=======================Electronic Edition========================
RACHEL’S HAZARDOUS WASTE NEWS #368
—December 16, 1993—
News and resources for environmental justice.
——
Environmental Research Foundation
P.O. Box 5036, Annapolis, MD 21403
Fax (410) 263-8944; Internet: erf@igc.apc.org
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THE PROMISE OF FUSION ENERGY
Scientists at Princeton University “plunged across a new physics
frontier yesterday with a series of experiments that may
eventually lead to an inexhaustible source of energy,” the NEW
YORK TIMES announced last week. [1]
The Princeton group had
produced a short, controlled burst of fusion energy inside a huge
machine called a tokamak near the university campus in central
New Jersey. Fusion is the same reaction that makes the sun shine
and makes an H-bomb so powerful. The TIMES went on to say that
nuclear fusion “produces virtually no dangerous waste and, in
a… reactor like a tokamak, the fusion reaction quenches itself
automatically and instantly if anything goes wrong.”
The WASHINGTON POST reported the breakthrough at Princeton,
saying the “long-repeated promise of abundant and clean
electrical power from controlled nuclear fusion–the same process
that drives the sun–took a large step toward reality here late
tonight as scientists achieved a new world record in the amount
of power produced in a fusion reactor.” [2] The POST went on to
point out that a fusion reactor “uses cheap, readily available
fuel and creates no hazardous waste.”
The TIMES added to the excitement with an op-ed piece by
distinguished Princeton professor Lyman Spitzer, Jr. who said
nuclear fusion reactors “would pose almost no risk and have
little adverse environmental impact.” [3] Professor Spitzer’s
point was this: “Since controlled fusion, potentially of enormous
importance to our future economy, requires sustained financing,
the public should understand the general status of this effort.”
What does “sustained financing” mean? Fusion buffs predict it
will take another 40 years before they can build a commercial
machine to generate electricity. So “sustained financing” means
4 more decades of increasing annual outlays, even if you accept
the optimistic 40-year timetable for solving fusion’s technical
problems. So far the U.S. has sunk $9 billion into fusion and we
are presently spending about $500 million each year on fusion
research, which is about 3 times what the federal government
spends to support public libraries.
At a time when we are closing libraries, cutting investment in
schools, and steadily reducing wages for American workers, does
it make sense to spend half a billion dollars each year on
fusion? It’s a fair question.
The idea of fusion energy was born when the first H-bomb exploded
in the 1950s. Scientists realized that, if they could control
all that energy, they could use it to boil water, turn a turbine,
and generate electricity. Unfortunately, scientists in the 1950s
underestimated how hard it would be to control a fusion reaction.
The theoretical scientific problems were big, but the practical
engineering problems were even bigger. Today’s nuclear power
plants work by fission, splitting atoms to release energy. A
fusion reactor would work by an entirely different principle.
The idea of fusion is to heat up deuterium and tritium (both of
which are hydrogen atoms with extra neutrons), making them so hot
that their electrons are stripped away and their nuclei fuse
together, forming a helium atom and releasing neutrons and energy
in the process. The heat in the middle of the fusion reaction is
enormous–200 to 300 million degrees Fahrenheit–and the release
of neutrons is very large. (A technical detail: the neutron flux
would be about 10 trillion neutrons per square centimeter per
second.) No material can survive such heat; at those
temperatures, everything turns into a kind of gas called a
plasma. Therefore, in a fusion reactor the hydrogen atoms are
compressed together inside an invisible “bottle” created by
powerful magnetic fields. Because the plasma can easily become
contaminated and stop working, the magnetic bottle itself must be
created inside a vacuum chamber.
In order to absorb the energy of the fusion reaction and to breed
new tritium fuel, the inner chamber of a fusion machine is
surrounded by a blanket of lithium about 3 feet thick. Lithium
burns spontaneously if it comes into contact with either air or
water. Six feet from the hot fusion reaction, where the huge
magnets sit the neutron flux must be nearly zero and the
temperature must be close to absolute zero (459 degrees below
zero, Fahrenheit). Engineering such a machine is exeedingly
complex.
In 1973, 20 years into the nation’s fusion energy research
program, the American Association for the Advancement of Science
(AAAS) raised a series of concerns about fusion energy, [4]
concerns that are still valid today. As AAAS said in 1973,
“Operation of a fusion reactor would present several major
hazards. The hazard of an accident to the magnetic system would
be considerable, because the total energy stored in the magnetic
field would be… about the energy of an average lightning bolt”
[100 billion joules, equivalent to roughly 45 tons of TNT]. An
even greater hazard would be a lithium fire, which might release
the energy of up to 13,500 tons of TNT. “But the greatest hazard
of a fusion reactor… would undoubtedly be the release of
tritium, the volatile and radioactive fuel into the environment,”
the AAAS said. Tritium is radioactive hydrogen gas; it is a tiny
atom, very difficult to contain. (It can escape from some metal
containers by slipping right through the metal.) Furthermore,
tritium is hydrogen, which can become incorporated into water,
making the water itself weakly radioactive. Since most living
things, including humans, are made mostly of water, radioactive
water is hazardous to living things. Tritium has a half-life of
12.4 years, so it remains hazardous for about 125 years after it
is created. The AAAS estimated in 1973 that each fusion reactor
would release one to 60 Curies of tritium each day of operation
through routine leaks, even assuming the best containment
systems. An accident, of course, could release much more because
at any given moment there would be 100 million Curies of tritium
inside the machine, a large inventory indeed.
