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

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.

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?

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.

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.

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.

> 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/

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).

> 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.

One of the more annoying pre-llm behaviours was responding with the first link of google when a question was asked (but not of them specifically).

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.

But are your numbers reliable? By your own admission you don't know. So you aren't contributing expertise but rather the brief use of a tool that everyone has ready access to and which doesn't necessarily return reliable answers. AKA noise, at least from the perspective of a community like HN.

Relax dude.

This site is intended to be a discussion between people. If we wanted to consult some other resource, we would go do that. Injecting unverified information is not a contribution to a discussion between people, especially if it isn't coming from a human source.

No _book_ knowledge please! Hard to know if an author actually knew their subject and was making up numbers.

I ONLY want to hear first person _human_ experiences.

Jfc mate

Are you a meat proxy for that blog post?

>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.

> 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.

It's a U.S. national security policy to prevent countries which don't already have capabilities to enrich uranium or reprocess spend nuclear fuel from aquiring such capabilities.

Technologies which have low energy consumption and need only small space and therefor are easier to hide, such Laser isotope separation, US wants to restrict to any country, even allies.

Re: laser enrichment -- there's a company called Hexium that's commercializing AVLIS (https://www.hexium.com/). My fund's an investor, and my partner wrote a post about them and laser separation last year: https://blog.humbaventures.com/p/the-elements-of-industry

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

"A calutron is a mass spectrometer originally designed and used for separating the isotopes of uranium. It was developed by Ernest Lawrence during the Manhattan Project and was based on his earlier invention, the cyclotron."

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

>1940s technology

yes, i'd have expected that laser enrichment would be more preferable technology for modern development

So will we start bombing Dallas now?

Might make it more walkable.

hah probably help cool things off too.

Hegseth is on it

No. Economic sanctions are in right now. Maybe tomorrow.

If they do I hope they leave Deep Elum alone. Some nice venues there for local, regional, and much more well-known bands. Also a few good restaurants in the area.

A few hundred thousand dollars worth of tech replacing what used to be a massive industrial investment is amazing. And I thought enriching uranium is something that counties with nukes go to extreme lengths to make it not accessible.

>And I thought enriching uranium is something that counties with nukes go to extreme lengths to make it not accessible.

low-enrichment (~20%) is what's happening here.

the bad stuff, for nukes, is ~90% enrichment.

It's the same process either way, and the first few percent are the hardest (as it's super dilute so you need to handle a lot of material). It's much easier to go from 20% to 90%, than it is to get to 20%.

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

5% enrichment (regular reactor grade) is 2/3 the way to weapons grade already.

https://world-nuclear.org/information-library/nuclear-fuel-c...

Hence there technically being no enrichment cap for any country that signed the NPT and stuff (not to be confused with protection from US bombs or rogue states that never signed the NPT).

The 90% level is not a strict number. You can have nuclear explosion with lower levels of enrichment, but the total mass of the uranium is very large, therefor not a practical weapon.

For example you need 100kg of 60% enriched Uranium-235

https://www.researchgate.net/figure/Critical-mass-of-a-bare-...

>And I thought enriching uranium is something that counties with nukes go to extreme lengths to make it not accessible.

It's not that difficult from an engineering perspective, the tech is almost a century old. It's just that we will drop bombs on anyone who tries.

Nuclear nonproliferation relies on active enforcement.

> It's just that we will drop bombs on anyone who tries.

I don't recall us bombing Pakistan, India, Israel, China, or North Korea.

> Nuclear nonproliferation relies on active enforcement.

The comedy hour at HN has arrived. See above ^^^

>I don't recall us bombing...China

As far as i know, USA was seriously considering doing this in 1964. However the soviets said that would mean war, so they didn't.

North Korea is so firmly in China and Russia's sphere of influence that bombing them would be hard, especially given how much conventional weapons they have pointed at south korea. That said, would you really want to be north korea? economic warfare has done a number on them. in many ways they are the poster child for nuke != winning.

Israel probably snuck through by doing it early enough and secretively enough that it was fait accompli. They probably tested their nukes before the nuclear non proliferation treaty was even signed.

so really you have india and pakistan. The fact there are so few exceptions kind of proves the system works.

> Nuclear nonproliferation relies on active enforcement.

