Soviet Tokamak T-15

Soviet Tokamak T-15
Name	T-15
Caption	T-15 tokamak at Kurchatov Institute (archival)
Country	Soviet Union
Institution	Kurchatov Institute
Type	Tokamak
Construction	1978–1983
Operation	1988–1995
Major dimensions	Major radius ~2.67 m; minor radius ~0.67 m
Toroidal field	~2.4 T
Plasma current	~1.5 MA
Heating	Neutral beam injection, ohmic, auxiliary RF
Decommissioned	1995

Soviet Tokamak T-15 The T-15 was a large magnetic confinement tokamak built in the late Soviet era at the Kurchatov Institute in Moscow to explore high-temperature plasma physics and fusion reactor technology. It combined engineering ambitions of the Soviet fusion program with experimental goals aligned to international efforts in tokamak research conducted by laboratories such as the Princeton Plasma Physics Laboratory, Culham Centre for Fusion Energy, and Max Planck Institute for Plasma Physics. The machine contributed to studies relevant to designs like the ITER project, the JET programme, and influenced subsequent devices in Russia and abroad.

Design and technical specifications

T-15 was designed by teams at the Kurchatov Institute, the General Physics Institute, and industrial partners such as NPO Energomash and Kurchatov Machine-Building Plant. Its vacuum vessel and toroidal field coils were engineered by specialists with experience from projects like Tokamak T-3, T-4, T-7, and collaborations with institutes including the Lebedev Physical Institute and the Institute of High Energy Physics (Protvino). The machine featured a vacuum chamber with a major radius of about 2.67 m and a minor radius near 0.67 m, similar in scale to contemporary reactors at the Princeton Beta Experiment and TEXTOR.

The magnetic system provided toroidal fields around 2.4 tesla produced by superconducting and copper coils developed with expertise from enterprises linked to the Ministry of Medium Machine Building and design bureaus such as KBKhA. Plasma currents up to ~1.5 MA were achieved using transformer action informed by earlier work at TRINITY-era projects and influences from designs tested at ASDEX and DIII-D. Heating systems included neutral beam injection (NBI) supplied by components developed with knowledge from the Institute for Nuclear Research (INR), radio-frequency (RF) systems based on research at the Institute of Applied Physics, and ohmic heating derived from conventional transformer drive technology used in devices like JT-60.

Diagnostics suites incorporated interferometry, Thomson scattering, soft X-ray cameras, magnetic probe arrays, spectrometers, and bolometry, developed in cooperation with groups from the Kurchatov Institute's Institute of Atomic Energy, Moscow State University, and the Institute of Spectroscopy. Control systems used industrial electronics from firms connected to the Soviet Academy of Sciences and algorithms inspired by control work at Oak Ridge National Laboratory and Los Alamos National Laboratory.

Construction and commissioning

Construction began in the late 1970s under project leadership drawn from the Kurchatov Institute leadership and engineers influenced by earlier Soviet tokamak builders linked to the Lebedev Physical Institute and the Institute of Atomic Energy. Major components were fabricated at enterprises associated with the Ministry of Power Engineering and assembled in dedicated halls at the Kurchatov campus alongside other installations like the T-10 tokamak. International contacts involved exchanges with scientists from the International Atomic Energy Agency and delegations that had visited facilities such as Culham and Princeton.

Commissioning phases included vacuum certification, cryogenic testing of coils, and integration of NBI systems. Early plasma discharges followed commissioning protocols similar to those used at ASDEX Upgrade and JT-60U, with stepwise increases in current and heating power. Diagnostic calibration drew on techniques employed at TFTR and JFT-2M, while safety and regulatory oversight referenced standards from the Soviet Academy of Sciences and industrial safety bureaus.

Operational history

T-15 entered experimental operation in the late 1980s and produced plasmas that enabled studies of confinement, MHD stability, and plasma-material interaction. Experimental campaigns were organized by research groups from the Kurchatov Institute, the Moscow Institute of Physics and Technology, the Bauman Moscow State Technical University, and visiting scientists from the Budker Institute of Nuclear Physics and the Institute of Plasma Physics (Princeton). Operations included comparative studies with machines such as JET, TFTR, and DIII-D to benchmark confinement regimes, and collaboration with teams from the European Fusion Development Agreement.

During operation T-15 explored high-temperature plasmas with auxiliary heating, producing results relevant to disruption physics studied extensively at ITER preparatory efforts and to divertor concepts under consideration at ASDEX. The machine also tested first-wall materials and limiter configurations similar to experiments at TEXTOR and Tore Supra.

Research and experimental programs

Research on T-15 covered magnetohydrodynamic (MHD) stability, plasma turbulence, transport barriers, and plasma-facing component performance. Experimental programs involved scientists from institutions such as the Kurchatov Institute, Moscow State University, Institute for Theoretical and Experimental Physics (ITEP), and the Russian Academy of Sciences. Studies linked to edge-localized modes (ELMs), sawtooth oscillations, and resistive wall modes drew comparisons with data from ASDEX Upgrade, NSTX, and KSTAR.

Material testing programs evaluated carbon, tungsten, and beryllium alloys similar to research at JET and Tore Supra, and diagnostics efforts advanced interferometry and Thomson scattering techniques refined at Culham Centre for Fusion Energy. Neutral beam experiments paralleled work at MTX and informed NBI system development at later Russian devices. Computational modeling used codes influenced by efforts at Princeton Plasma Physics Laboratory, Max Planck Institute for Plasma Physics, and academic centers like Moscow State University.

Decommissioning and legacy

T-15 ceased routine operation in the mid-1990s amid funding constraints after the dissolution of the Soviet Union and shifts in Russian science policy overseen by agencies such as the Russian Academy of Sciences and the Ministry of Science and Higher Education. Decommissioning activities followed protocols similar to those used at closed facilities like TFTR and involved dismantling of vacuum vessel components and salvage of diagnostic equipment that later supported projects at the Kurchatov Institute and regional fusion centers.

The legacy of T-15 endures through personnel, diagnostic techniques, and engineering lessons that informed later devices such as the T-15MD upgrade, collaborative work with ITER partners, and contributions to fusion programs at the International Thermonuclear Experimental Reactor planning forums. Alumni of the program continued research at institutions including the Kurchatov Institute, Budker Institute of Nuclear Physics, Moscow Institute of Physics and Technology, and international laboratories such as Culham and Princeton Plasma Physics Laboratory, preserving T-15's impact on global tokamak development.

Category:Tokamaks