TWENTY YEAR REPORTFOR ACTIVITIES REGARDING
JAPAN/U.S. FUSION RESEARCHCOLLABORATION(Expert Summary for 1980 [Nov.1979]-2000)

June 22, 2000

Japan/U.S. Coordinating Committee
on Fusion Energy

Under Agreement between the Government of Japan and theGovernment of the United States of America on Cooperation in
Research and Development in Energy and Related Fields

PREFACE

Preface
Fusion is a reaction providing energy to the sun and stars. In the future, when this reaction
is used as an energy source on earth, fusion power can be a most attractive energy source
because of almost inexhaustible fuel and its high safety and low environmental effect. The
first fusion related research for energy was conducted and reported in the 1950s, and considerable progress has been made, but it will still need several tens of years more before thedevelopment of a fusion reactor can be considered successful.
In 1977, President Carter and Prime Minister Fukuda discussed a new US-Japan cooperation
on fusion. Following development of the necessary agreement basis, the research cooperation
began on the Doublet III Tokamak machine in San Diego where a group of Japanese
researchers was dispatched and worked together with the US researchers and engineers,
producing many world-leading results. A number of Annexes to the main umbrella Agreement
have been added covering almost all areas of fusion research and development, and morethan 100 people per year traveled to other each other's country for the research cooperation.
Major items of the results are shown in the following pages along with several photos related
to the cooperation.
This cooperation has been continuing, for more than 20 years, with many excellent results
being obtained across the wide range of activities. Probably this cooperation is the firstaccomplishment in the world providing a proof that people with totally different history andculture could really cooperate and produce world leading results, even not so many years aftera very tense initial relationship between the groups representing the two countries. Part of thereason for this is that the research is completely oriented toward peaceful purposes.
Regular exchange of people, including many who stayed in the other country for years,
enhanced mutual understanding of cultures. Friendships developed through this cooperation
resulted in not only many good research results but also a merging of people and culture.
Fusion research cooperation led to the fusion of people and cultures.
Although many more years of fusion research and development will be required before therealization of a fusion reactor, the fusion work reported here has resulted in positive contributions, and to some, an important spiritual return as well. Based on the results of the US-Japan
collaboration we can have confidence to undertake larger scale international cooperation,such as the ITER project, which was started by four Parties, the US, EU, USSR and Japan.
We hope this report will help readers understand the meaning and importance of fusion
research and international cooperation.

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TABLE OF CONTENTSTABLE OF CONTENTS
Preface..............................................................................................................ii
CHAPTER 1

Doublet III...................................................................................1

CHAPTER 2 FPPC (Fusion Physics Planning Committee).................................3
2.1 Plasma Core Phenomena
2.2 Plasma Edge Behavior and Control
2.3 Heating and Current Drive
2.4 New Approach and Diagnostics Development
CHAPTER 3

JIFT (Joint Institute for Fusion Theory)........................................7

CHAPTER 4 Data Linkages............................................................................10
4.1 ESnet between LBNL and NIFS (DOE/MONBUSHO ANNEX II)
4.2 ESnet between LBNL and JAERI (DOE/JAERI ANNEX IX)
CHAPTER 5 FTPC (Fusion Technology Planning Committee)..........................11
5.1 DOE/MONBUSHO
5.2 DOE/JAERI
1) Superconducting Magnets
2) Plasma Heating Related Technologies
3) Blankets
4) In-Vessel/High Heat Flux Materials and Components
5) Others
CHAPTER 6 Annex I Programs –Materials-....................................................16
6.1 DOE/Monbusho Materials Program (DOE/MONBUSHO ANNEX 1)
6.2 DOE/JAERI Materials (DOE/JAERI ANNEX I)
CHAPTER 7 Annex IV Program – Fusion Fuel-..............................................22
7.1 DOE/JAERI TSTA (Tritium Systems Test Assembly)
CHAPTER 8 Completed Annex Projects (Associated with DOE/JAERI).............24
8.1 Annex II
DOE/JAERI Fusion Blanket Neutronics
8.2 Annex III
DOE/JAERI Fuel Cleanup Components
8.3 Annex V
DOE/JAERI Superconducting Poloidal Coil Technology
8.4 Annex VI MTX of FEL Heating and Current Drive
8.5 Annex VII New Tube Test with JT-60 ICRF System
8.6 Annex VIII DOE/JAERI Collaborative Program on the Testing of a
Negative Ion Source for Neutral Beam
8.7 Annex X
TVTS for JFT-2M
8.8 Annex XI Negative Ion Sources and Accelerators for NBI

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CHAPTER 1 Doublet III and DIII–D
Objectives
The cooperative activities in the Doublet III project were initiated at the end of August 1979, intended
to perform the advanced tokamak research, making use of plasmas with non-circular cross sections.

Activities
The Japan Atomic Energy Research Institute (JAERI) entered into an agreement with the U.S. DOE
to collaborate on the Doublet III (later DIII-D) tokamak at General Atomics (GA) in San Diego. This
Agreement has been extended to the present and has provided close collaborative coupling of theresearch programs at JAERI and GA for 20 years. In the last 20 years, JAERI has sent to GA a totalof at least 65 person-years of scientists and engineers. During a period from 1979 to 1984, many
JAERI scientists spent five years in residence in San Diego and one spent ten years on Doublet III
and DIII-D. This experience built enduring mutual respect and friendships between JAERI and GA
scientists and engineers. This collaboration has indeed strongly progressed in the last 20 years,
providing significant scientific achievements with much contribution to Japan’s JT-60 program andthus leading the world fusion program.

Administration
The Steering Committee Meeting is held every year throughout the period of collaboration between
the U.S.DOE and JAERI in order to coordinate the collaborative work program. During a period
between 1979 and 1985, JAERI provided a financial contribution of $70.1M, out of which $8.5M
was for the Big Dee project.

Accomplishments
The period of collaboration in the last 20 years can be categorized into three stages. In the first
period starting from 1979 to 1984, the U.S. and JAERI teams took turns in coordinating their
independent experimental programs, and each team would strive towards either higher
plasma performance by the shaping optimization or better physics understandings. JAERI
had a physics group of about 10 members on average at GA during 1979-1984.
Major facility components provided by JAERI were the main motor generator
and two of the four 7 MW, 80 kV neutral beam lines. During this time
the U.S. provided the JAERI team with dedicated facility researchtime, diagnostics instruments, and operations support. The
JAERI team on Doublet III made significant scientificdiscoveries and developed physics understanding
while they trained a generation of young scientists
and future JAERI program leaders.
The second stage from 1985 to 1994 is highlighted
by the modification of the Doublet III device ( Big Dee
project). The Doublet III device was enlarged in size
and named as DIII-D, to which 12 visitors from JAERI on
average per year participated in the experimental program
and theoretical studies. In particular, the principal issue ofcontroversy in this period was to untangle the physics of improved
plasma confinement by the direct comparison with theoreticalmodels, and the EXB shearing model was proposed. The high beta
study also advanced in this period, and the value of 13% was1

achieved. In addition, the neutral beam current drive was first
demonstrated on DIII-D, and fast wave current drive of 0.16 MA
was manifested, corroborating the theoretical predictions.
In the third period from 1995 to present, sustainmentof the integrated performance, namely improved
confinement with high beta, accompanied by a large
non-inductive current drive fraction and significant
divertor heat and particle disposition capabilities,
was accentuated, in part, facilitated by the reactorrelevant results produced by the large tokamaks
and progress in the ITER Engineering Design
Activities (EDA) design. It should be noted,
however, that the prominent results at JT-60
and other large tokamaks during this period
actually benefited much from the outstandingachievements produced under this U.S.-JAERI
collaboration program.
One of the most outstanding achievements in the recent years
is the establishment of the reversed shear plasmas, which exhibit
extremely high confinement properties at relatively high density, by the
optimized current density and pressure profile control. Accordingly, the DT
equivalent fusion energy amplification gain of 0.32 was obtained on DIII-D, andthe world record Q value of 1.25 was achieved on JT-60U. Strenuous effort has also
been devoted to the sustainment of reversed shear profile, as well as the improvement of thenormalized beta, which is a figure of merit for the effectiveness of a fusion reactor. As a result, theproduct of H factor (confinement improvement factor over the L-mode scaling) and normalized betaof 7 was sustained for 1.5 s. In addition, comparative investigations on the internal transport barrier,which is thought to be a key for the improved confinement in reversed shear plasmas, was also performed between JT-60U and DIII-D. Furthermore, stabilization of resistive wall mode in the reversed
shear plasmas has lead to an increase of normalized beta up to 2.8. On the other hand, collaborative
work is in progress related to the scaling of pedestal width an edge MHD stability analysis.
Development of an advanced divertor, which is capable of effective
heat and particle control, is another important issue of investigationconsidered under this collaborative framework. It was demonstrated
that efficient pumping from the divertor private flux region
resulted in the achievement of H factor of 1.9 at a density
1.4 times the empirically evaluated density limit.
Exploratory experiments on the tailoring of the current
density profile with electron cyclotron current drive are
expected to suppress the neoclassical tearing mode andimprove the normalized beta in a steady state.
Accordingly, relevant work for an increase of theelectron cyclotron current drive power is in progressin DIII-D, which is considered to take a significant
role both in the reversed shear experiment andinvestigations of dominant electron heatingplasmas anticipated in a fusion reactor.

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CHAPTER 2 FPPC (Fusion Physics Planning Committee)
The FPPC (Fusion Physics Planning Committee) is one of two Joint Planning Programs of US-Japan
collaboration on the experimental fusion research. In the initial phase of the US-Japan collaboration,
the experimental collaboration was planned and conducted to promote various concepts of fusion(tandem mirror, bumpy torus, helical system, tokamak, and so on) including fusion technology. Since
1992, the collaboration has been planned and conducted to promote physics of core plasma physics,
edge physics and so on. The separation of the FPPC and FTPC (Fusion Technology Planning
Committee) was established in 1991. The physics of inertial fusion is also discussed in this program.

