Discuss the concept of breeder reactors. How do they breed fuel? What type reactors can be used as breeders? What are some problems/benefits of breeders? Solution (1) Conceptof breeder reactors : A breeder reactor is a nuclear reactor that generates more fissile material than it consumes. These devices achieve this because their neutron economy is high enough to breed more fissile fuel than they use from fertile material, such as uranium-238 or thorium-232.Breeder reactors could, in principle, extract almost all of the energy contained in uranium or thorium, decreasing fuel requirements by a factor of 100 compared to widely used once-through light water reactors, which extract less than 1% of the energy in the uranium mined from the earth.The high fuel efficiency of breeder reactors could greatly reduce concerns about fuel supply or energy used in mining. A \'breeder\' is simply a reactor designed for very high neutron economy with an associated conversion rate higher than 1.0. In principle, almost any reactor design could possibly be tweaked to become a breeder. An example of this process is the evolution of the Light Water Reactor, a very heavily moderated thermal design, into the Super Fast Reactor concept, using light water in an extremely low-density supercritical form to increase the neutron economy high enough to allow breeding. (2) breeder reactors breed fuel by- A fast-breeder nuclear reactor produces more fuel than it consumes, while generating energy. Conventional reactors use uranium as fuel and produce some plutonium. Breeders produce much more plutonium, which can be separated and reused as fuel. (3) reactors that can be used as breeders- Aside from water cooled, there are many other types of breeder reactor currently envisioned as possible. These include molten-salt cooled, gas cooled, and liquid metal cooled designs in many variations. Almost any of these basic design types may be fueled by uranium, plutonium, many minor actinides, or thorium, and they may be designed for many different goals, such as creating more fissile fuel, long-term steady-state operation, or active burning of nuclear wastes. For convenience, it is perhaps simplest to divide the extant reactor designs into two broad categories based upon their neutron spectrum, which has the natural effect of dividing the reactor designs into those designed to use primarily uranium and transuranics, and those designed to use thorium and avoid transuranics. (4) benifits/problems of breeders- benifits: Breeder reactors use highly enriched fuels, which pose the danger of critical accidents. They also work at a very high temperature and a fast pace. Plutonium persists for a long time in the environment, with a half-life of 24,000 years, and is highly toxic, causing lung cancer even if a small amount is inhaled. The construction and operation is very costly. Between $4 to $8 billion is required in the construction alone. The byproducts formed during the fission of plutonium h.

1. Discuss the concept of breeder reactors. How do they breed fuel? What type reactors can be
used as breeders? What are some problems/benefits of breeders?
Solution
(1) Conceptof breeder reactors :
A breeder reactor is a nuclear reactor that generates more fissile material than it consumes. These
devices achieve this because their neutron economy is high enough to breed more fissile fuel
than they use from fertile material, such as uranium-238 or thorium-232.Breeder reactors could,
in principle, extract almost all of the energy contained in uranium or thorium, decreasing fuel
requirements by a factor of 100 compared to widely used once-through light water reactors,
which extract less than 1% of the energy in the uranium mined from the earth.The high fuel
efficiency of breeder reactors could greatly reduce concerns about fuel supply or energy used in
mining. A 'breeder' is simply a reactor designed for very high neutron economy with an
associated conversion rate higher than 1.0. In principle, almost any reactor design could possibly
be tweaked to become a breeder. An example of this process is the evolution of the Light Water
Reactor, a very heavily moderated thermal design, into the Super Fast Reactor concept, using
light water in an extremely low-density supercritical form to increase the neutron economy high
enough to allow breeding.
(2) breeder reactors breed fuel by-
A fast-breeder nuclear reactor produces more fuel than it consumes, while generating energy.
Conventional reactors use uranium as fuel and produce some plutonium. Breeders produce much
more plutonium, which can be separated and reused as fuel.
(3) reactors that can be used as breeders-
Aside from water cooled, there are many other types of breeder reactor currently envisioned as
possible. These include molten-salt cooled, gas cooled, and liquid metal cooled designs in many
variations. Almost any of these basic design types may be fueled by uranium, plutonium, many
minor actinides, or thorium, and they may be designed for many different goals, such as creating
more fissile fuel, long-term steady-state operation, or active burning of nuclear wastes.
For convenience, it is perhaps simplest to divide the extant reactor designs into two broad
categories based upon their neutron spectrum, which has the natural effect of dividing the reactor
designs into those designed to use primarily uranium and transuranics, and those designed to use
thorium and avoid transuranics.
(4) benifits/problems of breeders-
benifits:
Breeder reactors use highly enriched fuels, which pose the danger of critical accidents. They also

2. work at a very high temperature and a fast pace.
Plutonium persists for a long time in the environment, with a half-life of 24,000 years, and is
highly toxic, causing lung cancer even if a small amount is inhaled.
The construction and operation is very costly. Between $4 to $8 billion is required in the
construction alone.
The byproducts formed during the fission of plutonium have to be removed by reprocessing, as
they slow down the neutrons and reduce efficiency. However, this step of reprocessing produces
a very pure strain of plutonium, which is ideal for use in nuclear weapons. This poses a risk, as
in, terrorists may attempt to sabotage or steal the plutonium.
Till date, not a single breeder reactor has been economically feasible. Every year, billions of
dollars worldwide are spent for the safe storage of the plutonium produced, which is then
useless, as few reactors use it as fuel.
In practice, a breeder reactor requires 30 years to produce as much plutonium as it utilizes in its
operation.
It requires liquefied sodium or potassium metal as a coolant, as water would slow down the
neutrons. These metals can cause a mishap, as they react violently when exposed to water or air.
These reactors are complex to operate. Moreover, even minor malfunctions can cause
prolonged shutdowns. Their repair is tedious and expensive too.