Robert Mendelsohn and Eric Olszewski, the co-founders of the Dallas advanced-materials company Actinide, came on TBPN days after saying they had become the first startup to enrich uranium and produce HALEU. They explained what the fuel is for, why the machine that made it was invented for the Manhattan Project and then abandoned, how a field with a classified literature gets learned, and what a company sells while it waits for reactors. The news discussion the hosts ran earlier in the show is covered in a separate summary.
👤 Guests: Robert Mendelsohn, co-founder and chief technology officer of Actinide, and Eric Olszewski, its co-founder and chief executive, who built the company's own isotope-separation machines in Dallas
🎙️ Hosts: John Coogan and Jordi Hays, who present TBPN live on X and YouTube every weekday
📰 Published: 31 August 2026 on YouTube (TBPN)
🔴 YouTube | 🟣 Apple Podcasts | 🔗 Show notes | ⏱️ 2 hr 24 min
Key Takeaways
The fuel next-generation reactors are designed to run on cannot be bought in America
"It's the next gen fuel for next gen reactors." — and "There's no supply."
The alternatives are reprocessed material and Russia
The separator is a Manhattan Project design whose one fatal cost went to zero
Calutrons were retired for being power-hungry; superconducting magnets consume no power
"So it's very rare in the engineering fields that you'll find the major problem can actually go to zero."
Besides the centrifuge, it is the only enrichment method proven at scale
"I mean it's besides the centrifuge, the only thing that's been proven at scale."
The literature is classified, so the physics has to be rederived from nothing
Mendelsohn thought atomic separation would be an easy problem and says he has been humbled many times since
He does not use AI for the work and does not think it presents a proliferation concern, because the control point is the material rather than the knowledge
The company sells refined atoms, and medicine is paying before nuclear does
Enriched material at about $30,000 a gram has already been delivered commercially to Oklo Isotopes
Olszewski funded it himself after being told he had wasted his talent on finance and software
"I did put in over a million dollars of my own money."
"We were promised the atomic age, and it's something that we deserve."
America Has No Domestic Supply of the Fuel Its New Reactors Are Designed to Burn
Coogan introduced the pair as the first startup to produce HALEU and asked what it actually is. Olszewski confirmed the claim — Actinide was the first startup in history to enrich uranium — and Mendelsohn gave the plain version.
"It's the next gen fuel for next gen reactors."
There is nothing to buy. Asked where it comes from today, Mendelsohn said flatly: "There's no supply."
Coogan guessed it is mostly recovered from decommissioned nuclear material, such as submarine fuel, and refined back down
"You're exactly right. Or they get it from Russia." Mendelsohn said, and added: "Yeah. Russia. Not good."
"And that's something that we're aiming to change here in Dallas, Texas."
Olszewski framed the achievement as a small team doing something nation states have struggled with and failed at, and doing it in Dallas
The Machine Is an Eighty-Year-Old Design Whose One Fatal Cost Went to Zero
Coogan asked what the equipment is — whether it is a big centrifuge.
Mendelsohn said the machine is called the Calutron, "which was originally invented by Nobel laureates for the Manhattan Project. So they've already delivered to our country once before." They were retired because they are not energy efficient: they run on very large magnets.
The fix is a change of material, not of principle. "Now magnets don't consume power if they're superconducting for instance."
"And so it's very rare in the engineering fields that you'll find the major problem can actually go to zero. So yeah, we stand on the shoulders of giants in that way."
Coogan checked the claim: the same machine, with one piece redesigned to be more efficient. Mendelsohn said more or less — "It's the exact same principle though."
The competitive point is that there are only two proven routes. "I mean it's besides the centrifuge, the only thing that's been proven at scale."
The regulatory position follows from how close the material sits to the line. Olszewski said HALEU is "a smidge under highly enriched, and so you have to be in a category two facility", and that the company is looking to work with the appropriate regulators to scale production
"And but the separation technology itself is, 80 years old." The know-how is real, he said, but the principle is public
A Field Where the Literature Is Classified and You Derive It Yourself
Coogan asked for the lineage — how Mendelsohn got here and why nuclear.
