Q. Reactors for propulsion applications are designed for
- Any form of uranium
- Natural uranium
- Enriched uranium
- Plutonium
Answer: Enriched Uranium
Nuclear Marine Propulsion
Nuclear propulsion includes a wide variety of propulsion methods that fulfill the promise of the Atomic Age by using some form of nuclear reaction as their primary power source.
- Nuclear marine propulsion is the propulsion of a ship or submarine with heat provided by a nuclear power plant. The power plant heats water to produce steam for a turbine used to turn the ship's propeller through a gearbox or through an electric generator and motor. Naval nuclear propulsion is used specifically within naval warships such as supercarriers. A small number of experimental civil nuclear ships have been built.
- Compared to oil or coal-fuelled ships, nuclear propulsion offers the advantages of very long intervals of operation before refueling. All the fuel is contained within the nuclear reactor, so no cargo or supplies space is taken up by fuel, nor is space taken up by exhaust stacks or combustion air intakes. However, the low fuel cost is offset by the high operating costs and investment in infrastructure, so nearly all nuclear-powered vessels are military ones.
- While land-based reactors in nuclear power plants produce up to around 1600 megawatts of electrical power, a typical marine propulsion reactor produces no more than a few hundred megawatts. Space considerations dictate that a marine reactor must be physically small, so it must generate higher power per unit of space.
- As the core of a seagoing reactor is much smaller than a power reactor, the probability of a neutron intersecting with a fissionable nucleus before it escapes into the shielding is much lower. As such, the fuel is typically more highly enriched (i.e., contains a higher concentration of 235U vs. 238U) than that used in a land-based nuclear power plant, which increases the probability of fission to the level where a sustained reaction can occur.
- Some marine reactors run on relatively low-enriched uranium which requires more frequent refueling. Others run on highly enriched uranium, varying from 20% 235U, to the over 96% 235U found in U.S. submarines, in which the resulting smaller core is quieter in operation (a big advantage to a submarine). Using more-highly enriched fuel also increases the reactor's power density and extends the usable life of the nuclear fuel load, but is more expensive and a greater risk to nuclear proliferation than less-highly enriched fuel.
Reactors for propulsion applications are designed for enriched uranium.
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