Hello!

Thesis: Many people associate Uranium with nuclear weapons, and rightly so. If we could switch nuclear energy models to be Thorium-based, that might remove some of the inherent bias as well as potentially provide a better fuel source. But Thorium has its challenges too.

Uranium = Bad.

Thorium = Less Bad?

If you haven’t read my Nuclear Energy Primer, I’d highly recommend it before reading this article as some of the terminology associated with nuclear energy is difficult to understand without a decent background in the field.

Thorium 101:

What is Thorium? And for that matter, what really is Uranium?

Uranium is currently the most common fuel that is used in nuclear reactors. Uranium occurs naturally as Uranium 238 (99.2% of all Uranium) and Uranium 235 (0.7% of all Uranium). Uranium 238 is not really used in anything nuclear (although it can be made into Uranium 235). Uranium 235, however, is the fuel used to power nuclear reactors (and nuclear weapons).

It naturally releases neutrons which hit other Uranium atoms and cause them to release neutrons leading to a chain reaction releasing vast amounts of energy.

Credit Research Gate Hiroshi Sekimoto

Thorium is a rarely used nuclear fuel that occurs solidly under normal conditions. It is traditionally found in trace levels in soil, rocks, and water. Thorium is estimated to be 3x more abundant than Uranium in Earth’s crust. It exists naturally as Thorium 232 (which is the form needed for nuclear reactions). Thorium is not actually a “fuel” because it is not fissile (it doesn’t naturally release electrons like Uranium 235) and therefore cannot be used (in its natural form) to start or sustain a nuclear chain reaction.

Here is a relatively helpful diagram from NASA about the reaction process:

To reiterate, thorium itself cannot react and needs to be exposed to a neutron source to become Uranium 233 which can fuel nuclear reactors.

The only power sources of neutrons enough to break down Thorium 232 into Uranium 233 are Uranium 233, Uranium 235, and Plutonium 238.

Ironically, even for a reactor that would use Thorium, most energy produced would actually come from Uranium or Plutonium.

So why even use Thorium at all if it needs a power source?

Great question. And one that I’ll hopefully answer in a variety of ways. Let’s start with sourcing.

If you wanted to build a Thorium-powered reactor, where would you get the Thorium?

There are around 12 million tons of Thorium in the world, primarily in India, Brazil, Australia, and the United States. It’s not that easy though, as Thorium does not exist simply by itself.

The most common source of Thorium is the rare earth mineral monazite, which contains around 6% of Thorium on average. Thorium is typically mined as a byproduct of rare earth elements or of titanium mining activities which has been enough to meet the limited Thorium demand currently.

In addition, there isn’t a standardized market for Thorium, so the procurement and refining of potential Thorium as a byproduct is primitive at best.

Strike 1 to Thorium: The known reserves of economically extractable Thorium are similar to those of Uranium.

Strike 2 to Thorium: Large-scale mining isn’t as economical under current circumstances as it is with Uranium (basically if Thorium reactors were to be mass-produced, Thorium material couldn’t keep up with demand).

Okay, so it might be hard to get your hands on a lot of Thorium, but how much do reactors need?

A 100-megawatt reactor would require around 1000 - 2000 lbs of Thorium every year, so potentially possible in the future. Considering that current production is around 5,000 tons a year, you’re probably safe. This reactor could power around 60,000 homes (or around 150,000 people).

If reactors can provide power for so many people and the necessary Thorium exists today, why aren’t we building Thorium reactors?

Well, it depends on who you consider “we”. Many companies have historically experimented with the concept of a Thorium Reactor.

