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Abstract: Since Korea joined ITER as Korea was developing a fully super-conducting tokamak, KSTAR, the national plan for developing fusion energy was renewed and focused on a clear mission – developing a technological self-reliant program for a fusion demonstration device. A new technical roadmap was developed toward self-reliant technologies for constructing a fusion power plant in a similar time window as in the EU, Japan and the US. This looks tough and formidable but Korea could take advantage of their well-established nuclear technologies in power plant design, construction, and operation. The government and the legislature recognized the importance of this effort by establishing a special law for supporting it practically and for giving it a high priority in their R&D agenda. Under this favorable environment, various scenarios for finding the most effective and efficient path to achieve the goal were reviewed and some of the features of this review will be presented. [Copyright &y& Elsevier]

The Korea Superconducting Tokamak Advanced Research (KSTAR) is a medium size, fully superconducting tokamak, which is scheduled to begin operation in year 2006. The control system of KSTAR consists of a supervisory system, plasma control system, and local control systems for various subsystems. Modular system, high reliability, flexibility and long time maintainability are major factors for the system design. The EPICS is the first choice for the distributed system control and the MDSPlus will be utilized for the data handling and analysis. The reflective memory network will be used for the real time plasma control. A pilot system has been being developed with VME and Compact PCI buses. Current status of the development of KSTAR control system will be presented. [Copyright &y& Elsevier]

The Hanbit mirror device is equipped with three kinds of data acquisition hardware: CAMAC; VME eXtensions for instrumentation (VXI); and PCI eXtensions for instrumentation (PXI). This hybrid system is managed by several MDSplus servers that are linked across a standard TCP/IP network. Each server directly acquires data from one or two frames of digitizers, analyzes data, and then archives them onto a hard disk to produce a high performance distributed data acquisition system (DAS). CAMAC modules are controlled by a Dec Alpha computer through the drivers provided together with MDSplus. Only small number of VXI and PXI drivers have been available until now. Therefore, an application is developed in C which utilizes the manufacturer-provided drivers for VXI and PXI. By sending commands to the application, MDSplus indirectly controls VXI and PXI. This paper will describe how the whole system is integrated and how it is controlled in a centralized manner. [Copyright &y& Elsevier]

Abstract: Beginning the first plasma discharging experiment of KSTAR since 2008, KSTAR performed the third plasma discharging experiment by 2010. During the experiment of three times, KSTAR OPerator Interface (OPI) programs have been developed for KSTAR operation by itself. OPI programs used in KSTAR were implemented by KSTAR widget plug-in Toolkit (KWT). The KWT means the plug-in library implemented by Qt-based user interface development software. The main purpose of developing the KWT library is to implement full automation libraries having interface with the automated EPICS channel access (CA) guaranteeing the flexibility for requirements of operators. In addition, it has advantages in minimizing human code error and maximizing utilization of the limited human resource. According to the increasing of control systems, a number of OPI servers connected to one EPICS gateway server caused the connection problem and increased the amount of the network data packets. To solve these problems, an algorithm of “CachedChannelAccess” for shared memory base was implemented into an inner logic of the KWT library. KSTAR control system monitoring (CSM) program is one of applications developed by using KWT library. The function of CSM program is to notify alarm to operators by checking health status of every server's network health status and resource (cpu, memory, network packets, disk usage rate and system/user defined process) usage state. Another application is a post-shot sequencing program which is activated after every shot is completed. This application is to display major plasma parameters and diagnostic data in chart form, to save this data to database, and to transfer a chart image file to a web server. This paper describes the technical details how to develop OPI applications which have high productivity using Qt on the EPICS-based control system. [Copyright &y& Elsevier]

Abstract: The neutral beam injection (NBI) system was designed to provide plasma heating and current drive for high performance and long pulse operation of the Korean Superconducting Tokamak Advanced Research (KSTAR) device using two co-current beam injection systems. Each neutral beam injection system was designed to inject three beams using three ion sources and each ion source has been designed to deliver more than 2.0MW of deuterium neutral beam power for the 100-keV beam energy. Consequently, the final goal of the KSTAR NBI system aims to inject more than 12MW of deuterium beam power with the two NBI for the long pulse operation of the KSTAR. As an initial step toward the long pulse (∼300s) KSTAR NBI system development, the first neutral beam injection system equipped with one ion source was constructed for the KSTAR 2010 campaign and successfully commissioned. During the KSTAR 2010 campaign, a MW-deuterium neutral beam was successfully injected to the KSTAR plasma with maximum beam energy of 90keV and the L-H transition was observed with neutral beam heating. In recent 2011 campaign, the beam power of 1.5MW is injected with the beam energy of 95keV. With the beam injection, the ion and electron temperatures increased significantly, and increase of the toroidal rotation speed of the plasma was observed as well. This paper describes the design, construction, commissioning results of the first NBI system leading the successful heating experiments carried in the KSTAR 2010 and 2011 campaign and the trial of 300-s long pulse beam extraction. [Copyright &y& Elsevier]

