The Controversial one
Every living organism on planet Earth depends on the Sun, the main star in our system. In fact, the radiated energy of this star is the result of the fusion process of hydrogen atoms to form helium, so we could say that thanks to Nuclear Energy, life is possible on Earth.
We were used to relating the term ” Nuclear Energy ” to the fission that takes place today in power plants, although this term already defines the fusion process. In broad terms, we define fission energy as the energy obtained separating heavy atoms (uranium mainly) from lighter atoms, such as strontium or xenon, meanwhile, fusion allows obtaining energy from the combination of lighter atoms (deuterium and tritium mainly, hydrogen isotopes) to create a heavier nucleus.
Fusion reactions produce a very high amount of energy, four times more than that the generated by fission. Theoretically, with just a few grams of deuterium and tritium, one terajoule of energy can be obtained. This is equivalent to the energy needs of an inhabitant of a developed country over 60 years. Many actors are already involved in the research and development of first-generation fusion reactors. Among them, we can highlight the ITER Project, in which 35 nations headed by the European Union have joined forces to research and study plasma fusion and materials to manufacture a Tokamak reactor, with the goal to produce 500MW of fusion energy from an input of 50MW of heat energy (reverse active power factor Q=10).
Another very promising initiative is being carried out by the Technological Institute of Massachusetts (MIT) in collaboration with spinoff Commonwealth Fusion Systems; They are jointly developing a prototype for the reactor Tokamak for magnetic confinement fusion. In 2021 it was achieved that the superconductor magnets that confine the nucleus reached a magnetic field of 20T, allowing to isolate plasma (up to 150M Celsius degrees) from the reactor walls. That meant a landmark and a significant step in the project making MIT able to confirm that their first prototype for the fusion reactor would be ready in 2025.
Fusion energy will be one of the most powerful renewable production sources, if not the most powerful one, because after the initial fusion, the generated energy can be used to fuel future reactions, creating an unlimited supply. The process uses hydrogen isotopes, of which there are ample reserves: deuterium, obtained from distilling water in any of its states, and tritium is generated in the fusion reaction when neutrons interact with lithium, it is estimated there will be reserves for millions of years.
At present, only fission nuclear power plants are in operation. To refer to the start-up of this technology, we must go back to 1951. The Experimental Breeder Reactor built in Idaho was the first nuclear fission reactor to produce electricity. On the other hand, the first power plant dates to 1954 and was designed for the purpose of supplying power in Obninsk, Russia. At the national level, the first plant to start operating in Spain was the José Cabrera nuclear power plant in 1968, which was shut down by Ministerial Order in 2006.
Nuclear fission reactors, are generally fuelled by uranium pellets, as uranium atoms are relatively easy to separate. Uranium is a common element that can be found even in rocks. However, the element that is used as reactor fuel, U-235, constitutes less than 1% of the world’s available uranium. The main deposits are in Kazakhstan, Canada, South Africa, Brazil and China. On average, a reactor uses about 200 tons of this element per year. According to data compiled as of May 2022, there were then 439 operating fission nuclear reactors worldwide, with the United States having the largest number, followed by France and China, with 56 and 54 operating reactors, respectively. Spain is in eleventh place, with 7 plants currently in operation. In any case, and according to the Government’s plans, by 2035 all fission nuclear power plants in our country will have ceased their activity.
In terms of energy consumption from fission, according to 2021 data, the United States is again the country that leads the ranking, with 7.4 EJ, equivalent to about 2000 TWh per year, followed again by China and France, with an approximate consumption of 1000 TWh in 2021. In Spain, figures show that the consumption of electricity in nuclear power plants was significantly lower, resulting in a total of 141 TWh per year.
The graph below presents the forecast for nuclear generation between 2020 and 2050, showing that electricity production from fission power will remain almost constant, with renewable energy sources (including hydroelectric power plants) taking charge and decreasing generation from liquid fossil fuels to zero.
Recently, “micro-nuclear reactors” or “mini-nuclear batteries” initiatives have been presented that would constitute energy sources free of carbon dioxide emissions, and they could also be easily and safely installed wherever they were needed, since they do not require as exhaustive cooling as large power plants. MIT among others proposes micro-reactors that could reach up to 10MW and serve, for example, as a heat source for industrial processes or to supply electricity to entire neighborhoods or military bases. The extreme modularity of these solutions would allow nuclear energy to be considered as a product, and not as a mega-project, since they would be installed in just a few weeks and with a cost of approximately $20M, lower than the billions that large nuclear power plants cost and could be a viable alternative to the latter.
Fission nuclear energy is not considered renewable because it is obtained from isotopes of U-235, which is not a renewable resource. In addition, the by-products of the fission reaction are radioactive, as they constitute a collection of atoms with unstable nuclei that radiate energy, seriously affecting organisms and the surrounding environment. In any case, fission is considered “clean” since no carbon dioxide or greenhouse gases are emitted in the energy generation process.
Another advantage of fission nuclear power is the steady supply to the grid. That is something still complicated to ensure with renewable energy production, due to the variable nature of the resource. However, complementing wind and solar generation together with short- to medium-term development of storage systems, could make renewable production stable, thus ensuring continuous supply to the grid.