History of Nuclear Fusion Research in JapanHarukazu IGUCHI, Keisuke MATSUOKA1, Kazue KIMURA, Chusei NAMBA, and Shinzaburo MATSUDA2

Fusion Science Archives, National Institute for Fusion Science, Toki 509-5292, Japan1 Prof. Emeritus of National Institute for Fusion Science, Japan. 2 Tokyo Institute of Technology, Tokyo 152-8550, JapanE-mail:iguchi@nifs.ac.jp

The atomic energy research was declassified worldwide at the International Conference on the Peaceful Uses of Atomic Energy in 1955. In the late 1950s there was a lively discussion among scientists on the strategy of nuclear fusion research in Japan, leading to the conclusion that fusion research should be started from the basic, namely, research on plasma physics and from cultivation of human resources at universities under the Ministry of Education, Science and Culture (MOE). However, an endorsement was given that construction of an experimental device for fusion research would be approved sooner or later. Meanwhile, confinement studies were conducted specifically in USSR and USA with tokamaks and multipoles, respectively. In Japan, studies on toroidal plasma confinement started at Japan Atomic Energy Research Institute (JAERI) under the Science and Technology Agency (STA) in the mid-1960s. Successful results from tokamak researches in USSR encouraged scientists worldwide, which resulted in construction rush of tokamaks in Japan, too. However, dualistic fusion research framework established in 1960s has lasted until now; MOE for science and STA for development.

Extracted from “Presidential Address at the 1st International Conference on the Peaceful Uses of Atomic Energy” by Mr. Homi J. Bhabha (India) on 8 August 1955 (at Geneva)

It is well known that atomic energy can be obtained by a fusion process as in the H-bomb, and there is no basic scientific knowledge in our possession today to show that it is impossible for us to obtain this energy from the fusion process in a controlled manner. The technical problems are formidable, but one should remember that it is not yet fifteen years since atomic

REVIEW OF EXPERIMENTAL RESULTS by ARTSIMOVICH at 1st IAEA Conf., 1961 （Nuclear Fusion: 1962 Supplement, Part 1 p.9-14）

It is now clear to all that our original beliefs that the doors into the desired region of ultra-high temperatures would open smoothly at the first powerful exerted by the creative energy of physicists, have proved as unfounded as the sinner’s hope entering Paradise without passing through Purgatory. And yet there can be scarcely any doubt that the problem of controlled fusion will eventually be solved. Only we do not know how long we shall have to remain in Purgatory. We shall have to leave it with an ideal vacuum technology, with the magnetic configurations worked out, with an accurate geometry for the lines of force and with programmed conditions for the electrical contours, bearing in our hands the high temperature plasma, stable and in repose, pure as a concept in theoretical physics when it is still unsullied by contact with experimental fact.

Presiding over the opening session of theConference. Left to right: Mr. Max Petitpierre,President of the Swiss Confederation; Mr. DagHammarskjold, Secretary-General of theUnited Nations; Mr. Homi J. Bhabha, Presidentof the Conference; Mr. Walter G. Whitman,Conference Secretary-General

L. A. ARTSIMOVICH (Kurchatov Inst. , USSR)

The 3rd IAEA Conf. on Nuclear Fusion atNovosibirsk, 1968Successful experimental results on TokamakT-3 (Kurchatov Inst.) were reported. They were: Te ~ 100-2000 eV, Ti ~ 300 eV, ne ~ 1012-5x1013

cm-3, τE ~ 10 ms.These results were confirmed by Thomson Scattering measurements performed by researchers from Culham Lab. UK in 1969, which opened the age of Tokamak in fusion research.

2nd International Conference on the Peaceful Uses of Atomic Energy (ICPUAE) held at Geneva in September 1958

World Trend in Early Days as a Background

energy was released in an atomic pile for the first time by Fermi. I venture to predict that a method will be found for liberating fusion energy in a controlled manner within the next two decades.

H-PTh-14

1967 Comments by T.Ohkawa and S.Yoshikawa

1960 Heliotron B 

1958

2nd Geneva Conf.

1955

1st. Geneva Conf.

1961 1st. IAEA Conf.

(Purgatory)

“Ioffe bar”

1965 2nd. IAEA Conf.

