Verification and Optimization of Vacuum Vessel Supports Design in KTX

The Vacuum Vessel(VV) system is an essential component of Keda Torus for experiment(KTX),and various scenarios might take place on it.The VV’s supports should be adequately strong to stand against various loads on VV,which might happen in extreme scenarios.Therefore,the design of VV supports is verified in a single extreme scenario and is subsequently optimized in this report.The numerical simulation based on Finite Element theory is performed as the major method for analysis and optimization.The electromagnetic force in previous analyses serves as the load for the mechanical analyses of supports.During the optimization,the stresses of the W supports decrease remarkably after introducing cotters.Finally,the optimum design has been worked out.It satisfies the requirements regarding the strength and convenience in assembly.     

Linear Buckling Analysis of the HT-7U Vacuum Vessel

1. IntroductionHT-7U superconducting Tokamak, as a nationalproject, is an advanced steady-state plasma exper-imental device to be built in 2Oo3. Now all kindsof engineering design have been begun. The vac-uum vessel is one of the key parts for HT-7U de- vice, which can provide not only a clean and ultra-high vacuum env1ronment in the operatlon of plasmafor the production quilibrium and heating of thelasma, but also reliable supporting structure andvarious channels for a series of equipme…     

Analytical Analysis of the Electromagnetic Response for the Vacuum Vessel of EAST

During plasma disruptions and vertical displacement events (VDEs), time-varying eddy currents are induced on Vacuum Vessel (VV) and Plasma Facing Components (PFCs) of Tokamak. In this paper, we calculate eddy currents induced forces on VV and inner limiter (one of the PFC) during plasma disruption in Experimental Advanced Superconducting Tokamak (EAST). Various plasma transients—VDEs and major disruptions (MDs) are considered. And the study includes assessments of integral values (net vertical, hoop forces), time evolution, peaks of the force distribution. It is shown that the distribution pattern of the eddy currents for different scenarios differ greatly, therefore the resulting EMFs and torques cause different mechanical response.     

Numerical Analysis on Neutron Shielding Structure of ITER Vacuum Vessel

The neutron shielding component of ITER （International Thermonuclear Experimental Reactor） vacuum vessel is a kind of structure resembling a wall in appearance. A FE （finite element） model is set up by using ANSYS code in terms of its structural features. Static analysis, thermal expansion analysis and dynamic analysis are performed. The static results show that the stress and displacement distribution are allowable, but the high stress appears in the junction between the upper and lower parts. The modal analysis indicates that the biggest deformation exists in the port area. Through modal superposition, the single-point response has been found with the lower rank frequency of the acceleration seismic response spectrum. But the deformation and the stress values are within the permissible limit. The analysis results would benefit the work in the next step and provide some reference for the implementation of the engineering plan in the future.     

Design and Structural Analysis of Support Structure for ITER Vacuum Vessel

The International Thermonuclear Experimental Reactor (ITER) vacuum vessel (VV) is a safety component confining radioactive materials such as tritium and activated dust. An independent VV support structure with multiple flexible plates located at the bottom of VV lower port is proposed as a new concept, which is deferent from the current design, i.e., the VV support is directly connected to the toroidal coils (TF coils). This independent concept has two advantages comparing to the current one: (1) thermal load due to the temperature deference between VV and TF coils becomes lower and (2) the TF coils are categorized as non-safety components because of its independence from VV. Stress Analyses have been performed to assess the integrity of the VV support structure using a precisely modeled VV structure. As a result, (1) the maximum displacement of the VV corresponding to the relative displacement between VV and TF coils is found to be 15 mm, much less than the current design clearance of 100 mm, and (2) the stresses of the whole VV system including VV support are estimated to be less than the allowable ones defined by ASME Section III Subsection NF, respectively. Based on these assessments, the feasibility of the proposed independent VV support has been verified as a VV support.     

