The Nuclear Fuel Cycle
On the Macro Voices podcast last week, the main topic of discussion was Nuclear. Specifically, the Nuclear Fuel Cycle was mentioned and how bullish the two guests, Mike Alkin and Adam Rodman, are on it.
I decided to break down the Nuclear Fuel Cycle, and the case for Nuclear as an energy source and investment.
The nuclear fuel cycle is the process that turns uranium (or other elements?) into electricity. One key aspect of the fuel cycle is where this uranium comes from. Uranium is found quite abundantly in the Earth’s crust. It can be found in most rocks, soils, rivers, and seawater. It is also found in small concentrations in granite (0.0004%). Granite makes up 60% of the crust. There are 15 types of uranium deposits, too much to mention here! Any uranium that is extracted is named uranium ore.
The method for mining depends on how deep the uranium source is. Both open pit and underground mining are used. ISL mining is being used more frequently to extract uranium. In situ leach mining involves using oxygenated groundwater to flush out uranium oxide (U₃O₈). The U₃O₈ uranium oxide concentrate usually contains 80%+ uranium. This is the uranium ore that is traded.
Kazakhstan produced 45% of world uranium from mines in 2021. They were followed by Namibia (12%) and Canada (10%). Kazakhstan, a former soviet state, appears to be pivoting away from Russia and toward China. Export of radioactive chemicals from Kazakhstan to China between 2019 and 2020 increased by 72.5%, from $504M to $870M (OEC). Central Asia is important in China’s Belt and Road Initiative, as they look to bring trade back to land-based systems. The US control the world’s oceans. They have incredible coverage with many aircraft carrier groups. Look at how they sailed down the Taiwan Strait after Pelosi’s visit in August. As I’ve mentioned before, Mackinder’s Heartland theory applies here, up against Mahan’s Rimland theory.
Although Kazakhstan produced the most in 2021, they don’t hold the most reserves. Australia holds 28% of the world supply, equal to 1,692,700 tonnes of uranium. Kazakhstan is second with 15% of the world supply, and Australia third with 9% supply.
After mining and milling, the uranium is prepared for the nuclear reactor in the following stages:
1) Conversion - U₃O₈ isn’t usable in a reactor. Only 0.7% of naturally occurring uranium can be used in nuclear fission to produce energy. Uranium is of the form Uranium-235 to undergoes fission. The rest is uranium-238. The different numbers of uranium refer to different isotopes. This means they have the same number of protons (same element) but have a different number of neutrons (different mass) in the nucleus of the atom. This contributes to the isotopes having different physical qualities.
2) Enrichment – Separating the different uranium isotopes. Requires uranium hexafluoride (UF₆) from the earlier obtained uranium oxide (U₃O₈).
3) Deconversion – Uranium hexafluoride can be reconverted to uranium oxide. Some waste will be stored but the uranium oxide from deconversion can be reused for conversion and enrichment again.
4) Fuel Fabrication – The uranium oxide (UO₂) used as fuel is in the form of pellets. These pellets are what are put into the fuel rods which are used in the reactor. These are known as fuel assemblies. These fuel pellets and fuel rods are constructed to ensure consistency and safety in the reactor. This avoids criticality. Criticality is a reaction that can release radiation.
The uranium is then ready to be placed in a nuclear reactor to produce electricity.
5) Power Generation – A reactor is made up of hundreds of fuel assemblies. The U-235 undergoes fission. This means splitting the atom into many parts. This produces heat, through gamma radiation. Gamma radiation is more difficult to block when compared to alpha and beta radiation. The fuel pellets are encased in the fuel rods to stop the radiation from reaching the water that cools the reactor. The reactors also have metal walls, contained within a concrete structure. All this aims to stop radiation from leaking into the environment. The heat is used to produce steam and power a turbine and electric generator, like how fossil fuel power plants work.
6) Used Fuel – The fuel is removed from the reactor after 18-36 months. Every plant and country chooses how long it burns its fuel based on when it makes sense to stop. If it's not worth the yield produced and doesn’t make sense economically. This used fuel consists of 1% Uranium-235, 0.6% Plutonium (which can undergo fission), and 95% Uranium-238.
