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Researchers have come up with a preliminary design for a new reactor that requires only a small amount of enriched fuel--that is, the kind whose atoms can easily be split in a chain reaction, reducing the risks of nuclear-weapons proliferation and environmental pollution.The TWR can run for 50 to 100 years without refueling or removing any used fuel from the reactor. By greatly simplifying the nuclear fuel cycle, TWRs could improve the cost, safety, social acceptability, and long-term sustainability of nuclear energy as a source of emissions-free electricity.
Nuclear power plants produce electricity from the heat
generated when big and unstable atoms, such as plutonium
and the rare form of uranium called U-235, split apart into
smaller atoms. Each time a big atom splits (or “fissions”), it
releases fast-moving neutrons and other subatomic particles
that leads to a chain reaction.
The TWR, in contrast,
initially contains only a small igniter of fissile fuel, which
is used to kick off the chain reaction. The wave of fission
would move slowly through the core, splitting many more
of the fuel atoms than a conventional reactor would.
Gilleland's aim is to run a nuclear reactor on what is now waste.Conventional reactors use uranium-235, which splits easily to carry on a chain reaction but is scarce and expensive; it must be separated from the more common, nonfissile uranium-238 in special enrichment plants. Every 18 to 24 months, the reactor must be opened, hundreds of fuel bundles removed, hundreds added, and the remainder reshuffled to supply all the fissile uranium needed for the next run.
TerraPower’s scientists and engineers are investigating a
wide range of designs for TWRs. Small, modular units that
generate 100 megawatts of electricity may be feasible and
could fit the needs of emerging markets
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