Explain Nuclear Fission and Nuclear Fusion.
Nuclear Fission and Nuclear Fusion:
Isotopes: Isotopes are atoms that have the same atomic number (number of protons) but different mass numbers (numbers of neutrons) or both elements having the same atomic number.
Isobars: are atoms that have the same mass numbers (numbers of neutrons) but a different atomic numbers (number of protons) or both elements having the same atomic mass.
Nuclear fission: –
In the nuclear fission process, the atom splits generating large amounts of energy; For example, uranium (U-235) absorbs a neutron, fission occurs as it splits into two particles of uneven mass (smaller nuclei), an enormous amount of energy (~200Mev) with several neutrons. It produced a chain reaction as fission continues and the neutrons emitted bombard more uranium (U-235) nuclei. Experimentally, we find that spontaneous fission reactions occur for only the very heaviest nuclides those with mass numbers of 230 or more. Even when they occur, these reactions are often very slow. The half-life for the spontaneous fission of U-238 is 1016 years. In this process, isotopes of elements having atomic numbers greater than 80 can undergo fission and an extensive amount of energy is released that an atomic explosion occurs. Nuclear power plants operate under this principle.
A diagram of uranium-235 undergoing nuclear fission:
Nuclear fusion is the reverse process of nuclear fission; i.e. the nuclear fusion is the joining of two lighter nuclei and forms a heavier one. Mass is lost and it released an enormous amount of energy (even the energy amount is greater than the energy released in nuclear fission). Solar energy is fusion energy. When two isotopes of hydrogen combine at very high temperatures, fusion occurs. The fusion of four protons to form a helium nucleus, two positrons (and two neutrinos) generates 24.7 MeV of energy. Nuclear Fission and Nuclear Fusion
The fusion of protons produces most of the energy radiated from the surface of the sun to form helium atoms within its core.
Ex: hydrogen bomb
Properties of Nuclear Fission and Nuclear Fusion
- In nuclear fission, the splitting of a heavy nucleus into lighter nuclei.
- It is a chain reaction process.
- There is High temperature is not essential (Even Takes place at room temperature).
- The fission process is a controlled process, and energy released can be used for peaceful purposes.
- It produced a large number of radioisotopes and large amount of nuclear waste.
- In nuclear fusion, two or lighter nuclei combine to form a heavy nucleus.
- Nuclear fusion, not a chain reaction process.
- It required a high temperature (106 oC).
- The fusion process is hard to be carried out in a controlled manner.
- In this process, there is no nuclear waste is left.