It started as disbelief that the problem was open. "When I first heard about the problem of how do you atomically separate things, I couldn't believe that it hadn't been solved. And initially, I thought this would be an easy problem to work on. And so, I've been humbled since then many times."
Coogan offered the inversion of the Kennedy line — we do these things not because they are hard but because we thought they would be easy — and Mendelsohn said he could not agree more
"So time and time again, go, okay. Finally understand it. And then no."
The research problem is the classification. "This is not a very approachable field. A lot of things are classified, and you have to derive it for yourself."
A lot of smart people have had ideas here, he said, from the centrifuge to lasers to the calutron
On whether AI models refuse this work, Mendelsohn said he barely uses them. "I don't use a whole lot of AI." — mostly for finding vendors and suppliers
The models would not help much anyway given how obscure the engineering is, and he was clear about the risk: "I certainly don't think it presents a proliferation concern."
Coogan's framing, which Mendelsohn accepted, is that the control point sits in the physical world — at some stage you have to go and acquire a controlled material
Olszewski's concern is commercial rather than nuclear. "We're also pretty wary regarding kind of where sort of information within our business goes to."
"And so we have a lot of things that are still frankly analog or air gapped regarding any sort of things that are proprietary or trade secret."
Coogan put it back to him as intellectual property rather than launch codes; Olszewski agreed
The Product Is Refined Atoms, and Medicine Is Paying Before the Reactors Do
Coogan asked about go-to-market, noting how many new reactor startups would sign up for HALEU at scale.
The company is deliberately material-agnostic. "So we actually are kind of agnostic with the materials that we make. Generally, we refine atoms, and some of the first refined atoms that we made were for the medical industry."
"They go for about $30,000 per gram, which is like a paper clip sort of material for you patriots out there. And we delivered that to Oklo Isotopes. We've had a few commercial deliveries to them."
The HALEU business is at the announcement stage. The company had been in stealth for some time and, Olszewski said, "we kind of blew up Twitter with our announcement of coming out of stealth", with business-development conversations running that week and beyond
He was careful not to oversell the milestone. "Obviously, there's a big sort of gap between doing it once and being able to scale it up on both the technological and regulatory fronts"
Olszewski Put In More Than a Million Dollars of His Own After Being Told He Had Wasted His Talent
Hays asked about the self-funding and the motivation.
"Yeah. That's true. I did put in over a million dollars of my own money."
The conversation that turned him came with an insult attached. Olszewski had a background in finance and software, and Mendelsohn told him he was upset that so many brilliant engineers go into those fields rather than hard engineering
"Hey, I turned a buck from it." Olszewski said of his own career
So he asked what Mendelsohn was doing: "And he said, I'm working on what I think is the hardest, sort of unsolved problem in humanity."
The pitch he now repeats is a list of ages. "I truly agree that this is indeed humanity's largest unsolved problem. If you look at history, you got the stone age, bronze age, iron age, the silicon age. We were promised the atomic age, and it's something that we deserve. We're not playing with a full deck of materials."
The funding sequence went personal money, then institutional. "And so I began investing my own money and got to a spot where it was beyond r and d. We brought on a seed round and, here we are doing commercial deliveries and scaling into different markets."
Their bottom line is that the bottleneck in advanced nuclear is not reactor design but the material those reactors are meant to burn, and that the machine capable of making it domestically was invented eighty years ago and shelved for a reason superconductors have since removed.
Products, Companies & Tools Mentioned
Actinide (The Dallas company the guests founded, which says it is the first startup in history to enrich uranium and produce HALEU, using its own calutron)
Oklo Isotopes (The customer for Actinide's first commercially refined atoms — medical-industry material at about $30,000 a gram, with several deliveries made)
Books & Resources Mentioned
Actinide's coming-out-of-stealth announcement (The company's own write-up of the HALEU result that "blew up Twitter" and prompted the appearance)
Get the latest market chatter as it happens:
If this saved you the listen, send it to one person who would rather have the time back.