this post was submitted on 18 Apr 2025
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https://archive.is/2nQSh

It marks the first long-term, stable operation of the technology, putting China at the forefront of a global race to harness thorium – considered a safer and more abundant alternative to uranium – for nuclear power.

The experimental reactor, located in the Gobi Desert in China’s west, uses molten salt as the fuel carrier and coolant, and thorium – a radioactive element abundant in the Earth’s crust – as the fuel source. The reactor is reportedly designed to sustainably generate 2 megawatts of thermal power.

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[–] SirEDCaLot@lemmy.today 244 points 1 day ago (18 children)

For anyone not familiar with thorium...

Thorium is a great nuclear fuel. Much much safer than the uranium we currently use, because the reaction works best only within a narrow temperature band. Unlike uranium which can run away, a thorium reactor would become less efficient as it overheats possibly preventing a huge problem. That means the fuel must be melted into liquid to achieve the right temperature. That also provides a safety mechanism, you simply put a melt plug in the bottom of the reactor so if the reactor overheats the plug melts and all the fuel pours out into some safe containment system. This makes a Chernobyl / Fukushima style meltdown essentially impossible.

There are other benefits to this. The molten fuel can contain other elements as well, meaning a thorium reactor can actually consume nuclear waste from a uranium reactor as part of its fuel mix. The resulting waste from a thorium reactor is radioactive for dozens or hundreds of years not tens of thousands of years so you don't need a giant Yucca Mountain style disposal site.
And thorium is easy to find. Currently it is an undesirable waste product of mining other things, we have enough of it in waste piles to run our whole civilization for like 100 years. And there's plenty more to dig up.

There are challenges though. The molten uranium is usually contained in a molten salt solution, which is corrosive. This creates issues for pipes, pumps, valves, etc. The fuel also needs frequent reprocessing, meaning a truly viable thorium plant would most likely have a fuel processing facility as part of the plant.

The problems however are not unsolvable, Even with current technology. We actually had some research reactors running on thorium in the mid-1900s but uranium got the official endorsement, perhaps because you can't use a thorium reactor to build bombs. So we basically abandoned the technology.

China has been heavily investing in thorium for a while. This appears to be one of the results of that investment. Now this is a tiny baby reactor, basically a lab toy, a proof of concept. Don't expect this to power anybody's house. The point is though, it works. You have a 2 megawatt working reactor today, next you build a 20 megawatt demonstrator, then you start building out 200 megawatt units to attach to the power grid.

Obviously I have no crystal ball. But if this technology works, this is the start of something very big. I am sure China will continue developing this tech full throttle. If they make it work at scale, China becomes the first country in the world that essentially has unlimited energy. And then the rest of the world is buying their thorium reactors from China.

[–] fullsquare@awful.systems 14 points 21 hours ago* (last edited 21 hours ago)

You absolutely can make a nuke out of thorium-derived material (first in Teapot MET, 1955, then possibly later by India). It's not widely used because plutonium is similar and in some important ways superior material

The tradeoff in using salt as fuel/coolant is that now almost all the fission products are in soluble form, instead of nice ceramic chemically inert pellets, which makes any spill much worse, and i wouldn't say it's safer for this reason - it's different, and it's a tradeoff few thought it is worth making. We have figured out how to make PWRs not explode so it's not that big of a problem. This goes both for uranium or thorium as a fuel

The reason Yucca Mountain is needed is that nuclear waste exists, if US reversed their policy on reprocessing maybe it wouldn't fill up so quickly. It's a matter of political will

At least now, the chemical engineering for reprocessing fuel when reactor is on is not there. Maybe it'll get developed in this project, but this didn't happen yet. It all has to be weighed against existing alternatives, and it's possible to breed 233U in normal water-based reactors, so maybe there's a little reason to make MSRs in the first place. India has some thorium energy projects as well, but they're slowed down by lack of fissile material to bootstrap it (you can't fuel reactor using thorium only, it needs some fissile material)

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