What is Mass Defect?

A mass defect is a difference between the mass of the atom and the sum of the masses of protons and neutrons of the same atom. The unit of mass defect is atomic mass units. 

This mass is related to the binding energy of the atom. Einstein’s mass-energy equivalence formula converts this mass into equivalent energy by the formula 

E = mc2.

For example, when Uranium 235 has 92 protons and 143 neutrons. Its observed mass is 235.04393 atomic mass units. The sum of protons and neutrons 92 + 143 = 235 atomic mass units. Therefore, its mass defect observed will be 235.04393 – 235 = 0.04393 atomic mass units. 

Let us consider one more example of the hydrogen atom. The hydrogen atom consists of 1 proton and zero neutrons, and the observed atomic mass of hydrogen is 1.008 atomic mass units. The sum of the nucleons in hydrogen is 1. Therefore, the mass defect in a hydrogen atom is 1.008 – 1 = 0.008 atomic mass units. 

What is Binding Energy?

In general, the binding energy is the energy required to separate a particle from a system of particles. Binding energy is mainly applied to the subatomic particles of an atom and the ions in a crystal.

The term nuclear binding energy is used for the energy that is required to separate the atomic nucleus into its constituent protons and neutrons, collectively known as nucleons. It is calculated using Einstein’s mass-energy equivalence formula E = mc2, where m is the mass defect of the atom, and it should be in kg. 

For example, hydrogen, denoted by 1H2, consists of one proton and one neutron. When these nucleons are removed from the hydrogen atom’s nucleus, 2.23 million electron volt energy is supplied. 

Similarly, when these protons and neutrons are fused together to form a H2 atom, 2.23 million electron volt energy is released in the form of gamma radiation.

Applications of Mass Defect and Binding Energy in Nuclear Power Plants

Nuclear power plants utilise the process of nuclear fission reaction to produce electricity. The nuclear power plant generates 11% of the world’s total electricity. This process is similar to the coal-fired power plants. The only difference is that nuclear fuels like thorium and uranium are used in place of coal. Precautions must be taken while working in a thermal power plant because nuclear fuels are hazardous. 

The different components of a nuclear power plant and its operations are discussed in detail below:

  1. Nuclear Reactor: The nuclear reactor is the central part of the nuclear power plant. It contains nuclear fuel, the continuing nuclear chain process, and the nuclear waste product. Uranium is the dominant nuclear fuel used in nuclear reactors.
  2. Steam Generation: Its principal function is to generate steam. The boiled water is circulated to a heat exchanger, where it is boiled and converted to steam.
  3. Turbine and Generator: The steam is passed through one or more turbines, which in turn rotates the electric generator and produces electricity. 
  4. Cooling Towers: Their work is to expel the waste heat into the atmosphere. These plants do not release greenhouse gases which cause global warming and other climatic changes. 

Conclusion

This article explains the mass defect and binding energy from the basics considering several examples. By going through this article, one can easily understand the terms mass defect and binding energy. We hope that this article proved to be helpful.