Nuclear fusion is currently a dream of many powerful countries that hasn’t come true yet. Today, many countries around the world use nuclear power to generate electricity through the nuclear fission process. But the element isotope, nuclear fuel used for this, and the nuclear waste discarded from this nuclear fission process are highly radioactive. So the scientists decided to find a sustainable solution to eliminate the adverse effects of the nuclear fission process. This is how the concept of nuclear fusion was born.
Scientists have been studying and researching nuclear fusion since the 1920s, after discovering it powers the sun. The sun is considered to be one of the enormous naturally occurring nuclear fusion reactors. All life on earth exists due to nuclear fusion in the sun. Is there a way we can build an artificial sun on the earth? Yes, we can also construct a modest nuclear fusion reactor to harness the fusion power as a long-term solution to the future energy crisis. How we can accomplish that in practice is a problem that remains unsolved.
All the attempts made so far have failed. However, none of the companies that took the initiative is willing to admit their failure. Their most famous excuse is that they require more funding and government backing. It’s unknown how close we are to fusion power. Let’s take a detailed look at what this nuclear fusion energy is.
What is Nuclear Fusion?
The nuclei of two light atoms slam or collide together to form a heavy atom resulting in a mass loss. Nuclear fusion is the generation of electricity from the energy released by the mass loss that comes about in this nuclear fusion process. According to Einstein’s mass-energy equivalence principle, mass and energy are considered to be one and the same. Einstein devised the famous equation E = mc2 to represent this mathematically. This indicates that mass is concentrated energy, i.e., there is a whopping amount of energy in mass.
What Is The Difference Between Nuclear Fusion And Fission?
In contrast to nuclear fusion, fission energy causes the nucleus of a heavy atom to split into many light atoms. A neutron collides with a uranium atom and splits it inside the nuclear fission reactors, producing a massive amount of heat which is then used to generate electricity. Nuclear fission and fusion are both carbon-free energy sources. However, the materials and nuclear waste that are discharged during the nuclear fission process are incredibly radioactive. That is the main reason why scientists are trying so desperately to discover a solution to harness fusion power to generate electricity.
How Does Fusion Energy Work?
Hydrogen atoms must be placed in a doughnut-shaped chamber at high pressure and high temperature in order to produce nuclear fusion power. When this occurs, the hydrogen atoms are converted into plasma. The temperature within these chambers must be kept at a particular level for this reaction to take place effectively. This energy barrier is called the Coulomb barrier. Hydrogen would be used as fuel in fusion reactors.
Deuterium is formed when one hydrogen atom fuses with another hydrogen atom. This deuterium fuses with another hydrogen atom to produce the helium isotope. When two isotopes of helium are combined together, heavier helium is formed. As long as the required temperature level remains constant inside the chamber, this reaction will occur effectively, resulting in some mass deficiency that causes the release of an enormous amount of energy. This is referred to as a nuclear fusion reaction.
Scientists have developed three methods for heating plasmas to the point where they can fuse. This can be done using a magnetic field, super-powered lasers, and ion beams. Depending on the method they choose, a specific type of reactor will be required.
Types Of Reactors Used To Produce Nuclear Fusion
Magnetic Confinement Fusion
There are three states of matter, according to physics: Liquid, Solid, and Gas. When a gas (heavy helium) is heated to a high degree, it transforms into plasma consists of ions and electrons. Maintaining plasma stability in order to harness energy over extended periods of time is a difficult challenge. Scientists created magnetic confinement nuclear reactors after decades of research to overcome this obstacle. The most common magnetic confinement reactors in operation throughout the world are stellarators and tokamaks. The tokamak reactor is the most widely used nuclear fusion reactor of these two.
The Russian acronym Tokamak stands for the toroidal chamber with the magnetic coil. The extraordinarily high temperatures required to generate fusion power will melt any known material, making containing the hot plasma more challenging. The magnetic field is needed to steer the plasma energy around within the container in a spiral pathway without causing it to vaporize by touching the walls of the confinement chamber. This magnetic field is referred to as a toroidal magnetic field. The tokamak is the device that enables this process.
In a tokamak reactor, the central solenoid fixed in the center of toroidal field coils plays an integral part in this nuclear reaction process. When a solid variable current passes through it, it aggressively boosts all of the particles. As a result, the deuterium and tritium ions begin to move in one direction. In contrast, the electrons move in the opposite direction. The temperature of the plasma rises to millions of degrees when the particles collide.
However, scientists also employ alternative heating techniques to get the optimal temperature level required for fusion. Electromagnetic waves to irradiate the plasma and blasting it with high-energy neutral deuterium atom jets are alternative heating techniques commonly used in nuclear fission. Assume that the current technological issues are resolved, enabling deuterium and tritium enough kinetic energy to overcome their repulsive electrostatic force and form a tight bond. This will result in a massive energy release fusion reaction.
