EAST中性束注入器电源故障实时监测系统设计

为实现对EAST中性束注入(Neutral Beam Injection,NBI)器电源系统在线运行状态进行实时监测,论文提出了一个基于FPGA、百兆以太网和C#用户终端的全光纤组网实时故障态监测系统解决方案。系统对中性束注入装置各电源的故障态以及输出波形进行实时采集和组网传输,并拥有用户终端进行监测和控制操作,在中性束装置实验运行测试中获得了较好的结果。系统对于大量分散信号的分布采集和远程监测系统设计具有一定参考价值。     

EAST中性束注入器水流热量累积测量系统误差分析

水流量热法是强流离子束束功率测量常用的方法,由于测量仪表安装位置的问题,EAST(Experimental Advanced Superconducting Tokamak)全超导托卡马克中性束注入水流热量累积测量系统中存在不可忽略的误差。本文结合水流热量累计测量系统的原理分析其误差的来源,针对其中由于采集时间有限和真空室内外热传递损失三部分误差来源进行了详细的分析和修正,将沉积功率百分比由73.72%提高到86.27%,修正结果显著。最终将修正方法嵌入到现有的沉积功率计算系统中,实时地进行误差修正,从而得到更精确的沉积在热承载部件上的功率沉积,为功率沉积分布和中性化效率的精确测量提供依据。     

EAST中性束注入器大厅内辐射剂量计算与测量

利用解析方法对EAST大功率中性束注入器充氢运行时实验大厅内6个关键点的辐射剂量进行了理论计算,并利用光致光剂量计(OSL)对这些位置点进行了辐射剂量测量。理论计算和OSL测量结果表明:理论计算结果与实验测量结果具有一定吻合度。同时还表明:EAST中性束注入器现有的防护装置满足实验运行时辐射防护要求。     

EAST中性束注入射频离子源放电模拟研究

中性束注入加热是核聚变中非常重要的一种辅助加热手段,离子源所能达到的性能决定了东方超环(Experimental Advanced Superconducting Tokamak, EAST)中性束注入所能达到的指标。为了实现长脉冲和高功率加热的需求,采用射频离子源取代传统的热阴极离子源已成为未来离子源发展的一种趋势。本文对射频离子源的结构设计和放电特性进行了理论模拟研究,给出了线圈匝数、匝间距、驱动器尺寸、放电气压和射频功率等参数与等离子体参数间的关系,为接下来射频离子源的研制和实验奠定一定的理论基础。     

EAST中性束注入器稳态偏转磁铁的参数设计与估算研究

中性束注入器偏转磁铁是剥离束流中剩余离子的关键设备,它与剩余离子吞食器等内部部件构成了中性束注入器的束偏转系统。束偏转系统的性能对中性束注入器束流的品质及其束传输效率发挥着重要作用。本文根据EAST(Experimental Advanced Superconducting Tokamak,EAST)中性束注入器对束偏转系统的要求,对其偏转磁铁各性能参数进行了估算。为中性束注入器设计了一台用以剩余离子180°偏转的偏转磁铁。该偏转磁铁采用H型二极电磁铁结构;其磁极端面设计为138cm×47cm的圆角矩形结构;其线圈设计为每侧2饼,每饼2层,每层8根的串联结构,导线选用外方内圆空心铜导体,以满足偏转磁铁稳态运行的需要。该设计的偏转磁铁在370 A励磁电流条件下,可提供80keV氘离子束偏转所需的磁场。实验测试结果显示:500 A励磁电流稳态运行条件下,偏转磁铁线圈冷却水温升约21.5℃,该设计结构的偏转磁铁满足EAST中性束注入器满参数稳态运行和未来运行参数逐步提高的需要。     

ASDEX中性束注入器的供电系统

本文介绍ＡＳＤＥＸ中性束注入器供电系统概况，对注入器的高压电源，磁场反馈控制和弧打坑电路作较较详细的介绍。     

EAST中性束注入下快离子输运行为的研究

利用等离子体输运分析程序TRANSP和粒子导心轨道模拟程序ORBIT,结合聚变中子和等离子体储能诊断数据,对EAST(Experimental Advanced Superconducting Tokamak)托卡马克中性束注入加热时不同等离子体电流和纵场强度下的快离子输运行为进行了研究。实验和模拟结果表明:中性束反向束注入时的快离子初始轨道损失功率大于中性束同向束;中性束4条束线产生快离子初始轨道损失区域主要集中在装置中平面以下第一壁以及偏滤器区域;在EAST目前的运行参数范围内,提高等离子体电流和纵场强度,可以使等离子体中快离子的漂移轨道宽度和拉莫尔回旋半径缩小,更有利于快离子的约束,从而提高中性束的加热效率,增加聚变中子产额和等离子体储能。     

EAST托卡马克的中性束注入方案

高能中性束注入(Neutral beam injection,NBI)是核聚变装置托卡马克采用的芯部辅助加热和非感应电流驱动主要手段之一.本文介绍了国家大科学工程全超导托卡马克实验装置(Experimental advanced super-conductingtokamak,EAST)上的高能NBI加热方案及注入器的工程要求,并讨论了中性束在EAST等离子体中的传输等相关问题.     

