What is nuclear fission

Nuclear fission is the pillar of all existing nuclear powerplants around the world, but also of those that functioned in the past. Energy production through fission takes place when a tiny subatomic particle, called a neutron, collides with a uranium atom, splitting it.

This process leads to the release of more neutrons, which collide with more atoms and create a nuclear chain reaction. This chain of events produces large amounts of power, which we can use for the production of thermal of electrical power.

A heat exchanger is responsible for turning the water in a nuclear reactor into steam, which is then used to spool a turbine, producing electricity.

To control the process that takes place between the neutrons and the uranium, special nuclear rods are being introduced in the reactor, to prevent more neutrons from reaching the „combustion chamber” and thus, energy production is limited or simply stopped. These rods are being activated automatically and when they fail to activate or when water circulation for cooling stops, accidents such as Chernobyl are bound to happen.

Risky as it is, nuclear fission is a technology that proved to be indispensable throughout the decades and technological evolutions allowed it to become safer. The Kashiwazaki-Kariwa nuclear plant in Tokyo is among the largest in the world, with a capacity of 7.97 gigawatts and it is operational since 1985.

What is nuclear fusion

So, why do we need another type of technology for energy production? We can produce energy in large amounts with the help of a safer, more sustainable process, inspired by nature, through nuclear fusion.

Compared to nuclear fission, which involves the splitting of uranium atoms, fusion takes place by combining hydrogen, deuterium and tritium atoms, and the process is very similar to that one which fuels all the stars in the universe, including our Sun. Per mass unit, fusion produces up to 4 times more than fission when using one of the more popular nuclear fuels, U235 uranium.

Fusion energy production is also more sustainable, because it does not produce nuclear waste which need careful processing, but the problem lays within scaling this technology beyond lab only. To produce energy from fusion processes, we need an environment which can safely produce and sustain temperatures of above 150 million degrees Celsius. The only byproduct in this whole scenario would be helium, an inert gas.

To produce energy through fusion, we need to create an environment that can support the chemical reaction, which needs huge amounts of power, as well as creating a magnetic field in a circular, doughnut-shaped chamber, where atoms can move at a very high speed to generate the respective heat.

If these actions are interrupted, the reaction doesn't take place anymore, but there's no risk of a nuclear disaster, like in the case of fission powerplants.

Nuclear fusion and fission: advantages and drawbacks

Each of these technologies comes with its own advantages and disadvantages, making them more attractive on the short term or offering them more potential in the long run.

Nuclear fission comes with the advantages that:

  • it's a mature technology, which we have been using for the past decades to produce energy. Thus, safety has been greatly improved compared to powerplants in the past;
  • fission nuclear plants can be operated indefinitely, producing large amounts of power in the meantime;
  • they are less polluting compared to other power sources we can use at large scale;

The drawbacks would be that:

  • fission generates radioactive waste, which have a longer lifespan and which are costly to properly manage;
  • despite the fact that they are safer compared to models from 40 years ago, for example, there's still a risk we are taking when operating fission power plants;
  • the fuel used to power these plants, uranium and plutonium, are finite resources that can spark geopolitical conflicts;

Fusion's advantages are that:

  • it's based on a fuel that's easier to procure and which is available in larger quantities, such as hydrogen, deuterium or tritium;
  • the byproduct generated during the energy production process is not as radioactive and has a significantly lower lifespan, being easier to manage;
  • failing nuclear fusion reactions would completely stop the process, but wouldn't generate a nuclear meltdown, such as in the case of fission;
  • we can generate a large amount of power with a reduced cost to the environment: 60 kilograms of fuel for fusion has the potential to generate as much energy as 250.000 tons of petrol;

The drawbacks are the fact that:

  • it's a technology which continuously needs perfecting to reach commercial scale;
  • we need very specific environments and conditions to initiate the production process (huge temperatures and pressure levels);
  • the implementation costs could be very high;

Nuclear fusion as a solution for factories or companies

There are a number of companies that currently offer mini reactors based on fusion and which promise to offer factories, companies or local sites a solution to power themselves sustainably, and we wrote about some of them on Green Start-Up.

Nuclear fission and fusion play an important role in the future where we're going to power the entire planet in a sustainable way, being two technologies that can work together and which can help us satisfy our need for energy in the context of high-demand technologies, such as AI and data centers, becoming more popular.