Question

How is nuclear energy generated ? State in brief the process of utilising this energy in the productionof electricity. Mention the major hazard of nuclear power generation.

Answer 1

Nuclear fusion is the reaction in which two or more nuclei combine together to form a new element with higher atomic number (more protons in the nucleus). The energy released in fusion is related to E = mc2 (Einstein’s famous energy-mass equation). On earth, the most likely fusion reaction is Deuterium-Tritium reaction. Deuterium and Tritium are both isotopes of hydrogen.

21Deuterium + 31Tritium = 42He + 10n + 17.6 MeV

For a nuclear fusion reaction to occur it is necessary to bring two nuclei so close that nuclear forces become active and glue the nuclei together. Nuclear forces are small-distance forces and have to act against the electrostatic forces where positively charged nuclei repel each other. This is the reason why nuclear fusion reactions occur mostly in high density, high temperature environment.

 

Nuclear fission is the splitting of a massive nucleus into photons in the form of gamma rays, free neutrons, and other subatomic particles. In a typical nuclear reaction involving 235U and a neutron:

23592U + n = 23692U followed by 23692U = 14456Ba + 8936Kr + 3n + 177 MeV

For a fission reaction, two conditions need to be satisfied:

Critical mass of the substance (the minimum amount of mass is required for fission to be self-sustaining).

A relatively slow neutron is required to initiate the process.

 

Nuclear energy is generated for use in a nuclear reactor. Nuclear reactor is a device to harness nuclear energy (fission energy) in a controlled and economic way. The energy produced is used to generate electricity and to power ships. The basic working process is: the tremendous heat generated from the fission reaction heats the working fluid (water or gas) which drives the turbine to generate electricity or drives the propeller in ships.

 

Two disadvantages of using nuclear energy for producing electricity are:

1. Radiation hazard is always a disadvantage in application of nuclear energy. The radioactive wastes are equally dangerous and needs to be contained for a long time which adds to the cost of a nuclear power plant.

2. The nuclear fuels used in nuclear reactors can be stolen or diverted to the production of nuclear weapons.

Answer 2

nuclear energy is generated from the nucli of radioactive elements like uranium and thorium in a nuclear reactor. In this reactor it goes under nuclear fission and thus nuclear energy is created