Nuclear Fusion?

(An explanation of how it works and its future)

At school you learn about all types of energy. You learn about renewable energy (which is good for the environment) and non-renewable energy (which is bad). When we talk about the future of energy, the topic of nuclear energy always comes up.

There are two types of nuclear energy: Fusion and Fission. They sound similar. Everyone at school always mixes them up. Are they the same? No. Definitely not…

Source for Image

In my 5th grade science class, my teacher taught us about fission and fusion. She said that fusion is when you fuse two atoms together to create energy. Fission is when you divide an atom to create energy. However, only nuclear fission has been used as an energy source so far, not fusion.

I was taught these things, but I didn’t really understand how they worked.

I still had a lot of questions, such as:

• Where does the energy from splitting or fusing atoms come from?
• What type of atom do you have to use for this process?
• Why isn’t Fusion possible?

I learned about nuclear fusion and will answer these questions and many more in simple terms anyone can understand.

What is Fusion?

Nuclear fusion does not naturally occur on Earth, but it is constantly happening on the surface of the Sun. In a fusion reaction, two nuclei merge to form a single heavier nucleus. The mass of the resulting heavier nucleus is less than the added mass of the two original nuclei. (Source)

One thing still doesn’t make sense. How does the extra mass turn into energy? Einstein’s famous equation E=mc² shows that energy is equal to the mass times the speed of light squared. That might sound complicated, but it breaks down into a simple ratio. This equation (aka. Energy-mass equivalence) shows that energy (E) and mass (m) are different forms of the same thing.

(Source for Image) Note: Mass is the x axis.

For example, if you have a spaceship and you are burning fuel to drive it it faster and faster, it will get heavier and heavier. As the spaceship gets closer to the speed of light, it becomes infinitely heavy. Once it has reached this speed, even if you add more fuel, the ship won’t go any faster. The speed of light is the fastest any object can travel at (think of it as a universal speed limit). The energy used to push the spaceship gets turned into mass making the vehicle heavier. Mass turns into energy and energy can add to mass. Therefore, mass and energy are interchangeable. (Source)

What are the Technical Barriers of Nuclear Fusion?

Why is it still impossible? We know how it works so why can’t we do it? There are a few main reasons why.

The environment needed for nuclear fusion to work is very difficult to create. You need to get atoms so close together that the nuclear forces become active and the nuclei glue together. Nuclear forces have an enemy: electrostatic forces. Electrostatic forces make positively charged nuclei repel each other. So, you need enough external force to counteract the electrostatic forces so the nuclear forces become active. Naturally, nuclear fusion reactions occur in high density and high temperature environments like the sun. The sun is so dense and so hot that it provides enough pressure to act against the electrostatic forces. (Source)

It is very difficult to recreate this atmosphere here on earth. The sun weighs 333,000 TIMES MORE than earth. That mass creates very powerful gravitational forces which produce extreme pressures. This pressure, combined with temperatures up to 15 000 000℃, allows for atoms to fuse together easily. (Source)

Fusion produces a lot more radioactive waste than fission. Radioactive waste is extremely harmful to humans so it needs to be stored far away. Once radioactive waste has had 100 years to rest, the radiation levels become low enough that it can be used for fission again. (Source)

Fusion is a very expensive form of energy It is a very powerful energy source, but very difficult to create. I believe the potential power fusion reactors can provide will be worth the money being put into the technology.

How can we Overcome these Barriers?

There are still big technological barriers, but scientists are learning and testing new ways to overcome them. In fusion, the temperatures need to be so hot that hydrogen will become plasma. Plasma is a state of matter that exists when a gas’s atoms split into positively and negatively charged particles. To create the environment needed to keep plasma in place, there are two possibilities to achieve this. (Source)

Magnetic Confinement

The first possible solution, Magnetic Confinement is: holding plasma fuel in place with magnets. The plasma can then be heated up using a combination of microwaves, radio waves, and particle beams to reach the temperature needed for fusion. These magnetic confinement reactors can come in two shapes:

• A tokamak: a donut-shaped reactor. (Source)
• A stellarator: a twisted donut shaped reactor. (Source)

(Source for Image)

Which shape is better? Each option has its pros and cons. Stellarators need less injected power to sustain plasma. They have a greater design flexibility. Stellarators have a possibility for simplification of some aspects of plasma control. The stellarator is more costly than a tokamak because of the extra benefits. Both of these reactor shapes can keep the plasma in place. (Source)

Application of Magnetic Confinement Fusion Technology

In the 1990s, the European tokamak JET had achieved 16 million watts of fusion power in less than a second. The JET was able to reproduce 65% of the energy that went into the experiment. An international group is building the world’s largest fusion reactor. This is an even bigger tokamak called ITER. The goal of ITER is to produce 500 million watts of power for SECONDS at a time! The researchers aim to produce ten times more energy than what is used by the system. (Source)

Inertial Confinement

The second possible solution is Inertial Confinement. It is used by the National Ignition Facility (NIF) in Livermore, California and involves 192 lasers. The lasers fire at a tiny gold can, which vaporizes and gives off x-rays. Then, those x-rays then hit a spherical pellet of hydrogen fuel that’s smaller than a peppercorn (which is very small). The x-rays heat and compress the fuel, turning it into plasma. Finally, a small portion of that plasma fuses into helium, giving off energy and neutrons for a split second. (Source)

Application of Inertial Confinement Fusion Technology

In 2014, the NIF reported that the fuel pellet made more energy than it absorbed for the first time. The method isn’t useful for any practical real-world power needs yet: the experiment’s lasers used about 100 TIMES more energy than the fuel pellet produced! Still, it was promising. The results were in line with NIF’s computer predictions. This is a sign that physicists’ understanding of plasma is improving. (Source)

Soon enough, the environment needed for fusion will be recreated. There are so many projects working on it right now. Waste from fusion could potentially be stored the same way radioactive fission waste is stored: in very secured boxes far away from people. The technical barriers could be solved creating a possibility for fusion.

Which Companies are working on Fusion now?

The international group that worked with the ITER and the NIF are looking into developing Inertial Confinement. Many private companies are also interested. Canada has its very own nuclear fusion startup: General Fusion. General Fusion is developing utility-scale fusion power based on recent developments in Magnetized Target Fusion. The goal of General Fusion is to demonstrate and commercialize fusion as a power source by the end of the decade. (Source)

The Canadian government also uses nuclear fission energy. Nuclear power accounted for approximately 15% of Canada’s electricity in 2018. (Source) Since nuclear fission energy is being used by many countries, I think once fusion energy becomes widely available, many countries will try to implement it as well.

Conclusion

This article explained:

1. How nuclear fusion works
2. Its barriers and how to overcome them
3. The companies that are working on it and its possible future

That is just the beginning. Nuclear technology is an amazing new field with a promising future to come. If it is created safely, it can produce enough energy to fuel the ENTIRE WORLD!