24P118R
Historical Research on Fusion Science Based on Oral History Method-Interview to Dr. Shigeru Moriオーラルヒストリーに基づく核融合の歴史研究-森茂氏インタビューKazue Kimura, Harukazu Iguchi, Chusei Namba, Shinzaburo Matsuda,
Hidetoshi Yoshida, Takahisa Amemiya
木村一枝１，井口春和１，難波忠清１，松田慎三郎２
吉田英俊2，雨宮高久3
１．National Institute for Fusion Science, NIFS Fusion Science Archives
322-6,Oroshi-cho,Toki-city,Gifu 509-5292,Japan
2. Japan Atomic Energy Agency, 801-1Mukoyama, Naka-city, Ibaraki, 311-0193,Japan
3. Nihon University College of Science and Technology
1-8-14,Surugadai, Kanda, Chiyoda-ku,Tokyo 101-8308,Japan
１．	 核融合科学研究所アーカイブ室	  〒509-5292	  岐阜県土岐市下石町322-6
２．	 日本原子力研究開発機構核融合研究開発部門	  〒311-0193	  茨城県那珂市向山町801-1
３．	 日本大学理工学部物理学科	  〒101-8308	  東京都千代田区神田駿河台1-8-14
An interview to Shigeru Mori (former board of director at Japan Atomic Energy ResearchInstitute) was carried out in 2011. He basically considers fusion science not as an academic research but
research and development of mission oriented. What was talked in the interview showed thecircumstances of the first period of fusion research in JAERI. Those information, such as, theprocesses or backgrounds of each event, his thinking in decision making, communication among
researchers is generally not found in written materials. In this report, some details of the interview toShigeru Mori will be shown.

Oral history is a useful method for historicalresearches as complementary materials of written
documents. Fusion Science Archives at the National
Institute for Fusion Science (NIFS FSA) has
continued the activity for the last decade and stores
those interview records.
An interview to Shigeru Mori, the former
vice-president of Japan Atomic Energy ResearchInstitute, was carried out at the office of Japan
Atomic Energy Agency (JAEA) in Tokyo on March10, 2011. The interview was planned and conductedunder the collaboration with JAEA and Nihon
University. The interviewers were H.Iguchi andK.Kimura, from NIFS, S.Matsuda and H.Yoshidafrom JAEA and T.Amemiya from Nihon University.
The interview took about four hours, however, hekept on talking without any coffee break. Outline of
the interview is described below.

1. School Age
S. Mori was born in Hiroshima city in 1923 at afamily of traditional medical doctor. After finishing
the high school at Hiroshima, he entered theUniversity of Tokyo and chose nuclear physics
course under Prof. Goro Miyamoto. He was one of
the first students of the class of G. Miyamoto, who

had his own class being independent from Prof. R.
Sagane. However, close connection between thesetwo classes continued afterward. In this class, he
met Tihiro Ohkawa, who later became an active
fusion researcher in US, and Masaji Yoshikawa,
who later became a Director General of JAERI.
Because of the wartime, materials necessary forexperiments were short. They were involved in
making those things by themselves. S. Mori wasgood at these works. He experienced the air raid toTokyo on March 10th, 1945 by B-29 of US air force.
His family was suffered from the atomic bomb toHiroshima city on August 6th. He lived a difficult
age both for himself and his family.

2.About A-B dispute
In the early age of Japanese fusion research,
there was a severe discussion on strategy of fusion
research in Japan, which was called A-B dispute
later. Opinions were divided into two. One groupsupported an idea to start basic plasma physics andeducation (A-plan). Another group insisted that weshouldconstructamedium-sizedfusion
experimental device to catch up western researchlevel carried out in USA, England, USSR, etc.
(B-plan) S. Mori was in the latter group. He thoughtthat fusion research was a mission oriented one andwas not an academic research. After the decision wasmade to start from A-plan, the Institute of Plasma
Physics, Nagoya University was established as aninter-university collaboration organization. S. Moriand his colleagues had to wait for the B-plan to startfor several years.

