JP0055172

Current Status of the KSTAR Project

Duk-In Choi Korea Basic Science Institute

I. KSTAR Project Mission The project mission of the KSTAR (Korea Superconducting Tokamak Advanced Research) project is to develop a steady-state-capable advanced superconducting tokamak to establish the scientific and technological bases for an attractive fusion reactor as a future energy source. The KSTAR Tokamak Research Objectives are 1) To extend present stability and performance boundaries of tokamak operation through active control of profiles and transport, 2) To explore methods to achieve steady state operation for tokamak fusion reactors using non-inductive current drive, and 3) To integrate optimized plasma performance and continuous operation as a step toward an attractive tokamak fusion reactor. The design features of the KSTAR tokamak are 1) Fully superconducting magnets, 2) Long pulse operation capability, 3) Flexible pressure and current profile control, 4) Flexible plasma shape and position control, and 5) Advanced profile and control diagnostics.

National Fusion Council

Fusion R&D Committee

Project Lead (Management & Integration)

Korea Basic Science Institute Tokamak Physics & Modeling International Project Support KAIST & KBSI

1 Tokamak Structure Power & Heating & CD W, Cryo & PFC Control Systems

KBSI & Hanjung Postech & POSCON KAERI & Postech

Superconducting Diagnostics Fileling SL Vacuum Magnet System System KAIST & KBSI SAIT & SNU KJBSI & KRISS

Fig.l KSTAR Project organizational chart

The phases & milestones of the KSTAR Project are 1) Design & Construction Phase (1995 - 2002) where Conceptual Design Review Milestone (December 1997), Final Design Review Milestone (December 1998), and First Plasma Milestone (August 2002), 2) Basic Operation Phase (2002 - 2005) which includes Ohmic Discharge Baseline Operation, Basic Auxiliary Heating & Current Drive Experiment, and Advanced Diagnostics & Control

-10- Advanced Superconducting Tokamak R&D (HAN-Project) (Unit : Billion Won) ~~~~~-—^Project Year 1995 1996 1997 1998-2001 Sub-Total Funding CaTT"^-—^^^ Government 3.0 6.1 8.0 72.9 90.0 Atomic Energy fund - - 4.0 21.0 25.0 KEPCO 2.0 3.0 - - 5.0 Industries 1.5 2.0 4.0 22.5 30.0 Total 6.5 11.1 16.0 116.4 150.0

o Building and Conventional Facility Construction (Unit : Billion Won) ~—-~_ ___ Year 1997 1998 1999 2000 Total

Government 6.8 18.0 23.3 21.4 69.5

Table 1 KSTAR R&D and Construction Project Cost

Development, and 3) Advanced Mode Operation Phase (2006 - 2010) which includes High-b Experiment with Flexible Equilibrium Control, Profile Control for Confinement Improvement (J(r), P(r), etc.), Long-pulse Operation for Steady-State Issues and * Support ITER Physics Phase Issues.

^—^__ Parameters Remarks

Major Radius, Ro 1.8 meter Minor Radius, a 0.5 meter

Toroidal Field, &ro 3.5 Tesla • Nb3Sn, NbTi Plasma Current, Ip 2.0 MA Elongation, K 2.0 Triangularity, 5 0.8 • Double-null

Pulse Length 20 sec < tpUise < 300 sec • Current Drive Heating & Current Drive NBI • PI, NI ICRH / FWCD, LHCD, ECRH Plasma Species H/D • Neutron Budget

Table 3 Korean National Fusion Project - Advanced Superconducting Tokamak Experiment -

— 11 Fig. 2 KSTAR Overview

Neutral Beam Injector Vacuum Pumps

IR/FIR Interferorneter/Polarimeter

Visible Filteracope Visible Bremssrahlung Visible Survey Spectrometer Thomson scattering Visible Survey Spectrometer

Soft. X-ray Arrays Soft X-ray Spectrometer X-ray Pin hole Ca m er u Plasma /IR-TV ~ .___ Bolometer Arrays '—~ ECE Diagnostics X-ray Crystal Spectrometer UV Survey Spectrometer

Neutral Roam Injector

Multichannel Neutron Collima (.or Bolometer Arrays Charge Kxchange N. A. P)asma_/I_R TV

Multichannel Visible Spectrometer Neutral Beam Injector Reflectometer Charge Fusion Products

Fig. 3 KSTAR Experiment Layout

II. Issues of KSTAR Physics design issues of the KSTAR project are as follows. 1) Magnetic Field Requirements; Two-point Ripple Criterion (16 TF Coils) and Error Field Correction Coils ("Window-pane" type), 2) Flexible Operation Boundary & Plasma Shape Control; Wide- range k and d Values (PF Coil Capability), Double-null and Single-null Configurations, Two-pairs of Fast Position Control Coils (Field-null Quality), and to Explore Feed-back Stabilization Scheme, 3) Flexible Profile Control; J(r), n(r) & P(r) Control by NBI, FWCD & LHCD, Horizontally-stacked NBI, and to Explore Local Heating & CD using

-12- ECH/ECCD, and 4) Low Voltage Start-up Capability; ECH-assisted Start-up (possibly, LHH-assisted),and Good Field-null Quality. The functions of KSTAR Auxiliary Heating & Current Drive Systems are 1) Plasma Heating and Current Drive, 2) Profile Control, 3) Rotation Control, and 4) Plasma Initiation, which are arranged to allow flexible current & pressure profile control.