Abstract: The in-vessel control coil (IVCC) system, which has been designed for dedication of various active feedback plasma control functions, successfully fabricated and installed in the vacuum vessel of the Korea Superconducting Tokamak Advanced Research (KSTAR). The IVCC system consists of sixteen segmented coils that were independently fabricated outside the vacuum vessel and installed without any inside welding or brazing joints. The segmented coil system has several advantages such as eliminating possibility of cooling water leakage at the welded or brazed joints, simplification in fabrication and installation, and easy repair and maintenance of the coil system. Each segment contains eight oxygen-free high conductive coppers, which are grouped to four pairs, called as sections. Consequently, a segmented coil forms four sections for position control, field error correction (FEC), and resistive wall mode (RWM) control in accordance with electrical connection outside the cryostat. The eight conductors (or four sections) with internal coolant holes were enclosed in a rectangular welded jacket made of stainless steel 316LN and electrically insulated from the conductors by epoxy/glass composite layers. This coil system was commissioned up to 5kA (30kA-turns) for 5s to achieve tentative use for the fast vertical plasma position control in the 2010 campaign of the KSTAR. This paper describes the several remarkable results in the fabrication and installation of the IVCC as well as commissioning results. [Copyright &y& Elsevier]

Abstract: The KSTAR plasma facing components (PFCs) consist of inboard limiter, poloidal limiter, divertor, passive stabilizer and neutral beam armor. The main function of the PFCs is to define boundary of operating plasma and to protect the vacuum vessel and in-vessel components such as diagnostic components, in vessel control coil and several kinds of launchers for heating and current drive systems. The divertor is designed to enhance effective particle control to keep high quality plasma with various flexibilities in the shaping control for wide range of operational regime. The passive stabilizer that is made of CuCrZr alloy is designed to passively control the vertical position and MHD instabilities during operation as well as outer boundary of the plasma. Since fabrication has been started for all of the plasma facing components from middle of 2009, the inboard limiter, the divertor, and the passive stabilizer were successfully installed in the vacuum vessel, in turn. Moreover, one set of neutral beam armor and three strings of poloidal limiters were also installed according to the heating system that newly comes in 2010. All the PFCs tiles were baked to 200°C and the PFC system showed no vacuum leakage and other mechanical troubles. In this paper, key features, fabrication, results of assembly, and baking of the KSTAR PFCs are summarized in detail. [Copyright &y& Elsevier]

Abstract: In-vessel components of the Korea Superconducting Tokamak Advanced Research (KSTAR) were developed for 2010 campaign to provide a crucial circumstance for achieving the strongly shaped and diverted plasma. Moreover, the in-vessel components such as limiter, divertor, passive stabilizer, in-vessel control coil (IVCC) system demonstrated good performances satisfying the original design concepts. In addition to the plasma facing components and the IVCC, in-vessel cryo-pump (IVCP) system was also installed to leverage divertor operation. Besides the in-vessel components, there have been substantial progresses in development of the heating and current drive system. The KSTAR heating and current drive system includes all kinds of the major heating systems such as neutral beam injection (NBI), ion cyclotron range of frequency (ICRF), electron cyclotron resonance heating and current drive (ECH and ECCD), lower hybrid current drive (LHCD) systems. As an initial stage for full equipment of the heating systems to total power of 26MW, several key systems such as 1st NBI (called NBI-1), ICRF, and ECH-assisted startup system successfully demonstrated their excellent feasibilities in the design and performances for dedication to the 2010 campaign. [Copyright &y& Elsevier]