Objectives.
The FPPC (Fusion Physics Planning Committee) is responsible for organizing US-Japan collaborationon the experimental research of fusion plasma physics. The present subsections are now 1)
Planning, 2) Plasma core phenomena, 3) Plasma edge behavior and control, 4) Heating and current
drive, 5) New approaches and diagnostics development. The physics of various concepts of magnetic
and inertial confinement can be discussed together by this scheme of subsections, which allows us
to deepen the understanding of complex behaviors of confined plasmas.

Activities
The objectives are pursued by workshops and exchange visits of researchers. In 19 years under
US-Japan collaboration, 261 workshops and exchanges of visits were conducted and 607 researchers
were sent to US on various themes related to FPPC. In Japan, 212 workshops and exchange of visitswere held and 573 researchers were sent to Japan.

Administration
As for US-Japanese universities collaboration, 4 key-persons from Japanese universities are designatedfor the promotion of collaboration in each subsection of FPPC. The steering committees of FPPC areattended by US key-person of FPPC and a person in charge from JAERI and a person in charge fromuniversities and 4 key-persons for 4 subsections from Japanese universities.

Accomplishment and highlights
2.1 Plasma Core Phenomena(1) High triangularity research in JT-60
In 1994, the high triangularity (<~0.5) experiment started by modification of the poloidal coilsystem with good suggestions from a General Atomics (GA) scientist participating at JT-60U. After
that, the high triangularity shape produced significant improvements in plasma performance. The
grassy ELM regime, first discovered by a JAERI scientist working on the DIII-D tokamak in the early
90’s, was also established in JT-60U.

(2) Collaborations on Heliotron E before ATF operated and on CHS and LHD afterwards(a) export of the PROCTR transport code to Heliotron E and application to its experiments;(b) extensive study of MHD equilibrium and stability in Heliotron E; (c) extensive participation in
the ATF experiment by the Kyoto group; (d) participation in pellet injection experiments in LHD;
and (d) the CHS data acquisition and analysis system was exported from ATF.

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2.2 Plasma Edge Behavior and Control(1) Boronization in JT-60
In 1992, information on the boronization system of DIII-D at General Atomics (GA) was very beneficial
in the design, construction and operation of the boronization system in JT-60. The key person fromGA participated in the boronization experiments of JT-60U, leading to the successful improvement ofplasma performance in JT-60U.
Divertors and Remote Radiative Cooling: In the mid 1980’s, the JAERI team on Doublet III pioneered
ways to make divertor plasmas in the Doublet III vacuum vessel, introducing to the world suchconcepts as remote radiative cooling and the high recycling divertor. More recently, the DIII-D
team has researched close and pumped divertor geometries and results from those studies were
influential in modifying the divertor in the JT-60U tokamak to a closed pumped type divertor.

(2) Material test in JFT-2M
A long-term test has been conducted in the JFT-2M tokamak to determine the effects of environmental
exposure on the mechanical and chemical behavior of a low V-4Cr-4Ti alloy. Absorption ofinterstitials by the alloy appears to be limited to the very near surface, and neither the strength
nor the Charpy impact properties of the alloy appear to be changed from the exposure.

(3) Plasma-facing material
Under the U.S.-Japan collaboration, basic behavior of the lithium coating, which is successfully
conducted in TFTR, of plasma-facing material was investigated in a small apparatus in Japan withvery interesting information. The Japanese scientists proposed to use metal high-Z materials as
plasma-facing material and successfully received the useful data of discharge from Alcator-mod
molybdenum diverter and TEXTOR tungsten limiters. These experimental results are crucial forthe design of the first wall of the International Thermonuclear Experimental Reactor (ITER) andfuture fusion power reactors.

(4) Pumped Limiter and Helical Island Divertors
In the late 1980’s, divertor concepts applicable to helical systems were explored by
a GA team working on the JIPPT-2 (later CHS) device.

(5) Collaborations on Heliotron E before ATF operated and on CHS(a) ORNL installed a pump limiter from ISX-B on Heliotron E and conducted
experiments with for two years; and (b) ORNL installed and operated a fastpressure gauge in the local island divertor on CHS and conducted experiments for two years.

2.3 Heating and Current Drive(1) ECH program in JFT-2M
This program was initiated in 1979-1981 with the loan of a 200
KW, 38 GHz gyrotron for ECH experiments on JFT-2 (GA, PPPL,MIT team). In 1992, a loan of 60 GHz gyrotrons to JFT-2M wasproposed from GA to upgrade the ECH system. Installation of
3 gyrotrons including superconducting magnets, gyrotron
tanks, radio frequency (RF) transmission lines, windows andantennas was completed on JFT-2M in March 1996. They
have been quite useful in JFT-2M experiments up to now.

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(2) ICRF Experiments on CHS
The U.S. collaborated with Japan in establishing
ICRF heating capability in the CHS as well as
W-AS helical devices. Also, the U.S. and Japan
collaborated on the development of the folded
wave-guide antenna, an ORNL invention for applications on LHD. The ICRF heating of toroidal
plasmas using folded wave-guide antennas isconsidered to be important in fusion reactors. The
U.S. and Japan have also been working on the combline
antenna invented at GA. This antenna has the advantage that it has only one feed but has multiple emitterswith variable phase difference, and could be very economical for the LHD experiment.

(3) Development of various ECH components in GA
GA has developed a number of high-quality submillimeter wave components in plasma diagnostics andECH heating. JAERI has used many of these components such as corrugated waveguides, notchfilters.

(4) Collaborations on Heliotron E before ATF operated and on CHS
and LHD afterwards(a) ORNL loaned a 35-GHz gyrotron to Heliotron E for two-frequency ECH experiments;(b) ORNL contributed equipment and participated in ICRF experiments in CHS; and(c) ORNL collaborated on folded waveguide ICRF experiments in LHD.

2.4 New Approach and Diagnostics Development
Remote diagnostics in JT-60: Scintillating fiber neutron detectors developed by
the Los Alamos National Laboratory (LANL) were installed on JT-60U in March
1994 for the triton burn-up studies. In 1995, JAERI developed the remotediagnostics system for the neutron detectors using Internet and TV conference equipment. The U.S. collaborators could control the diagnostics andacquire the data from their home institutes. Collaborations to produce andpublish atomic and molecular data for fusion between NIFS and JAERI and
U.S. laboratories have been productive for more than 20 years.

(1) Optimization of helical systems/stellarators
Search for improved helical system/stellarator configurations is intensively
pursued in both the U.S. and Japan. Extensive contributions to the design of both CHS
and LHD were made by researchers at ORNL. In recent years the U.S.-Japan collaboration inthis area has been conducted through several workshops and personal exchanges. Dr. PaulGarabedian at New York University (NYU) made major contributions to the design of the new
Heliotron J at Kyoto University as well as to development of the quasi-axisymmetric (qa) stellarator
approach being developed in both Japan and the U.S. The proposed CHS-qa at NIFS and NCSX at
PPPL would address similar issues for the qa stellarator through different designs. Detailed
comparisons of ideas and designs in this area is very useful to both groups.

(2) Collaborations on Heliotron E before ATF operated and on CHS and LHD afterward(a) extensive contributions to the design of both CHS and LHD; and (b) ORNL developed andinstalled an innovative compact 2-D neutral particle analyzer on LHD.

5

Early cooperative work was done with scientists from GA on the Gamma-10 and RFC-XX devices.

(3) Participation in the LHD experimentParticipation in the LHD program is an important element of increased collaboration between the
U.S. and Japan. ORNL developed and installed an innovative compact 2-D neutral particle analyzer
on LHD in collaboration with NIFS. PPPL installed a TFTR 1-D scanning neutral particle analyzer on
LHD and started measurement of the ion energy distribution along different tangential lines of sight.
These measurements will enhance the understanding of the effect of the electric field on trapped
particles due to the loss cone in LHD. PPPL also installed an ECE diagnostic on LHD and conducted
experiments with magnetic probes. A researcher from MIT made a significant contribution to theunderstanding of the “breathing” phenomenon in LHD. LANL developed and installed a 2-D infraredbolometer on LHD and conducted experiments with it in collaboration with NIFS. ORNL also
participated in hydrogen pellet injection experiments in LHD.
Extensive long-term collaborations occurred between the Heliotron E and ATF programs. The ORNLPROCTR transport code was applied to analysis of Heliotron E experiments and later to CHS.
Extensive study of MHD equilibrium and stability was carried out in Heliotron E by an ORNL
researcher, and there was extensive participation in the ORNL ATF experiment by the Heliotron Egroup. The ATF data acquisition and analysis program was exported to the CHS experiment for joint
experiments on CHS. MIT installed an impurity diagnostic on Heliotron E and conducted experiments.
To summarize, the U.S. labs contributed significantly to the Japanese stellarator program:(a) PPPL installed a TFTR 1-D scanning neutral particle analyzer on LHD (1.4); (b) PPPL installed an
ECE diagnostic on LHD and conducted experiments with magnetic probes (1.4); (c) MIT installed an
impurity diagnostic on Heliotron E and conducted experiments (1.4); (d) LANL installed a 2-D
infrared bolometer on LHD and conducted experiments (1.4); (e) NYU (P. Garabedian) made major
contributions to the design of Heliotron J at Kyoto (1.4); (f) MIT was involved in the understanding of
the “breathing” oscillation in LHD (1.4); and (g) GA was involved in collaboration on a combline ICRF
antenna for LHD (1.3).

