Atomic Energy Example

Physics / by admin / November 13, 2021

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Atomic energy is the ability to do work, obtained from the decay of the atoms of the Radioactive Elements. It is obtained thanks to the stimulation of this disintegration.

Energy in nuclear processes

Chemical reactions are accompanied by a variation of Energy, generally in the form of heat, which comes off (Exothermic Reactions) or is absorbed (Endothermic Reactions). When a substance is formed from the constituent elements, heat is given off (Positive Heat of Formation), Although in some cases, such as in obtaining Ozone from atomic oxygen, there would be a release of hot.

If these same ideas are applied to the (assumed) formation of atomic nuclei from protons and neutrons, it is clear that energy will be released in this formation, and given the nature of the links involved, the energy released here will be considerably greater, so much so that the loss of mass that will accompany said energy variation is already ponderable. (According to Einstein's principle, the change in Energy ΔE is equivalent to the change in mass Δm, so that ΔE = Δm * C², where C is the speed of light).

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Thus, for example, for the element Lithium Li-7, formed by 3 protons and 4 neutrons, in the formation of a gram-atom of Lithium nuclei of atomic mass 7, we will have:

3 Protons = 3 * 1.00756 g = 3.02268 g

4 Neutrons = 4 * 1.00893 g = 4.03572 g

The Result of the Sum is 7.05840 g.

The Atomic Mass of Lithium-7 has a value of 7.01645 g

It follows, comparing the values, that the change in mass Δm = 0.04195 g, and they are equal to 9.02 * 10¹¹ calories, calculated with the Einstein Equation ΔE = Δm * C².

The hypothetical reaction of nuclei formation from protons and neutrons gives off an enormous amount of energy, millions of times superior to that of more exothermic ordinary chemical reactions.

Each particle of nucleus o Nucleon (proton or neutron), for being part of any nucleus, it has experienced a loss of mass, which is not constant, but has a maximum value for the intermediate elements of the periodic system of atomic numbers 20 to 51, then slowly decreasing with increasing number atomic.

The atom stores immense amounts of energy

The atomic bomb

Uranium 235 and Plutonium 239 divide by neutron bombardment, and emit enormous amounts of energy, releasing new neutrons.

The condition for the multiplication process to take place is that more than one neutron produced in each cleavage is capable of producing a new cleavage or division.

In the Uranium pile, the neutrons produced partly escape through the material's surface and are partly absorbed by Uranium 238 to form the heavy isotope Uranium 239, which decays successively into Neptunium and Plutonium.

But if it is pure Uranium 235 or Plutonium 239, the possibility of loss of neutrons through the surface of the same leads to know the Critical Size necessary for the chain reaction to develop within it.

The Critical Size of the sample is the one in which the chain reaction, splitting the atom, develops almost immediately.

If the sample of cleavable material (divisible by neutron bombardment) has a diameter smaller than the mean path that a fast neutron must traverse to produce the cleavage process, it is understood that the neutrons produced in the occasional splits by traveling neutrons will escape through the surface without attacking any other core.

On the contrary, if the sample is greater than the critical size, the occasionally produced neutrons, on their way through through it, they will have a great probability of splitting new nuclei, thus continuing, at an accelerated rate, the process of division.

If a sample is greater than the Critical Size it will suffer an instantaneous explosion, whereas if it is smaller it will produce a slow cleavage which, however, should be avoided. For this, the cleavable material is kept in thin layers inside Cadmium containers that are kept inside Water; occasional incident neutrons will be slowed down by water and then captured by cadmium before they can reach the protected material.

If several pieces of cleavable material are rapidly mixed, each one somewhat smaller than the critical size, a single mass (atomic bomb) is formed, which immediately explodes. The speed with which the pieces of cleavable material must be collected must be very high to avoid that when the reaction starts in The chain, being very close together, the energy released disperses the pieces of said material before completely coming into contact.

There are two pieces of cleavable material that are adequately protected with neutron scavengers and a few centimeters apart. At the opportune moment one of the pieces is fired on the other with the speed of a fast projectile.

The details of the construction and mechanism of the experimental atomic bomb that exploded in the early morning of July 16, 1945 in the New Mexico desert, they were led by Professor Oppenheimer, a theoretical physicist at the University of California.

The two bombs dropped weeks later against Japan were constituted, the first for Uranium 235 and the second for Plutonium.

Although the energy released in the cleavage of a Uranium nucleus is calculated at about 200 million electron-volts, that is, about 2x10¹⁰ Kilocalories per Kilogram of cleaved Uranium, only 1-5% remains usable, which corresponds to a explosive energy available per kilogram of U-235 equivalent to that of about 300 tons of trinitrotoluene (TNT, trilita)

To the explosive wave originated in the explosion of the atomic bomb are added the terrible incendiary effects produced by the intense gamma radiation emitted, which determines how a miniature Sun, although briefly duration.

The devastation caused by isolated bombs over the Japanese cities of Hiroshima and Nagasaki are proof of the enormous Atomic Energy that is released in atomic disintegration.

It is hoped, however, that Atomic Energy can be applied to peaceful uses in the future, especially in cases where a large concentration of energy in a small amount is desirable of material.