Beyond SMRs: Molten Salt, TRISO & Microreactor Stocks

60-second answer: Most advanced reactor developers are private or pre-revenue, so the investable list is short and mostly indirect. BWX Technologies (NYSE: BWXT) is the cleanest listed proxy for TRISO fuel and high-temperature reactor work; Oklo (NYSE: OKLO) is the one public microreactor developer; Centrus (NYSE: LEU) supplies the HALEU that most of these designs need. Terrestrial Energy (NASDAQ: IMSR) became the listed molten-salt pure-play when its SPAC merger closed in October 2025; Kairos, TerraPower (Natrium and MCFR), X-energy's reactor business and Radiant remain private. If you want liquid exposure to the whole category rather than one licensing docket, the fuel side (enrichment and uranium miners) is the lower-variance way in, because every one of these reactors buys fuel.

Our SMR stocks guide covers the small light-water names; the thorium reality check audits that corner. This page sorts the rest of the advanced-reactor zoo (molten salt, TRISO, microreactors, fast reactors) by two questions that matter to an investor: what type is it, and can you buy it? The short answer: you mostly can't. The value is knowing that before you hunt for a "molten salt reactor stock" that doesn't exist, and understanding the one thread that ties the category back to a tradeable market: fuel.

The advanced reactor taxonomy, sorted by investability

"Advanced reactor" and "SMR" are separate, overlapping classifications: SMR describes size, and the NRC's advanced-reactor category spans non-water designs and innovative light-water ones (NRC). This page covers the non-light-water families, which split by coolant and fuel. Here is the map, with example companies and whether you can buy them.

The developer column is mostly private companies, and the reliably liquid names sit in the bottom row: suppliers whose revenue comes from the specific programs they are contracted to, not from the category as a whole.

Molten salt reactor stocks: mostly a private club

Molten salt reactors are the design enthusiasts love most and investors can access least. The concept (fuel or coolant carried in liquid salt at atmospheric pressure) promises passive safety and high-temperature industrial heat. The developers are almost all private:

• Kairos Power: fluoride salt as coolant around solid TRISO pebbles, which puts it at the edge of the MSR label; building its Hermes demonstration reactors in Oak Ridge, Tennessee, with Google as an offtake partner. Private.
• Terrestrial Energy (NASDAQ: IMSR): the Integral Molten Salt Reactor, a true liquid-fuel design with uranium dissolved in the salt, running on standard sub-5% LEU rather than HALEU. Listed October 29, 2025 after completing its SPAC combination with HCM II (company release). A young, pre-revenue listing; check current filings before acting.
• TerraPower's MCFR: a longer-dated molten chloride fast reactor program inside a private company focused first on its Natrium sodium reactor.
• Copenhagen Atomics: thorium-adjacent molten salt, covered in our thorium guide. Private.

IMSR is now the one listed molten-salt pure-play, young and pre-revenue; the deeper-liquidity exposure still runs through fuel and component suppliers. The closest listed exposure runs through fuel and component suppliers (below), not the reactor developers themselves.

TRISO fuel stock: why BWXT is the listed proxy

TRISO (tri-structural isotropic) fuel encases uranium kernels in layers of carbon and ceramic, each particle its own containment. It fuels most gas-cooled high-temperature reactors and several microreactors, prized for withstanding extreme temperatures. See our TRISO glossary entry for the mechanics, and the full account of TRISO manufacturing and qualification for who actually produces it and at what stage each plant is.

The marquee TRISO reactor developer, X-energy (Amazon-backed, building the Xe-100 HTGR with Dow in Texas), is private. Per-design reactor fuel specifications are compared in our fuel guide; the tradeable TRISO angle is the fuel manufacturer:

BWX Technologies (NYSE: BWXT) is the cleanest listed TRISO exposure with real deliveries behind it: it shipped the full Project Pele core in late 2025 and holds a commercial TRISO partnership with Kairos, alongside its naval-reactor base, and it is profitable today. The exposure is to the programs BWXT is contracted on, not to every design in the field; a reactor that uses metal fuel or a rival's pebbles buys nothing from it. Less upside than a developer if that developer's design wins; less downside when timelines slip, which advanced nuclear's reliably do.