(4) Diagnostic Highlights from 20 Years of the US/Japan Bilateral
The Los Alamos National Laboratory and the National Institute for Fusion Science have an on-going(4-year) collaboration to develop infrared imaging bolometers for long-pulse plasma operation. Built
in the US, and based on Dr. Glen Wurden's idea (US Patent 5,861,625, Jan. 19, 1999), a prototype
has been installed by Japanese colleagues on the Large Helical Device in Toki, Japan. Further
refinements and data analysis are underway.
The Los Alamos National Laboratory and JT-60U implemented a remote collaboration capability thatallows real-time audio/video/data transfer. This system enabled remote control of a scintillating fiber
neutron detector diagnostic that was installed by LANL (Glen Wurden) on JT-60U for triton burn-up
studies.
The University of California, Davis (Neville Luhmann/Calvin Domier) and the University of Tsukuba(A. Mase) have successfully collaborated on an ultrashort pulse reflectometer (USPR) that was
installed on the Gamma-10 mirror machine. Data from the USPR show promise for simultaneousdensity profile and density fluctuation measurements. Prof. A. Mase (currently affiliated with the
University of Kyushu) is investigating the fabrication of a similar diagnostic for the Large Helical
Device at NIFS.
The Oak Ridge National Laboratory and JT-60U collaborated on the successful installation andperformance verification tests, on JT-60U, of a confined alpha particle diagnostic developed by ORNL.
On JT-60U, the system will be used for the measurement of an ion tail, similar to an alpha particle
distribution in a burning plasma experiment.

6

The collaboration between RPI and Japan on the development and installation of heavy ion beamprobe (HIBP) diagnostic systems on several U.S. and Japanese fusion facilities has contributed
significantly to a special issue on HIBPs in IEEE Transactions on plasma science. The collaborationis also the subject of an internal report by the Japanese National Institute for Fusion Science.

CHAPTER 3 JIFT (Joint Institute for Fusion Theory)
The Joint Institute for Fusion Theory (JIFT) is one of the three programs through which the
U.S.-Japan Fusion Research Collaboration is organized. For twenty years, JIFT has contributed tothe development of productive working relationships between Japanese and U.S. scientists in carryingout theoretical and computational research on fusion plasmas and related scientific issues.

Objectives
The distinctive objectives of the JIFT program are: (1) to advance the theoretical understanding ofplasmas, with special emphasis on stability, equilibrium, heating, and transport in magnetic fusion
systems; and (2) to develop fundamental theoretical and computational tools and concepts forunderstanding nonlinear plasma phenomena.

Activities
The JIFT objectives are pursued through collaborations between U.S. and Japanese scientists bymeans of three types of exchange program activities: workshops, exchange visitors, and joint
computational projects. The JIFT program each year usually has four topical workshops (two in eachcountry), approximately six exchange scientists (three from each country), and a fluctuating numberof joint computational projects (on the order of a dozen). So far, during its 19 years of successful
operation, JIFT has sponsored 114 long-term visits by exchange scientists, 71 topical workshops,
and 111 joint computational projects.
The workshops typically have an attendance of 25-35 participants of whom usually three to sevenscientists (depending on the particular workshop) travel to the workshop from the non-host country.
Scientists from countries other than the U.S. and Japan are also often invited to participate in JIFT
workshops, either as “observers” or members of multilateral collaborative programs.
Of the approximately three exchange visitors in each direction every year, one (called the “JIFT Visiting
Professor“) is supported by the host country, while the others (called “Exchange Scientists”) are supportedby the sending country. The visits of the Exchange Scientists usually last from several weeks to a monthor two in duration, whereas, the Visiting Professors normally stay for at least three months.
The third category of JIFT exchange activities consists of joint computational projects. In generalthese are continuing collaborations on various problems of current interest, which initially develop
out of interactions at workshops and through individual exchange visits.

Administration
JIFT has a Steering Committee of eight members, four from each country, with two co-chairmen.
The Co-chairman on the Japanese side is the Director of the Theory and Computer Simulation
Center at the National Institute for Fusion Science (NIFS). The Co-chairman on the U.S. side is
the Director of the Institute for Fusion Studies (IFS) of the University of Texas at Austin. Two othermembers of the Steering Committee, called co-executive secretaries, are responsible for the ongoing
daily oversight of the progress of JIFT activities. Also, on the Japanese side there is an official
advisor, who is from the Japan Atomic Energy Research Institute (JAERI); and on the U.S. side there
is an advisory committee whose membership is drawn from universities and national laboratories.
The Japanese and U.S. members of the Steering Committee select the topics and the participating
scientists for the JIFT exchange visits, workshops, and joint computational projects. Criteria include
having a balanced representation of critical issues in magnetic fusion research, which includes both7

fundamental problems as well as questionsof near-term significance, and also taking
into account the specific capabilities andinterests of both countries. The Steering
Committee submits annual reports concerning JIFT activities to the U.S.-Japan
Executive Secretaries Meeting.

Accomplishments
A number of general benefits have resulted
over the years from the JIFT program. In particular,
the following may be cited: JIFT has provided efficient communication channels for the latest theoretical research results, techniques,and directions; JIFT activities have attracted serious participation from allied fields
such as fluid turbulence, statistical physics, computational science, and space plasma physics,
which brings new scientific tools into the fusion program and enhances the stature of fusion physics;
JIFT exchanges have contributed to efficient utilization of international research facilities; and, JIFT
emphasis on large-scale computational studies has reaped significant mutual benefits from thesupercomputer resources and code-building expertise of both countries.
JIFT activities have led to the publication of numerous scientific papers, as well as review articles
and books. JIFT research has also been featured in a number of invited talks at major international
meetings (e.g., the biennial IAEA Conference on Plasma Physics and Controlled Nuclear Fusion
which is now called the IAEA Fusion Energy Conference).
Through JIFT, close and long-lasting scientific connections have been established between the U.S.
and Japanese fusion theory communities. Not only have senior scientists profited from thesecollaborations, but also young scientists—and even, on occasion, two advanced graduate students—
have had many opportunities to enhance their research careers. The lectures given by JIFT visiting
professors during the first decade of the program were published in a book for the benefit ofscientists and students.

Themes
The topics of the 35 workshops held during the pastnine years are indicative of scientific themes that JIFT
has pursued. These topics can be partially categorized as:(1) MHD equilibrium, stability, sawteeth oscillations, anddisruptions; (2) High-beta plasmas and beta limits;(3) Highly energetic particles and their effects onstability; (4) Turbulent transport, transport barriers,
and confinement; (5) Theory and new concepts forhelical confinement configurations; (6) Bootstrap
current; (7) Edge physics; (8) Dense plasmas;(9) Interactions of intense electromagnetic waves
with plasma and matter; (10) Dynamo phenomena;(11) Reconnection; (12) Self-organization; (13) Numericalsimulation codes, visualization techniques, and virtual reality;and (14) Innovative concepts. The workshops were organized so as not
to focus on only one specific fusion device, but instead to aim at a generalscientific understanding of fusion plasmas and of basic plasma physics and thedevelopment of tools for large-scale computer simulations. Rapid progress in numericalsimulation methodology has especially marked the past decade of JIFT activities.

8Significant Highlights
Through the years, a number of JIFT workshops
and scientific exchanges have made significant
the oretical contributions to the design and data
analysis of helical confinement configurations
and stellarators (e.g., Heliotron E, CHS, and LHD
in Japan and ATF in the U.S.). New concepts for
improved configurations have also been considered,
relevant to the current U.S. stellarator design effort and to
future plans for Japanese helical systems. For example, a JIFT
visiting professor invented a new topology (so-called “wavy” vertical fieldcoils) for a quasi-axisymmetric stellarator that simplifies coil shapes, has improved
access, and may allow the design of a divertor. Two well-known books on the physics andnumerical simulation of helical plasmas have been written as the result of JIFT activities.
A long-standing JIFT effort was the benchmarking of stability predictions from various MHD codesthat were applied to a common three-dimensional stellarator equilibrium configuration. The resultsof this important work, pursued over several years among Japanese, U.S., and Russian scientists,
were published in a detailed paper. Three-dimensional plasma equilibria including magnetic islands
were extensively studied with the HINT code. Progress was made in analyzing whether island formation
is a global effect due to the Pfirsh-Schluter current or a local effect due to resistive interchange. The
phenomenon of “self-healing” was discovered, and its physics mechanism compared to that for theneoclassical tearing mode. These studies suggested that the bootstrap current can play an importantrole in suppressing islands, which is of interest to current LHD experiments.
Several workshops focused on understanding the universal properties of high-beta plasmas, not limited
to any specific device. Stability beta limits and the bootstrap current fraction have been explored.
Other problems considered were neoclassical tearing modes, resistive wall modes, equilibrium andstability for the field-reversed configuration, stability for the spheromak and the reversed-field pinch,
and liquid lithium walls.
Another area of continuing interest in workshops and scientific exchanges has been the physics ofparticles with high energies. Fruitful results have been obtained in theoretical understanding of the
burst modes observed in CHS experiments, in interpreting observations of toroidal Alfven instabilities
in JT-60U and TFTR deuterium-tritium discharges, in modeling ripple loss of fast particles, and indeveloping theory and simulations for the nonlinear behavior of fast particle instabilities.
Many published papers and invited talks at various conferences have resulted from collaborations on
plasma turbulence and anomalous transport. A recent book written on this subject is now a standard
reference in the field. Other books were published as proceedings of JIFT transport workshops.
A particular result was a new understanding of how the Hasegawa-Mima equation and HasegawaWakatani equation, as well as the Waltz model, contribute to plasma turbulence. Also, insight has
been gained concerning the formation of sheared plasma flow due to Reynolds stress.
A long-standing JIFT collaboration on the physics of spheromak plasma and magnetic reconnection
resulted in MHD code simulations of internal reconnection events in a spherical torus device, which
reproduced experimental results extremely well. Also, a simulation of collisionless reconnection
with a particle code revealed physics of interest to the reconnection experiment at the Princeton
Plasma Physics Laboratory (PPPL). The comparison of theoretical predictions and simulation resultsof collisionless reconnection has been very fruitful for both countries.
Dynamo simulations for the generation of the earth’s magnetic field attracted attention from thegeneral physics community. These simulations showed the importance of self-consistent nonlinear
dynamic processes.