“Min.B in Ohkawa Torus”

1968 3rd IAEA Conf. ”Results from T‐3 

tokamak”

1968 JAEC

Expert Committee 

“Fusion Nominated as National Project”

1958 JAECExpert Committee for Nuclear Fusion

1959 SCJ Special Committee for Nuclear 

Fusion1965 SCJ Special 

Committee 

Pink Pamphlet on  Future Strategy

1959 JAERI

Fusion Lab.

Experimental and Theoretical 

Activities 

in JAERI, ETL, RIKEN, 

Universities

1959Heliotron A 

1965 Heliotron C (through Collaboration with IPP）

1969

Te meas. by D.C.Robinson in T‐3

1958 Kakuyugo‐Kondankai (Fusion 

Society)

AB‐Dispute

JAEC: Japan Atomic Energy Commission

SCJ: Science Council of Japan

1961 Institute of Plasma Physics (IPP), Nagoya Univ.

QP, TP, BSG

(STA)

(MOE)

(International Relation)

1986 JAEC Nuclear Fusion Council “On Framework of Next Stage of Fusion Research”

1992 JAEC Report on “3rd. Stage of National Project of Fusion”

2001 JAEC Report on “Promotion of ITER”

2002 Council for Science and Tech. Policy, Cabinet Office

and Cabinet Councilaccept ITER

1992 ITER EDA 2001 Intergovernmental Negotiation for ITER

1986MOE  Panel on Fusion “Future Plan in Univ.”

2001 LHD Te of 10 keV

1998 17th. IAEA Conf.（Yokohama）

1986 11th. IAEA Conf.（Kyoto）

1988 Task Force and Preparatory Office for Future Plan 

1989 NIFS1988 CHS

1998 LHD

2000 Heliotron J

1999 High Temp. Plasma Center (Univ. of Tokyo)

1988 

W7‐AS

1991 JET Burning Experiment

1993 TFTR Fusion Power of 10 MW

1993 JT‐60 CD of 3.6 MA

1998 JT‐60 Qeq=1.25

2003 LHD β=4.1%, 756 sec. Discharge1999 CHS ITB

2003 TRIAM‐1M

5 hr. Discharge

1989 TRIAM‐1M

CD for >1 hr.

1996 JT‐60 Fusion Triple Product of 1.5×1021keV・m‐3・sec

1988 ITER CDA

1991 Gekko XIIImploded Density:103×Solid Density

2002 Fast Ignition 1 keV(LFEX laser)

1991 JT‐60 Modified for High Ip Operation

1989 NIFS

1993 NIFS Super Computer 

2003 MEXT Science and Tech. Council, Working Group “On Future of Fusion Research In Japan”

2005 JAEC Report on “Future Strategy on Fusion in Japan”

2006 ITER Sign‐up of Agreement

2007 ITER Validation of Agreement, Construction Started

2005 LHD Input Energy of 1.6 GJ, 1hr. Discharge

2008 QUEST

2006 LHD β5% ne of 1x1021m‐3

2006 JT‐60 Spontaneous Current: 70 % of Ip, 8 sec. Discharge

2005 ITER Site

2007 BA  Agreement Sign（Feb.）、Validation（June）

2004 NIFS Bidirectional Collaborative Research Project

1985 Tritium Process Laboratory  (TPL)

1981 Fusion NeutronicsSource  (FNS) 

1986 JAEC Nuclear Fusion Council “On Framework of Next Stage of Fusion Research”Two Sectional Committees on Fusion Eng. 

1983 HFIR/ORR 

（HFIR in Operation）

(J.‐US Joint Project)

1980 OKTAVIAN(Osaka Univ.)

1980 Tritium Research Center (Toyama Univ.)

1981 JT‐60 NBI Proto‐type Unit(Since 1987 Utilized as PBEF for Reactor Eng. Studies)

1982 TSTA

1985  LCT

1979 Japan‐US 

Cooperation 

Agreement

1987‐1994FFTF/MOTA

(J.‐US Joint Project)

1981‐ 1986

RTNS‐II

(J.‐US Joint Project)

1976 JAEC Sectional Committee on Tritium

1977 JAEC Sectional Committee on Biological Effect of Tritium

*

(International

Relation)