ITER is the largest tokamak fusion reactor being built in southern France in collaboration with 35 nations. This fusion experiment project was officially launched in 1985. ITER is designed to generate 500MW of fusion energy from 50 MW of heating power. That means it is aimed to achieve a ten-fold return on energy input. They intend to carry out their first experiment in 2025 and start the production of nuclear fusion by 2035. Click here to learn more about nuclear fusion reactor France.
Inertial Confinement Fusion
Inertial confinement is achieved by directing a strong laser onto a fuel pellet consisting of deuterium and tritium, causing the atoms within it to be instantaneously heated and fused together. The pellet’s outer layers are blown off by this heating. It will result in intense collisions that push a chunk of the pellet inward. The density of the inner core increases extraordinarily, and its temperature rises to the level where fusion can occur.
This inertia confinement approach is employed at the National Ignition Facility (NIF) in California. They utilize 192 powerful laser beams housed in a 10-story structure almost the size of three football fields that are fired simultaneously at a tiny hydrogen fuel pellet. The ultimate objective of doing this is to induce a nuclear fusion reaction. This is the world’s largest laser machine ever built.
Why Is Nuclear Fusion Better Than Nuclear Fission?
- A fusion reaction can produce four times more power than a fission reaction. It generates approximately four million times more energy than burning coal or gas.
- It releases no greenhouse gases into the atmosphere, such as carbon dioxide (CO2), nitrous oxide (N2O), or methane (CH4)
- There is plenty of fuel for nuclear fusion. It can be found all around the world. Deuterium can be extracted from seawater, while tritium is released during the fusion reaction process.
- The byproduct of this nuclear fusion process is helium. This inert, non-toxic gas does not pose a threat to the ecosystem or humans.
- Unlike the nuclear fission process, there are no concerns about proliferation as these nuclear fusion reactors do not use enriched radioactive materials like Uranium.
- There is no room for a runaway reaction since any disruptions occurred during the process cause the reactors to cool off immediately and stop the reaction.
Why Don’t We Have Fusion Power?
Three challenging conditions must be met for fusion to occur. Scientists are currently focusing on developing a fusion reactor that can fulfill all three of these conditions.
- Temperature – The reactor core temperature must be raised to around 100 million degrees Celsius. (The Sun, the largest natural nuclear fusion reactor on the planet, has a temperature of only 15 million degrees Celsius at its core)
- Density – Sustain a sufficiently high density of plasma to ensure collisions occur. We need a lot of energy to keep the nuclear fusion reaction going. At the moment, fusion reactors at the experimental stage consume more energy than they produce. The key objective is to use less energy for nuclear reactions while creating a tremendous amount of energy.
- Time of Confinement – Plasma must be confined for a prolonged time for fusion to take place. We must also discover a material that can survive such high temperatures for an extended period of time.
Aside from these three conditions, there are other factors that indirectly impact the development of fusion nuclear power worldwide. The cost of research and development for these experiments is too high. Billions of dollars are invested yearly even without seeing satisfactory results of creating a sustained fusion reaction. There is no assurance of success.
Another concern is the aversion of society to have nuclear power plants operate in their countries. The consequences of nuclear disasters they have witnessed in the past have terrified them. To name a few Chernobyl Nuclear Power Plant explosion in Ukraine, the Fukushima Daiichi Nuclear Power Plant meltdown, and the Hiroshima and Nagasaki atomic bombings in Japan.
Following these terrible occurrences, governments opted to impose stricter regulations limiting the operations of nuclear experiments, which eventually improved the safety and quality standards of nuclear power plants. Under these laws and safety standards, building a nuclear power plant will cost more than $10 billion and take nearly ten years.
Is Nuclear Fusion Possible?
Scientists believe so. We all know nuclear fusion powers the sun. It is uncertain when we will be able to do the same here on earth. Even if scientists could generate fusion electricity in the future, it wouldn’t be available in the market at a lower price due to the high production cost. However, technology is evolving at a rapid pace. So, we all hope that scientists will figure out a way to make nuclear fusion more economical.
In the meanwhile, companies such as TerraPower are working on the next generation fission reactors. They are highly sophisticated and much safer fission reactors. Terrapower Reactors are “walk-away safe,” according to them. This means that the plant will cool down and stabilize in an emergency even if no operator is present. It also produces 80% less radioactive waste than traditional nuclear fission reactors. Enrichment of uranium is also less required for the next generation fission reactors. Click on the link to learn more about how nuclear fission is used to generate electricity.