In addition to this, many countries are currently experimenting with Thorium-powered nuclear reactors. I’ll detail the main ones below:

• China:
  • China is developing a prototype 2MW Molten Salt Reactor (a type of Thorium reactor) in the Gobi Desert with help from the Shanghai Institute of Applied Physics. It was completed in 2021 and has since received a license to operate. They are also looking into a 100MW High-Temperature Gas Reactor (a different type of reactor design)
• China & Canada Joint Venture:
  • Thorium-based fuels have been designed and tested in Canada for more than 50 years. In 2017, China finalized an agreement with Canada to continue to develop improved PWR reactors using Thorium and Uranium as fuel. In 2019 two reactors were under construction in the Gobi Desert (completion 2025). China expects to put them into commercial use by 2030.
• India:
  • As part of India’s 3-phase nuclear energy infrastructure plan, India has developed a 300MW Advanced Heavy Water Reactor (another type of reactor) that uses Thorium fuel. Approximately 75% of the power comes from Thorium. This reactor started construction in 2017 with an expected conclusion around 2027.
  • India has been operating a 30kW U-233 fueled reactor named Kamini since 1996. It is the only U-233-fueled reactor in the world but does not directly support itself through Thorium. (For importance U-233 is what Thorium becomes).
  • The Indian government is developing up to 62 reactors (mostly Thorium-based) which they expect to be operational by 2025. The size of these reactors is unknown.
• Canada:
  • In 2013 Canada started developing Thorium power projects in Chile (10MW) and Indonesia.
• United States:
  • The United States has not made any effort to use Thorium. With the newly passed Infrastructure Bill, the United States has funded a new advanced reactor built by TerraPower. Their Natrium reactor will be a 345MW Molten Salt Reactor fueled by Uranium but if successful will provide helpful data for future Thorium projects. Completion is hoped for by 2028.

Point in Favor of Thorium #1: Many countries are interested in and/or are currently pursuing Thorium as a power source.

Yet, even though countries are pursuing Thorium as a potential energy source, a working reactor does not currently exist that runs entirely on Thorium, so any tests currently being done may be substandard.

In addition, members from the UK National Nuclear Laboratory stated in 2012:

• “It is conceivable that Thorium could be introduced in current generation reactors within about 15 years, if there was a clear economic benefit to utilities. This would be a once- through fuel cycle that would partly realize the strategic benefits of Thorium.”
• “To obtain the full strategic benefit of the Thorium fuel cycle would require recycling, for which the technological development timescale is longer, probably 25 to 30 years.”
• “To develop radical new reactor designs, specifically designed around Thorium, would take at least 30 years. It will therefore be some time before the Thorium fuel cycle can realistically be expected to make a significant contribution to emissions reductions targets.”

Strike #3 for Thorium: As opposed to Uranium technology which is currently being used, Thorium reactor technology is still in the initial phases of development and deployment.

So if Thorium technology won’t be potentially viable until after 2030 and even potentially after 2050, why do I care to educate you about it right here, right now?

Thorium has many potential benefits over Uranium from the initial research that has been completed.

Point in Favor of Thorium #2: Thorium is estimated to produce up to 200x more energy than current Uranium production capabilities.

To explain the science a little here in plain terms, when a reaction happens, neutrons are released to go hit other atoms and make them react to release more neutrons. This becomes a chain reaction. In a normal Uranium reactor, these neutrons are fired out of the atoms at very high speeds, leading to less chance of hitting another atom. With a Thorium reactor, these neutrons are naturally slower, which leads to more reactions.

In addition, the number of neutrons produced per reaction is higher when using Thorium in comparison to Uranium 235. This means that more reactions are happening which produce more power.

Wild Stat: It has been projected that 1 ton of Thorium can produce as much energy as 200 tons of Uranium or 3.5 million tons of coal.

Credit Worker Education & Training Program

Point in Favor of Thorium #3: Thorium can also be used in a wide variety of other applications.

