Nuclear Power

We explain what nuclear energy is and how it is obtained. Also, what it is for, advantages, disadvantages and some examples.

What is nuclear energy?

Nuclear energy or atomic energy is the result of reactions that occur in atomic nuclei or between them that is, it is the energy released in nuclear reactions. These reactions can occur spontaneously or artificially.

Nuclear reactions are processes of combining or fragmenting the nuclei of atoms and subatomic particles. Atomic nuclei can combine or fragment so that they release or absorb large amounts of energy in the process. When nuclei fragment, the process is known as nuclear fission, and when they combine it is called nuclear fusion.

Nuclear fission occurs when a heavy atomic nucleus is fragmented into several lighter nuclei, and can also produce free neutrons, photons and fragments of the nucleus. Nuclear fusion occurs when several atomic nuclei with similar charges combine to form a new nucleus of greater weight. These reactions occur in the nuclei of the atoms of certain isotopes of chemical elements such as uranium (U) or hydrogen (H).

The large amount of energy involved in nuclear reactions is fundamentally due to the fact that part of the mass of the reacting particles is converted into energy directly. This process was argued by the German physicist Albert Einstein by stating his equation:

E = mc²

Where:

• AND: energy
• m: mass
• c: speed of light

As you can see, the equation proposed by Einstein relates mass and energy.

The energy released in nuclear reactions can be used for electricity generation in thermonuclear power plants, in nuclear medicine, in industry, in mining, in archeology and in many other applications.

Its main use is in the generation of electrical energy, where nuclear energy is used to heat large volumes of water or to generate gases, whose heat energy is then used to move large turbines that produce electricity.

The controlled use of nuclear energy is used for beneficial purposes. It is a very important source of energy but also, unfortunately, used for war purposes for the production of nuclear weapons of mass destruction.

See also: Alternative energies

How is nuclear energy obtained?

Nuclear energy is obtained as a result of the nuclear reaction in certain atomic nuclei of certain chemical elements. Some of the most important processes to obtain nuclear energy are the fission of the isotope uranium-235 (²³⁵U) of the element uranium (U) and the fusion of the deuterium-tritium isotopes (²H-³H) from the element hydrogen (H), although nuclear energy can also be obtained from nuclear reactions in the isotopes thorium-232 (²³²Th), plutonium-239 (²³⁹Pu), strontium-90 (⁹⁰Sr) or polonium-210 (²¹⁰Po).

The fission of uranium-235 (²³⁵U) is an exothermic reaction that is, it releases a lot of energy. The energy released heats the medium in which the reaction is occurring, which could be water, for example.

For fission to occur, the isotope ²³⁵U is bombarded with free neutrons (although it can also be bombarded with protons, other nuclei or gamma rays) whose speed is very controlled. In this way, a free neutron can be absorbed by the nucleus, causing it to destabilize and fragment, generating other smaller nuclei, free neutrons, other subatomic particles and large amounts of energy. It is important to control the speed of the neutrons because if it is too high they could simply collide with the nucleus or pass through it, and would not be absorbed to produce fission.

The particles generated as a result of the fission of a nucleus can, in turn, be absorbed by other neighboring nuclei, which will also fission, and the particles generated as a result of this other fission may, again, be absorbed by other nuclei. , and so on, producing what is known as: Chain reaction.

Controlled nuclear chain reactions have many beneficial applications as mentioned above. However, when the chain reaction is uncontrolled, it continues until there is no more material left to fission, which occurs in a short time. This uncontrolled process is the principle of operation of the atomic bombs dropped by the United States on Japan in World War II.

Besides, the fusion of the deuterium-tritium pair (²H-³H) is the simplest nuclear fusion process that exists. For this fusion to occur, it is necessary to bring two protons closer together (one coming from the ²H and another of ³H) so that the strong nuclear interaction forces (forces that unite the nucleons, that is, the protons and neutrons, and that must overcome the repulsion force between protons, since they have the same charge) exceed the forces of electrostatic interaction, since protons have a positive charge, so they tend to repel each other. To achieve this, certain pressures and decompressions are applied, as well as very specific temperatures. This fusion process produces a nucleus of ⁴Hey, a neutron and a lot of energy.

Nuclear fusion is a process that occurs spontaneously in stars for example, the Sun, but which has also been generated artificially.

In general, nuclear reactions produce unstable atoms which to stabilize themselves emit excess energy into the environment for a certain time. This emitted energy is called ionizing radiation, which has enough energy to ionize the matter around it, which is why it is extremely dangerous radiation for all forms of life.

See also: Chemical element

What is nuclear energy for?

The peaceful uses of nuclear energy are numerous, not only for the generation of electricity (which is already of enormous importance in today's industrialized world) but also for the production of usable and reducible heat energy, or mechanical energy, and even forms of ionizing radiation that can be used to sterilize medical or surgical material. It is also used to propel vehicles like atomic submarines.

Advantages of nuclear energy

The advantages of nuclear energy are:

• Little polluting As long as there are no accidents and radioactive waste is properly disposed of, nuclear power plants pollute the environment less than the burning of fossil fuels.
• Safe As long as safety requirements are met, nuclear energy can be reliable, consistent and clean.
• Efficient The amounts of energy released through these types of nuclear reactions are massive, compared to the amount of raw material they demand.
• Versatile The application of radiation and other forms of nuclear energy in various areas of human knowledge, such as medicine, are important.

Disadvantages of nuclear energy

The disadvantages of nuclear energy are:

• Risky In cases of accidents, such as the one that occurred with the Chernobyl nuclear reactor in the former Soviet Union, the civilian population and even animal life are at high risk of radioactive contamination.
• Disposal Radioactive byproducts from nuclear power plants are difficult to handle and some have a very long half-life (the time it takes for a radioactive atom to decay).
• Expensive The creation of nuclear power plants and the use of this technology is usually very expensive.

Characteristics of nuclear energy

Broadly speaking, nuclear energy It is powerful, effective, a true achievement of human mastery over physics. However, it is also a risky technology: after seeing the disasters caused by the atomic bombs of Hiroshima and Nagasaki, or the Chernobyl accident in the USSR, it is known that this type of technology represents a real danger to life on the planet. as we know it.

Examples of nuclear energy

A peaceful example of the use of this energy is any nuclear electricity plant, such as Ikata, in Japan. An example of its war use was the bombing of the Japanese cities of Hiroshima and Nagasaki in 1945 during World War II.