(STA)

(MOE)

1980 FMIT (IEA) FMIT: Fusion Materials Irradiation Test Facility

TSTA: Tritium Systems Test Assembly

HFIR: High Flux Isotope Reactor

ORR: Oak Ridge Research Reactor

1968  JMTR

JMTR: Japan Materials Testing Reactor

1988‐1993ESNIT Program

1999 NIFS Fusion Eng. Res. Center

1994 JT‐60 Negative‐NBI

2000 JAEC Nuclear Fusion Council “On Development Procedure of First Wall Materials” 2002 Council for Science and 

Tech. Policy, Cabinet Office and Cabinet Council accept ITER

1991 Gyrotron Test Facility

1989 JAERI Electron Beam Irradiation Stand (JEBIS)

1996 Large Scale SC Coil Test Stand for ITER

1994MeV‐class Ion Source Test Stand

2002 Stable Operation of 1 MV in Vacuum Insulated Accelerator

1997 Development & Validation of Diamond Window

1994 Energy Recovery Efficiency of 50% for 110 GHz Gyrotron

1990 Negative Ion Beam of 10 A

1994 Negative Ion Beam of >10A & >100kV for LHD

1998 Operation of Negative Ion Beam

1990 Large Scale Test of SC Coil for LHD

1998 LHD SC Coil

1986 Negative Ion Beam of １ A 

1992 ITER ７Major Eng. R&D

2000‐ 2003 KEP1994 IFMIF CDA

2001‐2006JUPITER‐II(J.‐US Joint Project)

1995‐2000 JUPITER(J.‐US Joint Project)

*1999 Hydrogen Isotope Research Center (Toyama Univ.)

1992 JAEC Report 

on “Third Stage of 

National Project of Fusion”

1987‐2001 Japan‐US Cooperation (Annex IV on Tritium)

ESNIT: Energy Selective Neutron Irradiation Test Facility

2000 CS Model Coil for ITER 13 Tesla

Fusion Science Archives, National Institute for Fusion Science / Oct. 2008

CONFINEMENT

JFT-2 (JAERI)

JIPP T-II (IPP, Nagoya) CHS (IPP, Nagoya) Heliotron E (Kyoto Univ.)

TRIAM-1M (Kyushu Univ.)

GAMMA 10 (Univ. Tsukuba)

1980 ICPP（Nagoya）

1969‐1973 JFT‐1

1972‐1981 JFT‐2

1974‐1980 JFT‐2a

1979 Japan‐US Cooperation Program Including 

DIII‐D Collaboration

1983‐2003 JFT‐2M

1978‐1987

INTOR

1974 5th IAEA Conf. (Tokyo)

1984 Science Council“Future Plan of Fusion in Universities”

1980 Science Council“Long‐term Strategy of Fusion in Universities”

1975 MOE Science Council, Report on “Promotion of Fusion”

→Panel on Fusion

→Set‐up of Centers

1975 JAEC “2nd Stage ofNational Project of 

Fusion”

1970 JIPP‐1 Stellarator

1976 JIPPT‐II

1976 Heliotron (Kyoto)

1976 Laser (Osaka)

1978 Fusion Theory (Hiroshima)

1979 Plasma Research (Tsukuba)

1980 Tritium (Toyama)

1980 New‐type Laser(Tokyo)

1983 JIPP T‐IIU

1970 Heliotron D

1985 JT‐60

1980 Heliotron E (H‐E)

1977 Gekko IV

1978 GAMMA 6 1982 GAMMA 10

1986 TRIAM‐1M1978 TRIAM‐1

1982 Gekko XII

1970 C Stellarator→ ST Tokamak

1982 TFTR

1983 JET

1971 Neutron Generation with Laser by Osaka Univ.’ group at IPP, Nagoya Univ.

1983 Gekko XII neutron 4×1010

1986 Gamma 10 Thermal Barrier

1986 Gekko XII neutron1013

1982 Currentless Plasma in H‐E

1982 H‐mode（ASDEX）

1982 CurrentlessPlasma (W7‐A)

1978 Ti of 7 keV (PLT) 

1978 Reacting Plasma Project (R‐project)

1983WT‐2 Tokamak

Discharge w/o OH from Start‐up

1984‐2000 WT‐3

1985 StellaratorAgreement (IEA)

1992 Japan joined

1978 TEXTOR Agreement (IEA)

QUEST (Kyushu Univ.)