• Thorium can be added to tungsten electrodes to increase the brightness of the electric arc used in helium-arc welding.
• Thorium is an important alloying agent in magnesium as it provides greater strength and resistance at high temperatures.
• Thorium oxide is used as an industrial catalyst.
• Thorium dioxide is added to glass during manufacture to increase the refractive index, producing thoriated glass for use in high-quality camera lenses.
• Thorium oxide has a very high melting point (3300°C) and has many industrial uses.
• Thorium when alloyed with tungsten is used in filaments for high-powered magnetrons for radar technology.
• Thorium metal has been used as electrode material in gas discharge lamps.
• Thorium is highly refractory and can be used for high-temperature furnace linings.

Let’s tally the points so far.

Strikes: 3

Favor: 3

Is this it? Did we just find another technology with some drawbacks and benefits?

Yes and no. When you consider some more factors, I think the answer speaks for itself.

Strike #4 for Thorium: Thorium byproducts are just as dangerous as those from Uranium.

Thorium byproducts, specifically Uranium 232 and Thorium 228 are extremely radioactive and are harmful even in tiny quantities. In addition, Thorium reactions also create byproducts that last for hundreds of thousands of years just like Uranium reactions. However, 83% of Thorium byproducts aren’t toxic, meaning that many can be repurposed into other ventures.

Point in Favor of Thorium #4: Thorium is ready for nuclear application in its natural state (99% of existing Thorium), yet Uranium is only ready in its 235 form (0.7% of existing Uranium) so it mainly needs to be refined from 238.

Point in Favor of Thorium #5: Thorium is arguably slightly safer than Uranium based on chemical makeup.

Unlike Uranium, Thorium is not fissile (doesn’t produce neutrons on its own). That means no matter how much Thorium you have, they will not explode by themselves. If you want to make the Thorium react, you have to provide an external source to start shooting neutrons at them. Then, when you need the reaction to stop, simply remove the external source and the whole process shuts down.

Credit Reuters

Strike #5 for Thorium: Thorium byproducts can be used to create nuclear weapons.

One big concern with nuclear power is the ability to weaponize the components. A common myth is that Thorium process cycles do not make elements that can be used in weapons. This is not true.

Thorium (Th - 232) cannot be used in nuclear weapons, but its byproducts can be. Among other things, when going through the fuel process, Thorium becomes Uranium 233 and creates Neptunium 237.

Uranium 233 has been tested in nuclear weapons by the USA during the Cold War. It is possible to use Uranium 233 in a nuclear weapon, and in 1955 the USA detonated a device based on U-233 in Operation Teapot. In 1998, India detonated a very small device based on U-233 called Shakti V. The International Atomic Energy Agency considers 8 kilograms of Uranium 233 to be enough to construct a nuclear weapon.

Thus only 1.6 tons of Thorium would be required to produce 8 kilograms of U-233 and could feasibly be obtained in less than a year.

Ideally, Uranium 233 will stay within the core and never leave, so obtaining or stealing it for weapons purposes could potentially be very difficult.

Also, the Neptunium 237 created by the reaction can be refined down to become Plutonium 238, an element still used in nuclear bombs today. The Plutonium output isn’t reused within the reaction, so it will be a risk from using the Thorium process.

In addition, to start the reaction process at the very beginning, Thorium needs to be activated by neutrons fired by Uranium 233, Uranium 235, or Plutonium 238. This means that potential bomb material is needed to start the reaction and will be present on-site while the reactions are beginning to become self-sustainable.

Made up your mind yet?

I don’t claim to be a nuclear scientist or expert, but from the data, I don’t really see any true benefits from using Thorium technology, so why are the actual experts putting time and effort into Thorium?

Well, that statement is misleading. They aren’t putting super substantial time into Thorium, they are putting time into developing a new reactor that could sustain a Thorium reaction.

This new generation of nuclear reactor designs, dubbed “Gen IV” are vastly safer than the current reactors today. These proposed reactors cannot “melt down” which was the cause of some major nuclear disasters throughout history.

And from a public perspective that’s incredibly important when it comes to nuclear energy and its future.

Anywho, that’s all for today.

-Drew Jackson