologies involved in the production of large superconducting magnets. This paper presents a review of the status of the structural designs, analysis methods, and verification tests being performed by the participating LCP design teams in the US, Switzerland, Japan, and the Federal Republic of Germany. The significant structural mechanics concerns that are being investigated with the LCP are presented.     

Calculation of AC Losses of CICC for Superconducting Outsert Coils in a Hybrid Magnet

This paper is devoted to predict AC loss of Cable in Conduit Conductor (CICC) which is of importance in the design of conductors. The consideration for the conductor’s design and main parameters for the magnets are introduced. In order to attain a good accuracy in the calculation of AC losses, the field distribution within superconducting outsert should be considered. Calculation of the AC losses, including hysteresis losses and coupling losses, is conducted. An emphasis is put on the hysteresis loss during the ramp up of the current to the operational current (15.3 kA) and the coupling loss of the conductor in a power-down condition for insert. The results are obtained to be 74.9kJ and 950J for 40 T hybrid magnets, respectively. Based on the calculation, a brief analysis of losses effect on the conductor design and the operation of magnet is given for the purpose that the capacity of the cryogenertor can be evaluated and the stability regime can be improved in our future work on the hybrid magnets.