9Over several years, macro-scale particle simulations and gyro-kinetic particle simulations were compared and discussed. This led to a new direction to develop hybrid MHD-Vlasov simulation methods.
A JIFT exchange scientist made a breakthrough in object-oriented simulation techniques, viz., expression
templates, and applied it to develop high-performance particle simulation capabilities that were thenutilized for efficiently running a large Monte-Carlo type of code on a parallel processor computer.
Visualization methods, including virtual reality, have been recognized as critically useful for present
and future large-scale simulations. JIFT research activities have made use of the NIFS CompleXcope
and the Virtual Reality Simulation Laboratory. At a JIFT workshop on Nonlinear Plasma Simulation
and Visualization held jointly with the 1998 International Conference on Numerical Simulation of
Plasmas, two Japanese fusion scientists won Buneman Awards for their work in this field.
Another continuing JIFT research area has been plasma complexity in systems that are nonlinear,
non-equilibrium, and open. Simulations of plasma self-organization, both on macro-scales and on
micro-scales, excited considerable interest in the formation of order and structure. Also, recently
the self-organization of plasmas with flow is being jointly studied in several areas—the stability of
non-Hermitian plasmas with flow, the interpretation of the H-mode as self-organization of ashear-flow plasma at the edge, and double curl Beltrami flow–diamagnetic structures.
A well-attended annual series of workshops on the interaction of high-intensity electromagnetic
waves with plasma and matter have attracted scientists from research areas such as ultrashortpulse laser-plasma interactions, laser acceleration, laser Compton scattering, nonlinear plasma
dynamics, fast ignitor concept, energy research, X-rays, and laser astrophysics. This has stimulated
opportunities for cross-field synthesis. The proceedings of the most recent of these workshops willsoon be published.

CHAPTER 4 Data Linkages
4.1 ESnet between LBNL and NIFS (DOE/MONBUSHO ANNEX II)
The Data Link between the Energy Sciences Network (ESnet) at the Lawrence Berkeley National
Laboratory (LBNL), in California (U.S.), and the NIFSnet at the National Institute for Fusion Science,
NIFS (Japan), consists of leased communication circuits operated under Annex II, which started in
December 1988 and was extended twice in 1993 and 1998. The Data Link was upgraded from
64 kbps to128 kbps (256 kbps Max) in 1996 to accommodate the needs of increased data transfer.
The U.S.-Japan Data Link has been invaluable for communications between fusion researchcollaborators in the U.S. and Japanese Universities. It provides visiting scientists with access totheir home institution’s computer systems. It also provides the means of exchanging information
between the U.S. and Japanese scientists by electronic mail and file transfers of theoretical,
experimental and design data, as well as computational programs.
The Data Link has made great contributions to joint code developments and usage, and joint data
analysis and theory/experimental comparison and enhanced the productivity of the U.S.-Japan fusion
research activities. The U.S.-Japan (NIFS) Data Link is important in promoting the U.S.-Japan Fusion
Cooperation Program and it should be maintained and enhanced to meet future program requirements.

4.2 ESnet between LBNL and JAERI (DOE/JAERI ANNEX IX)
The Data Link between the Energy Sciences Network (ESnet) at the Lawrence Berkeley National
Laboratory (LBNL), in Berkeley, California (U.S.), and the Japan Atomic Energy Research Institute(JAERI), at Naka (Japan), consists of leased international communication circuits operated under
Annex IX, which started in January 1990 and was extended twice in 1995 and 2000. The Data Link
was upgraded from 64 kbps to 128 kbps in 1993 and from 128 kbps to 768 kbps in 1997 toaccommodate the needs of increased data transfer.

10The U.S.-Japan Data Link has been invaluable for communications between U.S. and JAERI researchcollaborators. It provides visiting researchers with access to their home institution's computer
systems. It also provides the means of exchanging information between the U.S. and the JAERI
scientists by electronic mail and file transfers of theoretical, experimental and design data, as wellas computational programs.
In the early phase, the Data Link made great contributions to joint code developments and usages,
and joint data analysis and theory/experimental comparison and enhanced the productivity of the
U.S.-Japan fusion research activities. Recent remote collaboration activities between JAERI and U.S.
laboratories, such as Princeton Plasma Physics Laboratory (PPPL), Los Alamos National Laboratory(LANL), etc., have demonstrated the potential value of a high capacity Data Link for joint fusion
research. The U.S.-Japan (JAERI) Data Link is important in promoting the U.S.-Japan Fusion
Cooperation Program and it should be maintained and enhanced to meet future program requirements.

CHAPTER 5 FTPC (Fusion Technology Planning Committee)
5.1 DOE/MONBUSHOThe U.S./Japan-Monbusho (MOE) collaboration on fusion technologies has now been active andsuccessful for 20 years. It produces a mutually beneficial scientific bilateral collaboration between
the MOE Universities and NIFS, and the DOE research institutions and Universities.
There are five FTPC categories at present,(1) Superconducting Magnets(2) Plasma Heating Related Technologies(3) Blankets(4) In-Vessel/High Heat Flux Materials and Components (HHFC)(5) Others
During the 20 years of this FTPC, unique and individual activities in these categories provided
numerous useful results for the fusion program. The Japanese Universities engage in a wide variety
of technologies, based on their own research interests. In addition, since NIFS was founded in 1988,
these activities increased through the coordinating efforts of the fusion research network. In general,
MOE funded research has historically focused on issues of basic technology development. This is aconspicuously different approach than JAERI. JAERI has strong obligation and responsibility for mission
oriented research directed at Tokamak type fusion devices, and this focus has become especially tightafter the start of the ITER EDA. This may be recognized as a restriction in general that may limit
flexibility of DOE-JAERI collaboration. Therefore, the U.S.-Japan MOE collaboration is complementaryin allowing a full mix of collaborative research that meets the requirements for both sides.
Each year FTPC plans several workshops and related personnel exchanges. The outline of thisU.S.-Japan collaboration is shown in the Figures attached, which show the workshops and personnel
exchanges for the past 10 years, and give detailed information on activities in each category.
Workshops covering basic activities in several technology areas will be summarized. These wereorganized for HHFC, Blanket, Reactor Design, and Heating Systems. Information has been actively
exchanged and scientific evaluations useful to both sides were effectively executed.
The materials research has been covered by Joint Projects (FFTF-MOTA and JUPITER Projects).
These are independently described in other chapters of this report.
In the HHFC area, workshops highlighted the effort to develop components needed for fusion
devices. As a result of this series of workshops, the research programs of both sides were wellorganized and optimized. Several institutions, NIFS, JAERI, Sandia, etc. have high heat flux test11sources and tests have been conducted that contributed
significantly to the development of robust materials
and components. An especially important example istesting of grades of graphite which will withstand a heat
flux of 5 to 10MW/m2. These graphites are widely
utilized by present large tokamaks and by LHD.
For the blanket technology, originally each side had
different interests, in liquid, ceramic, and molten
salt blankets and the associated individual databases. Information exchange has been usefuland has stimulated collaboration. In thiscontext, Japanese Universities contributed
to development of an evaluation frameworkand models, based on their original component
test data. These workshops have successfully
contributed to the further development of designs using
the existing experimental data bases in each country.
In the technology area of reactor design, output from various groups have beencombined and design ideas were effectively merged, further contributing to theemergence of new ideas. These workshops helped to develop and apply design evaluation
principles and methodologies. The systematic approach used in the U.S. and the multiple pathapproaches in Japan have been well highlighted by these workshops, and have helped each side
move toward more attractive designs.
There are three main subjects in the plasma heating category, i.e., NBI, ECRH and ICRF. These havedifferent research concepts and issues, depending on experimental device applications, i.e., energy,
power, frequency, etc. Exchange of the results from different component tests and plasma experiments has effectively allowed each side to move into the next upgraded steps. NIFS, JAERI, ORNL,PPPL, MIT, and GA are the major institutions which have large development programs. Furthermore,
after an experiment is started, both sides continued to exchange data and personnel. This allows
further results on plasma experiments to be used to develop and apply MW class heating power
to the experimental devices.
Late in the 1980's, when the LHD project started, several superconducting magnet technology(SC) workshops were held. These made a large contribution to the evaluation of the existing design
data base and helped to develop the necessary recommendations used in final design. Personnel
exchanges afterwards contributed to the SC technology development for both sides.
Recently, two new categories of Fusion Technology Planning have been introduced. These are
Tritium and Blanket Heat Exchange/Removal, and workshops have been organized and the activity
levels are increasing. Since the start of operation of LHD in 1998, personnel exchanges related to LHD
technologies have dramatically increased. Major areas of collaboration are HHFC, Heating, Pellet
Injection, and others. LHD has provided these new possibilities for collaboration, in addition to the
LHD physics collaboration.
As we move to the future of the US/Japan-MOE collaboration on fusion technology, the FTPC
activities will continue and expand. The FTPC remains an important component of the US/Japanfusion collaboration.

125.2 DOE/JAERI(1) Superconducting Magnets
DOE-JAERI collaborative programs for the development of superconducting coils for fusion havesuccessfully been carried out including the program in the development of superconducting poloidal
coil technology (Annex-V) which began in 1988 (see Chapter 8.3).

Installation and testing of the ITER Central Solenoid Model CoilThe ITER Central Solenoid (CS) Model Coil was developed through international collaborations by the
U.S., Japan, the European Union (EU), and the Russian Federation under the ITER technology R&D
program. The CS Model Coil has an outer diameter of 3.6m, a height of 2.8m and winding weight is
110 ton. It is composed of the Inner Module that was wound by the U.S. and the Outer Module thatwas wound by Japan. Since the U.S. had to withdraw from the ITER Program in July 1999 at congressional direction, the installation and testing of the CS Model Coil have been carried out at the
JAERI Naka Fusion Research Establishment based on the agreement as recorded in the Minutes ofthe 20th U.S.-Japan Coordinating Committee on Fusion Energy (CCFE) held on May 17, 1999.
Under this agreement, five scientists and engineers were assigned to JAERI for installation, and theinstallation work was successfully completed by the end of 1999 by the U.S.-Japan installation team.
The experiment of the CS Model Coil was started with the initial cool down in March 2000 that was
followed by the charging experiment from April 11, 2000. On April 19, 2000, the CS Model Coil was
successfully charged up to 46kA and 13T, generating a stored energy of 640MJ. Another important
goal to demonstrate stable pulsed operation by charging to 13T at 0.4T/s and discharging from
13 T at 1T/s was successfully achieved on May 24, 2000, by using thepower supply of the JT-60. By these results, the objectives of the CS
Model Coil were fulfilled and a new frontier in the superconducting
magnet technology was opened.