Baseline Upgrade Remarks

8 MW 24 MW 120 keV Neutral Beam 1 Co 2 Co, 1 Ctr - 300 sec

6 MW 12 MW 30-80 MHz ICRF/FWCD 1 Launcher 2 Launchers -300 sec

3.7 GHz LHCD 1.5 MW 4.5 MW - 300 sec

80 GH* ECH 0.5 MW ECH Start-up (0 5 sec)

Table 4 KSTAR Auxiliary Heating & Current Drive Systems

To meet KSTAR Mission and Research Objective, especially, active control of Profiles and transport, and steady-state operation, KSTAR Tokamak requires 1) Advanced Profile and Control Diagnostics; Poloidal field & plasma current measurement, Spatially & temporally resolved density and temperature for each plasma species, and to Explore Diagnostic Neutral Beam for Higher Resolution MSE & CERS. and 2) Development Steady-state Capable Diagnostics & Control Techniques. To meet aggressive schedule and resource limitation, KSTAR Project requires Phase Diagnostics Implementation; Basic Diagnostics Set, Baseline Diagnostics Set I & II, and Mission-Oriented Diagnostics Set.

The Engineering Design Issues of KSTAR are 1) Superconducting Magnet Systems; ITER HP-1 based Capable-In-Conduit type Conductor, 16TF Coils, and 8 Segmented Central Solenoid, 2) Plasma Facing Components; Initially, 20 second Full-power Capability with Upgrade Provision to 300 Second, and 3) Vacuum Vessel; Double-walled Toroidal Shell Construction with SS316LN (Borated water for Nuclear Shielding) The KSTAR project will make critical contributions to the world fusion research and development program. It will 1) extend advanced tokamak research to high performance and steady state operation regimes, 2) contribute techniques for successful steady state physics operation of ITER, and 3) compare advanced tokamak physics results with those from superconducting stellarators and spherical tokamaks. Successful construction and operation of KSTAR tokamak will advance Korea's scientific and technological capability in significant ways, such that 1) large scale superconducting magnet design, manufacture and operation, 2) high power neutral beam, microwave and radiofrequency technology, 3) state-of-the-art plasma diagnostics and controls, and 4) advanced computational methods. The major milestones of the KSTAR project are that 1) Design point definition workshop (February 1997 at PPPL), 2) Physics validation review and engineering workshop Qune 1997 at KBSI), 3) Tokamak systems engineering review (December 1997 -13- at KBSI), and 4) Auxiliary systems engineering review (March 1998 at KBSI).

III. Reviews of KSTAR The summary of findings and recommendations of the KSTAR physics validation review is as follows. The reviewers find that the KSTAR machine rightly focuses on areas which are crucial for development of fusion reactors. The reviewers also find that the KSTAR design team have incorporated state-of-the-art knowledge of plasma physics and operation to meet the goals, and that the present design of KSTAR, with 40MW of heating power and 300 sec pulse length, and with a high degree of flexibility, adequately meets its requirements. Moreover, the reviewers find that the construction of KSTAR is very timely; the knowledge of plasma physics is now mature enough to support the design of advanced tokamaks like KSTAR, and the advanced tokamak experiments i n KSTAR in the middle of the next decade will contribute to filling the possible gap between the present tokamak devices and ITER, and also benefit the ITER project by exploring these operational scenarios which might well be applicable to ITER. Moreover, KSTAR long pulse experiments will further comparisons among different magnetic confinement schemes. The reviewers also find that the design of KSTAR is flexible, which is essential for experimental exploration of optimized regimes and testing of innovative concepts. The KSTAR device will be even more attractive as a result of the planned upgrades, including increases of heating power, modification of the geometry and/or materials of plasma facing components, and extension of the pulse length, ultimately approaching steady state. The reviewers expect that the advanced capability of KSTAR will assure that KSTAR will be able to significantly contribute to the world's fusion research and development for many years to come. The KSTAR project is also expected to demonstrate many areas of technology, highlighted by the full deployment of superconducting magnets, and should bean important stimulus for Korean industrial development. Furthermore, the KSTAR with its Advance Mode Operation Phase can continue to play a complementary and important role even after the start of operation of ITER. The reviewers also endorse the staffing plan as proposed by the KSTAR team as reasonable and necessary to carry out a vibrant research program. To summarize the reviewers find that 1) The physics requirements and design for KSTAR device are sound and they adequately support the KSTAR project objectives and the program goals, and that 2) The KSTAR device provides a very important vehicle for innovative plasma physics research that will enhance the state of the art and that is directly in support of tokamak fusion reactor development.

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