Temperature Field and Thermal Stress Analysis of the HT-7U Vacuum Vessel

1.IntroductionHT-7UsuperconductingTokamakisanadvancedsteady-stateplasmaphysicsexperimentaldevice.ThedevicewillbebuiltattheinstituteofPlasmaPhysics,theChineseAcademyofSciencesintheyear2003.Itscessionistodevelopthescientific.basisandtechnologicbajsisforthefutureTokamakfusionreactorsandtostudyphysicalissuesonthesustenanceOfanon-burningplasmascenarioforthesteady-stateoperation.TheHT--7Uhasacapabilityforlongpulse(60-1000s)operation.Theprojecthasbeenapprovedandfundedasanationalmegscience-engin…     

KTX反场箍缩装置纵场线圈结构设计与电磁分析

KTX反场箍缩装置的主要参数介于RFX装置与MST装置之间。反场箍缩的外加纵场需跟随等离子体电流的演化而变化,同时由于RFP中的磁面对于外部特别是等离子体边界处的径向磁场较敏感,所以需外部线圈的磁场更加精细,这对于线圈的磁场分布、误差场以及波纹度等的设计提出了更高的要求。根据KTX物理目标参数要求,提出矩形和楔形截面纵场磁体线圈设计方案,借助有限元软件和程序分析了其电磁场空间分布和结构受力大小。结果表明,6.4°楔形截面方案相比矩形截面方案在控制误差场方面更具有可行性。     

Electrical Parameters of the Vacuum Vessel in HT-7U Tokamak

1. IntroductionThe time-t'arying currents in plasma and poloidalfield coils induce the eddy current on the vacuumvessel of tokamak- The magnetic field produced bythe eddy currents has an effect on the penetrationof poloidal field, the position and the shape of theplasma: t'.hich is related to the structure of the yao-uum vessel and the distribution of the eddy currentsThe level of the effect can be described by the electrical parameters of the vessel, being of very importance in the study Of t…     

The Design of the Plasma Control System in KTX

KTX(Keda Torus for eXperiment)is a new reversed field pinch device.The KTX plasma control system(PCS)can provide real-time,stable,flexible plasma control which is designed by ASIPP(Institute of Plasma Physics,Chinese Academy of Sciences),based on the Linux cluster system and EPICS(Experimental Physics and Industrial Control System)framework,and developed from DIII-D(Doublet III-D)PCS.The control of the equilibrium field in KTX uses a PID(Proportional-Integral-Derivative)feedback controller.The control of the gas injection is an open loop control.The plasma control simulation system is one part of the plasma control system,which is used to test the plasma control algorithm if it is revised and updated.The KTX PCS has been successfully tested using HT-7(Hefei Torus 7)experiment data in simulation mode.In the next phase,an error field feedback control and KTX simulator will be added to the KTX PCS,and the KTX PCS will be applied in experiments in the future.     

Electromagnetic and Structural Analysis on Vacuum Vessel for CFETR During Plasma Major Disruption

China Fusion Engineering Test Reactor (CFETR) is a superconducting magnet tokamak and its goal is to achieve the magnetic confinement fusion. The electromagnetic (EM) transients cause mechanical forces, which represent one of the most vital loads for tokamak vacuum vessel (VV). This paper is focused on calculational methods and results for the EM loads on the simplified but practical model of CFETR VV with respect to plasma major disruption scenarios as a reference of the design and analysis. Commercial finite element method software, ANSYS, was employed to evaluate the eddy current on the VV module with the 22.5 ° sector model for major conducting structure of the tokamak including double-walled VV, T-shape rib, and three ports. The plasma current is damping as exponential function 36 ms corresponding to the current simulating in ITER outputs, which are one of major sources of EM loads on VV components. As the results of calculating the eddy currents and EM forces, stress and deformation on CFETR VV can be obtained, which is useful for the structural design of VV.     

Capability Assessment of the Equilibrium Field System in KTX

Radial equilibrium of the KTX plasma column is maintained by the vertical field which is produced by the equilibrium field coils.The equilibrium is also affected by the eddy current,which is generated by the coupling of copper shell,plasma and poloidal field coils.An equivalent circuit model is developed to analyze the dynamic performance of equilibrium field coils,without auxiliary power input to equilibrium field coils and passive conductors.Considering the coupling of poloidal field coils,copper shell and plasma,the evolution of spatial distribution of the eddy current density on the copper shell is estimated by finite element to analyze the effect of shell to balance.The simulation results show that the copper shell and equilibrium field coils can provide enough vertical field to balance 1 MA plasma current in phase 1 of a KTX discharge.Auxiliary power supply on the EQ coils is necessary to control the horizontal displacement of KTX due to the finite resistance effect of the shell.     

