All you must know about SMR

by Dongeun Paeng, Senior Partner

1. How nuclear power plants work

Nuclear power plants use the heat generated from nuclear fission to heat water into steam. Fission occurs when a heavy atomic nucleus, usually uranium-235 or plutonium-239, is split into smaller parts, releasing a large amount of energy in the process. Because the fission reaction is exothermic (i.e. releasing heat energy), it produces heat that is used to boil water in a reactor's cooling system.

The steam produced from the boiling water turns a turbine (i.e. a giant fan) connected to an electrical generator (i.e. a giant magnet). Therefore, the mechanical energy of the spinning turbine is converted into electrical energy through electromagnetic induction (i.e. a spinning magnet generates electricity, which is a remarkable phenomenon of the universe we live in). This electricity is then transmitted to the power grid for use in homes and businesses.

2. How nuclear fission work, exactly?

Let's talk about a nuclear fission of uranium-235 for example. But first, you need to know a little bit about atoms.

An atom consists of a nucleus and electrons. The nucleus contains protons, which are positively charged, and neutrons, which have no charge. Electrons, negatively charged, occupy electron clouds around the nucleus. Protons and neutrons are made of quarks, bound by the strong nuclear force. Electrons are elementary particles, meaning they're not made of smaller components. The number of protons defines the element; naturally, the number of electrons and protons are the same.

Now, let's get back to our uranium-235 ("U-235"). A neutron collides with a U-235 nucleus, making it unstable. The unstable nucleus then splits into smaller nuclei, typically resulting in krypton and barium. This splitting process also releases additional neutrons and a large amount of energy in the form of heat. This is because the total mass of the split particles is slightly less than that of the original U-235 nucleus. You might wonder how splitting something could reduce its mass. In this case, a small amount of mass is converted into energy, according to Einstein's equation, E=mc^2. Therefore, this energy manifests as heat, which is then used to generate steam and electricity.

3. No politics please

Nuclear power generation has significant advantages, primarily its low greenhouse gas emissions. Because it doesn't rely on fossil fuels, it is considered a clean source of energy. Additionally, nuclear energy is extremely efficient; just 1 kg of uranium-235 can produce as much energy as 3000 tonnes of coal. Therefore, it presents a sustainable option for meeting the world's growing energy demands while minimizing environmental impact.

However, the perception of danger surrounding nuclear energy cannot be ignored. While statistically, events like Three Mile Island, Chernobyl, and Fukushima have resulted in fewer deaths compared to fossil fuel-based energy production, the long-term environmental damage and potential for catastrophic failure make many wary. These incidents, although rare, have long-lasting consequences and contribute to public fear and opposition. Therefore, despite its advantages, the "fear factor" and environmental risks associated with nuclear waste and potential accidents remain significant drawbacks.

Politicians often enjoy using this "fear factor." There's an old saying that "to do politics well, use fear," which is a perfect phrase to describe the political manipulation that exaggerates fears about nuclear power.

We have to get away from politics when talking about science.

4. 1,000x safer nuclear power plants - SMR

When lithium-ion batteries are punctured, short-circuited, or exposed to high temperatures, they can undergo thermal runaway. In this exothermic reaction, the internal temperature rises rapidly, breaking down the electrolyte (a liquid that conducts electicity) and causing it to release flammable gases. These gases can ignite, leading to explosion or fire. Which means, there is a bomb in your hand.

If the likelihood of a lithium-ion battery exploding is so low that you've never witnessed it, then you may choose to overlook the risk. The same applies to nuclear power plants. While there is a risk, it is getting smaller with newer technologies.

Small Modular Reactors (SMRs) are a type of nuclear reactor that are smaller in size and capacity compared to traditional reactors. The main advantage of SMRs is their enhanced safety features, which often include passive cooling systems that function without external power. This makes them less vulnerable to the kind of catastrophic failures seen in larger reactors.

The evolution of nuclear reactors is categorized by safety and economic viability. Second-generation reactors were popularized from the 1970s to the 1990s. Third-generation reactors were developed in the 2000s, following increased public concern due to accidents like Chernobyl in Russia and Three Mile Island in the U.S. The likelihood of a major accident in third-generation reactors was reduced from 1 in 10,000 to 1 in 100,000. SMRs have reduced this probability even further by more than a thousandfold.

Specifically, in the case of SMRs, even if an accident occurs, the damage is minimal. While the emergency planning zone for large reactors extends up to 30 km in radius, for SMRs it is only 300 meters.

Conclusion

The full-fledged operation of SMRs is expected to start in 5-6 years. Da Vinci Technologies has a vision to become a software consulting firm that takes pride in contributing to humanity. We aim to contribute to the development of the SMR industry wherever possible, including in the nuclear plant decommissioning market and in CAE training and development.

I strongly recommend that you learn a little bit more about SMRs, as well as other climate-related technologies such as Green Hydrogen and CCUS (Carbon Capture, Utilisation and Storage).

The more you learn, the more fascinating it becomes. This is far from a dull subject—truly.

Until next time,

Dongeun

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