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Greeting from the Director

Yasuhiko Takeiri Director Department of Fusion ScienceApril, 2015
竹入康彦 専攻長

Solar energy, which is the source of life on Earth, and the energy of stars glowing in the night sky both are born of nuclear fusion. If we can achieve on Earth the fusion energy that has been produced in space without pause since the Big Bang 13,700,000,000 years ago, the human race will gain never-ending energy. At the Department of Fusion Science, School of Physical Sciences, SOKENDAI (The Graduate University for Advanced Studies), education focusing on fusion energy science is conducted aiming at the cultivation of human resources in the fields of advanced science technologies in our country. Study in the Department of Fusion Science undertaken at the National Institute for Fusion Science (NIFS), which is in the National Institutes of Natural Sciences, Inter-University Research Institute Corporation. NIFS promotes leading-edge research in nuclear fusion science to realize a sun on Earth.

In order to achieve the use of fusion energy, plasma having a temperature higher than 120,000,000 degrees should be steadily maintained. At NIFS, using the world’s largest superconducting large-scale device, Large Helical Device (LHD), based upon an idea unique to Japan called the heliotron system, we are advancing greatly in this research through high-temperature plasma experiments using the magnetic field. The behavior of such high temperature plasmas is extremely complicated and draws our intellectual curiosity. In order to make clear the physics in those plasmas, we also promote research utilizing theory and simulation in parallel with the experiment. In addition, we are developing fusion engineering research that includes super-conducting technology and plasma heating devices for further technical enhancements. Moreover, we also devote much effort to academic research in fields across physics and engineering, including the engineering design of a future reactor and related studies such as material development and the engineering system.

The subjects of fusion research cover a broad range of academic research, and we can only realize the use of fusion energy by correlating them with each other and by integrating them as a whole. In the Department of Fusion Science, students are guided according to their interest under a supervisor conducting research at the highest level in the world. The advantage of the Department of Fusion Science is that students are guided by more than one leading scientist and they are trained to be internationally active researchers through discussions with foreign researchers and through opportunities to attend international conferences.

More than fifty years have passed since the development of fusion energy began. Now, the generation of fusion energy through ITER (International Thermonuclear Experimental Reactor) is planned for 2027. However, there still remain issues to be solved and it will take at least thirty years to realize a fusion reactor.

Because the fuels deuterium and lithium are found in seawater in nearly inexhaustible amounts, there is no worry of their supply running out. Further, because the fusion reaction does not emit carbon dioxide, there is no strain placed upon the environment, and these fuels are excellent in terms of safety. Now we need the power of young generations. Let’s pursue realization of fusion energy, the dream of all humanity.

History and Organization – SOKENDAI

1988 Oct The SOKENDAI (Graduate University for Advanced Studies) was established with a three-year PH.D. program system.
1989 May The National Institute for Fusion Science (NIFS) was established in Nagoya.
1992 Apr The Department of Fusion Science established at the School of Mathematical and Physical Science were established.
Atsuo Iiyoshi inaugurated as the first Chair of the Department.
1997 Jul NIFS moved to Toki city, in Gifu Prefecture.
1997 Dec Construction of the LHD was completed.
1999 Apr Masami Fujiwara inaugurated as the second Chair of the Department.
2003 Apr Osamu Motojima inaugurated as the third Chair of the Department.
2004 Apr A National Unicersity Corporation reformulated SOKENDAI.
2006 Apr The 5-year Ph.D. program system was introduced.
2009 Apr Akio Komori inaugurated as the fourth Chair of the Department.
2015 Apr Yasuhiko Takeiri inaugurated as the fifth Chair of the Department.


Organization chart

About Us


SOKENDAI is a graduate university which provides superior doctoral studies programs in international research fields and learning environments. Students develop an outstanding knowledge of scientific frontiers while working with leading researchers in the world. SOKENDAI was established in 1988 as the first independent graduate university in Japan that does not provide undergraduate courses.

The administrative office of SOKENDAI is in Hayama-cho, Kanagawa Prefecture. Other campuses where academic activities are promoted in fields ranging from the arts and humanities to science and engineering are located in various areas of Japan.