3. Spherator to Tokamak
Fusion research at JAERI started in the middleof 1960s by constructing a toroidal device withmultipole field configuration (a hexapole device).
Then S. Mori and his colleagues planned to build
the next step machine with the Spherator
configuration, which was developed by Shoichi
Yoshikawa at PPPL in USA, because Spherator
experiment showed unique experimental results that
could be explained by theoretical predictions.
However, T-3 tokamak results were reported from
USSR that it overcame the serious barrier of Bohm
diffusion. S. Mori decided to change the next step
plan from Spherator device to tokamak andrequested for approval to Japan Atomic Energy
Commission, whose chairperson was S. Kikuchi. It
was natural and smooth transition for S. Mori,because tokomak was considered to be an internalcurrent system that carries current by plasma itself
instead of material conductors. It has a merit as a
future commercial reactor that energy loss at thesupport of current conductors could be eliminated.
However, S. Kikuchi did not accept his idea at first,
saying that he did not believe such a person whochanged his idea over one night. There was a hard
open discussion between S. Kikuchi and S. Mori,
which was called as “an air-fight between Mori andKikuchi”. The situation tended to worse at thismoment. However, a bureaucrat at JAERI watching
this scene suggested S. Mori that his explanation
wasnoteasy
tounderstandforanon-fusion-researcher. He set up an occasion for S.
Mori to explain to S. Kikuchi on the reason tochange the plan more in detail. Finally S. Kikuchi
understood Mori’s idea and accepted the new plan.
Tokomak experiments using JFT-2 weresuccessful. H. Yoshimura of Nihon University, who
was a co-secretary of Nuclear Fusion Committee atScience Council with S. Mori, stated this successful
step that Japanese fusion research took off finally.

4. US-Japan Collaboration
US-Japan collaboration on energy researchstarted 1978 after the Fukuda-Cater agreement in
the previous year. Trade friction between two
countries due to a large Japanese surplus was thebackground of this movement. Japan wanted toplace fusion research with top priority, and decided
to join the Doublet experiment, which was a
non-circular tokamak device lead by T. Ohkawa at
GA. It was agreed that the JAERI team and the GAteam shared machine time every other week. TheJAERI team showed high performance inexperimental research, which drastically raised thestatus of Japanese fusion researchers. On the otherhand, JAERI had to give up its own program on
non-circular tokamak experiment JT-4, although its
design activity had been in progress. Since thedecision was made after discussion in researchers,
not by top-down style, this change of plan wasaccepted without confusion.

5. R&D in Fusion TechnologyS. Mori found in early 1960s that there was areactor design using stellarator configuration atPPPL, the Stellarator-D. He got the blue copy ofthis thick report stored as an Atomic Energy
Commission report in USA and read it. The design
adopted the magnet coils with normal conductors
cooled at minus 20 ℃. The power loss at the coils
was so huge and the thermal power output was 10GW. He was much shocked at this result and feltthat fusion energy is just a dream. However, it soon
became clear that a super-conducting magnet could
be used for commercial purposes. He learned about
super conductor from N. Yasukochi of Nihon
University, who was a specialist on this filed. S.
Mori decided to list up this technology as one offour main R&D issues in fusion technology atJAERI. S. Shimamoto was called to join thisresearch from France. About tritium handling, Y.
Naruse who was working at Radio Isotope section
joined fusion research. R. Hashiguchi of Tokyo
University of Science contributed much to material
researches. In addition, reactor design study had
been continued and enforced. Such research
activities at JAERI on various field of fusion
technology to be necessary in a commercial reactor
were evaluated that fusion research at JAERI wasperformed as really mission oriented style.

6. Other topics
In this interview, many other topics wereintroduced. Those were INTOR workshop in which
he played a chairperson of this big international
collaboration, and Japan Atomic Industrial Forum(JAIF) for which he became a senior adviser. He
also talked about recent personnel life.
The interview record will be registered andstored at NIFS FSA soon.