A Fast Breeder Reactor (FBR) is a nuclear reactor that uses fast neutrons to generate more nuclear fuels than they consume while generating power, dramatically enhancing the efficiency of the use of resources. Nuclear fission by fast neutrons causes the increase in neutrons generated.
Features of Faster Breeder Reactors
- Besides fission of Uranium-235, there is gainful conversion of the 99.3% Uranium-238 to Plutonium-239, which in turn is a fissionable material.
- No moderator is used to slow down the neutrons, because fast neutrons transmute uranium-238 much more efficiently than slow neutrons.
- Further, because the sodium used as coolant absorbs fewer neutrons compared to light water, more neutrons remain within the reactor.
- Increased number of neutrons causes a higher proportion of uranium-238 converting into plutonium-239 and yields more plutonium than original nuclear fuel.
- Natural uranium consists primarily of U-238, which does not fission readily, and U-235, which does.
- Natural uranium is unsuitable for use in a nuclear reactor, because it is only 0.72% U-235, which is not enough to sustain a chain reaction. Commercial nuclear reactors normally use uranium fuel that has had its U-235 content enriched.
- Although the U-235 does most of the fissioning, more than 90% of the atoms in the fuel are U-238-potential neutron capture targets and future plutonium atoms.
Faster Breeder Reactor in India
- The prototype fast breeder reactor (PFBR) is a nuclear power reactor currently under construction at the Madras Atomic Power Station in Kalpakkam, Tamil Nadu.
- The PFBR in Kalpakkam will use a mixed oxide of plutonium-239, derived from reprocessed spent fuel from the thermal pressurised heavy water reactors and uranium-238 as fuel to generate energy in a nuclear reaction.
- The plutonium generated will then be processed and used as nuclear fuel in a chain of commercial FBRs that constitutes stage II of the nuclear programme.
- The stage will also include FBRs that will use thorium-232, mined in India, as a blanket. Thorium will get converted to uranium-233, which will serve as the fuel for advanced reactors in stage III.
- Ultimately, these reactors will burn uranium-233 and convert thorium-232 to more uranium-233, creating a self-sustaining cycle of nuclear power generation.
Other Types of Nuclear Reactors
- Boiling Water Reactor:
. They only have one coolant loop.
. The hot nuclear fuel boils water as it goes out the top of the reactor, where the steam heads over to the turbine to spin it.
- Pressurized Water Reactor:
. The primary cooling water is kept at very high pressure so it does not boil.
. It goes through a heat exchanger, transferring heat to a secondary coolant loop, which then spins the turbine.
- Canada Deuterium-Uranium Reactors:
. They contain heavy water, where the Hydrogen in H2O has an extra neutron.
. Deuterium absorbs many fewer neutrons than Hydrogen, and CANDUs can operate using only natural uranium instead of enriched.
- High Temperature Gas Cooled Reactor:
. Gas such as helium or carbon dioxide is passed through the reactor rapidly to cool it.
. Due to their low power density, these reactors are seen as promising for using nuclear energy outside of electricity: in transportation, in industry, and in residential regimes.
. They are not particularly good at just producing electricity.
