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The First Thorium Salt Reactors in Over 40 Years Were Just Switched on in Europe

This could mean safer, cleaner nuclear energy.

25 AUG 2017

A Dutch energy company has just embarked on a series of experiments testing the use of molten thorium salts in producing power from nuclear fission, the first of their kind since the early 1970s.

It's still early days, but the use to thorium as an alternative to uranium could provide a cleaner, safer fuel source that would be harder to weaponise. With nuclear energy a booming industry in countries such as China and fear of nuclear threats on the rise, returning to this controversial topic could be well worthwhile.


Netherlands-based nuclear power provider, NRG, are taking a gamble. They're conducting experiments that could see a shift from uranium-based nuclear power to thorium.

In the historical battle between using uranium or thorium as a nuclear fuel, uranium provided both sides of the Cold War with a potential source of weapons-grade plutonium.

But the world is changing, and with global warming, anxiety over nuclear accidents, and the promise of more countries going nuclear, thorium is back on the table as a viable energy resource.

"This is a technology with much perspective for large scale energy production. We want to have a head-start once the technology will break through," says NRG researcher Sander de Groot.

Thorium is an element high up on the periodic table. Similar to uranium, its various isotopes are unstable, meaning the atoms decay by spitting out alpha particles – helium atoms without the electrons.

One key difference is uranium can undergo a chain reaction when squeezed into a small space. Thorium doesn't – its isotope Th-232 requires another source of neutrons to bombard its nucleus, at which point it transmutes into an isotope of uranium called U-233.


A significant advantage of using thorium over uranium is it doesn't produce the same kinds of heavy isotopes, meaning its waste is considerably less toxic over long time scales.

Its fuel can also be reprocessed without needing to throw in additional mined resources.

Unlike reactors that start with uranium, the products of thorium power production can't be turned into weapon's grade plutonium with anywhere near the same efficiency.

Lastly, technologies that employ thorium for nuclear fission power can also be made relatively meltdown proof.

With all of these pros, it seems like switching from uranium would be a certain bet.

Unfortunately, research on thorium technology has lagged significantly since the 1970s. It's harder to prepare than uranium, and while potentially safer on some fronts, isn't completely risk free.


Shifting gears so late in the game for nuclear-energy dependent nations such as the US and Russia isn't seen as an economically viable option. But for nations like China, a growing nuclear power industry could see thorium as a sweeter deal. 

With its abundance of the resource, India is another country already marching ahead in developing reactors that make use of thorium rods.

With decades of research on ice, companies like NRG are now looking to make up for lost time.

"There was both internal and external support for our idea to start the SALIENT experiments", says Sander.

SALIENT stands for SALt Irradiation ExperimeNT. The goal is to study energy production from thorium salts suspended in a molten mixture and develop efficient processes.


Molten salt reactors use fluoride salts under low pressures as a coolant for the nuclear reaction. Dissolving the thorium salts into this molten liquid and irradiating it with neutrons to kick off the transmutation is one way to extract energy from the process.

In the first of their experiments, the team has been investigating how nickel removes fissile products from the molten mixture in an effort to find ways to 'clean' the salts.

Future experiments will be conducted to explore other salt mixtures, and the effects the highly corrosive salts have on surrounding components.

Nuclear power in all of its forms remain highly controversial in today's world.

For some, the risks of meltdowns and production of long-term waste make it an unappetising, dangerous option. Any money spent on nuclear research would be better spent on renewables or fusion technology.

To others, the risks are overblown, especially as our current dependence on fossil fuels for cheap energy continues to threaten our health and global ecology. 

But if there's a sure bet that can be made, it's that we're only just seeing the start of thorium's return. 


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