Nuclear fusion operation
Two nuclei of light atoms, usually hydrogen isotopes (deuterium and tritium), are subjected to high temperatures, merging into a denser and heavier nucleus, usually helium. This reaction generates a large amount of energy in the form of gamma rays that add to the kinetic energy of the neutrons that are emitted.
Deuterium is a stable isotope, made up of a proton and a neutron. The energy content of deuterium is very high, so the energy contained in a liter of seawater is equivalent to having 250 liters of oil. Tritium is an unstable isotope, made up of a proton and two rapidly decomposing neutrons. Although tritium is rare in nature, it can be generated from lithium, abundant in the earth’s crust and in seawater.
For this reaction to occur, the following is required:
- Very high temperatures.
- Large amounts of water to evacuate the high temperatures generated in the reaction.
- Maintain a sufficient number of cores to obtain sufficient energy to heat and retain the gas.
- Keep the cores together as they tend to repel each other.
- The solutions found so far to achieve this reaction are:
- Accelerate nuclei in an energy-intensive particle accelerator.
- Inertial confinement with laser.
- Magnetic confinement by thermal agitation with the problem of the high temperatures reached.
Lockheed Martín, an aerospace company in the United States, claims, but without providing concrete data, to have made a great advance in the field of nuclear fusion, which consists of how to contain the amount of heat generated in the reaction, which can reach hundreds of people. Millions of degrees. They confirm that in less than 10 years, small fusion power reactors, capable of supplying small cities, could be operating. This company also argues that “the thermal energy generated by this compact fusion reactor will run the turbine generators, replacing the combustion chambers with simple heat exchangers, while the turbines will generate electricity or energy.”
A more tangible case is the ITER (International Thermo-nuclear Experimental Reactor) project, which is building its demonstration plant in Cadarache, in the south of France. It is a research project in which the European Union, Canada, the United States, Japan and Russia participate to determine the technical and economic feasibility of nuclear fusion by magnetic confinement for power generation.
Where does the uranium appear, which deals with nuclear energy?
So far we have talked about atoms and they form matter; well, uranium is this issue, that is, the atoms that decompose releasing energy are uranium. Radioactive waste can be of low activity (they do not generate heat and their half-life is less than 30 years) and of high activity (they contain alpha-emitting radionuclides and have not decreased their activity in the environment for more than 30 years).
Where does nuclear energy come from?
We have to refer to Einstein and his famous equation E = mc2 (energy equal to mass times the speed of light squared). Simplifying the process and making it more understandable, we could say that the key is the disintegration of the atoms. An atom is made up of a central nucleus with protons (with positive energy) and neutrons (without charge) connected, around which electrons (with negative energy) orbit.
Well, the disintegration of an atom is achieved by releasing the energy of its nucleus and heavy that it is possible to literally bombard with neutrons, so it decomposes into two light nuclei and the so-called fission process generates energy. In fission, two or three neutrons are emitted that can continue to interact with other nuclei, reproducing the same process. This is what is commonly known as a “chain reaction.” Explained in this way, one can think of an uncontrollable and therefore dangerous chain reaction. The core of the matter and the basic principle of a nuclear reactor lies in the control that only one of the released neutrons produces a subsequent fission. If the neutrons do not continue, the reaction is lost, and if there are more than two, control is lost and the nuclear explosion occurs.
Which is nuclear fusion?
It is rather a process in which a large amount of energy is also released, but which, unlike the previous one, instead of separating heavy nuclei, what happens is that two light nuclei (leading to a heavy one). It is a much more complex process than fission and is not used in nuclear power plants. In fact, its viability in terms of safety, quantity and costs is being studied in the ITER (International Thermonuclear Experimental Reactor) project. If research is successful, it can become a clean source of energy.
And how is electricity produced then?
The energy released by uranium produces heat with which the water in the reactor vessels is boiled. Next, steam is generated that drives the turbines and, after passing through an alternator. Nuclear energy has become one of the sources of electricity production that generates the most controversy and public rejection. However, its advocates, including leading organizations and some environmentalists, argue that it is a safe, clean and cheap alternative.
Advantages of nuclear energy
Ensures the electrical supply:
Nuclear power is the energy source that works the longest hours a year. They are available 24 hours a day, 365 days a year, thus guaranteeing the supply of electricity. Other sources of energy, such as wind or solar, lack security of supply when exposed to weather conditions.
It is a clean energy and does not generate CO2:
Nuclear energy does not emit polluting gases or particles into the atmosphere, a key advantage in containing climate change. It does not use fossil fuels, so it does not emit carbon dioxide (CO2), the main greenhouse gas. A third of the energy generated in Europe comes from atomic energy, which avoids the emission of 700 million tons of CO2, in addition to generating the exhaust of 200 million vehicles and other pollutants generated by the burning of fuels. Fossils
It is one of the cheapest sources of electricity production:
According to the Spanish Nuclear Forum, 32.3 kilograms of uranium have an energy equivalent to 100,000 tons of coal. The weight of the uranium raw material is small in relation to the total cost of producing electricity and its price is stable, obtaining the kilowatt-hour (kWh) at reasonable costs.
Discharges from nuclear power plants abroad are minimal:
Most of them are expelled in gaseous form from the plant chimney (air with very little radioactivity), and in liquid form through the discharge channel. Due to their low polluting power, nuclear power plants reduce acid rain and the accumulation of toxic waste in the environment.
They generate employment:
Nuclear power plants, like other electrical installations, generate employment and wealth in their area of influence. An estimated 500 people work in each reactor. In total, the Spanish nuclear sector employs some 30,000 people in direct and indirect positions.
What is nuclear fuel?
We refer to nuclear fuel for the material that is used to generate nuclear reactions. As we have already said, nuclear reactors generate nuclear fission reactions. So for this type of reaction, you need a material, an atom, which is very unstable; which is so unstable that when it collides with a single neutron, it decomposes.
The vast majority of nuclear reactors use enriched uranium as nuclear fuel. Uranium is a very unstable element that occurs naturally. Although it is unstable, it goes through an enrichment process that makes it even more unstable and therefore more efficient for nuclear power plants. That following a certain process is enriched to make it more unstable.