7) Storage - The used fuel emits radiation. So it is placed in a storage pond. Water in the pond shields radiation and reduces the heat. The fuel is held in these pools for months, or even years, before being transferred to dry storage.
8) Disposal – The options from dry storage are to reprocess through plutonium oxide. This can be input back into the fuel fabrication stage as it is fissionable. The second option is permanent storage for disposal.
9) Reprocessing – The used fuel still has 96% of the original uranium. But, the amount of U-235 that can be used in fission is less than 1%. Around 3% of the used fuel is waste products and 1% is plutonium. The uranium and plutonium are separated through reprocessing. This is done by dissolving the fuel rods in acid. This means the uranium and plutonium can be recycled and used again as fuel at the conversion stage.
Plutonium is sometimes referred to as MOX fuel. This means mixed oxide fuel because it is a combination of uranium and plutonium oxides.
Uranium-238 is not fissionable. Yet, it could be in the future, in a fast neutron reactor. This could make used fuel even more useful as a resource, and a lot less wasteful. This comes even though so many of the products present after the reactor process can be recycled and reused. Finding a way to reuse waste products will make the process even more sustainable in energy production yield. It could provide us with energy for a long time. This is the power of fission.
This could mean we never need a replacement for uranium and could never run out. The supply and demand of the uranium market will depend on trade and geopolitics. With US hegemony giving way to a multipolar world, will every country have friends who can provide them with the uranium needed?
The main issue with uranium energy production is the radioactivity of the waste produced. Over time, radioactive decay limits how radioactive this nuclear waste is. Half-life is the term used to describe how long it takes for the radioactivity to half from its original levels. Uranium-238 has a half-life of four billion years. This means high-level waste is stored for about 50 years before disposal. As discussed earlier, this is through water storage and then dry storage. Disposal then occurs deep underground in most cases.
The cost of nuclear power is competitive when compared to other methods. This excludes fossil fuel-based power when cheap materials are sourced. Building a nuclear power plant is expensive, but once set up is cheap. The World Nuclear Association go into great detail comparing the costs of nuclear power against other energy production methods.
Sentiment has been damaged over and over about nuclear energy. Three Mile Island (1979), Chornobyl (1986), and Fukushima (2011) were all majorly covered nuclear disasters
You can see how uranium imports dropped after all three events. Exploring how these disasters unfolded is a thread for another day. But we learn from our mistakes. Although it isn’t enough reason to adopt nuclear, safety measures have developed, and more extreme scenarios are planned and protected against. Fukushima was caused by a flooded nuclear reactor. The plant had a wall built in the case of a tsunami, but the wall wasn’t big enough.
Similar disasters have a smaller chance of happening again. Containing the reaction, accident management, seismic activity, flooding, the presence of hydrogen causing explosions, and even terrorist attacks have all been considered. Only three major accidents in all the nuclear reactors present in the world represent a safe energy production method.
With the green transition from oil and natural gas to renewables, we need uranium. Wind and solar are weather dependent. Many electrical grids have small storage capacities for any spare energy produced through wind and solar. Many countries aren’t playing to their strengths based on their geography. For example, the UK using tidal energy, as it is surrounded completely by the ocean. It makes a lot of sense! Regardless of the environment, Uranium doesn’t rely on the weather, the supply is plentiful, and most countries will have access to it through trade. If the plants are already built then that’s great. If not, it’s a long, costly process to build them. As nuclear becomes more popular again, investment will rush in. Just like it already is. Just check the nuclear price over the last few years. The spot price was 24.63 in January 2020, and is now at 51.25. A nice 108% increase.
These are key points I noted while teaching myself about the uranium fuel cycle. I hope it can help some of you too! Credit to the World Nuclear Association website for most of the information.
I’m going to start producing a research poster detailing all the important data from my Thursday threads on a topic that interests me. These threads will provide the background. I’m hoping the posters will back up the background and provide proof. The poster will be published on Saturday.