Past Activities on Magnets
1980’s
Large Coil Project on Superconducting Magnets - While this project
to design, build and test superconducting magnets was under the
auspices of the International Energy Agency, it was a major success in fusion collaboration. This lead to a collaboration
between the US and Japan involving the loan of one of the US
coils to Japan. This coil, along with a Japanese counterpart,are now on display at NAKA as a tribute to this collaboration.

1990’sDemonstration Poloidal Coil - This test in Japan involving US
and Japanese superconducting magnets provided important
insights on the behavior of superconducting magnets during current
ramping.

(2) Plasma Heating Related Technologies
The most noteworthy activity during the 20 year
period is the annual bilateral exchange workshop on RF Heating Technologies, hosted alternatively
by the two countries. These workshops have provided a forum to develop close communication
between the RF technologists in both counties and to establish many mutually beneficial collaborative
activities. These exchanges have been typically
6-10 per year with 20-30 participants.

13

For example, the most pronounced collaboration in the JAERI-DOE collaborative program was thedevelopment of a new high power tetrode tube. It was developed by the U.S. and tested on the
JT-60 ICRF system from 1988 – 1992 (ANNEX VII). The tests validated the performance of the tube
X2274 at an output power level of 1.5 MW for 5s at 130MHz, setting a world record. Use of thistube permitted the upgrade of the JT-60 ICRF system with minor modifications.
In addition, there have been a number of joint projects, some of them are listed as below.

ECRF
1) Cryogenic window development (1992 - 1994)
JAERI fabricated the cryogenic sapphire window and demonstrated the 400kW x 1sec transmission
using DIII-D ECH system in 1994. This was the world’s first demonstration of a high powertransmission of the cryogenic window.
2) Distributed window test (1994 - 1995)
New concept of robust ECH window developed by GA was tested in the JAERI teststand. The highpower density, which is required for the ITER window, was demonstrated.
3) High Efficiency ECH System Design and millimeter wave component development (1994 - 2000)
GA has the most experience of millimeter wave transmission components and JAERI has the mostexperience of the energy recovery gyrotron operation. These technology information exchanges
contributed to the development of gyrotrons and a better design of the ECH system of both sides,
which were applied to the JT-60U, DIII-D and ITER.
4) The CPI gyrotrons on LHD were based on a Japanese design and make use of a visor at the outputof the Vlasov launcher. Tests showed that the output beam profile was very unsatisfactory. MIT
worked with NIFS to install a corrective external mirror system that was already validated on DIII-D
gyrotrons and improve the beam profile.

ICRF
1) Tetrode test (1988 - 1992, see 8.3)
Eimac fabricated 2 megawatt prototype tetrodes and JAERI successfully tested in Japan at a higher
frequency than it would have been possible in the US.
The new U.S. tetrode tube X2274 was tested in the JT-60 ICRF system and demonstrated 1.5 MW
for 5 seconds at 130 MHz, which was a world record at that time (1988-1992).
2) Feed-through test (1993 - 1995)
The test of various designs of the ICRF feed-throughs from Japan and the U.S. was done using the
T-60 ICRF system and the results contributed to the design optimization.
Japan is now fabricating and installing a Folded Waveguide Antenna system on LHD in collaboration
with ORNL. Although this antenna concept was invented and validated on test-stands in the US, thiswould be the first time it would be used on a large functioning fusion experimental device.
Inadequate funding in the US has prevented the fabrication and tests of a “Combline Antenna”
invented in the US. But the collaboration with Japan has made it possible to conduct preliminary
tests in Japan and validate the concept. The collaboration on the topic is still in progress.

NBI
The collaborative efforts between Japan and the US using the quardrupole accelerating systemdeveloped in the US and a source composed of several merging beams validated in Japan established the viability of producing very high energy negative ion based neutral beam systems for JT-60.

14

The collaboration has been very fruitful and new activities like remote steering ECH antenna areplanned. We can expect further progress of collaboration in this area.

(3) Blankets
Objectives
The in-pile functional tests of blanket mock-up will be planned in the JMTR. Now, the design ofblanket mock-up is conducted and the fabrication development of pebbles (ceramic tritium breeders
and neutron multiplier), un-irradiated and irradiated properties of pebbles, etc., have been investigated
for the in-pile functional tests. To make clear in-pile functional tests of blanket mock-up in detail,the following items will be discussed during the next three years.
• Experimental procedures for the in-pile functional tests• Fabrication development and characterization of ceramic tritium breeders (pebble)• Characterization of beryllium with high fluence, etc.

Results
Meetings are held once per year for three years and the planning for in-pile functional tests of blanket
mock-up is discussed. In 1998, an information exchange of the activity for blanket irradiation studyof JAERI and the U.S. was carried out in the U.S. In 1999, a coordination on experimental sharing
of JAERI and U.S. was performed in the U.S. On the development of tritium breeder pebbles,
irradiation test results of ceramic breeder with FFTF and JMTR will be evaluated. On thedevelopment of neutron multiplier pebbles, tritium release behaviors at low neutron fluence andreactivity with water will be evaluated. On the development of irradiation technique, technology
assessment of dosimetry and control of irradiation environment will be discussed. In 2000,
detailed planning on the cooperation of JAERI and the U.S. will be discussed.

(4) In-Vessel/High Heat Flux Materials and Components
High Heat Flux Materials and Components
In the development of high heat flux materials and components, collaborative studies on erosionof plasma facing materials, and studies on thermal hydraulics of high performance cooling tubes
for fusion reactors have been carried out both in an electron beam test facility in JAERI and in a highheat flux test facility at the Sandia National Laboratories New Mexico (SNL). As a result of the collaborative studies, the dependence of critical heat flux on subcooling has been clarified on the high heat flux
cooling tubes, and this result has strongly affected the design of fusion experimental reactors.
Furthermore, the workshop on “Plasma wall interaction and high heat flux components for next fusion
devices” has been held to discuss the latest results from JAERI and the U.S. every year. In this workshop, many of the first results in the world have been reported and have lead the direction of research inthis field, e.g., erosion enhancement of carbon based materials by hydrogen and helium mixture beams.

Remote Welding Cutting of Vacuum Vessel
Aiming at the development of remote assembly and disassembly of the tokamak vacuum vessel,
the cooperative activities concerning the experimental evaluation of remote welding and the cuttingof the vacuum vessel were initiated in 1999. For this joint activity, one U.S. member from
ORNL/Boeing was assigned to JAERI for three months and participated in the remote welding test
between the ITER full-scale sector model and full-scale port extension by using full-remote welding
robots fabricated by the U.S. Home Team during the ITER-EDA.

15

(5) Others
Remote Handling Technology
Aiming at the development of remote handling technology for a fusion experimental reactor, thecollaboration activities on the control of telerobotic manipulation of heavy payload was initiated in
1998. Through the technical discussions between both the U.S. and Japan participants, it was agreed tohold workshops and conduct joint simulation and critical feature experiments. The informationexchange on the sensor-based force control of heavy payload manipulator is being continued to develop
possible future joint experiments.

Safety Monitoring Program
To insure the safety and health of US and Japanese scientists when they work in each other facilities,
the US-Japan Safety Monitoring Program was established. This Program has been instrumental, since
its beginning in 1995, in enhancing the safety awareness of all foreign collaborators visiting andworking in various facilities and in safe operation of equipment exchanged between institutions.

CHAPTER 6 Annex I Programs –Materials–
6.1 DOE/MONBUSHO MATERIALS PROGRAM (DOE/MONBUSHO ANNEX 1)
This collaboration is the joint research project between DOE of U.S. and MONBUSHO of Japan inFundamental Studies of Irradiation Effects in Fusion Materials Utilizing Fission Reactors. For twenty
years, this program has contributed to the research and development of fusion materials throughproductive efforts between Japanese and U.S. scientists in carrying out a series of irradiation
experiments, post-irradiation testing, and analysis on the subjects.

Objectives
The objective of the collaborative program is to understand materials behavior in fusion reactor
irradiation environments with particular attention to the correlation of the effects of fission andfusion environments and high and low fluence phenomena. Research program has been focused
mainly on (1) the elementally process of radiation damage caused by D-T fusion neutrons at low
fluence levels in the first phase, (2) the cumulative radiation effects at high temperatures caused by
fast reactor irradiation at high fluence levels in the second phase, and (3) the dynamic and variablecomplex irradiation effects during fission neutron irradiation in the third phase.

Activities
The activities of the collaborative program include: (1) planning of the experimental program,(2) design and conduct of the irradiation experiments, (3) post-irradiation testing, examination,and evaluation, (4) exchange of personnel and information necessary to carry out the collaborative
program, and (5) prompt exchange of data and results arising from the collaborative program.
The first phase of the Japan-U.S. collaboration on fusion was the ‘RTNS-II Program’ for fiscal years
1981-1986, and this program utilized the Rotating Target Neutron Source (RTNS-II) at the Lawrence
Livermore National Laboratory (LLNL) in Livermore, CA. The second phase, known as the‘FFTF/MOTA Program’, was performed during fiscal years 1987-1994 and used the Fast Flux Test
Facility (FFTF) in conjunction with the Materials Open Test Assembly (MOTA) at the Hanford site in
Washington. The third phase, which began in 1995 and is scheduled to end at the conclusion of fiscal
year 2000, is called the JUPITER Program. It uses the mixed spectrum High Flux Isotope Reactor(HFIR) at Oak Ridge National Laboratory (ORNL) in Oak Ridge, TN and Advanced Test Reactor (ATR)
at Idaho National Engineering and Environment Laboratory (INEEL) in Idaho Falls, Idaho.