Manufacturing preparations for the European Vacuum Vessel Sector for ITER

The contract for the seven European Sectors of the ITER Vacuum Vessel, which has very tight tolerances and high density of welding, was placed at the end of 2010 with AMW, a consortium of three companies. The start-up of the engineering, including R&D, design and analysis activities of this large and complex contract, one of the largest placed by F4E, the European Domestic Agency for ITER, is described. The statutory and regulatory requirements of ITER Organization and the French Nuclear Safety regulations have made the design development subject to rigorous controls. AMW was able to make use of the previous extensive R&D and prototype work carried out during the past 9 years, especially in relation to advanced welding and inspection techniques. The paper describes the manufacturing methodology with the focus on controlling distortion with predictions by analysis, avoiding use of welded-on jigs, and making use of low heat input narrow-gap welding with electron beam welding as far as possible and narrow-gap TIG when not. Further R&D and more than ten significant mock-ups are described. All these preparations will help to assure the successful manufacture of this critical path item of ITER.     

Design of the poloidal field system for KTX

The design of the poloidal field (PF) system includes the ohmic heating field system and the equilibrium (EQ) field system, and is the basis for the design of a magnetic confinement fusion device. A coupling between the poloidal and plasma currents, especially the eddy current in the stabilizing shell, yields design difficulties. The effects of the eddy current in the stabilizing shell on the poloidal magnetic field also cannot be ignored. A new PF system design is thus proposed. By using a low-μ material (μ=0.001, ε=1) instead of a conductive shell, an electromagnetic model is established that can provide a continuous eddy current distribution on the conductive shell. In this model, a 3D time-domain problem with shells translates into a 2D magnetostatic problem, and the accuracy of the calculation is improved. Based on these current distributions, we design the PF system and analyze how the EQ coils and conductive shell affect the plasma EQ when the plasma ramps up. To meet the mainframe design requirements and achieve an efficient power-supply design, the position and connection of the poloidal coils are optimized further.     

氚在真空贮存容器材料中的吸附和渗透行为

研究了贮存氚靶约4 a和20 a的两个316 L不锈钢真空贮存容器(以下简称贮存容器)及其垫片材料对氚的吸附行为,并对氚在贮存容器材料中的渗透速率进行了测量和分析。结果表明,贮存容器外表面氚污染为几十Bq/cm2,不锈钢与陶瓷中吸附的氚活度均为106Bq/g;热解吸至1 273 K过程中,材料中99%的氚释放出来;在解吸出的氚中,陶瓷中的HTO比例高于不锈钢;贮存温度对氚靶贮存容器的渗氚速率有较大影响,夏季约为冬季的4倍。上述结果提示,氚在贮存容器材料内表面吸附后,一部分会向晶格扩散并滞留下来;另一部分则透过材料向外环境渗透,其中温度是影响氚向外环境渗透的主要因素之一。     

CFETR真空室超压保护系统管道设计与优化

真空室超压保护系统(VVPSS—Vacuum Vessel Pressure Suppression System)是中国聚变工程实验堆(CFETR—China Fusion Engineering Test Reactor)中重要的安全系统之一,它目的是预防在泄漏事故下,真空室和相关组件可能产生的过压损害。本文简述了VVPSS的总体设计和管道优化。主要介绍了VVPSS各个部件之间的联系和作用,初步得到管线布局;利用有限元分析软件对两种管路方案进行流体分析比较,得出对流体流动影响最小的方案;对是否能通过增加支路数目来减小爆破片的直径做出了初步探究,为核聚变装置中真空室超压保护系统的设计提供一定的参考依据。     

CFETR真空室超压保护系统管道设计与优化

真空室超压保护系统(VVPSS—Vacuum Vessel Pressure Suppression System)是中国聚变工程实验堆(CFETR—China Fusion Engineering Test Reactor)中重要的安全系统之一,它目的是预防在泄漏事故下,真空室和相关组件可能产生的过压损害。本文简述了VVPSS的总体设计和管道优化。主要介绍了VVPSS各个部件之间的联系和作用,初步得到管线布局;利用有限元分析软件对两种管路方案进行流体分析比较,得出对流体流动影响最小的方案;对是否能通过增加支路数目来减小爆破片的直径做出了初步探究,为核聚变装置中真空室超压保护系统的设计提供一定的参考依据。