[cdn-nucl-l] Downsized ITER Fusion Reactor - in Canada ?

["Franta, Jaroslav" <frantaj@aecl.ca>]

FYI,

http://www.aip.org/pt/iter.htm
Remaining ITER Partners Settle on an Outline Design for a Downsized Fusion
Reactor 
If a smaller, cheaper version of ITER actually goes ahead, the US might just
rejoin the project.	
Plans to build a large tokamak as a step toward one day producing fusion
energy are back on track after having been derailed in 1998, when the US
pulled out of the International Thermonuclear Experimental Reactor (ITER)
project. This past January the remaining partners-the European Community,
Japan, and Russia-agreed on a design for a smaller machine that is supposed
to cut the original cost in half, to about $4 billion.
The scaled-down design has more modest physics and engineering goals, but
holds to the overall aim of trying to learn enough to build a prototype
fusion power plant. ITER would study fusion of deuterium and tritium to
yield neutrons and alpha particles-similar to the process that powers stars.
Project supporters claim fusion is the best long-term choice for a safe,
clean energy source: It wouldn't pollute the atmosphere with carbon dioxide;
there is no danger of a chain reaction should something go wrong inside the
reactor; and much less long-lived radioactive waste would result than from
fission. But critics have doubts about fusion energy's feasibility and
implementation, among other things, and also worry about the high
development costs. It wouldn't solve all the waste and proliferation
problems associated with fission, says Edwin Lyman, of the Washington,
DC-based Nuclear Control Institute. "It's a really regressive dream to try
to make fusion energy work. If anything like the tens of billions of dollars
that's been spent on fusion R&D had gone into soft, renewable energy-such as
solar and wind-who knows where we'd be  now. . . . "	
The ITER partners need to win wide support for fusion energy. In addition,
before the new ITER can happen, they still need to refine the design, get
funding, and choose a site-Japan and Canada (which participates in ITER as a
member of the European team) are both keen to host it. The biggest
difficulties in going ahead with ITER, says project director Robert Aymar,
"are not scientific or technical, but financial, political, and social. ITER
could go on-line by around 2013. And fusion energy could become commercially
available in the second half of the 21st century." 
A smaller, cheaper ITER
The new ITER abandons the goal of ignition, or infinite power gain, aiming
instead for a gain of 10 or more (Q  <<...>> 10) with an inductively driven
plasma, and Q  <<...>> 5 for steady state. Backing off from ignition is no
great loss, ITER scientists insist, because a power station would need a
steady-state gain of about 30, rather than the less controllable ignition.
When deuterium and tritium fuse, a fifth of the energy goes to alpha
particles, which heat the plasma. So for Q > 5, the alpha heating tops the
input energy. That, says Aymar, "is a big step for physics, and it will
require new engineering." The standing gain record is 0.6, held by the Joint
European Torus, in the UK, which besides Princeton University's now-defunct
Tokamak Fusion Test Reactor, is the only place where deuterium-tritium
experiments have been done.
The biggest dent in the cost of ITER would come from reducing the tokamak
size-the planned radius is now 6.2 m, down from 8.1 m-with the plasma volume
being correspondingly more than halved. The expected burn time, plasma
current, power, and other parameters have also been cut. (See the table
below for a comparison of some key parameters.)
	new ITER	original ITER	
Construction cost*	$3.2 billion	$5.8 billion
*In January 1989 dollars. IN today's dollars, the current estimate for the
new ITER is about $4.3 billion.
	
Q (inductively driven plasma)	10	 <<...>> 	
Q (steady state)      	5	10-15	
Tokamak major radius	6.2 m	8.1 m	
Tokamak minor radius	2.0 m	2.8 m	
Burn time (inductively driven plasma)	400 s	1000 s	
Burn time (steady state)	~ 2000 s	~ 10,000 s	
Power output     	400 MW 	1500 MW 	
Plasma current  (inductively driven plasma)	15 MA 	21 MA 	
Plasma current (steady state)	9-12 MA 	12 MA 	
Plasma volume  	840 m3	2000 m3	
Average neutron wall load	0.6 MW/m2	1 MW/m2	
Integrated average neutron wall load	0.3 MW-year/m2	1-3 MW-year/m2
	