16

The various important irradiation experiments has been carried out in these phases. Irradiation
experiments using low-fluence fusion neutrons from cryogenic temperature to high temperatures
were done in the first phase. A series of elevated temperature irradiation at high damage levels using
precisely temperature-controlled assembly were performed in the second phase. The in-situ type
experiments and varying temperature irradiation using mixed-spectrum reactor has been done in
the third phase. Associated in-situ experiments, post-irradiation testing and analysis have been
performed during and after these irradiation experiments.

These activities are persuaded through collaboration between U.S. and Japanese scientists by meansof two types of exchange activities: workshops and exchange assignees. The program each year
usually has several workshops (about two in each country) and approximately about ten exchange
assignees (about eight from Japan to U.S. and about two from U.S. to Japan). So far, during its twenty
years of successful operations, the materials program has supported these systematic
workshops and long-term assignees.

Administration
The general management of the collaborative
program has been carried out by the Steering
Committee. The Steering Committee has been
composed of two persons for each party. These are
Representatives of DOE and MONBUSHO sides and theProgram Coordinator for each party. Each party has one
vote in the Steering Committee and all decisions havebeen approved by unanimity. The Steering Committee has
functions described as follows;(1) Develop the Annual Program of Work,(2) Review the implementation of the Collaborative Program,(3) Recommend the Annual Program of Work to bothparties for approval by the US-Japan Coordinating Committee
on Fusion Energy,(4) Select the time and place for the next Steering Committee
meeting, and(5) Consider other matters pertinent to the execution of the Collaborative Program as mutuallyagreed upon.
Each party designates, in writing to the other, its Representative who serves as co-chairman of theSteering Committee. Each party designates, in writing to the other, one Program Coordinator.
Communication concerning planning and execution of the Collaborative Program, including planningand arrangements for the Steering Committee meetings and communication with the Steering
Committee, has been channeled through the Program Coordinators.

Accomplishments and Highlights
The first phase of program utilizing RTNS-II clarified the elementary process of radiation damage ofvarious materials caused by 14 MeV neutrons through D-T fusion reactions in the low fluence levelup to 0.01 dpa. The second phase of program obtained important results on cumulative irradiation
effects for fluences up to about 100 dpa. The third phase of program are studying dynamic effects
and variable-complex irradiation effects in fusion reactor materials. The following are the results forthe last ten years.

171) Highlights of materials development research in the FFTF/MOTA Program
In this program, high fluence neutron irradiation experiments were performed using the preciselytemperature-controlled MOTA test vehicle. A Post-irradiation evaluation was done at the PacificNorthwest National Laboratory (PNNL) in Richland, Washington. Irradiation experiments using theExperimental Breeder Reactor-II (EBR-II) at Argonne National Laboratory-West in Idaho Falls, ID andthe mixed spectrum reactor, HFIR, at ORNL were also performed in the later period of the program.
Important results on alloy development and the optimization of low activation structural materials
which can survive up to high neutron-fluences were obtained. Some notable results are finding the
optimum concentration of chromium for resistance to radiation embrittlement in low activation
ferritic steels, designing a Fe-Cr-W alloy system with superior high-temperature strength and fracture
toughness compared to conventional steels (which has
been selected as one of the internationally importantresearch objectives), and selecting guidelines for designing
low activation vanadium alloys with acceptable ductility
after high fluence irradiation. For functional materials,
establishment of a heat treatment to suppress theirradiation embrittlement of molybdenum for highheat flux materials, and evaluation of the irradiation
performance of composite materials were successful.
2) Damage mechanisms information obtained fromthe FFTF/MOTA Program
Several experimental studies to provide information
on damage mechanisms were conducted. Thesestudies on the influence of additional elements on
the swelling properties of austenitic steels andvanadium alloys, the application of various helium
production methods and related mechanistic
studies of helium effects, the prediction of swelling bycomputer simulation, and the study of irradiation history effects were
performed with successful results. Of special note was the evaluation of irradiation
history effects. This study raised new issues about predicting the behavior of fusion reactor
materials under non-steady state operation.
3) Development of irradiation experiment technology in the FFTF/MOTA Program
The irradiation technique called the Dynamic Helium Charging Experiment (DHCE) was developedby a collaboration on design and experiment to study the fusion relevant effect of helium in vanadiumalloys. An experimental technique for the in situ measurement of electrical resistivity of ceramics inreactors was also successfully developed. For post-irradiation- evaluations, a fully automatic, high-temperature, in cell tensile testing machine called MATRON and a remote-control impact testingmachine were developed. The small specimen test technologies developed in this program werealso found to be useful for various other research and technology areas. The design windows offusion structural materials such as austenitic steels, ferritic steels and vanadium alloys were clarified,and materials with wide design windows were proposed through this program.
4) The outline and study of dynamic irradiation effects in the JUPITER Program
In this program, dynamic irradiation behavior of materials was obtained using HFIR instrumented
capsules, and the effects of nuclear transmutation and varying temperature on material irradiation
performance were studied using high thermal- and fast-neutron fluences. The in-situ technique to
directly measure the electrical properties of ceramics was successfully used to follow the change ofelectrical conductivity of alumina ceramics during high-temperature irradiation to a fluence of 3 dpa.

18This result is very useful for the design of insulating materials for the International Thermonuclear
Experimental Reactor, ITER. Irradiation creep was studied for vanadium alloys, and the influence of
applied stress was established.
5) The investigation of variable and complex irradiation effects in the JUPITER Program
Irradiation techniques using capsules with and without a europium thermal-neutron shield weredeveloped. This is a very powerful tool to study the effects of nuclear transmutation of both gas andsolid elements in low activation fusion materials. A multi-stage variable temperature capsule wasdeveloped, and high-temperature cyclic irradiation was successfully completed to study the effectsof variable irradiation conditions on the microstructural evolution and the associated mechanicalproperties change of materials. These techniques are very important in experimentally evaluating
materials behavior under fusion operating conditions where irradiation conditions vary strongly andtransmutation reactions are abundant.
6) Modeling study in the JUPITER Program and development of the next research project
It is necessary to investigate material behavior at the atomic scale and to correlate the microstructures with macroscopic properties in order to better predict materials performance in fusion conditions where there are dynamic and variable/complex irradiation effects. In the JUPITER Program,
molecular dynamics techniques were used to calculate the defects structure of reference materials.
The results were successfully applied to aid in understanding the experimental results.
Based on the above important results on the irradiation properties of low activation materials, thenext research project called JUPITER-II with the subtitle of ’Materials Integration Utilizing Reactor
Irradiation and Related Basic Research for Advanced Blankets’ is being jointly planned and willencompass a variety of fusion technology areas in order to study the issues of materials systems
which will be used interactively with coolant, etc., in fusion reactors.

6.2 DOE/JAERI MATERIALS PROGRAM (DOE/JAERI ANNEX I)
This program has contributed for twenty years to the development of fusion reactors by the scientificand engineering products about the irradiation damage on the structural materials obtained by U.S.
and Japanese Scientists.

Objectives
The objective of this collaboration is to design, conduct and evaluate joint irradiation experiments in
the High Flux Isotope Reactor (HFIR) of the Oak Ridge National Laboratory for the purpose of investigating the irradiation response of Japanese and U.S. structural and special purpose materials to highlevels of atomic displacement and Helium content in order to establish the database on the properties
and behavior of such materials and to evaluate their performance for the use in future fusion reactors.

Activities
The collaborative Program consists of the following;(1) planning of the collaborative program;(2) design and conduct of irradiation experiments in HFIR;(3) technology development for evaluation, post-irradiation testing;(4) exchange of personnel and information necessary to carry out the collaborative program; and(5) exchange of results arising from the collaborative program.
Three phases of the collaborative Program have been completed. These phases had begun in ‘83, ‘88 and‘94, respectively. Phase IV of the program started in ‘99 and is expected to continue until March 2004.

19

Phase I of the program focused on the effects of high concentrations of transmutation produced
helium coupled with displacement damage on mechanical properties and swelling behavior of theJapanese and US austenitic stainless steels. Phase II was also devoted to the understanding of theirradiation effects of austenitic alloys. Spectral and isotopic tailoring techniques were developed andutilized to reproduce the ratio of the generation rates of helium and the displacement damage(He/dpa ratio) typical of the fusion reactor environment. Also, irradiation behavior of the variety of
weld materials was evaluated. In phase III of the program, examination of the irradiation responseof advanced materials for DEMO reactors was initiated. Materials of the reduced activation
ferritic/martensitic steels, vanadium alloys, SiC/SiC composites and titanium aluminides were
included. Also, in situ test techniques to evaluate thermal conductivity and electro-resistivity of ceramicmaterials (SiC/SiC composites, Alumina etc.) during irradiation have been developed in the collaboration,and the measurements were carried out. During the phase IV, it is expected to obtain the understanding of the effect of helium on the loss of fracture toughness by irradiation for the improvementof the reduced activation ferritic/martensitic alloys. Development of the reduced activation ODS
ferritic alloys and SiC/SiC composite materials are also the important subjects in this phase.

Administration
The general management of the Collaborative Program has been carried out by a Steering
Committee. The Steering Committee has been composed of four members, two each are assigned
by JAERI and DOE and conduct following assignments.
(1) Plan the Collaborative Program, and develop the annual work plan which shall be included theannual budget and the financial contributions of JAERI and DOE.
(2) Review the cost and the projection of expenditures.
(3) Review plans for joint paper publication.
(4) Discuss personal assignments.
(5) Recommend the annual program of work, budget and personnel assignments and other suchmatters to JAERI and DOE approval.
(6) Report to the Japan-U.S. Coordinating Committee on Fusion Energy through the Contact Persons
on the technical progress in the current annual work and make recommendations for approval of
the next annual work plan and budget and for the financial contributions of JAERI and DOE to theCollaborative Program to the next annual program of work.

