Comment by fodkodrasz
9 hours ago
So this is basically a calutron... a huge mass spectrometer. 1940s technology, upgraded with state-of-the-now control systems, and electromagnets. A formidable engineering work, but more of a breakthrough from legislation and compliance perspective possibly.
IIRC Calutron's were basically abandoned because they were massively inefficient compared to gaseous diffusion and, particularly, centrifuges.
What has changed here to make them competitive again? Or are they counting on selling small quantities at close to any cost for R&D reactors?
Speaking of which, whatever happened to laser enrichment? That was apparently very promising at some point?
> What has changed here to make them competitive again?
The article has to be read carefully. "On Actinide's engineering estimates, a single Fortitude machine would provide roughly half the isotope-separation capacity of the U.S. government's current electromagnetic fleet."
The "U.S. government's current electromagnetic fleet" is tiny. Oak Ridge is building a modest plant.[1] Idaho has a benchtop-sized separator. That's what Actinide is comparing against. Not the rows of basketball court sized calutrons from WWII. So the announcement gives the impression of a larger operation than it really is.
> Speaking of which, whatever happened to laser enrichment? That was apparently very promising at some point?
That is a very good question. A company called Silex, and their subsidiary Global Laser Enrichment, has been trying to commercialize this for years.[3][4] Exactly how they do this is classified.[5]
There's another startup in this area, crawling along, underfunded, but building something.[6]
Meanwhile, URENCO continues to operate a centrifuge plant in New Mexico.[7] URENCO is a a European company, and seems to be the leader in centifuge technology. Units in France, Germany, the Netherlands, and the US.
I've been expecting something big to happen in the laser enrichment area since the 1990s, but it never has. This suggest that it either doesn't work very well or is being suppressed because it works too well.
[1] https://www.energy.gov/science/articles/doe-expands-stable-i...
[2] https://inldigitallibrary.inl.gov/content/uploads/50/2026/04...
[3] https://www.silex.com.au/
[4] https://www.gle-us.com/
[5] https://www.nrc.gov/docs/ML2304/ML23045A117.pdf
[6] https://laseristech.com/
[7] https://urencousa.com/
A friend of mine was involved with AVLIS and Pu-AVLIS. There were/are significant counterproliferation concerns with them. I'm not sure if that has anything to do with the lack of major commercialization, but I wouldn't find it shocking if it were true. As I understand it, it's one of those technologies that the US doesn't strictly need, but we really don't want the Iranians (or similar weapons-pursuing state) to have it.
They talk about that in the article:
>"A centrifuge plant does one thing, costs billions, and takes years to stand up. Our machines cost a few hundred thousand dollars, produce material within months, deploy anywhere, and are able to be reconfigured in a matter of days to separate various isotopes as they are needed," said Robert Mendelsohn, co-founder and CTO of Actinide.
The obvious thing to consider is throughput and yield/loss. A centrifuge plant can produce kilograms of material and doesn’t fundamentally misplace any material, although it may struggle to extract all the inputs that are the correct isotope. A calutron needs to ionize every single atom, accelerate it to an appropriate energy, deflect it, and decelerate it without losing it. And it needs to deal with inadvertently multiply-charged ions. And if you’re dealing with radioactive source material, you need to deal with the atoms that embed themselves in your apparatus.
At least uranium isn’t actually all that radioactive.
This is a bit uncharitable to the concept of a centrifuge here. The Iranian nuclear program seems to have centrifuges that are a lot smaller and cheaper, and you can certainly build one that meets these needs.
yeah they don't talk about cleaning them either... that's a massive problem in this kind of ion separation techniques, things splatter and stick everywhere.
> What has changed here to make them competitive again?
Nothing. This is a company that specializes in making medical isotopes, which is something Calutrons are good for - you need high levels of enrichment in a single step, you don't need to process large quantities, and the energy consumption doesn't matter. Any talk of using it for reactor fuel production is pure PR spin.
Take these numbers with a grain of salt because I got them by chatting with AIs, but if you're producing electricity from HALEU, then centrifuges require reinvesting <1% of the output, whereas historical calutrons required 200% (useless) and modern technology could potentially bring that down to 10%.
So calutrons will always be less energy efficient than centrifuges, but if the capital cost and construction time is low enough, calutrons might still be economically viable.
If we wanted to find out what an LLM thought we'd ask the LLM. Don't be a meat proxy.
https://gruhn.me/blog/2026-08-03/
7 replies →
>Under the Atomic Energy Act, all information not specifically declassified is classified as Restricted Data, whether it is privately or publicly held
https://en.wikipedia.org/wiki/Separation_of_isotopes_by_lase...
Well, for one thing, the only existing Yb-176 production facilities are in Russia. That means demand for a domestic supply is pretty high right now.
The other thing is that for a nuclear reactor, you need many kilograms of uranium. But for a Pluvicto patient, you need less than a gram of ytterbium.
>1940s technology
yes, i'd have expected that laser enrichment would be more preferable technology for modern development
That's fine
Totally agree, just summarized what I found in the press release. Even boring engineering is honest work, and this is not boring, even if not cutting edge in my understanding. Nuclear operations have their special challenges which need special care, also from engineering side. Still I think this is less of an engineering news.
Anyways, I didn't mean to downplay it.
But mass spectrometers don't use uranium.
they can absolutely see uranium. It ionizes and thus get separated like many other things https://pmc.ncbi.nlm.nih.gov/articles/PMC7470433/
Calutrons are using the same principle of separating ions by their mass/charge ratio, just in a preparative scale (you want to collect what is separated) rather than analytical (you just want to know how much of what).
sounds like this is similar to doing basic paper chromatography and cutting out the strip with scissors just to get the desired substance, spectrometry as means to produce the material rather than means to analyze
Mass spec is about separating things by mass... exactly what enrichment requires.
A mass spec used as an instrument measures the components of a substance, this is just the same concept for actual separation of components not just to look at them