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By Matt McGrath
Science reporter, BBC World Service
An international plan to build a nuclear fusion reactor is being threatened by
rising costs, delays and technical challenges.
Emails leaked to the BBC indicate that construction costs for the experimental
fusion project called Iter have more than doubled.
Some scientists also believe that the technical hurdles to fusion have become
more difficult to overcome and that the development of fusion as a commercial
power source is still at least 100 years away.
At a meeting in Japan on Wednesday, members of the governing Iter council will
review the plans and may agree to scale back the project.
'Size of a battleship'
On a windy construction site in the south of France, the lofty scientific goal
of developing nuclear fusion as a power source is starting to take on a more
substantial form.
Covering an area of more than 400,000 square metres, workers have built a
one-kilometre-long earthen platform on which the experimental reactor will sit.
"This is going to be the world's biggest science experiment," says Neil Calder,
Iter's head of communications.
"This is a vast global project to show the scientific feasibility of fusion as
a limitless source of energy.
"On top of this platform we are going to build 130 buildings. The main building
will contain the Iter machine itself.
"It will be huge - the size of the Arc de Triomphe in Paris - and it'll weigh
about the same as a battleship - 36,000 tonnes of metal and instrumentation."
Controlling fusion
Iter was formally launched in 2006 as collaboration between the European Union,
the United States, Russia, Japan, China, India and South Korea. The plan was to
build the world's most advanced fusion experiment within 10 years for a budget
of $6bn ( 3.6bn).
But the grand scheme has been dogged by soaring costs caused by more expensive
raw materials and increases in staff numbers. Emails seen by the BBC indicate
that the total price of constructing the experiment is now expected to be in
excess of $16bn ( 10bn).
Professor Sebastien Balibar is research director for the French national
research laboratory in Paris. He says that if the rising price of Iter is met
by cutting back other research programmes that would be a disaster for science.
"If Iter is built on money having to do with energy or oil, that is perfectly
good, I hope it works and in one hundred years I hope we know how to control a
fusion reaction. But if it is taken from the public support of research in
physics or biology then I would be very upset," says Professor Balibar.
'Different road'
Costs are not the only problem; Iter is also beset by huge technical
challenges.
Fusion takes place when a superheated gas called a plasma reaches a stage
called ignition, where hydrogen atoms start to fuse with each other and release
large amounts of energy. Iter aims to achieve this but only for a few minutes
at a time.
MIT professor Bruno Coppi has been working on fusion research in Italy and the
United States for many decades. He believes that Iter is the wrong experiment;
it is too costly, will take too long and may not deliver fusion. He says we
should be looking at other options.
"We are pressed for time, the climate situation is worse. I think we should go
with a faster line of experiments. Iter should admit its limitations and it
will give a limited contribution to fusion, but to get to ignition you need to
follow a different road," he says.
Fusion is like trying to put the Sun in a box - but we don't know how to make
the box
Professor Sebastien Balibar
Another huge hurdle is how to contain gases that are 10 times hotter than the
Sun. The materials required simply haven't been invented yet.
Professor Balibar explained: "The most difficult problem is the problem of
materials. Some time ago I declared that fusion is like trying to put the Sun
in a box - but we don't know how to make the box.
"The walls of the box, which need to be leak tight, are bombarded by these
neutrons which can make stainless steel boil. Some people say it is just a
question of inventing a stainless steel which is porous to let these particles
through; personally I would have started by inventing this material."
Failure a possibility
In Provence, the scientists working on Iter say they have faith that the
project will deliver the most effective path to fusion.
Dr Norbert Holtkamp is the man tasked with building the machine.
"Iter is a step that will demonstrate whether fusion is viable. But whether it
is easy then depends on the cost of energy at that time on the cost of oil, but
certainly Iter has the potential.
Dr Holtkamp recognises that Iter is a scientific experiment - and as such it
has the possibility of failure.
"Any project can fail, especially if it's one of a kind or the first of its
kind. It would be irresponsible for any scientist or project manager to say
that in a science project it cannot fail."
Long-term plan
The rising costs of construction and technical challenges are to be reviewed at
a meeting of the Iter council in Japan on Wednesday and Thursday. It is
possible that by the end of this year, a new scaled-down version of Iter will
be agreed.
Dr Holtkamp says the view that the project is to be scaled down is wrong.
"Fusion is not going to be the alternative in the next 20, 30 or 40 years, that
is correct. But there needs to a long term plan; 40 years is little more than a
generation. We need to think about the next generation and the many after
that."
Professor Balibar says that the end result of the ballooning costs and
increasing technical challenges will be a further slowing of the path to
fusion.
"The consequence of all these difficulties is that it's not going to be
tomorrow that one succeeds with fusion. But the energy problem and the climate
problem are urgent," he says.
"The global warming is now - one needs to find a solution immediately, one
cannot wait 100 years. The solution to the climate and energy problem is not
Iter, (it) is not fusion."
While fusion offers a long-term hope of securing energy supplies, the changing
climate and the pressing need for greener energy may ensure that renewables get
greater political support in the short to medium term.
Ultimately fusion may be a technological dream that is just too hard to turn
into reality. And Iter, in a beautiful setting in the south of France, may
become the graveyard of a good but impossible idea.