Gekko IV (Osaka Univ.)

Gekko XII (Osaka Univ.) LFEX (Osaka Univ.)

TPL (JAERI) FNS (JAERI)

LHD (NIFS) JT-60 (JAERI)

Heliotron J (Kyoto Univ.)

FUSION ENGINEERING

2005MeV Accelerator Produced ITER‐class Power Density of Negative Ion Beam

2006 170 GHz Gyrotron 1 MW/ 800 sec/ Efficiency 55%, ITER Mission Achieved

2006 170 GHz Gyrotron 1hr. Operation

2003 LHD Negative NBI Input Power 13 MW

2007‐2012TITAN(J.‐US Joint Project)

2007 EVEDA Eng. Validation, Eng. Design

Brief description of early phase of fusion research in Japan

In 1950s information on nuclear fusion research in the world was rather widely spread among nuclear physicists, astrophysicists, researchers of electric engineering and others in Japan. Experimental and theoretical studies started at JAERI, ETL (Electrotechnical Labo-ratory, former AIST), RIKEN and universities nationwide.

These activities made industry-government-academia aware of importance of nuclear fusion. As a result, Japan Atomic Energy Commission (JAEC) that is under Cabinet Office, and Science Council of Japan (SCJ) organized “expert committee on fusion” in April 1958 and “special committee on fusion” in April 1959, respectively. Scientists who gathered from various fields established Kakuyugo Kondankai nominating Nobel Prize winner Hideki Yu-kawa as a chairman in Feb. 1958. Kakuyugo Kondankai was the voluntary association of fu-sion community and was reorganized to establish The Japan Society of Plasma Science and Nuclear Fusion Research in 1983.

Lively discussion was made between A-plan and B-plan, the so-called AB-dispute. The policy of A-plan is to start fusion research from the basics, putting emphasis on understand-ing basic plasma physics, finding new ideas and cultivating scientists. B-plan is based on the idea to promote fusion research by constructing the medium-sized machine taking account of the running machines in the world, such as stellarator, mirror, and so on. The expert com-mittee of JAEC finally adopted the A-plan. As a result, Institute of Plasma Physics, Nagoya University was established in 1961. On the other hand, there was agreement among govern-ment and scientists that the B-plan should be executed sooner or later.

In the first half of 1960s scientists in Japan had difficulty in finding how they should for-ward magnetic confinement research and getting rid of Bohm diffusion as was symbolized by “purgatory” by Artsimovich. The special committee of SCJ made an open argument among researchers and outlined the direction of fusion research in Japan, taking consideration of the guiding principle of min. B shown by T. Ohkawa at the second IAEA Conference in 1965. In 1968 JAEC designated fusion research as one of the national projects of Atomic Energy Research. This decision-making was an important step to promote the research in Japan. To-kamak was adopted as the machine of the national project and JFT-2 was constructed at JAERI. In universities JIPP-I stellarator and heliotron D were constructed at that time. It can be said that in 1970 the foundation of magnetic confinement was laid in Japan.

The laser confinement fusion was originated in the neutron generation with laser at IPP, Nagoya University which was done by guest scientists from Osaka University. Major part of fusion engineering studies commenced in 1970s and advanced being inextricably linked with plasma confinement studies.

According to the Atomic Energy Law that was effective since 1955, JAEC had been in charge of atomic energy researches of which budget (Atomic Energy Fund) was funded by STA (Science and Technology Agency), while MOE funded the university-based researches of which budget was not Atomic Energy Fund. There were two different funding lines in Japan.

Acknowledgement: The author thanks The 50-year Celebration Committee of “The Japan Society of Plasma Physics and Nuclear Fusion Research” for providing him with photos and fruitful comments.

Gyrotron (JAEA)

MeV Ion Source Test Stand (JAEA)

LCT (JAERI)

CS Coil (JAERI) JFT-1 (JAERI)

JFT-2a (JAERI)

JFT-2M (JAERI)

WT-2 (Kyoto Univ.)