what is the cause of release of unusually large energies in nuclear fission reaction?

Question

How is the energy per fission calculated?

Answer 1

When fission occurs, the nuclei of the fissile atoms (usually uranium or plutonium) split into smaller nuclei. The sum of the masses of the smaller nuclei is less than the mass of the original uranium or plutonium nuclei - not by much, but enough to matter. The difference in masses is converted into energy per Einstein's equation E=mc^2.

Answer 2

This is simplifying things a little, but to understand what causes the release of energy in fission, you need to start by talking about the forces of nature. Gravity doesn't have any meaningful effects at the atomic scale, but the strong and weak nuclear forces and the electrostatic force do. The nucleus of an atom is composed of positively charged protons and chargeless neutrons. By themselves, the protons want to repel each other, and the repulsive force acts over relatively large distances. Countering that is the strong nuclear force that causes a strong attraction between neutrons and protons, but its effects are only felt over very small distances - approximately the width of a proton. For larger atomic nuclei, such as Uranium, the cumulative effect of the positive charges in the protons repulsing each other eventually balances the short-range attractive nuclear forces between the nucleons and the atom becomes unstable. When a neutron is absorbed by an atom of Uranium-235 or other fissile isotope it becomes too much and the nucleus flies apart.

As to calculating the energy, when neutrons and protons join to form atomic nuclei, some of their mass disappears and contributes to the "binding energy" - the glue provided by the strong nuclear force. The sum of the masses of the fragments of a fission reaction is less than the original Uranium nucleus (and the binding energy per nucleon is correspondingly higher in the fragments). The difference in mass, when converted using Einstein's equation, represents the energy released per fission.

Answer 3

Plutonium or Uranium is split into two smaller atoms and some extra nuetrons. These two atoms (and the nuetrons) have a mass that is just a little less than the original Plutonium or Uranium atom which split. A great deal of atoms are undergoing this same process at the same time in a fission reaction. The total amount of mass that is lost is converted into energy using E=mc^2.

In a fusion reaction two Hydrogen atoms are fused to make Helium and the resulting mass loss is converted into energy.

Answer 4

When two molecules of deuterium fuse into helium there is an extra neutron left over. This neutron has an extremely high velocity which then converts to heat energy. The energy is equal to 14 million electron volts per neutron.

Don't ask me how to calculate it.

Answer 5

It is a long process of chain reacton
Summary: when uranium isotopes (uranium with different atomic weight) broken, new isotopes are formed with loss of mass
This mass is converted to energy according to Einstein's mass-energy relation, E = mc^2 which is huge

"A gram of mass could (theoretically) be converted entirely into approximately:

* 90,000,000,000,000 Joules (90 terajoules)
* 25,000,000 kilowatt-hours
* The energy in 21 kilotons of TNT"