When one thinks of nuclear power, thoughts often include nuclear fission weapons (AKA atomic bombs) and their dangerous consequences. However, new research in sustainable energy production indicates that another type of nuclear energy could be an infinitely-abundant energy resource for the planet. It’s called fusion. Though challenging to produce, fusion’s high-energy yield and limited by-products make it an important resource to consider for the future.
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What is fusion?
Nuclear fission is when a heavy atom, such as uranium, breaks down into smaller parts. This process releases significant energy and creates long-lived radioactive waste, which is harmful to living organisms. On the other hand, nuclear fusion is the opposite of fission. It is when two lightweight atoms such as hydrogen, collide to form a heavier atom, such as helium. This process releases enormous amounts of energy, which can be used to power cities efficiently and sustainably.
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Unlike nuclear fission, fusion produces no long-term radioactive waste and yields much more energy. Though scientists have already produced fission reactions, fusion reactions are much more challenging to produce. Proficiency of nuclear fusion reactions would allow us to lessen our dependence on fossil fuels and could consequently prevent the exacerbation of climate change.
Stars, such as the sun, create energy through nuclear fusion, which takes place in the star’s core. Stars are fusion factories that consist of giant balls of burning plasma. This is the fourth state of matter and is like a gas that is electrically charged. Its freely moving electrons give it unique properties that allow it to drift between solid, liquid and gaseous states. Plasma is the state of matter at which nuclear fusion reactions can take place.
Nuclear fusion also requires extensive amounts of energy to carry out and control. This is because particles have to be heated to extreme temperatures so that despite their extremely repulsive electrostatic forces, they can be forced to fuse together. Every second, our sun uses these extreme conditions to fuse hundreds of tons of hydrogen into helium. Up until recently, it was unknown if these conditions were replicable on Earth.
Emulating the stars
To mimic the process that takes place in stars, scientists use a donut-shaped machine called a tokamak. Tokamaks, such as the one at the International Thermonuclear Experimental Reactor (ITER) in France, use giant magnets to create strong magnetic fields that bottle up the intense heat produced by the reaction. These machines need to contain extreme temperatures, reaching over 150 million degrees celsius.
To fuse the atoms, the tokamak is supplied with fuel and the giant magnets are activated to create plasma. The temperature inside the machine is then raised by over 100 million degrees and the hydrogen fuel particles are forced to bond. In doing so, this creates helium gas and free-floating neutrons. The neutrons can escape the plasma and hit the walls of the tokamak, where their kinetic energy transfers as heat. This heat can be used to boil water and create steam, which can power turbines for electricity. The energy can also be used to run more fusion reactions in the future.
In February 2022, scientists in Culham, near Oxford, England, announced an extraordinary breakthrough. They were able to generate and sustain 59 megajoules of fusion energy for five seconds. This was only enough to power a single house for a day and more energy had gone into its production than was actually extracted. However, it proved that fusion is indeed possible on Earth.
A future energy alternative to fossil fuels
Once nuclear fusion energy production is mastered, its efficiency will be too good to pass up. One gram of hydrogen fuel can produce the same amount of energy as eight million grams of oil. ITER’s objective is to develop fusion processes to such an extent that they can be utilized commercially on a global scale. This way, nuclear energy prices will drop and fossil fuels such as coal, oil and gas can be phased out. By transitioning to resources that do not emit greenhouse gases, we can avert the irreversible effects of climate change.
Alongside its incredible efficiency, energy from nuclear fusion does not produce harmful by-products. These include greenhouse gases such as carbon dioxide and methane, which retain heat in the atmosphere. In fact, the main by-product of the process is helium gas, which is non-toxic and inert. The radioactive waste produced by the reaction is also short-lived. Materials exposed to fusion can be recycled within 100 years, unlike the long-lived radioactive waste produced by fission. This is key as long-term and/or high exposure to radioactive materials can alter DNA in the cells of living organisms, leading to health and reproductive issues.
Since fusion does not require the use of fissile elements, the material in fusion reactors cannot be misused for nuclear weaponry. Additionally, since maintaining the precise conditions to carry out fusion requires meticulous care, nuclear accidents are not possible in tokamaks. If any disruption occurs, the plasma will cool instantly and the reaction will not take place.
Nuclear fusion is also very sustainable in the long run. Hydrogen fuels, such as deuterium and tritium are found in nature. Deuterium is easily available and plentiful. It can be distilled from fresh and seawater, providing enough fuel to sustain human activity for millions of years. Tritium, though rare, can also be produced synthetically and used alongside deuterium in nuclear reactions. In fact, the deuterium from 500 milliliters of water and a small amount of tritium could power a house for an entire year.
Looking to the future
Because of its impressive qualities, the possibility of using nuclear fusion was discussed by the United Nations in their dialogues at the COP26 Climate Summit 2021. By further developing this clean energy production process, the current over-reliance on fossil fuels could shift to more efficient, eco-friendly energy sources. Though the transition may come with its own challenges, including managing short-lived radioactive waste and tritium production costs, it could be one of several resources used to generate electricity. Consequently, fusion could help alleviate the effects of large-scale environmental degradation and the ongoing climate crisis.
via CNN, CommercialWaste, ITER and TWI
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