US scientists achieve ‘turning point’ in fusion energy
quest
Will Dunham | Reuters
Published — Thursday 13 February
2014
A handout photo obtained from
Nature shows a Hohlraum geometry with a capsule inside, through the cut-away of
the hohlraum wall. Experiments have succeeded in releasing more energy through
a fusion reaction than is absorbed by the fuel (to trigger the reaction). (AFP
photo / Nature/ Lawrence Livermore National Laboratory and member of high-foot
team)
WASHINGTON: US
scientists announced on Wednesday an important milestone in the costly,
decades-old quest to develop fusion energy, which, if harnessed successfully,
promises a nearly inexhaustible energy source for future generations.
For the first time, experiments
have produced more energy from fusion reactions than the amount of energy put
into the fusion fuel, scientists at the federally funded Lawrence Livermore National Laboratory in California said.
The researchers, led by physicist
Omar Hurricane, described the achievement as important but said much more work
is needed before fusion can become a viable energy source. They noted that did
not produce self-heating nuclear fusion, known as ignition, that would be
needed for any fusion power plant.
Researchers have faced daunting
scientific and engineering challenges in trying to develop nuclear fusion — the
process that powers stars including our sun — for use by humankind.
“Really for the first time anywhere,
we’ve gotten more energy out of this fuel than was put into the fuel. And
that’s quite unique. And that’s kind of a major turning point, in a lot of our
minds,” Hurricane told reporters.
“I think a lot of people are
jazzed.”
Unlike fossil fuels or the fission
process in nuclear power plants, fusion offers the prospect of abundant energy
without pollution, radioactive waste or greenhouse gases.
Unlike the current nuclear fission
energy that is derived from splitting atoms, fusion energy is produced by fusing
atoms together.
Experts believe it still will be
many years or decades before fusion can become a practical energy source.
“I wish I could put a date on it,”
said Hurricane. “But it really is (just) research. And, you know, although
we’re doing pretty good, we’d be lying to you if we told you a date.”
Of the uncertain path ahead in
fusion research, Hurricane compared it to “climbing half way up a mountain, but
the top of the mountain is hidden in clouds. You can’t see it. You don’t have a
map.”
The research was conducted at the
laboratory’s National Ignition Facility (NIF), which was completed in 2009.
ZAP A TINY TARGET
The scientists used 192 laser
beams to zap a tiny target containing a capsule less than a tenth of an inch
(about 2 mm) in diameter filled with fusion fuel, consisting of a plasma of
deuterium and tritium, which are two isotopes, or forms, of hydrogen.
The fuel was coated on the inside
of the capsule in a frozen layer less than the width of a human hair.
At very high temperatures, the nucleus
of the deuterium and the nucleus of the tritium fuse, a neutron and something
known as an “alpha particle” emerge, and energy is released.
The experiments, published in the
journal Nature, created conditions up to three times the density of the sun.
In two experiments described by
the researchers that took place in September and November of last year, more
energy came out of the fusion fuel than was deposited into it, but it was still
less than the total amount deposited into the target.
The deuterium-tritium implosions
were more stable than previously achieved. The researchers did so by doubling
the laser power earlier in the laser pulse than in earlier tries.
The fusion-energy yield was
increased by about tenfold from past experiments, in a series that started last
May. One of the experiments produced more than half of the so-called Lawson
criteria needed to reach ignition — but only about one-100th of the energy
needed for ignition.
Lawrence Livermore National
Laboratory, located about 45 miles (70 km) east of San Francisco, is overseen by the National
Nuclear Security Administration, an agency of the US Department of Energy.
Eager to exploit the potential
this type of energy offers to reduce dependence on oil and other fossil fuels,
the United States
and other nations have invested many millions of dollars into fusion research,
often with uneven results.
There are two main approaches.
This team focuses on what’s known as inertial confinement fusion energy — using
lasers to compress fuel pellets, which triggers fusion reactions.
Other labs like the Culham Center
for Fusion Energy, which is the British national laboratory for fusion
research, and the Princeton Plasma Physics Laboratory in New Jersey focus on magnetic confinement
fusion energy — putting plasma in a magnetic container and heating it up until
nuclei fuse.
Steve Cowley, director of the Culham Center,
called new findings “truly excellent” but said different measures of success
make it hard to compare with his type of research.
“We have waited 60 years to get
close to controlled fusion, and we are now close in both magnetic and inertial
confinement research. We must keep at it,” Cowley said in a statement.
Mark Herrmann, a fusion researcher
at Sandia National Laboratories in New
Mexico which is also overseen by the US National
Nuclear Security Administration, called the new findings important, but sees a
“very long road to assessing the viability of fusion as a long-term energy
source.”
“I believe a compact carbon-free
energy source is very important for humankind in the long term,” he said by
e-mail.
“Fusion is one bet. If it pays
off, the return will be big.”
Lawrence
Livermore
National Laboratory
Lawrence
Livermore National Security, LLC manages the Lawrence Livermore National Laboratory.
Note: University
of California is a partner with the Lawrence Livermore
National Security, LLC.
Richard
C. Blum is a regent at the University of California,
married to Senator Dianne Feinstein,
and an honorary trustee at the Brookings
Institution (think tank).
Foundation
to Promote Open Society was a funder for the Brookings Institution
(think tank).
George Soros
was the chairman for the Foundation to Promote Open Society, and is the
founder & chairman for the Open
Society Foundations.
Open
Society Foundations was a funder for the Atlantic Council of the United
States (think tank).
John
A. Gordon is a director at the Atlantic
Council of the United States
(think tank), and a governor for the Lawrence Livermore
National Security, LLC.
Ellen
O. Tauscher is a director at the Atlantic
Council of the United States (think tank), a governor for the Lawrence Livermore National Security, LLC,
and was the special envoy for strategic stability & missile defense at the U.S. Department of State for the Barack Obama administration.
Steven E. Koonin
is a governor for the Lawrence Livermore
National Security, LLC, was the under secretary of science at the U.S. Department of Energy for the Barack Obama administration, and the provost
for the California Institute of
Technology.
Harold
Brown is a life trustee at the California
Institute of Technology, and an honorary director at the Atlantic Council of the United States (think tank).
Robert S. McNamara
was a life trustee at the California
Institute of Technology, an honorary director at the Atlantic Council of the United
States (think tank), and an honorary
trustee at the Brookings Institution (think tank).
John
S. Chen is a trustee at the California
Institute of Technology, and was a trustee at the Brookings Institution
(think tank).
Richard
C. Blum is an honorary trustee at the Brookings
Institution (think tank), married to Senator Dianne Feinstein, and a regent at the University of California.
University
of California is a partner with the Lawrence Livermore
National Security, LLC.
Lawrence
Livermore National Security, LLC manages the Lawrence Livermore National Laboratory.
No comments:
Post a Comment