Magnetics Business & Technology - July/August 2019 - 38

VISIONS

General Atomics Reaches Milestone in Making The World's Largest Pulsed
Superconducting Magnet

Artist rendition of the ITER tokamak
General Atomics recently completed a major step in the development of the world's largest pulsed superconducting magnet which
will be utilized for the world's largest fusion energy project, ITER,
taking place in southern France by a global consortium of nations.
The magnet is known as the ITER Central Solenoid, and a critical
milestone was reached in early May when GA completed fabrication of the first of six modules that will make up the solenoid. The
central solenoid, sometimes referred to as the heart of ITER, will
be 59 ft tall and reside in the center of the ITER tokamak. Operation of the magnet will enable ITER to create and sustain fusion on
a scale unprecedented on earth by providing 15 million amperes
of plasma current. This current simultaneously heats and confines
the plasma, a state of matter with large quantities of ionized particles, enabling sustained temperatures in ITER that are over ten
times those of the sun.
"The central solenoid is essential to the operation
of ITER, which makes this a significant milestone
for the global fusion energy community," said Jeff
Quintenz, senior vice president of GA's Energy
Group. "The engineering challenge we took on
with this project was enormous, but today we are
seeing the payoff for that effort. The successful completion and operation of ITER should
help lead to the development of fusion ener- Jeff Quintenz,
gy, a nearly limitless, clean energy source for senior VP of GA's
Energy Group
our world."
The completed central solenoid will consist
of six stacked modules made of niobium-tin cable encased in a
stainless-steel jacket. Fabrication of each module occurs over a
24-month period, beginning with precise winding and joining of
seven conductor segments totaling 3.6 miles to create a layered
module with strict tolerances - the two ends must be within a quarter of an inch. The module then spends a month in a massive oven

Magnetics Business & Technology * July/August 2019

to convert the niobium and tin core into superconducting material.
Every turn of the conductor must be separately wrapped with six
layers of insulating tape, totaling over 180 miles per module. The
entire module is then insulated before being encapsulated in a
special epoxy resin to stabilize and protect the coil.
All of the manufacturing processes were developed by GA under
a contract from UT-Battelle, which manages Oak Ridge National
Laboratory for the U.S. Department of Energy.
"GA has done an outstanding job to reach the difficult and important milestone of completing Module 1 fabrication," said Wayne
Reiersen, US ITER magnet team lead based at Oak Ridge. "This
is the culmination of an eight-year effort involving concurrent engineering of the module design, creating a facility in which these
powerful superconducting magnets could be built and tested,
qualifying the manufacturing processes, and then building this
first-of-a-kind module."
GA has over-six decades of research experience with fusion technology. In addition to its work on ITER, the San Diego-based company operates the DIII-D National Fusion Facility owned by DOE,
which is the largest magnetic fusion research facility in the U.S.
Like other members--India, the U.S. directs much of its ITER contribution toward domestic manufacturing of components. This approach allows member countries to support the global effort while
developing expertise and resources at home. While the U.S. is
contributing about nine percent of ITER's construction cost, it will
have access to 100 percent of the results. America's investment in
ITER to date surpasses $1.1 billion, with more than 80% spent in
the U.S. to enable domestic industries, national labs, and universities to deliver contributions for the project.
Continued on page 37...

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