Energy - Environmental Science - page 305

These advanced light-water reactors (ALWRs) have
built-in passive safety features designed to make ex-
plosions or the release of radioactive emissions al-
most impossible. However, according to Nucleonics
Week, an important nuclear industry publication, “Ex-
perts are flatly unconvinced that safety has been
achieved—or even substantially increased—by the
new designs.” In addition, these new designs do not
eliminate the threats and the expense and hazards of
long-term radioactive waste storage and power plant
decommissioning.

subsidies, this technology remains at the laboratory
stage.
Nuclear fusion is a nuclear change in which two iso-
topes of light elements, such as hydrogen, are forced
together at extremely high temperatures until they
fuse to form a heavier nucleus, releasing energy in the
process. Scientists hope that controlled nuclear fusion
will provide an almost limitless source of high-tem-
perature heat and electricity. Research has focused on
the D-T nuclear fusion reaction, in which two isotopes
of hydrogen—deuterium (D) and tritium (T)—fuse at
about 100 million degrees (Figure 2-7, p. 28).
With nuclear fusion, there would be no risk of
meltdown or release of large amounts of radioactive
materials from a terrorist attack and little risk from ad-
ditional proliferation of nuclear weapons because
bomb-grade materials (such as enriched uranium-235
and plutonium-239) are not required for fusion energy.
Fusion power might also be used to destroy toxic
wastes, supply electricity for ordinary use, and decom-
pose water to produce the hydrogen gas needed to run
a hydrogen economy by the end of this century.
This sounds great. So what is holding up fusion
energy? After more than 50 years of research and huge
expenditures of mostly government funds, controlled
nuclear fusion remains in the laboratory stage. None
of the approaches tested so far has produced more en-
ergy than it uses.
If researchers can eventually get more energy out
of nuclear fusion than they put in, the next step would
be to build a small fusion reactor and then scale it up
to commercial size. This is an extremely difficult engi-
neering problem. Also, the estimated cost of a building
and operating a commercial fusion reactor (even with
huge government subsidies) is several times the costs
for a comparable conventional fission reactor.
Proponents contend that with greatly increased
federal funding, a commercial nuclear fusion power
plant might be built by 2030 or perhaps by 2020. How-
ever, many energy experts do not expect nuclear fu-
sion to be a significant energy source until 2100, if then.

Science: Breeder Nuclear Fission
Because of very high costs and bad safety experiences
with several nuclear breeder reactors, this technology
has essentially been abandoned.
Some nuclear power proponents urge the development
and widespread use of breeder nuclear fission reac-
tors, which generate more nuclear fuel than they con-
sume by converting nonfissionable uranium-238 into
fissionable plutonium-239. Because breeders would
use more than 99% of the uranium in ore deposits, the
world's known uranium reserves would last at least
1,000 years, and perhaps several thousand years.
However, if the safety system of a breeder reactor
fails, the reactor could lose some of its liquid sodium
coolant, which ignites when exposed to air and reacts
explosively if it comes into contact with water. The po-
tential result: a runaway fission chain reaction and per-
haps a nuclear explosion powerful enough to blast
open the containment building and release a cloud of
highly radioactive gases and particles into the atmos-
phere. Leaks of flammable liquid sodium can also cause
fires, as has happened with all experimental breeder re-
actors built so far.
Existing experimental breeder reactors also pro-
duce plutonium so slowly that it would take 100-200
years for them to produce enough plutonium to fuel a
significant number of other breeder reactors. In 1994,
the United States ended government-supported re-
search of breeder technology after providing about $9
billion in research and development funding.
In December 1986, France opened a commercial-
size breeder reactor. It was so expensive to build and
operate that after spending $13 billion the government
spent another $2.75 billion to shut it down perma-
nently in 1998. Because of this experience, other coun-
tries have abandoned their plans to build full-size com-
mercial breeder reactors.

Politics: Nuclear Power's Future
in the United States
There is disagreement over whether the United
States should phase out nuclear power or keep this
option open in case other alternatives do not
pan out.
Since 1948, nuclear energy (fission and fusion) has re-
ceived about 58% of all federal energy research and de-
velopment funds in the United States—compared to
22% for fossil fuels, 11% for renewable energy, and 8%
for energy efficiency and conservation. Because the re-
sults of this huge investment of taxpayer dollars have
been largely disappointing, some analysts call for

Science: Nuclear Fusion
Nuclear fusion has a number of advantages, but after
more than five decades of research and billions of
dollars in government research and development