It relies on getting nukes being an irrational move for most countries. Yes part of that is your enemies will start preventive wars to stop that. A very major part of it is the economic consequences of developing nukes is usually not worth it. Part of it is the smart strategy is to just do most of the work and stop before getting nukes - if shit hits the fan you can get nukes quickly, but going up to the line without crossing it has none of the negative consequences.

North Korea isn't doing so well, but it's doing better than Iraq, Libya, or Venezuela at least as far as the leadership is concerned. Their conventional forces being within artillery range of Seoul probably helps but having multiple credible nukes really has helped them to avoid being a target of regime change.

The US tried regime change in 1950. The issue was that china didn't want an american puppet state on its borders so intervened. That is just as true now as it was 75 years ago.

Iraq, Libya and Venezuela don't have powerful friends willing to go to bat for them.

I suspect the US allows/ignores some nuclear programs if they think it's in their geopolitical interest. India is a counter-balance to China and Russia. Pakistan is a counter-balance to India. Keeping everyone armed to the teeth and on their toes is better for the US than forming blocs.

U.S. opposed India nuclear program for many years.

"Twenty-six years after the nuclear tests at Pokhran in May 1998 led to an embargo on several Indian atomic energy companies, the US is set to lift the sanctions, opening the route for closer cooperation in the civil-nuclear sector."

https://www.tribuneindia.com/news/india/26-years-after-pokhr...

You argued against your own point beautifully.

> I don't recall us bombing Pakistan, India, Israel, China, or North Korea.

pakistan and india did it in secret.

incidentally, its alleged that one of the countries on that list killed a very prominent american in order to prevent us from stopping them from creating a nuclear program.

India had quite advanced nuclear program even in 1940s, with Indian nuclear scientists working with scientists from UK and Canada.

"Following the atomic bombing of Hiroshima in August 1945, R. S. Krishnan, a nuclear physicist who had studied under Norman Feather and John Cockcroft, and who recognised the massive energy-generating potential of uranium, observed, "If the tremendous energy released from atomic explosions is made available to drive machinery, etc., it will bring about an industrial revolution of a far-reaching character." He further noted, however, the difficulties in harnessing nuclear power for peaceful usage, "...a great deal more research work is needed before atomic power can be put to industrial use."

"In March 1946, the Board of Scientific and Industrial Research (BSIR), under the Council of Scientific and Industrial Research (CSIR), set up an Atomic Research Committee under Bhabha's leadership to explore India's atomic energy resources and to suggest ways to develop and harness them, along with establishing contacts with similar organisations in other nations."

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

US didn't much opose the nuclear programs in Pakistan and Israel (probably even supported nuclear program in Israel).

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

US bombed North Korea a lot.

Nuclear nonproliferation relies on surveillance/monitoring and statecraft.

There are many, many steps before "drop bombs".

It's not difficult from a conceptual engineering perspective but it is difficult from an industrial scale perspective. It requires a tremendous amount of hardware and energy and precision equipment.

It's actually the opposite. Centrifuges are a cheaper and easier enrichment method. A single uranium centrifuge is on the order of $10,000 to $20,000. It's economical to run lots of centrifuges, but you could in theory get up to high enrichment just using the same centrifuge again and again.

Lot's of non-nuclear weapons states do have access, the Netherlands for example enriches more uranium annually than the UK. It's the components of centrifuges that are tightly controlled. Building enrichment facilities is well within the capabilities of pretty much any nation state, it's doing it secretly which is the hard part.

This alternative technique only makes sense at extremely small quantities. For their primary market of making medical isotopes, it makes a lot of sense. For nuclear reactor fuel it's incredibly impractical.

I have a bad feeling.

Is it the menacing guys in the photo, or that headache-inducing logo?

The logo. Definitely the logo. It both sucks you in and repels you at the same time. 'eye catching' to say the least, but so are laser pointers.

If we didn't have a lunatic in the whitehouse, I'm sure we could negotiate with Iran.

With Texas, I'm not so sure...

Private enterprise enriching uranium is a seriously worrying development...

