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.

https://en.wikipedia.org/wiki/Calutron

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jabl 3 hours ago | parent | next [-]

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?

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Legend2440 3 hours ago | parent | next [-]

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.

	▲	ta988 2 hours ago \| parent [-]
		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.

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p1mrx 2 hours ago | parent | prev | next [-]

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.

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KennyBlanken 2 hours ago | parent [-]

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/

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tmp10423288442 an hour ago | parent | next [-]

But you weren't going to ask the LLM, and now you know something you weren't aware of. Seems no different than someone reporting what they found out in a Google Search, as long as they disclose that they used an LLM (as long as they used one that actually searches the web, but pretty sure even ChatGPT Free does that these days).

	▲	ben_w an hour ago \| parent [-]
		> but pretty sure even ChatGPT Free does that these days). It can do, but won't do so reliably; and the guessing it does if it's not grounding with a search is still like someone in a pub saying "I recon…". Admittedly, a Cambridge pub like the Carlton Arms used to be when I lived there (sometimes I'd be the only one at the table who wasn't studying for a PhD), but still, pub.

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woah 5 minutes ago | parent | prev | next [-]

Are you a meat proxy for that blog post?

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p1mrx 30 minutes ago | parent | prev [-]

Even if you ignore my LLM numbers, "what percent of a reactor's output must be reinvested to enrich its own fuel?" is a meaningful contribution to the discussion.

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piyh 3 hours ago | parent | prev | next [-]

>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...

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scythe 2 hours ago | parent | prev [-]

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.

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bpodgursky 3 hours ago | parent | prev | next [-]

That's fine

	▲	fodkodrasz 2 hours ago \| parent [-]
		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.

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shevy-java 3 hours ago | parent | prev [-]

But mass spectrometers don't use uranium.

	▲	ta988 3 hours ago \| parent \| next [-]
		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).
	▲	numpad0 2 hours ago \| parent \| prev \| next [-]
		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
	▲	colechristensen 2 hours ago \| parent \| prev [-]
		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