Accomplishments and Highlights
One of the major outcomes from phase I of the Program is the optimization of the chemicalcomposition and the heat mechanical treatment of the Japanese and US austenitic stainless steels.
The features of phase II are (i) utilization of the spectral and isotopic tailoring techniques to reproduce
the ratio of the generation rates of helium and the displacement damage (He/dpa ratio) typical of thefusion reactor environment, and (ii) the evaluation of irradiation behavior of the variety of weld materials.
Results from phase I and II are utilized to establish service conditions of the austenitic alloys for the
first wall of ITER, although the postulated service conditions at the beginning of the Program wasconsiderably different from that of ITER. One of the major accomplishments during phase III is thedevelopment of the Japanese and U.S. reduced activation ferritic/martensitic alloys. These alloys
exhibited superior resistance for irradiation and low induced activities after fusion neutron irradiation.
Another important result of phase III is the evaluation of electrical and thermal properties of ceramicmaterials under irradiation using the in sit measurement technique. During the phase IV, it is expected
to obtain the understanding of the helium effect on the degradation of fracture toughness for the
improvement of the reduced activation ferritic/martensitic alloys. Development of the reduced activation ODS ferritic/martensitic alloys and SiC/SiC composites are also the important subjects in phase IV.

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Several of the highlights during three phases are briefly described below.
• Austenitic stainless steel(i) Irradiation response to high damage levels
Changes of microstructures, tensile strengths and fatigue properties induced during irradiation
to high damage levels (e.g. 50 dpa; displacement per atom, 5000 appmHe; helium atoms were
produced by transmutation reactions) were examined.
Results indicated that titanium modification, increase of nickel content by several percent and cold
working to introduce dislocations are quite effective to suppress microstructural changes including
swelling during irradiation. This shows that the concept of the alloy designing for Japan and US PCA
worked well; optimization of the chemical composition and the heat mechanical treatment of the alloys.
Irradiation caused increase in strength at temperatures below 400C, while a slight softening
occurred at temperatures above 500C. Increase in strength below 400C is accompanied with asevere reduction of uniform elongation. Decrease in uniform elongation may introduce difficulties
in structural designing. Although the severe decrease in elongation values, ductility (evaluated fromreduction of area) levels are quite high even after irradiation.
No strong irradiation effect is detected for post irradiation fatigue properties, except for the behavior
at low strain amplitude levels. The reduction at the low amplitude levels seems to be the result of
dislocation channeling induced by irradiation hardening.
(ii) Behavior of weldment
Welding introduces variety of microstructures including segregation (nonuniform distribution) of
alloying elements. This nonuniformity clearly affected the distribution of cavities formed during
irradiation. That is, swelling in the region with higher nickel content was small.
Although the relatively strong effect of welding on the microstructural evolution during irradiation,
the effect on mechanical properties is rather small. This indicates that welding introduces no large
problems to irradiation resistance of mechanical properties.
(iii) Spectral tailoring experiment
Ratio of the production rates of He atoms and the displacement damage during irradiation strongly
affects the irradiation response of the materials. Spectral tailoring irradiation technique to adjust
thermal neutron flux level to achieve He/dpa ratio typical of fusion neutron environment has beendeveloped (This technique is only applicable for nickel containing materials). The results by the spectral
tailoring experiment delivers irradiation response of the austenitic alloys with improved accuracy.
Results clearly shows that He/dpa ratio for fusion environment accelerates the microstructural
evolution during irradiation. Results also exhibited that Japanese and US PCA have superior resistance to irradiation induced microstructural change compared to commercial austenitic alloys. Effectof He/dpa on tensile properties below 400C is not strong, and this indicates PCAs have acceptableperformences in the fusion neutron environment.
(iv) Fracture toughness
Although fracture toughness is an important properties for the structural application, limited dataof the irradiation effect were available. Irradiation to 3 dpa caused strong reduction of fracture
toughness. The degradation tends to saturate with neutron dose. Although the reduction byirradiation is large, the residual fracture toughness level is not small, and the level evaluated tobe high enough as a structural materials for the blanket.

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(v) Irradiation assisted stress corrosion cracking (IASCC)
Because He/dpa ratio affects microstructural evolution including
irradiation induced segregation, effect of neutron spectra on
IASCC need to be evaluated. Evaluation of the susceptibility tostress corrosion cracking is rather complicated for the natureof the phenomenon. EPR (electochemical potentiokinetic
reactivation) method and SSRT (sow strain rate tensile) test
were applied for the evaluation of irradiated specimens.
Comparing with the result on the specimens irradiated in
FBR, result clearly shows that He/dpa ratio for fusion condition accelerated degradation. This also implies theimportance of the effect of He/dpa for the evaluation of
the IASCC susceptibility of LWR core component where
He/dpa ratio stringly depend on the position.
• Low activation ferritic/martensitic steel
During phase II JAERI and ORNL (including the out side activitiesof the Collaboration) carried out irradiation experiments on ferritic/martensitic steels withchromium (Cr) content levels of ranging from 2.25 to 12 percent. Results indicated Cr content strongly
affects irradiation hardening, and the hardening exhibits minimal at 7-9 Cr. Taking these things into
account; the knowledge and experiences about microstructural stability, strength at high temperatures
and also for the low residual activities, JAERI designed F82H with NKK corporation and ORNL madeseveral of 9Cr-W-V-Ta heats. Those alloys irradiated at temperatures from 200 to 600C to the damagelevels of 60 dpa, and exhibited good resistance for irradiation over
• In situ testingElectrical and thermal conductivities of ceramic materials are tend to be affected not only
accumulated damage level but also dose rate during irradiation. Techniques for the in situ testingof thermal and electrical conductivities of ceramic materials have been, therefore developed. As
preliminary results, the degradation of thermal conductivity decreases rapidly with dose andsaturates during the early stage of irradiation.

CHAPTER 7 Annex IV Program – Fusion Fuel7.1 DOE/JAERI TSTA (Tritium Systems Test
Assembly)
Annex IV was signed on June 11, 1987 for a
five-year period (Phases 1 and 2). It was amended
in 1992 (Phase 3), in 1994 (Phase 4), in 1997
(Phase 5) and in 1998 (Phase 6). Phase 6 is athree-year program, which is now under way
until June 10, 2001.
The objective of this program in Phases 1, 2
and 3 was to evaluate the joint operation andexperiments on fusion-fuel technology with
Tritium Systems Test Assembly (TSTA) at theLos Alamos National Laboratory (LANL), Los
Alamos, New Mexico. It was successful inmeeting all of its technical objectives. During
this period until 1994, fusion-fuel processing

technology was successfully demonstrated throughthe operation of the TSTA fusion-fuel processing loop
system in which the processing rate reached up to
one-fifth of that estimated in a fusion experimental
reactor. The JAERI-developed Fuel Clean-up
System (JFCU) was installed in the TSTA system
and reliable processing was demonstrated by the
successful 25-day continuous operation of thisU.S.-Japan combined system. It was also
verified that this system could process various
non-steady state input coming from a pulsed
tokamak operation with enough flexibility.
Beginning in 1994, safety technology of fusion fuel was emphasized, and theactivities in Phases 4 and 5 were focused to enhance safety of the fusion-fuel system.
During the period from 1994 to 1998, actual tritium migration behavior in a large room was
successfully investigated by releasing 37 GBq {1 curie} of tritium to the 3000 m3 TSTA main cell.
Using the Tritium Plasma Experiment apparatus, a powerful tritium plasma source, tritium retention
studies on plasma facing materials of a fusion reactor were performed and valuable data was obtained.
Through successful decommissioning of the JFCU, experience of decommissioning and decontaminationof tritium-contaminated components was gained. In this period, radioactive reaction studies with tritium
were performed at JAERI’s Tritium Process Laboratory and unique data was obtained.
The Annex was further amended in 1998 to emphasize and extend tritium safety technology including
new activities to understand tritium behavior in a tokamak. During the period from 1998 until
2001, the collaborative program was expanded to include both TSTA and the Tokamak Fusion Test
Reactor (TFTR) at the Princeton Plasma Physics Laboratory (PPPL). Research of off-normal events inthe fuel system and tritium inventory control studies on process components are underway at TSTA.
At PPPL, research of tritium distribution in the TFTR vacuum vessel, analysis of tritium behavior
during TFTR deuterium-tritium operation, research and development for decontamination and decommissioning of TFTR and basic research on advanced radioactive liquid waste treatment techniques arecontinuing. Characterization studies on materials exposed to tritium are in progress both at TSTA and
TFTR. A significant amount of useful data is being obtained from all of these efforts.
Technology for Fusion Fuel Processing (Annex III and Annex IV)• Developed and demonstrated, at the Tritium Systems Test Assembly (TSTA) facility, the full
fuel handling and processing system and technology for next step fusion devices. This includes
demonstrating the ability to handle large quantities of tritium safely and response of the system
to off normal occurrences.
• Developed and tested a number of tritium analytical techniques and environmental and personnel
protective systems for tritium handling. In addition, increased the fusion scientific database in thearea of tritium materials interaction and qualified equipment and components for tritium service inthe fusion program.
• Performed tritium release experiments, within the TSTA building, to determine how tritium could
migrate to the environment in the event of a release.
• Developed database on decontaminating and decommissioning fusion systems, such as the JFCU
and the Tokamak Fusion Test Reactor (TFTR), for use in the design of future fusion facilities.