I’m no expert, but I don’t believe that “high-assay low-enriched uranium” is the sort you can use in nuclear weapons, per it being “low-enriched”. According to the DOE, HALEU only goes up to 20% enrichment [0]. Nuclear weapons, it seems, need it to be enriched beyond 20% [1]

[0] https://www.energy.gov/ne/articles/what-high-assay-low-enric... [1] https://en.wikipedia.org/wiki/Enriched_uranium

Dirty bombs

Uranium-235 isn't useful for dirty bombs: it's too long-lived and not radioactive enough. Making dangerous levels of radiation requires short-lived isotopes. Some of these are the products of uranium fission, which is why spent uranium fuel is a radiation hazard. But isolating U-235 just to fission it to get radioactive isotopes like cesium-137 would not be the easiest way to get them.

"Uranium-235 isn't useful for dirty bombs"

It is when your goal is to throw a ton of alpha emitters into the environment for the population to ingest. Do you remember your nuclear cookie thought experiment?

Uranium-235 has a half-life of 704 million years.

It emits so slowly that the main hazard is heavy metal poisoning, which you'd also get from the depleted uranium that's a waste product from enrichment.

From the numbers I see on https://www.iaea.org/topics/spent-fuel-management/depleted-u..., if a dirty bomb with 1kg of 100% pure Uranium-235 exploded and evenly deposited a fine dust over a 170 by 170 meter square of typical soil, the total Uranium-235 (and specifically that isotope) of the top meter would only double; the total mass of uranium in that volume would only go up by 0.7%.

  The average concentration of natural uranium in soil is about 2 parts per million, which is equivalent to 2 grams of uranium in 1000 kg of soil. This means that the top metre of soil in a typical 10 m ´ 40 m garden contains about 2 kg of uranium (corresponding to about 50,000,000 Bq of activity just from the decay of the uranium isotopes and ignoring the considerable activity associated with the decay of the progeny. Concentrations of uranium in granite range from 2 parts per million to 20 parts per million. Uranium in higher concentrations (50 - 1000 mg per kg of soil) can be found in soil associated with phosphate deposits. In air, uranium exists as dust. Very small, dust-like particles of uranium in the air are deposited onto surface water, plant surfaces, and soil. These particles of uranium eventually end up back in the soil or in the bottom of lakes, rivers, and ponds, where they mix with the natural uranium that is already there. Typical activity concentrations of uranium in air are around 2 µBq per cubic metre. (UNSCEAR 2000).

- ibid

I’m just waiting for one of these private rocket companies to buy a private nuclear enriching company

We could reach Lex Luther level villainy in no time at all

Pantex is outside Amarillo, that's where all the US's nukes come from. If Texas wanted nukes ( well more nukes actually ) they'd juts place an order.

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

Pantex doesn't power a panopticon, nor does it threaten my livelihood.

Since I got downvoted for posting that, I'll also add that Pantex doesn't cause a sudden and massive spike in electricity usage, with the potential for related costs to be socialized into my bill.

>Private enterprise enriching uranium is a seriously worrying development...

Or seriously exciting. We might actually get affordable, clean nuclear energy this century.

Urenco USA is a private enterprise that enriches uranium. It built its first American enrichment plant 20 years ago, and lately it has been expanding capacity:

https://urencousa.com/about/our-history

The parent Urenco company has been operating private uranium enrichment plants in Europe since the 1970s.

Iran is essentially finished at this point - they no longer have control over the Strait of Hormuz, and oil is rapidly flowing through the strait (to say nothing of the oil already exported via other pipelines, or the impetus the war gave to accelerate pipelines under construction, such as the Iraq-Turkey pipeline).

"Calutron" -- I wonder, is this the same "calu" from the name Calumon, from Digimon Tamers? (In the story, Calumon is like a source of "digital evolution", and the symbol that denotes this is somewhat like a different kind of radiation symbol.)

> "Actinide’s flagship commercial product: enriched ytterbium-176,"

To save HN a search: a stable isotope used as a neutron capture target, to produce lutetium-177[i], used in targeted radioligand therapies[ii]. Discussed once on HN[iii].

[i] https://isotopes.gov/Ytterbium-176_is_Available_Now

[ii] https://en.wikipedia.org/wiki/Lutetium_(177Lu)_vipivotide_te...