Abstract: The optical diagnostic system of KSTAR consists of visible diagnostics including toroidal and poloidal Hα monitors, a visible survey spectrometer, and filterscopes. A re-entrant cassette made of stainless steel, containing five optical quartz windows has been developed to allow easy access of the visible diagnostics to the plasma. The configuration and manufacturing design of the diagnostic cassette and the installation of optical diagnostic systems within the cassette are described. The structural and thermal analysis of the diagnostic cassette and in situ calibration of optical diagnostics have also been performed. The optical lens system showed good image quality by spot diagram analysis. [Copyright &y& Elsevier]

Abstract: It is possible to detect the presence of small field errors in a tokamak with an electron beam. This was demonstrated earlier on T-15 and TEXTOR. This paper discusses the concept, past experience on these tokamaks, calculations for the Korea Superconducting Tokamak Advanced Research (KSTAR) device, an electron beam source, measurement devices for these measurements, and some results. It is shown that small toroidally averaged field errors can be detected by this method. A low voltage electron beam (e-beam) gun and fluorescent screen were mounted in a vertical port and inserted into the vacuum vessel at the end of the KSTAR 2nd campaign plasma experiments. A camera with a narrow field of view was mounted in midplane port in a tube tangent to the field lines at R ∼1.3m and photographed the beam striking the screen. The poloidal field (PF) currents were held constant during the camera exposure period. Many shots with various PF coils energized were made and the deflections of the e-beam were measured. The measurements were made with a camera integration time of 300ms because of the low light intensity. The results show that there are large field errors that diminish as the PF currents are raised. There appears to be no significant up–down asymmetry for static fields. Measurements with a 7 PF coil scenario with a calculated field null located at e-beam radial position show much larger fields than calculated. KSTAR was constructed with Incoloy 908 conduit using cable-in-conduit conductors (CICC) in 10 of the 14 PF coils and all 16 of the toroidal field (TF) coils. Incoloy 908 has a relative magnetic permeability, μ, of about 10. The field errors appear to be largely due to Incoloy 908. [Copyright &y& Elsevier]

Abstract: After successful achieving first plasma, Korea Superconducting Tokamak Advanced Research (KSTAR) is now preparing second operation that includes power supplies with full power operation and more diagnostic systems. During first campaign the Experimental Physics and Industrial Control System (EPICS) was adopted as a control middleware of the KSTAR control system showed stable and reliable results and did not reveal any significant system failures. The EPICS based plant control system is used for data acquisition, data archiving and data visualization and is interfaced with Central Control System (CCS). A plant control system requires an EPICS Input Output Controller (IOC) and its own DAQ system. During the first operation the EPICS based control systems were mainly used slow data acquisition at a rate less than 10Hz. The hardware platforms were Programmable Logic Controller (PLC) and PCI eXtensions for Instrumentation (PXI). In this paper we will describe following items: the details of control function, implementation of each plant control system, operation results and analysis, focusing on the Tokamak Monitoring System (TMS), the Vacuum Monitoring System (VMS), the Current Lead System (CLS), the Helium Distribution System (HDS), and the Heating Systems. [ABSTRACT FROM AUTHOR]

Abstract: The supervisory interlock system (SIS), the personal safety interlock (PSI) and the radiation monitoring system (RMS) are the safety and protection system for the KSTAR operations. The supervisory interlock system prevents men and devices from an accident and it protects auxiliary systems and the superconducting tokamak against the propagation hazardous events. SIS is collecting events of the tokamak and auxiliary systems and decides a level of the event and command to stop the actions of local I&C for the KSTAR operation. The local interlock system is self-protecting from local accidents and executing orders from supervisory interlock system. SIS had accomplished its own functions at the first campaign of the KSTAR. Even though several unexpected incidents and mismanagement had occurred, the interlock function had been properly responding. We have test result of the emergency stop function for the superconducting magnet power supplies against accidents. We measured different shutdown time of each magnet power supply, which is about 1min, but we need to more analysis to the source of delay. We had inserted the current and density fault protection logics to stop the ECH and the ICRF at central control system through the first campaign. The short message system (SMS) had helped to restore fast of faults in local and KSTAR integrated control system (ICS). The processor regular scanning time is about 75ms that is longer than recommended scanning time of the redundancy system. We had reduced it <20ms by optimization of logic program during the maintenance period. This paper describes the interlock system functions of the first campaign, operation results, and update contents and results. [ABSTRACT FROM AUTHOR]