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CHAPTER 8 Completed Annex Projects(Associated with DOE/JAERI)
8.1 DOE/JAERI FUSION BLANKET NEUTRONICS (ANNEX II)
Introduction:
This Collaborative Program officially started on October 24, 1984, for three years as Annex II to
the Implementing Arrangement between JAERI and USDOE on Cooperation in Fusion Researchand Development. The collaboration was extended for another three years starting from October 23,
1987 to cover other aspects of the collaboration (see below) and the third (and final) renewal was
made in October 1990. The program was officially concluded by the end of October, 1993.
Technical meetings followed by Steering Committee meetings were held annually to discuss progress
and annual reports were submitted to the U.S./Japan Coordinating Committee on Fusion Energy (CCFE).
The collaboration was in the form of a mutual and equitable participation from both sides in carryingout more than 20 integral experiments on mockups of various configurations that simulate theengineering features of fusion blankets that include a first wall, neutron multiplier, coolant channels,
heterogeneity, armor layer, large openings, etc. Both point 14 MeV source and a simulated line source
were used to generate the representative neutron source which was tailored to have as much simulation
to the energy and angular distribution of neutrons emitted from plasma in a fusion reactor. The Fusion
Neutron Source (FNS) Facility at JAERI was used to perform these experiments. Each experiment was
carefully pre-analyzed to ensure optimal arrangement and experimentalists from both sides participatedin performing the experiments and processing the experimental database in a usable form. The U.S.
and JAERI performed, independently, the post analysis of these experiments using state-of-the-art
computational tools and nuclear databases available in the U.S. and Japan.

Objectives and Phases of the Program:
The main objectives of the Program have been: (a) to establish new experimental techniques for
performing fusion neutronics integral experiments, (b) to provide experimental data for evaluating
the accuracy of basic nuclear data and calculational methods for fusion system design, (c) to provide
estimates of uncertainties in the calculation of tritium breeding, nuclear heating, and induced radioactivity and decay heat, (d) to provide feedback for future nuclear data measurements and evaluations
and calculational method improvements, and (e) to provide guidelines for fusion system designers,
particularly the magnitude of safety factors required to compensate for quantified uncertainties.
Phase I of the program included experiments that were performed in an open geometry where test
assemblies were loaded in the experimental cavity in the wall between two large rooms. Li2O blocks
were used to form the breeding zone. Combination of first wall (316SS) and beryllium in various
configurations (front layer, sandwiched layer, etc) were utilized. In Phase II, the experiments were
performed in a closed geometry where the test assembly was placed at one end of a rectangular
enclosure made of Li2CO3 and the D-T neutron source was placed inside the cavity. Several
experiments with FW, and beryllium in various arrangements (e.g., as a liner) were also carriedout to study the multiplication effect of beryllium and the prediction capability of present codesand databases. This phase also focused on studying the heterogeneity effect of coolant channels on
tritium breeding rates (TPR) and nuclear and decay heating. In Phase III, a novel approach togenerate a simulated line source was applied where an annular test assembly with inner squarecavity was moved periodically back and forth relative to a stationary point source and, hence, asimulated line source was created. Several experiments on Li2O and Li2CO3 breeding materials
were performed in this phase which also included a neutron streaming from a large opening on
one side of the assembly and its impact on TBR and neutron spectrum inside the test assembly.

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Major Accomplishments
This 10-year program was an exemplary international collaboration, which produced a wealth of experimental data on TBR, in-system neutron spectrum, and nuclear heating and decay radioactivity. Analysisof the experiments were performed using 3-D Monte Carlo and 2-D discrete ordinates codes and the latest
nuclear data libraries in the U.S. and Japan. Significant differences among measurement techniques andcalculational methods were found. To assure a 90% confidence level for tritium breeding calculations not
to exceed measurements, designers should use a safety factor > 1.1 to 1.2, depending on the calculational
method. The radioactivity measurements were performed for more than 20 materials with the focus on
gamma emitters with half-lives < 5 yr. The ratio of the calculated-to-experimental (C/E) values ranged
between 0.5 and 1.5, but it deviates greatly from unity for some materials. Most of the discrepancies were
attributed directly to deficiencies in the activation libraries, particularly errors in cross sections for certain
reactions. The microcalorimetric technique was vastly improved through the program. It allowed measurements of the total nuclear heating with a temperature rise as low as 1 _K/s. The C/E ratio for nuclear
heating deviated from unity by as much as 70% for some materials but only a few percent for others.
The main findings from this Collaborative Program have been published in several scholarly journals
and discussed in various workshops and international meetings on fusion neutronics.The mostcomprehensive discussion of these findings and accomplishments have been documented in 16 manuscripts that appeared in a special issue of the Fusion Technology Journal as Volume 28, No. 1&2, 1995.

8.2 DOE/JAERI FUEL CLEANUP COMPONENTS FOR THE
TRITIUM SYSTEMS TEST ASSEMBLY (ANNEX III)In 1986, Annex III was signed between DOE and JAERI for the development of improved components for the fuel cleanup system (FCU) for the Tritium Systems Test Assembly (TSTA) facility at theLos Alamos National Laboratory (LANL). The purpose of the FCU is to separate out the hydrogenisotopes from all impurities that may be found in the exhaust coming from the plasma or breedingblanket. The major objective of the Collaborative Program was to test with tritium at TSTA two
process-ready components, the palladium diffuser and the ceramic electrolysis cell. These components were designed and manufactured by JAERI. Both of these components were critical parts of a
new FCU design that JAERI was developing for future fusion experimental devices. The tests at TSTA
were very successful. Eventually, these two components became the key parts of the JAERI FCU,
which was also tested successfully as part of Annex IV.

8.3 DOE/JAERI SUPERCONDUCTING POLOIDAL COIL TECHNOLOGY (ANNEX V)
In 1988, Annex-V was signed between DOE and JAERI for the development of supeconducting
poloidal coils. The implementing institutes are the Massachusetts Institute of Technology (MIT) in
the U.S. and JAERI in Japan. The major goal of the program was to develop superconducting pulsed
coils that could be charged up to 7T and 20MJ in one second by using newly developed Nb3Sn
pulsed superconductors. The U.S. coil was called “US-DPC” and the Japanese coil was called “DPC-EX.”
Both coils were tested one by one by using the Demo Poloidal Coil Test Facility at JAERI’s Naka
Fusion Research Establishment. The facility also included a pair of NbTi backup coils, 1.2-kW
forced-cooled cryogenic system and the high power supply of the JT-60 to charge the coil swiftly. The
newly developed coils achieved a pulsed charging up to 7T within the range of 0.5 to 3.0 seconds
and established a new technology of using Nb3Sn coil as a large pulsed coil for fusion by 1992.

8.4 DOE/JAERI FEL HEATING AND CURRENT DRIVE ON MTX (ANNEX VI)
The Japan-U.S. Collaborative Program for Annex VI was established in May 1988. Under this Annex,
the Microwave Tokamak Experiment (MTX) was carried out to evaluate the application of highpower, pulsed microwaves to plasma heating under the collaboration between JAERI and LLNL.
The microwaves generated by the FEL were injected into the tokamak and the hot electrons generated
were observed in the summer of 1992. JAERI provided the key components to conduct the25experiments, including the mirrors to transform FEL microwaves to the appropriate modes, calorimeter tomeasure the microwave power and the various diagnostic systems to verify the hot electron generation.

8.5 DOE/JAERI NEW TUBE TEST WITH JT-60 ICRF SYSTEM (ANNEX VII)
The new U.S. tetrode tube X2274 was tested with the JT-60 ICRF system and demonstrated 1.5 MW
for 5 seconds at 130 MHz, which was a world record at that time (1988-1992).

8.6 DOE/JAERI Collaborative Program on the Testing of a Negative Ion Source for
Neutral Beam Injectors (ANNEX VIII)
Annex VII was singed between DOE and JAERI in December 1988 for the development of ahigh current negative ion source for neutral beam injectors. A 'volume type' negative ion source
developed by JAERI was transported to Lawrence Berkeley Laboratory (LBL) and tested both inhydrogen and deuterium operation. High current density negative ions of 10.4mA/cm2 H- and8.4mA/cm2 D- were successfully produced with an arc discharge power of 40kW. It was found thatthe isotope effect for the deuterium negative ion current was about 0.8 of the hydrogen negative ion
current. To obtain the high D- current density, it was important to optimize the magnetic filter
strength of the volume negative ion source. Electrons accompanying with the negative ions wereeffectively suppressed by biasing the plasma grid positively with respect to the anode. The ion
source was sent back to JAERI in 1989.

8.7 DOE/JAERI THOMSON SCATTERING SYSTEM FOR JFT-2M (ANNEX X)
The U.S. DOE and JAERI signed Annex X on October 25, 1989, for a collaborative program on the
JFT-2M TV Thomson Scattering System. In May-July1991, the TVTS fabrication was carried out on
JFT-2M in collaboration with PPPL. In February 1992, the first measurement of the Thomson
scattered light was done and the TVTS hardware worked routinely since May 1992.

8.8 DOE/JAERI NEGATIVE ION SOURCES AND ACCELERATORS FOR NEUTRAL BEAMINJECTORS (ANNEX XI)
A high current source using multiple merging beams was developed by Japan and was incorporated
into the neutral beam accelerator system which was tested at the Lawrence Berkeley National
Laboratory (LBNL) in Berkeley, California. Japan needed to develop a 500 keV source for use on
JT-60 and the U.S. wanted to develop 1.3 MeV source for the multilateral ITER project. Although thecollaboration successfully demonstrated high current operation of neutral beams with energy up to
200 keV, the ITER Director announced that neutral beams might not be used on ITER. The U.S.
initiated the cancellation of Annex XI.

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U.S.-JAPAN FUSION RESEARCH COOPERATION
79

80

81

82

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86

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95

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97

98

99

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01

A. Overall Planning
B. Joint Planning Program
Fusion Physics Planning Committee(FPPC)
Fusion Technology Planning
Committee (FTPC)
C. Joint Institute of Fusion Theory (JIFT)
D. Doublet III / DIII-D
E. Cooperations with Annexes
JAERI-DOE
Annex I (HFIR / ORR)
Annex II (FNS)
Annex III (TSTA I)
Annex IV (TSTA II)
Annex V (DPC)
Annex VI (MTX)
Annex VII (Tube test)
Annex VIII (NNBI)
Annex IX (Data Link)
Annex X (TVTS)
Annex XI (NNBI)
Monbusho-DOE
Annex I (JUPITER)
Annex II (Data Link)

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