[iii] https://news.ycombinator.com/item?id=40690196 ("Radioactive drugs strike cancer with precision (knowablemagazine.org)")

They are killing the environment now. I remember this discussion some 25 or 30 years ago in serbia, e. g. depleted uranium. Well, guess some company always wants to find ways for dumping or lifting-up radioactive substance.

Why is it careless? and how do you know they didn't invest effort in the homepage, maybe even more with AI than if they didn't use it.

Plenty of human made websites with terrible graphics. We'd complain, but we wouldn't say the content is worthless because the art looks bad.

Only if you round down, because you're right, most internet traffic these days are bots anyway. The bots definitely don't care if you AI generate your writing.

Many humans do care if you AI generate your writing, and won't read it if it's blatant. But as you say, the humans are a tiny fraction of total net traffic, who cares.

I like the part where you act like they would have ever had images otherwise

Pointless images are bad. Like those images at the top of blog posts, I didn't like those pre AI.

That would have been fine.

I've been following SuperCritical, a new startup working on Uranium extraction from sea water. My understanding is that the process is much more sustainable than mining, which makes it easier/faster to establish a domestic source vs the permits needed for a new US based mine.

https://www.globenewswire.com/news-release/2026/08/26/335139...

Will it be economic source uranium? Current price of uranium is quite low.

https://tradingeconomics.com/commodity/uranium

If you look at the 10y plot you will see the price is about $90/lb, up from $30/lb 6 years ago. Their target has been $55/lb, so the dramatic price increase is working in their favor.

That being said, I think their initial customer base would be the US government, who has no issue spending extra for domestic material.

General Matter is also working on HALEU https://en.wikipedia.org/wiki/General_Matter

Investors groups include: Neo Ventures - SE European VC group with mostly Bulgarian leadership and a diverse portfolio that doesn't mention Actinide at all; Mana Ventures - one of their companies is Flock Safety, the ubiquitous surveillance company in the recent news; Discipulus Ventures - MAGA supporting religious nutjobs from their own description in their opening paragraph [0], and from Forbes (paywalled) [1];

[0] https://www.discipulusventures.com/ [1] https://www.forbes.com/sites/davidjeans/2025/02/10/silicon-v... (paywall)

Interesting revival of or use of old technology to accomplish their goal. I'm not sure this belongs as a private tech company. I feel like it should be under the control of the federal government and no, I don't care what the libertarians on HN think about it. This needs to be a regulated company and process with clear reporting responsibilities and permanently disruptive penalties for noncompliance by individuals and the corporation.

You can bet your sweet patootie that even under the current government, any company producing radioactive isotopes is not operating without regulation or supervision.

wow

This is highly dangerous, right? If a bad actor possess centrifuge technology and can divert this <20% enriched uranium, they are essentially days or weeks away from achieving weapons-grade material.

This severely reduces the "breakout time" the international community relies on to detect and stop nuclear proliferation.

Centrifuge and nuclear technology is not some latest and greatest super complicated and barely understood technology with hard to source components anymore. Old restrictions like ball bearings quality on export and such are basically meaningless today. You can buy common tooling today from China that would trounce anything people were using 60 years ago and nobody has stopped people from studying and researching nuclear technologies.

It is mostly a matter of money and international politics now. It takes a significant amount of money to build and power, and it is hard to hide the scale of building and power usage from international watchdogs. Because nothing consumes tons of energy and doesn't output tons of product to sell except for nuclear material refinement for weapons.

> it is hard to hide the scale of building and power usage from international watchdogs. Because nothing consumes tons of energy and doesn't output tons of product to sell except for nuclear material refinement for weapons.

Until datacenters

Just wait, we might well have some sort of AI nonproliferation effort soon enough. I eagerly await any chip under 5 nm being subject to national security regulations.

If the bad actor has centrifuge technology and access to low enriched uranium, they are already weeks away from achieving weapons grade material. If a country with Iran's enrichment capabilities had a sufficient LEU stockpile swapped for an equivalent amount of HALEU, it would shave about 7 days off the time necessary to produce a bomb's worth of weapons grade uranium.

For nations with enrichment capabilities, enrichment is not a major contributor to overall breakout time. Enrichment doesn't take much time, it's building enrichment facilities that takes a while, especially clandestinely.

why dudes look so mean in the picture.. chill out kings