To develop fusion power as a future energy source, scientific understanding of high temperature plasma physics and advanced engineering for realizing a fusion power plant are absolutely necessary. For these purposes, we promote a complementary approach of high temperature plasma experiments, integrated theoretical research, numerical simulations using a supercomputer, and material studies.

The unique point of the department is that students learn a wide range of cutting edge scientific and engineering knowledge such as plasma physics, atomic physics, electrical and mechanical engineering, superconductivity engineering, material engineering, vacuum engineering, and information engineering. This is because fusion science requires highly integrated synthetic research.

The Frontier of Nuclear Fusion Research

Ultimate Energy for Creating the Future

All of the stars in the universe are bright because of nuclear fusion energy. It is a great dream for humanity to realize the controlled nuclear fusion reaction on Earth and utilize the energy for life.

The nuclear fusion reactor can produce a great amount of energy, and ensures safety, good environmental acceptability, and a rich resource. The nuclear fusion reactor has the following advantages and problems for its realization.

  • Advantages

    • The fuel is inexhaustible because it exists in the sea.
    • The emitted CO2 and/or air pollution material is small.
    • The produced energy density is high.
    • The nuclear fusion reaction is intrinsically safe. When accidents occur, the reaction automatically stops.
    • High-level radioactive waste is not generated.
  • Problems

    • The fuel plasma must be steadily confined at an extremely high temperature and in a high density condition. These have not yet been attained simultaneously.
    • The in-vessel structure of the reactor, which has the property of high heat resistance as well as low radioactivation, is under development.
    • A reliable system that converts the nuclear fusion energy to heat energy is being developed.
    • This costs a great amount of money because of the large facility that is necessary for research and development.

The nuclear fusion reactor is currently expected to be realized in 30 years.

Nuclear Fusion Research in the World

There are two principal systems for plasma confinement. One is the “magnetic confinement system” as represented by the helical type and the tokamak type. The other is the “inertial confinement system.” In the magnetic confinement system, high temperature plasmas are confined using a strong magnetic field. At the National Institute for Fusion Science, plasma physics, technology, and simulation research are being conducted concentrating on the Large Helical Device (LHD), which is the world’s largest helical system. The concept of the helical system originated in Japan. The helical system has the excellent property of steady-state plasma operation because the confinement magnetic field can be produced using only the external magnetic coils. The best performance of the steady-state plasma has been achieved at the LHD. Plasma research using a helical device has been conducted in Japan, Germany, Spain, Australia,and other countries. A tokamak-type device achieved the world record of the fusion criterion, which is determined as the product of the ion temperature, the ion density, and the energy confinement time. The tokamak system requires a plasma current to produce the confinement magnetic field. The accurate control method of the plasma current is one of the most important issues of the tokamak system in order to realize the steady-state operation. Tokamak plasma physics have been investigated in Japan, the United States, the United Kingdom, Germany, China, Korea, and other countries. For the inertial confinement system, the nuclear fusion reaction occurs by implosion of the fuel by an instantaneous strong force using high energy lasers or ion beams. The inertial confinement system has been investigated mainly in the United States and Japan.

  • Helical system
  • Tokamak system

TOPICInternational Thermonuclear Experimental Reactor (ITER)

  • ITER
  • he energy confinement property of fusion plasma improves as the plasma volume grows. Thus, the upsizing of the fusion experimental device and the increasing costs are inevitable for realizing the reactor. Also, there still remain technological problems relating to the reactor structure. In response to this present situation, the project of constructing the unprecedentedly large fusion experimental device to obtain comprehensive understanding of the fusion plasma has started under international collaboration.
    The device is a tokamak type and is called “International Thermonuclear Experimental Reactor (ITER).” The ITER project started in 1985, and Japan, the European Union, Russia, the United States, China, Korea, and India are participating in the project. ITER is now under construction at Cadarache in France with a total cost of 14.5 billion Euro. ITER is expected to operate for 20 years from 2020.

    In Japan, the “ITER Broader Approach (BA)” activity has been conducted. The objective of the ITER-BA is (1) to complement and support the ITER project and (2) the establishment of the technological basis required for the prototype reactor, in particular, the material testing of the reactor components, computer simulation of the fusion plasma, and the simulation experiment using a satellite tokamak device. The ITER project is typically called “big science”, and is now off and running.