It seems that nuclear power has a key role to play in our future because is a stable, reliable, clean, and always available source of energy.
However, when I talk about the future of nuclear power, I’m not talking about nuclear fission, I’m actually talking about nuclear fusion because this is the only source of clean energy that can seriously reduce the level of air, soil and water pollution on the planet.
As we are trying to replace coal and oil with low-carbon and green energy sources, besides increasing the generation capacity for solar and wind power, teams of scientists are working hard to master the nuclear fusion reaction.
Nuclear fusion is the same source of energy that powers our Sun and all the other stars in the known universe, and is a nuclear reaction that generates clean energy without producing dangerous nuclear waste.
What is Fusion in Nuclear Energy?
Fusion in nuclear energy refers to a nuclear reaction that turns one element into another with the release of energy.
The nuclear reaction that takes place in the Sun and turns two hydrogen atoms into a larger helium atom is called fusion.
It is called fusion for the following reason. The Sun is also made of atoms, but being so big, it has an extremely strong gravity. This gravity pulls the hydrogen atoms together, and even if in normal conditions atoms don’t want to stay that close together (the protons repel each other), the Sun’s gravity is so strong that it overcomes that.
When two hydrogen atoms get close enough together, they merge or fuse, to become a new atom (an atom of helium).
The nuclear fusion reaction is a much cleaner nuclear reaction because it turns one element into another with the release of energy.
The nuclear fission reaction instead splits one unstable atom into two or more pieces that are stable, but beside the energy release, it also produces hazardous nuclear waste, which is very harmful for any living being.
The Sun is the Ultimate Source of Power
The Sun is the ultimate source of energy for mankind because it heats the air on our planet, causing the wind, it’s behind the water cycle causing rain and giving us hydroelectric power. Sunlight is the foundation of life, and the sunlight from ancient times was deposited into the ground, giving us the today’s fossil fuels: coal, oil and natural gas.
Actually, all the energy produced on our planet comes from the Sun or from nuclear power.
The Sun is also a great model for us to replicate the nuclear fusion reaction powering the Sun here on Earth.
However, to make nuclear fusion a major game changer for our civilization, we have to learn how to harness this tremendous source of clean power here on the planet in an efficient and secure way.
How Does Nuclear Fusion Create Energy?
Scientists have started in the 1920s to study the nuclear fusion reaction because they have found that this is the nuclear reaction that powers the Sun.
In the fusion reaction, extreme temperatures and intense pressure cause hydrogen atoms to fuse together to form helium atoms. In the process, the atoms lose some mass, which is converted into huge amounts of energy.
The nuclear fusion reaction of hydrogen can produce four times more energy than the nuclear fission reaction, and four million times more energy than burning coal or natural gas.
Another way to think how much power is produced in the nuclear fusion reaction: two pounds of nuclear fuel for fusion (hydrogen isotopes: deuterium and tritium) can produce the same amount of energy as about fifty five thousand barrels of oil, and all the energy produced through fusion is clean.
The fuel used in the nuclear fusion reaction is plentiful and can be found essentially everywhere on the planet. The radioactivity would be short-lived, there is no possibility of a runaway reaction, so it’s a much safer system compared to today’s nuclear fission power plants.
Deuterium is stable and can be found in abundance in sea water, but tritium is much harder to find here on the planet and is also radioactive.
Helium-3 is an isotope of helium and seems to be a great substitute to tritium. Unfortunately, helium-3 is also rare on the planet, but on the Moon, due to billions of years of solar winds, we can find massive deposits of helium-3 that can power our civilization for thousands of years.
Is Nuclear Fusion Energy Possible?
We haven’t found yet the way to produce more energy than we consume in the nuclear fusion reaction, and this is happening after decades of research and billions of dollars invested.
However, the nuclear fusion reaction is possible, we can see it every second in our Sun because the Sun is powered by this nuclear reaction.
Even so, scientists still have not found a way to create a sustained fusion reaction here on the planet, because this technology is so advanced that it just might take an international effort.
The ITER Project
The ITER project, known as the International Thermonuclear Experimental Reactor proposed nearly 35 years ago at the Geneva Superpower Summit, joins the efforts of scientists from China, the European Union, India, Japan, Korea, Russia and the United States.
All these countries are working now together to build what would be the world’s largest tokamak reactor, a doughnut shaped device used for magnetic confinement fusion.
Currently under construction, ITER’s tokamak reactor will be twice the size of the current largest machine (the Joint European Torus), and is aimed to produce 500 MW (megawatt) of fusion power from 50 MW of heating power.
However, this would be more challenging than putting a man on the Moon because the level of technology required is beyond today’s capacity.
The immediate goal of ITER is not energy production, though the project will eventually become commercial.
The 20 yards in diameter and 20 yards in height tokamak reactor will be completed around 2024, and will go nuclear in the next decade (by 2035).
By 2040, ITER will gain all the information that will allow the next generations to build demos.
These demos will achieve ignition, and will open the door for industrial scale reactors that will generate electricity for the grid.
Why is Fusion So Hard?
The Sun shines due to nuclear fusion, and this is a thermonuclear process that uses extremely hot particles.
The temperature is so high that atoms are stripped of their electrons, making a plasma where nuclei and electrons bounce around freely.
Nuclear fusion of hydrogen powers the Sun, image source: pixabay.com
Since nuclei are all positively charged, they repel each other, and to overcome this repulsion, the particles need to move extremely fast, and this again means that they need to be extremely hot (millions of degrees).
Stars reach such a temperature due to the fact that they are so massive, and the pressure in their cores generates the heat required to squeeze the nuclei together until they merge and fuse creating heavier nuclei and releasing a huge amount of energy in the process.
On Earth, we can’t use this brute force method to create fusion (huge pressure), so in order to build a reactor that generates energy from fusion, we have to understand the entire process in a more profound way.
By now, scientists have invented two ways (two types of reactors) of making plasma hot enough to fuse.
1. Magnetic Confinement Reactor
This reactor squeezes plasma in a doughnut shaped chamber where the reactions take place. These magnetic confinement reactors like the reactor built by the ITER project in France, use superconducting electromagnets cooled with liquid helium to within a few degrees to absolute zero (−273.15 °C).
Stellarator is another magnetic confinement reactor that relies primarily on external powerful magnets to confine a hot plasma.
2. Inertial Confinement Reactor
This reactor uses pulses from super-powered lasers to heat the surface of a pellet of fuel, imploding it, and briefly making the fuel hot and dense enough to fuse.
A Z-pinch (zeta pinch) reactor is a type of plasma confinement reactor that relies on an electric current in the plasma that generate a magnetic field to compress the plasma.
Conclusion
However, all these reactors are today just experiments because although we can achieve fusion, it costs more energy to do the experiment than the energy produced in the fusion reaction.
The technology has a long way to go before becoming commercially viable here on the planet.