Abstract: The construction of the Korea Superconducting Tokamak Advanced Research (KSTAR) device has been completed by August 2007. Key achievements in the KSTAR construction are (i) fabrication process establishment in the Nb3Sn superconducting coils including interface components, (ii) development of magnet structures to resist high magnetic force and thermal loads of TF and PF coils, (iii) accurate assembling of all components using special assembly tools, and (iv) development of ancillary systems including a control system, magnet power supplies, diagnostic systems, heating systems, and cryogenic facility. Device commissioning has been started and the milestone for first plasma discharge is by the end of 2008. The KSTAR operation plan is targeted on the high performance plasma confinement research and long pulse operation achievement using the fully superconducting tokamak device. There is a lot of engineering similarity between KSTAR and ITER, such as using Nb3Sn superconductor for TF and CS magnets. The experience of the KSTAR device could be an important technical basis for the design, procurement, and initial operation of the ITER device, as a role of a ITER pilot device. [Copyright &y& Elsevier]

Abstract: KSTAR is fully superconducting tokamak under construction, capable of quasi-steady state, and long pulse operation. KSTAR has two parts of vacuum system. One is the cryostat vacuum system to maintain low temperature (4/80K) for thermal shielding of superconducting magnets. Other is the vacuum vessel to contain the plasma in double-walled evacuated space. For integration of KSTAR machine control, we chose experimental physics and industrial control system (EPICS) as a middleware at the engineering phase. Because EPICS is a good solution to implement the distributed control and the real time control for the tokamak, aiming at long pulse operation. The vacuum control system is the first local control system implemented using EPICS, and becomes an important pilot system to demonstrate the capability of EPICS on the machine control system. In this paper, we describe a procedure from designing hardware drivers to realizing operation panel. [Copyright &y& Elsevier]

Abstract: The time synchronization system (TSS) for KSTAR has been devised and is under development to support steady-state real time control for discharge operation, plasma diagnostics, and collection of a huge amount of data. The purpose of the system is to provide synchronized operation of all experiments according to the reference scenario, universal time for all the tokomak systems and appropriate time-stamping on all acquired data and events. The central timing system and local timing units, which comprise the time synchronization system, are connected via the dedicated optical time network. The TSS communicates via the giga-bit machine network for the provision of universal time, and uses the shared memory-based real-time network for real-time feedback control. A prototype timing modules has been developed and tested, it is based on the VME–bus standard and uses FPGA and micro-processors to implement the major functions such as time decoding, a 64-bit time counter, data processing, clock/pulse generation, etc. We are testing the pilot timing system with central and local timing units, and operated in an EPICS environment, the middleware program of the KSTAR control system. This paper presents features of KSTAR timing system and details of the developed prototype timing modules. [Copyright &y& Elsevier]

Abstract: The Korea Superconducting Tokamak Advanced Research (KSTAR) control system will be developed with several subsystems, which consist of the central control system (e.g. plasma control, machine control, diagnostic control, time synchronization, and interlock systems) and local control systems for various subsystems. We are planning to connect the entire system with several networks, viz. a reflective-memory-based real-time network, an optical timing network, a gigabit Ethernet network for generic machine control, and a storage network. Then it will evolve into a network-based, distributed real-time control system. Thus, we have to consider the standard communication protocols among the subsystems and how to handle the various kinds of hardware in a homogeneous way. To satisfy these requirements, EPICS has been chosen for the KSTAR control. The EPICS framework provides network-based real-time distributed control, operating system independent programming tools, operator interface tools, archiving tools, and interface tools with other commercial and non-commercial software. The most important advantage of the use of the EPICS framework is in providing homogeneity of the system for the control system developer. The developer does not have to be concerned about the specifics of the local system, but can concentrate on the implementation of the control logic with EPICS tools. We will present the details of the integration issues and also will give a brief summary of the entire KSTAR control system from an integration point of view. [Copyright &y& Elsevier]

Abstract: A complete software suite for integrated tokamak plasma control has been developed within the DIII-D program. The suite consists of software for real-time control of all aspects of the plasma, modeling, simulation and design tools for analysis and development of controllers, a flexible and modular architecture for implementation and testing of algorithms and many fully validated models. Many elements of the system have been applied to and implemented on NSTX and MAST. The DIII-D realtime plasma control system together with the integrated modeling and simulation suite have been selected for operational use by both the KSTAR and EAST tokamaks, and are also being used at General Atomics to investigate control issues for ITER. [Copyright &y& Elsevier]