Thorium: The Green Energy Source of Future

At the dawn of the atomic age, uranium and thorium were equally important as the element of choice for nuclear energy. Either one could have fuelled the world’s reactors. But it was uranium that won out, and thorium, which is far cleaner, safer, denser and more abundant than uranium, was relegated to the dustbin of science. With it went the possibility of creating a low risk nuclear energy source to power our planet. Now, as the world searches for cheap, non-carbon-emitting energy sources, thorium is re-emerging as an overlooked solution that could provide hundreds of years of clean, safe power.

The Thorium Advantage

More abundant: It is a naturally-occurring element with very low radioactivity. Thorium is approximately three times as abundant as uranium in the earth’s crust, reflecting that thorium has a longer half-life.

Denser fuel: In addition, thorium generally is present in higher concentrations (2-10%) by weight than uranium (0.1-1%) in their respective ores, making thorium retrieval much less expensive and less environmentally damaging per unit of energy extracted and generates more energy per ton. The pro-thorium lobby claim a single tonne of thorium in a liquid fluoride thorium reactor (LFTR), can produce one gigawatt of energy. A traditional pressurised water reactor (PWR) would need to burn 250 tonnes of uranium to produce the same amount of energy.

Nuclear safety: There is a safety side of thorium reactions. Unlike U235, thorium is not fissile and does not undergo chain reaction. To make thorium nuclei split apart, it must be bombarded with neutrons. Then, when there is a need of shutting down the reaction, simply turn off the source of neutrons and the whole process shuts down.

Manageable waste: In thorium based nuclear reaction by-products are far less radioactive, which stays radioactive for only 500 years, instead of 10,000 years in the case of uranium.

Why are we using Uranium

Researches related to nuclear reactions were initially driven not by the desire to make energy, but by the desire to make nuclear weapon. Because the plutonium needed to make fission devices come from reactors based of Uranium fuel. The $2 billion Manhattan Project that produced the atomic bomb sparked a worldwide surge in nuclear research, most of it funded by governments embroiled in the Cold War. The fact that Thorium reactors could not produce fuel (Plutonium) for nuclear weapons, we discarded the much cleaner and safer Thorium. 

Challenges for Thorium

One of the biggest challenges in developing a thorium reactor is finding a way to fabricate the fuel economically. Making thorium dioxide is expensive because its melting point is the highest of all oxides, at 3,300° C. The options for generating the neutrons needed to kick-start the reaction come down to uranium or plutonium, making it uranium or plutonium dependent.

The Bottom Line

Thorium is three times more abundant in nature than uranium. The concentration of thorium is much higher in its ore, which means it does not require enrichment. Thorium-based reactors are safer because the reaction can easily be stopped. Compared to uranium reactors, thorium reactors produce far less waste and the waste that is generated is much less radioactive and much shorter-lived.

To top it all off, thorium would also be the ideal solution for allowing countries like Iran or North Korea to have nuclear power without worrying whether their nuclear programs are a cover for developing weapons.