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fusion reactor feasibility. The first third of the twenty-first
century may then see a prototype fusion power plant in operation,
depending on the energy cost and environmental situation at that
time. The cost of nuclear fusion is expected to be very high in
comparison with alternative nuclear reactor designs. On the other
hand, nuclear fusion offers additional environmental protection
compared to nuclear fission. By midcentury, some fraction of energy
to the national electrical grids might possibly come from fusion
reactors.
The advantages of fusion power with respect to safety and the
environment follow:
• No danger from nuclear reactor runaway. The amount of
nuclear fuel in the reaction chamber at any given time is
minuscule, and a system failure of any sort can lead only to a
cooling down of the reacting plasma.
• Enormously reduced amounts of nuclear waste. The nuclear
ash from fusion is helium, a stable and totally benign gas. Almost
all of the neutrons coming out of the reacting gas will be absorbed
in a lithium 6 blanket, generating fresh tritium to replace that
used up in the deuterium tritium reactions. Also, although the
vacuum-chamber wall is expected to become radioactive due to
bombardment by these transiting neutrons, the material of the
vacuum chamber can be chosen to reduce the radioactivity level and
character of this radioactivity and problems associated with
storage or disposal. Further research is needed in this area.
• No production of gases deleterious to the environment
such as oxides of carbon and nitrogen; however, there is some
concern on the potential leakage of tritium into the water
supply.
• No inherent production of fissile materials.
The acid test of fusion power feasibility—achieving nuclear
ignition in a confined plasma—is anticipated no earlier than
the end of this decade, and a prototype fusion power plant should
not be expected before the year 2020. Further progress is clearly
needed in the science, technological development, and economics of
nuclear fusion before it can actually be implemented. Nevertheless,
in view of its minimal impact on atmospheric pollution and
greenhouse warming, and the very much reduced level of nuclear
hazard, controlled fusion still merits its reputation as a major
option for the future generation of electric power.
Reference
Golay, M. W. 1990. Testimony before the U.S. House Committee on
Interior and Insular Affairs. Washington, D.C., March 10, 1990.
