12.2 The Production of Nuclear Energy

Meaning of Nuclear Energy

Nuclear energy is energy resulting from reactions in the nucleus of atoms.
It is produced through nuclear fission and nuclear fusion.

Nuclear fission is the process of splitting a heavy radioactive nucleus into two or more nuclei which are lighter and more stable, together with the release of energy.
A slow neutron bombards a heavy radioactive nucleus such as uranium-235.
The bombardment splits the nucleus into two or more lighter, stable nuclei and releases a large amount of energy.
A neutron may bombard and split another new nucleus of large mass. Continuous fission forms a chain reaction.

Diagram description — nuclear fission of uranium-235:

Nuclear fusion is the process of fusing or combining two light radioactive nuclei to form a heavier nucleus, with the release of energy.
Example: deuterium and tritium, which are hydrogen isotopes, combine to form a helium nucleus, releasing a neutron and energy.
Occurs at a very high temperature.
Releases more nuclear energy than nuclear fission.
Occurs continuously in the Sun because the Sun has hydrogen isotopes and a high temperature.
Energy released by fusion in the Sun is the main energy source for life on Earth.

Nuclear fission	Nuclear fusion
Splits one heavy radioactive nucleus into lighter, more stable nuclei	Combines two light radioactive nuclei into a heavier nucleus
Example: uranium-235 bombarded by a slow neutron	Example: deuterium combines with tritium
Can produce a chain reaction	Requires a very high temperature
Releases a large amount of energy	Releases more nuclear energy than fission

The main use of nuclear energy is to generate electricity in a nuclear power station.
A nuclear power station consists of a nuclear reactor and a generator.

Nuclear reactor components:

Uranium fuel rods: Release heat energy through nuclear fission to heat the gas flowing through the reactor core.
Graphite moderator: Slows down neutrons.
Boron control rods: Absorb surplus neutrons and control the rate of the nuclear fission reaction.
Cooling agent: Absorbs heat produced by the nuclear reaction.
Concrete shield: Prevents radioactive radiation from leaking out of the reactor.

Energy-generation sequence:

Nuclear fission in the uranium fuel rods releases heat energy.
The cooling agent absorbs the heat and transfers it to water, producing hot steam.
Steam rotates the turbine, causing magnets in the generator to spin.
The electricity generator generates electricity by electromagnetic induction when the magnets spin inside a coil.
The condenser cools and condenses the steam into water.
The water is pumped back through the system; the cooling tower cools the circulating water.

Lack of other energy sources: Countries lacking coal and petroleum avoid the high cost of importing these sources by using nuclear energy.
Vast country and high population density: China can produce enough electricity through nuclear energy for its large area and population.
Source of national income: Slovakia can sell surplus electricity to neighbouring countries.
Sophisticated technology: Continuous research and development enables countries to improve nuclear technology and reduce reactor risks; an example is Argonne National Laboratory, United States of America.

Malaysia has a 1 megawatt nuclear reactor owned by the Malaysian Nuclear Agency.
TRIGA PUSPATI Reactor (RTP) began operating on 28 June 1982.
It is a pool-type reactor designed to allow experiments in the reactor core.
Used only for training, research and radioisotope production, not electricity generation.
To generate electricity from nuclear energy, Malaysia would need a reactor capable of producing 1 000 megawatts.