Nuclear power
Nuclear power

Nuclear power

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TL;DR

While nuclear power is often surrounded by controversy, we are unlikely to decarbonize electricity production without it. New advancements in nuclear are promising cheaper costs, safer operation, and less waste to deal with. Challenges still lie in proving some of the technology beyond theory, improving the public perception of nuclear, and financing the nuclear ecosystem.

The Basics

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Fission vs Fusion Overview
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Radioactive material (fuel)
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Traditional reactors

Next-generation fission reactors

The next generation of nuclear reactors is aiming to be more cost-effective, reliable and safer to operate than older generations.

  • Molten salt reactors (MSR): Can be built anywhere and are considered safer, but are more expensive to build. Allows operation at higher temperatures (more efficient) and lower pressure (less risk of explosion).
    • Concerns:
      • Salt can be corrosive to the structure of the reactor at high temperatures and under radiation
      • Reprocessed waste as fuel: A more expensive fuel source than fresh uranium and requires the construction of additional (expensive) facilities for reprocessing and management. It also introduces new forms of waste that we don’t really know how to deal with yet.
      • Liquid sodium: It is opaque—making safety inspections more difficult; sodium reacts violently with water; if the temperature gets too high it can create a positive feedback loop leading to rapid increases in temperature and pressure
  • Small modular reactors (SMR): Produce 50-300 MW (versus the 600 MW - 1.5 gigawatts of average reactors). Constructed in a factory and installed on-site, rather than needing to build on location. Smaller in size, and lower cost to build.
  • Microreactors (MMR): 1-50 MW; Meant for industrial applications and replacing expensive and unreliable diesel generators in remote communities. Microreactors are designed for easy setup and operation, can go years without needing to be refueled, and do not require active cooling systems.
    • There is one 5 MW test unit under construction in Canada (Chalk Rivers), scheduled to be finished by 2026. It is designed to operate for 20 years and then the core can either be replaced, or the plant can be shut down.

Why don’t we have fusion yet?

No one has been able to produce a fusion reactor that generates more power than it consumes.

The fusion reaction happens when two atoms are combined. In the sun, this happens when two hydrogen atoms (one proton each) combine to form helium (two protons). The problem is that protons repel each other because they have identical charges, so very high temperatures are needed to force them together.

We don’t have a reliable fuel source.

Hydrogen always has one proton, but for fusion reactions, we need the hydrogen isotopes with extra neutrons—Deuterium w/ one neutron and Tritium w/ two neutrons. The problem here is that Tritium is radioactive and very rare (it represents only trace amounts of naturally occurring hydrogen). Helium-3 is a possible substitute for Tritium. It is also incredibly rare, but we can artificially produce tritium by irradiating Lithium.

Arguments against nuclear power

A small snapshot of some of the arguments against nuclear power and counterpoints to those arguments.

  1. It’s dangerous, just look at Chernobyl (1986), Three Mile Island (1979), and Fukushima (2011).

    2. Besides these disasters, mining uranium releases carcinogenic radon gas and is heavily polluting soils, air, and groundwater.

    Counterargument: Air pollution from fossil fuels has claimed millions of lives, making nuclear a much safer alternative. The problem is that when nuclear fails, it fails spectacularly and so people tend to remember that very clearly. However, every major nuclear disaster has been related to cooling failures in water-based thermal reactors, and many of the next-generation reactors are moving away from these systems.

    Source:
    Source: Our World in Data, 2020
  2. It’s too difficult to manage and store the waste.

      3. None of the countries that use nuclear energy have successfully constructed a usable geologic repository for spent fuel material.

      Counterargument: One of the alternatives to storing spent nuclear fuel is repurposing it into new fuel sources. It’s also possible to produce less waste in the first place with improved fuel efficiency or using Thorium as an alternative source. Thorium hasn’t been a cost-effective alternative for nuclear power generation before now, but new reactors that can operate at higher temperatures like the Molten Salt Reactors are better suited for this purpose than past designs.

    1. It is important to note that you can’t just use spent nuclear material as fuel. The material must be reprocessed by first separating it into its individual elements. Once the fissile uranium has been extracted, it needs to be remixed into usable proportions. This process is currently very expensive, emits radioactive gas, and introduces new forms of waste that must be dealt with.
  3. Nuclear power plants are too expensive to build and maintain.

    4. There is a large risk associated with building nuclear versus other types of power plants. To build a new nuclear power plant costs $8-10 billion and takes around a decade. There will be many years of loss before any profit is seen and then it takes even more time to break even on the project (around 16 years after construction begins).

    Counterargument: Yes, there is a significant investment required upfront, but a single uranium fuel pellet can release the same amount of energy as one ton of coal or 1/2 ton of natural gas. To produce 1000 MW (over one year), a nuclear reactor needs about $64 million worth of fuel, while it would take $450 million of natural gas to produce the same amount.

  4. It can be used to create nuclear weapons.

    5. Nuclear reactor fuel and an atomic bomb contain similar ingredients. Plutonium, which is a by-product of the Uranium fuel cycle, is the key ingredient to creating nuclear weapons.

    Counterargument: Nuclear weapons are almost pure fissile material, while fresh reactor fuel is around 5%. The spent fuel from a nuclear reactor isn’t even acceptable for powering a new reactor, so it is simply not possible for it to power a weapon. As Mike Short (Associate Professor of Nuclear Science and Engineering at MIT) puts it: “A nuclear reactor and a nuclear weapon are about as similar as a hamster and an alligator. They are both made of cells, but one is clearly more dangerous than the other.”

Geopolitics

There are 439 nuclear reactors in operation around the world, 365 of which are light water-cooled. Another 52 are under construction, 46 of these are light water-cooled. The highest capacity is currently in North America and Western Europe, but that capacity will soon be surpassed by Asia.

Source: IAEA PRIS (
Source: IAEA PRIS (Accessed Jan 2022)
  • United States: The US has more operational nuclear power plants than any other country (93) and about 20% of energy in the US comes from nuclear, but 40 reactors have been permanently shut down.
    • The US Department of Defense is investing in the development of microreactors as portable power sources.
    • Until 2020, all spent nuclear material in the US had to be disposed of. The first permit to test fuel from spent uranium was granted in Feb 2020 to Okla.
  • China: 14 of the 52 reactors under construction are located in China.
  • France: 70% of electricity in France is produced by nuclear energy and the country currently has 56 active reactors. In Oct 2021, the government announced its plans to invest €1 billion in small modular reactors, with the first demonstration plant to be built by 2030.
    • Legislation passed after Fukushima says France will need to shut down many of its reactors and reduce its power generation from nuclear to 50%.
    • The European Pressurised Water Reactor (EPR) in Flamanville, France, is 10 years behind schedule and around €9 billion over budget.
  • Germany: Closed half of its nuclear power plants between 2011 and 2021 and now only 3 of its 36 reactors are still in operation, but those are scheduled to close by the end of 2022. Initially started in response to the Fukushima disaster, but now keeping the plants open would require “hundreds of millions of euros of investment.”
  • European Union: The European Commission announced plans in Jan 2022 to label nuclear energy as green under its classification scheme for green investments. The plan has been met with significant opposition, especially from Germany, due to concerns over waste management and radiation risks.

Resources

A special thank you to Leslie Dewan, CEO and Co-Founder of RadiantNano, for providing invaluable insights into the world of advanced nuclear.

Last updated: Aug 2022