EAST-NBI离子源电极打火分析及处理

强流离子源是EAST(Experimental Advanced Superconducting Tokamak)中性束注入器(Neutral Beam Injector,NBI)最关键的核心部件,其能达到的性能在很大程度上决定了EAST中性束注入器所能达到的指标。离子源在束引出时电极打火现象偶有发生,这对于离子源的正常运行有非常严重的影响,甚至危害离子源的寿命。本文结合离子源运行过程中的束引出实验波形和水流量热计(Water Flow Calorimetry,WFC)系统的测量数据得出等离子体发射面的束流光学系统一直处于非最佳聚焦状态是导致打火的原因,试通过优化高压投入时刻等离子体与高压的匹配,实现高压的稳定投入有效抑制打火现象的发生,并且给离子源加入硬件保护机制,为离子源安全稳定运行奠定基础。     

Optimization of the gas flow in the neutralization region of EAST neutral beam injector

According to the problems encountered in the experiments of the EAST neutral beam test stand, the design of neutralizer of EAST neutral beam injector is suggested to modify to optimize the gas flow in the neutralization region. The modifications contain narrowing the slits between the neutralizer and the mounting flange hole, and rotating the gas injection angle from 90° to 60° in the neutralizer. In this paper, an adjusted Direct Simulation Monte Carlo (DSMC) code was used to estimate the modification. The results show that a little change of the slits width causes a large variation of gas target thickness, and the rotation of the gas injection angle can effectively reduce the gas density near the accelerator but with a little of decrease of target thickness.     

Design of the reflection magnet and its shielding effect analysis for the neutral beam injector of EAST

In this paper,a reflection magnet to be installed in the EAST neutral beam injection system is simulated and designed.The field intensity of reflection magnet of 42-cm maximum bending radius is about 1.539×10-1 T for 100 keV deuterium beam.The shielding cage is formed by rods.Using the ANSOFT software,the magnetic shielding effect was estimated at about 3% at the magnet pole region.     

Gas flow and related beam losses in the ITER neutral beam injector

The gas flow in the ITER neutral beam injectors has been studied using a 3D Monte Carlo code to define a number of key parameters affecting the design and operation of the injector. This paper presents the results of calculations of the gas density in the two accelerator concepts presently considered as options for the ITER injectors, and the resultant stripping losses of the negative ions during their acceleration to 1 MeV. The sensitivity of the model to various parameters has been studied, including the gas temperature in the ion source and the subsequent accommodation by collisions with the accelerator structure, and the degree of dissociation of the D₂ or H₂ in the ion source, and subsequent recombination during collisions with the accelerator structure. Additionally the sensitivity of the losses to details of the beam source design and operating parameters are examined for both accelerator concepts.     

The influence of neutral beam optimization for DEMO on injector design

The requirements for neutral beam injection (NBI) on DEMO are assessed and the consequences for the design of the injectors discussed. Optimization of current drive requires NBI within a 2 m × 2 m envelope at large tangency radii. This is compatible with beamlines of 20 m length and moderate high voltage stand-off distances between injectors. However, q-profile control will necessitate at least three beamlines of different injector types and may not be compatible with shinethrough. Material irradiation studies show that, with three exceptions, there is no significant design issue for distances greater than 3 m from the tokamak wall.     

Design study of a 120-keV,3He neutral beam injector

We describe a design for a 120-keV, 2.3-MW,³He neutral beam injector for use on a D-³He fusion reactor. The constraint that limits operating life when injecting He is its high sputtering rate. The sputtering is partly controlled by using an extra grid to prevent ion flow from the neutralizer duct to the electron suppressor grid, but a tradeoff between beam current and operating life is still required. Hollow grid wires functioning as mercury heat pipes cool the grid and enable steady state operation. Voltage holding and radiation effects on the acceleration grid structure are discussed. We also briefly describe the vacuum system and analyze use of a direct energy converter to recapture energy from unneutralized ions exiting the neutralizer. Of crucial importance to the technical feasibility of the³He-burning reactor are the injector efficiency and cost; these are 53% and $5.5 million, respectively, when power supplies are included.The beam is composed of 91 separate, parallel currents that flow in the gaps between the elements or wires of a grid. Each such flow is referred to as a beamlet. The current densities in Figs. 5, 8, and 9 are values within a beamlet, as measured at the beam-forming grid. They are not values averaged over the entire beam cross-section.     

Simulation of EAST off-axis neutral beam heating and current drive

The capability of off-axis neutral beam heating and current drive has been investigated with NUBEAM for Experimental Advanced Superconducting Tokamak (EAST). Three different approaches to realize off-axis Neutral Beam Injection (NBI) have been studied. Simulation results for on- and off-axis NBI are reported. The effects of the alignment of NBI relative to the magnetic field pitch on off-axis neutral beam heating and current drive are observed and discussed qualitatively. By comparing the numerical results, a most favorable off-axis NBI configuration is recommended. The capability to control sawtooth is also investigated by comparing locations of the q = 1 rational surface and the peak of the fast ion density profile.