[ RadSafe ] Article: China set to make fusion history
crispy_bird at yahoo.com
Thu Aug 24 07:19:41 CDT 2006
Nature 442, 853(24 August 2006) Published online 23
China set to make fusion history
Abstract: Plasma physics comes under scrutiny in new
breed of tokamak.
The world's first fully superconducting tokamak is
soon to produce a discharge of ionized gas or plasma.
If all goes as planned, China's Experimental Advanced
Superconducting Tokamak (EAST) project will make its
first plasma in the next few weeks.
EAST uses superconducting coils to create a magnetic
field that confines plasma inside a doughnut-shaped
vessel known as a tokamak. The behaviour of the plasma
should shed light on the potential of nuclear fusion
as an energy source.
Conventional experimental fusion machines use copper
coils, or a combination of copper and superconducting
coils, to trap the hot plasma. But copper coils heat
up and need to be cooled down regularly, thus limiting
operating time. EAST has only superconducting coils so
it can be operated continuously.
The US$25-million machine sets the stage for the
multibillion-dollar ITER fusion experiment that is to
be built in France; ITER, due to start operations in
2016, is similarly designed to be all-superconducting.
[Picture] In the lead: if China's EAST project is a
success, it will pave the way for other major fusion
experiments around the world.
"We'll need new energy resources for a long-term
period, and fusion will be one of them," says Peide
Weng, deputy manager and chief engineer of the EAST
project at the Institute of Plasma Physics of the
Chinese Academy of Sciences. "For commercial use, it
should be superconducting because it will need
China approved the machine in 1998, as part of a push
towards new energy sources. Construction then began in
2000 in Hefei, in southern China. The 150-member EAST
team imported some material and components, but
designed and fabricated the bulk of the equipment on
EAST is only one-tenth the volume of Japan's JT-60
tokamak, and one-hundredth the expected volume of
ITER. It won't produce fusion power, and is designed
to study advanced tokamak physics. The first plasma,
created from heated hydrogen gas, will probably last
for only a few seconds. Still, "it will be a very
important step forward," says Toshihide Tsunematsu,
director-general of the Naka Fusion Institute of the
Japan Atomic Energy Agency, who visited EAST a few
weeks ago. The agency owns the JT-60 tokamak.
Eventually, the EAST team aims to hold a plasma for
study for as long as 1,000 seconds. In other tokamaks
plasmas last for only a few tens of seconds.
South Korea is currently developing a tokamak similar
to EAST, called the Korean Superconducting Tokamak
Reactor (KSTAR), whose construction is expected to be
completed at the end of 2007. Japan also plans to
upgrade its JT-60 machine to make it fully
superconducting in a few years.
International physicists praise what China has
accomplished so far. In 2003, 25 physicists visited
EAST as part of its international advisory committee.
"Everybody came away very impressed," says Dale Meade,
a physicist with the Princeton Plasma Physics
Laboratory in Princeton, New Jersey, and a member of
the group. The committee plans to hold another meeting
in October, when China hosts a conference of the
International Atomic Energy Agency.
In the meantime, the EAST researchers have plenty to
work on, says Tsunematsu. They will have to improve
key technologies, such as a device to heat the plasma,
and be able to effectively control high-temperature
plasma for a long period of time. "China will face a
real challenge," he says.
>From an article about physicians doing clinical studies:
"It was just before an early morning meeting, and I was really trying to get to the bagels, but I couldn't help overhearing a conversation between one of my statistical colleagues and a surgeon.
Statistician: "Oh, so you have already calculated the P value?"
Surgeon: "Yes, I used multinomial logistic regression."
Statistician: "Really? How did you come up with that?"
Surgeon: "Well, I tried each analysis on the SPSS drop-down menus, and that was the one that gave the smallest P value"."
John Jacobus, MS
Certified Health Physicist
e-mail: crispy_bird at yahoo.com
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