The main sacrifices in downsizing ITER follow from reducing the gain. With
less alpha heating, exploration of plasma behavior won't as closely approach
the relevant regime for a commercial reactor. "We can still achieve a Q of
10, the minimum acceptable value," Aymar says. "We would like to reach
higher values, and are therefore fighting against performance-limiting
boundaries." And the decreased neutron flux means that "we cannot see the
longtime effects of radiation on materials." Parts of the tokamak would
become radioactive by absorbing neutrons, and before going ahead with a
prototype power plant, a separate neutron source might be needed to test for
long-lasting materials that would keep radioactivity lifetimes and levels
low.
Despite the lower neutron flux, Aymar says ITER would still be useful for
materials testing. It would be used to study tritium breeding, for instance.
Part of the original ITER design, the idea is to place a lithium-containing
blanket such that fusion neutrons get absorbed to form tritium, which is
then sent back to the plasma to feed fusion. "Such tritium fuel breeding
will be an essential part of a commercial reactor," says Aymar. "We have
frozen the main physics parameters, the structural design, and the size. But
we have left open technical options, such as how to make the coil windings
on the magnets," continues Aymar. In the next year or so, details about such
things as what materials to use closest to the plasma, the design of the
exhaust divertor, and the superconducting magnets will have to be worked
out. But agreeing to the outline design means that the partners have settled
on a strategy, says Aymar: "To go with ITER-not with smaller experiments."
Crucial timing
The timing of the agreement was crucial for tying into the long-term budgets
in both Europe and Japan. This summer, the European Commission will start
laying out its Sixth Framework Programme, the five-year R&D funding plan
that begins in January 2003, and ITER planners want to make sure the project
gets included from the start. Similarly, in Japan the aim is to have ITER
ready for the government to consider by next January, when a spending
moratorium on large scientific projects is expected to be lifted.
Umberto Finzi, who oversees fusion research in the European Union, expects
intergovernmental negotiations on ITER's legal framework to start by the end
of the year. "We feel strongly that the legal aspects should be kept
separate from the site decision. Then, wherever it's built, we would all
have guarantees of access to decisions and to results." In Japan, he adds,
there are "big difficulties in accepting something that is completely
independent from the national authorities."
The partners would all contribute more to ITER in components than in cash.
The host country would be expected to pony up at least 25% of the total
outlay for construction, on top of sharing the rest, which would probably be
covered mostly by Europe and Japan, with Russia putting in 10-15%, and
additional contributions coming from any future new members-China and South
Korea are interested in joining ITER, for example. (US costing methods
differ from those of the ITER partners, which is why the US estimate for
building the original ITER was $10 billion, compared to $5.8 billion-see
table. These figures are in January 1989 dollars, as that is how the ITER
partners do their accounting.) ITER's running costs are estimated to be
about $3.5 billion over the project's expected 20-year lifetime.
Japan or Canada
As Japan sees it, hosting ITER could be a ticket to a leading role in
international science R&D. And the local governments where ITER might go are
also keen to promote domestic industry and regional development, notes
Saichi Nakazawa, the deputy director of Japan's Science and Technology
Agency's atomic energy bureau. The three sites being considered are Naka, on
Japan's main island, Honshu, and home to the Japan Atomic Energy Research
Institute, one of the country's main fusion labs; Rokkasho, on the northern
tip of Honshu; and Tomakomai, on the island of Hokkaido. Before officially
bidding to host ITER, however, Japan is carrying out studies on such things
as the technical feasibility of both fusion energy and alternative energy
sources; the country's long-term energy needs; the distribution of money
across all fields of research; and the nitty-gritty of participation in an
international project.
The other possible host is Canada, where two sites are being considered.
Bruce and Darlington, both near Toronto, Ontario, are on land owned by a
nuclear power utility, which could speed up the licensing process. The sites
are also already equipped to handle nuclear waste, and they are near the
reactor that would supply ITER with tritium, so it wouldn't have to be
shipped far. What's more, Canada's cheaper labor and electricity would save
an estimated 15-20% on operating ITER compared to Japan. Finally, locating
ITER in Canada could give added incentive to the US to rejoin the project,
says Don Dautovich of the nonprofit organization ITER Canada. If Canada is
chosen, he adds, "it would be natural [for it] to be an ITER party. . . . We
might want to negotiate on our own basis," instead of as a junior partner.
Japan and Canada are expected to put in formal bids next year to host ITER,
with a decision likely to follow sometime in 2002. And, although Canada is
widely seen as more technically and geographically attractive, Japan is
expected to put more money on the table.
The US and ITER
The European Commission, Japan, and Russia all hope the US will rejoin
ITER-both for its expertise and its money. And many in the US fusion
community would like to be a part of the project too. Congress ended US ITER
activity in 1998 because it didn't want money spent on a project it believed
would never be built, and because, in the words of one Department of Energy
(DOE) official, " 'energy crisis' had been dropped from our lexicon." (See
Physics Today, November 1998, page 48.)
At the time, continued involvement in ITER was controversial in the US
fusion community, recalls Charles Baker, who headed up US ITER activities
and now coordinates fusion technology work for DOE. "People tended to worry
that putting money into ITER would hurt the rest of the program." Since the
US withdrew from ITER, however, US funding for fusion research has
increased, and the controversy has died down considerably. Ironically, adds
Baker, "the new design includes a lot of things that we had been advocating
to improve the tokamak and cut the cost."
Perhaps in hopes of rejoining ITER, US scientists seem to see the project
more as a plasma physics experiment than as a step toward a power station-a
view more in line with the US government's emphasis on basic fusion research
than with the ITER partners' perspective. In any case, says Baker, "I'd like
to be optimistic, but in my realistic reading of the present situation, I
cannot see the US rejoining ITER. It would take some major external
change-like the others going ahead, not contingent on us joining, and then
asking us if we'd like to join." That's the tack the ITER partners plan to
take. 
--Toni Feder