In 1983, Lawrence Lidsky, a professor of nuclear engineering at
Massachusetts Institute of Technology (MIT), associate director
of MIT’s Plasma Fusion Center, and editor of the journal, FUSION
ENERGY, added to the world’s knowledge of potential problems with
fusion energy in a candid critique of the technology. [5]
Lidsky compared the accident potential of today’s existing
nuclear fission reactors to fusion reactors. Fusion reactors
could not melt down the way today’s fission reactors can. And
the radioactive waste from a fusion machine would be much less
(perhaps 0.03 percent as much waste from a fusion reactor as from
a fission reactor, Lidsky believes).
However, Lidsky pointed out, “Current analyses show that the
probability of a minor mishap is relatively high in both fission
and fusion plants. But the probability of small accidents is
expected to be higher in fusion reactors. There are two reasons
for this. First, fusion reactors will be much more complex
devices than fission reactors. In addition to heat-transfer and
control systems, they will utilize magnetic fields, high power
heating systems, complex vacuum systems, and other mechanisms
that have no counterpart in fission reactors. Furthermore, they
will be subject to higher stresses than fission machines because
of the greater neutron damage and higher temperature gradients
[differences]. Minor failures seem certain to occur more
frequently,” Lidsky said.
Lidsky then pointed out that there would be too much
radioactivity inside a fusion reactor to allow maintenance
workers inside the machine. When things break, repairs will not
be possible by normal procedures. This alone will make fusion
plants unattractive to electric utilities, Lidsky points out.
Lidsky says no one was hurt at Three Mile Island, yet the
accident was a financial disaster for the owner of the plant and
ultimately for the nuclear power industry. An accident at a
fusion plant could have similar consequences, he says.
Lidsky pointed out that a fusion reactor would have to be
physically larger than a fission reactor to create an equivalent
amount of electricity, perhaps 10 times larger. Such huge
machines would be enormously expensive to build, and utilities
have already turned their backs on huge machines. From the
viewpoint of generating reliable power, it makes more sense for a
utility to invest in several smaller machines, rather than
putting all their eggs in one large, unreliable basket, Lidsky
says. “All in all, the proposed fusion reactor would be a large,
complex, unreliable way of turning water into steam,” Lidsky
concludes.
As if to drive a final nail into the coffin of fusion, Lidsky
pointed out that, “One of the best ways to produce material for
atomic weapons would be to put common uranium or thorium in the
blanket of a D-T [deuterium-tritium fusion] reactor, where the
fusion neutrons would soon transform it to weapons-grade
material. And tritium, an unavoidable product of the reactor, is
used in some hydrogen bombs. In the early years, research on D-T
fusion was classified precisely because it would provide a ready
source of material for weapons. Such a reactor would only abet
the proliferation of nuclear weapons and could hardly be
considered a wise power source to export to unstable governments.”
Everyone in the fusion business agrees that the main attraction
of fusion is the inexhaustible hydrogen fuel, offering a
potential for large power output. Everyone in the fusion
business also agrees–though no one ever speaks of it–that there
is another inexhaustible source of energy even larger than the
potential of fusion energy: light from that great fusion reactor
in the sky, our sun. If we refine techniques for converting
sunlight into electricity via photovolatic cells (or other ways),
we will have achieved the dream of the fusion gurus, but without
the radioactive hazards or the risk of proliferating weapons of
mass destruction. Fusion energy would require investment of
billions of dollars in each fusion reactor, thus centralizing
control of our energy sources in the hands of governments,
utilities and multinational corporations. Solar electricity, on
the other hand, could be developed on a small scale, thus
liberating people from central control. These are some of the
issues the public must be informed about before an appropriate
fusion research budget can be established. Puff pieces about
fusion energy in the NEW YORK TIMES and the WASHINGTON POST
contribute little of value to such a debate.
–Peter Montague, Ph.D.
===============
[1] Malcolm W. Browne, “Into a New Frontier After Fusion
Success,” NEW YORK TIMES Dec. 11, 1993, pg. 10.
Descriptor terms: princeton university; plasma physics
laboratory; ppl; new york times; ny times; nyt; washington post;
wp; controlled fusion energy; tokamak; lyman spitzer, jr.;
h-bomb; hydrogen bomb; nuclear weapons; tritium; deuterium;
plasma; hydrogen; helium; neutrons; lithium; american association
for the advancement of science; aaas; lawrence lidsky;
massachusetts institute of technology; mit; fission; nuclear
power; accidents; leaks; radioactivity; radiation; radioactive
waste; proliferation;