Nuclear Energy – An Alternative Source of Energy

Introduction:

In this lesson, we will learn how to explain how energy is produced by nuclear fusion and fission in the context of nuclear power plants.

Explanation:

Nuclear Energy:

A reaction wherein the nucleus of an atom changes to form a new atom and releases a huge quantity of energy is known as a nuclear reaction. Huge energy is released during a nuclear reaction, called nuclear energy.

Two different types of nuclear reactions for obtaining nuclear energy are:

1. Nuclear fission
2. Nuclear fusion

Nuclear Fission Reaction:

When an unstable heavy nucleus is bombarded with slow-speed neutrons, it splits into two small stable nuclei and liberates an enormous amount of heat and light energy.

In nuclear fission Uranium, 235 atoms are bombarded with slow-moving neutrons, breaking up into two small stable nuclei of Barium and Krypton. The process also produces three neutrons and an enormous amount of heat energy and light energy.

The reaction involved is as under:

A little amount of matter is produced in all nuclear fission processes, i.e., the total mass of all fission products is smaller than the total mass of the reactants. Any nuclear fission reaction converts this lost matter into energy, which is released. The famous Einstein’s equation gives the energy (E) obtained as a result of the loss of matter of mass m.

E = mc²

Nuclear Fusion Reaction:

Hans Bethe in 1939 stated that the word ‘fusion’ means ‘to combine fusion means the combining of two or more nuclei to form a single nucleus. This is a process in which two lighter nuclei fuse or combine to form a stable heavier nucleus with a simultaneous release of a very large amount of energy is called nuclear fusion.

The energy released in a fusion event is far greater than that released in a nuclear fission reaction.

Nuclear fusion is also called thermonuclear reaction as nuclear fusion takes place only at very high temperatures, about 4 – 15 million degrees (4 x 10⁶   ̊C – 15 x 10⁶   ̊C).

Nuclear Reactor:

The main components of a nuclear reactor are listed below.

• The Core stores all the fuel and produces the heat needed for energy production.
• Coolant circulates through the core, absorbing heat and transporting it to the turbines.
• The Turbine converts mechanical energy into electrical energy.
• The Cooling Tower removes any heat that hasn’t been transformed or transported.
• Neutron Moderators are used to slow down rapid neutrons emitted during fission reactions, allowing them to sustain a nuclear chain reaction. Regular water (used in 74.8 percent of the world’s reactors), solid graphite (20 percent of reactors), and heavy water are all common moderators (5 percent of reactors).
• Containment is the enclosing structure that keeps the nuclear reactor isolated from the rest of the world.
• Neutron Poison/ neutron absorber is a material with a significant cross-section for neutron absorption.

Advantages of Nuclear Energy:-

The advantages of nuclear energy are:

1. It generates a significant amount of useful energy from a small amount of nuclear fuel (like uranium-235).
2. The nuclear power plant may provide electricity for two to three years after the nuclear fuel (such as uranium-235) is fed into the reactor. There is no need to keep placing nuclear fuel in the reactor.
3. It does not emit gases such as carbon dioxide, which contributes to the greenhouse effect, or sulfur dioxide, which contributes to acid rain.

Disadvantages of Nuclear Energy:-

The disadvantages of nuclear energy are:

1. The storage and disposal of spent or used fuels – the uranium still decaying into hazardous subatomic particles – is a key hazard of nuclear power generation (radiations).
2. Contamination of the environment occurs as a result of improper nuclear waste storage and disposal.
3. There is a possibility of nuclear radiation leaking by accident.
4. Large-scale usage of nuclear energy is impractical due to the high expense of constructing a nuclear power station, the significant risk of environmental contamination, and the restricted availability of uranium.Nuclear reactors in India

The list of the locations of the installed nuclear reactors in India is given below.

1. Rajasthan (Rawatbhata)
2. Tamil Nadu (Kudankulam; Kalpakkam)
3. Gujarat (Kakrapar)
4. Uttar Pradesh (Narora)
5. Karnataka (Kaiga)
6. Maharashtra (Tarapur)

Questions and Answers

Question 1: List any three hazards of nuclear waste. How does the disposal of nuclear waste pose a problem for the flora and fauna?

Answer. A few hazards of nuclear waste are:

1. Radioactive compounds in nuclear waste emit dangerous nuclear radiation.
2. There is a significant risk of contamination of the environment.
3. It is extremely poisonous.
4. Nuclear waste has an impact on plant and animal life because the radiation it emits penetrates deep into the human or animal body, harming biological cells and producing cancer or genetic disorder. Plant, soil invertebrates, and mammalian death, as well as reproductive losses in plants and animals, have all been documented.

Question 2: How are the wastes produced in nuclear power plants different from those produced in thermal power plants? What happens to the waste of a nuclear power plant?
Answer. Nuclear power plant waste is extremely radioactive and emits hazardous radiation, whereas thermal power plant waste is non-radioactive.

The following is the procedure for dealing with nuclear waste:

1. Some nuclear waste is placed in sealed steel/lead containers, buried beneath the ground, or dumped in abandoned coal mines for long-term storage.
2. Other waste materials decompose or have a shorter half-life, resulting in less dangerous chemicals.