Microreactor stocks: Oklo is the one you can buy

Microreactors are the smallest class: roughly 1 to 20 megawatts, designed to be factory-built, truck-portable, and dropped onto remote mines, military bases, data centers, or islands. Sometimes marketed as "mini nuclear reactor" plays, the category is heavy on ambition and light on tickers: Whether any of these units can beat delivered diesel or industrial gas is the commercial question; our guide to microreactor business cases frames the break-even.

• Oklo (NYSE: OKLO): the one public microreactor developer. Its Aurora fast microreactor targets data-center and off-grid customers directly. Pre-revenue, richly valued, and volatile; our Oklo stock explainer breaks down what you own. This is the highest-beta name in the whole advanced-reactor set.
• Radiant: the Kaleidos portable microreactor, a genuine frontrunner in the class. Private.
• Westinghouse eVinci: a 5 MWe (~13 MWth) heat-pipe microreactor inside a company owned by Cameco and Brookfield, so exposure is indirect. See our Westinghouse note.

If "microreactor stock" is the search that brought you here, OKLO is effectively the only direct answer, and it is a speculative one.

Fast reactors: TerraPower's Natrium, still private

Sodium-cooled fast reactors run a fast neutron spectrum and are the most construction-advanced advanced reactor in the West. TerraPower's Natrium plant broke ground at Kemmerer, Wyoming, and signed offtake interest with Meta, but TerraPower is private, backed by Bill Gates and a roster of strategic investors. There is no Natrium ticker. The listed proxies are, again, the fuel and component suppliers, plus utilities with skin in specific projects. Track which projects have actually signed versus merely announced in our reactor tracker.

The through-line: every one of these reactors needs fuel

Here is why this taxonomy loops back to a market you can trade. Sort the designs above by what they burn and a pattern appears: most need HALEU, high-assay low-enriched uranium enriched between 5% and 20%, versus the roughly 3% to 5% conventional reactors use (Terrestrial's IMSR is the standard-assay exception). TRISO fuel starts as HALEU kernels; Natrium's first core needs roughly 15 to 20 tonnes of it; molten salt and microreactor designs lean on it too.

HALEU barely exists at commercial scale today, which makes the fuel chain the tightest, most investable choke point in advanced nuclear. That points to two tradeable layers:

• Enrichers who make HALEU: Centrus (NYSE: LEU) is the US name that appears in nearly every advanced-reactor supply diagram.
• Miners who dig the uranium that becomes that fuel, into a market our supply and demand model already reads as structurally short deep into the 2030s.

You can be genuinely unsure which reactor design wins (molten salt, TRISO, microreactor, or fast) and still be confident every one of them buys enriched uranium. That is the argument for owning the fuel cycle rather than a single developer's licensing docket. It is the same conclusion the SMR guide reaches from the other direction.

How to think about position sizing

Conservative framing, because this is real money. Direct developer stocks (where they exist at all) belong in the speculative sleeve, sized so a total loss is survivable; the few that are buyable (OKLO, thinly listed developers) trade on narrative and burn cash. The lower-variance expression is the supplier layer: BWXT for TRISO and components, LEU for enrichment, diversified miners for the raw pounds. Before buying any developer, check what it has actually signed on our reactor tracker, not what it has announced.

Frequently asked questions

Are there any molten salt reactor stocks? One pure-play: Terrestrial Energy (NASDAQ: IMSR), listed October 2025 via SPAC and still pre-revenue. Kairos Power, TerraPower's MCFR program, and Copenhagen Atomics are private. The most liquid exposure runs through fuel and component suppliers like BWX Technologies.

What is the best TRISO fuel stock? BWX Technologies (NYSE: BWXT) is the cleanest listed proxy: it runs a TRISO production line, is profitable, and supplies multiple advanced reactor programs. The leading TRISO reactor developer, X-energy, is private.

Can you buy microreactor stocks? Oklo (NYSE: OKLO) is the one direct public microreactor developer, and it is pre-revenue and volatile. Radiant is private, and Westinghouse's eVinci sits inside Cameco-and-Brookfield-owned Westinghouse, so that exposure is indirect.

Why do advanced reactors keep pointing back to uranium? Because almost all of them (TRISO HTGRs, molten salt, microreactors, sodium fast reactors) need HALEU, a more-enriched form of uranium that barely exists at commercial scale. That makes the fuel chain the tightest choke point and the most investable part of the theme.

What's the difference between an SMR and an advanced reactor? They are overlapping labels: SMR describes size (under ~300 MW), while the NRC's advanced-reactor category covers new technologies including some innovative light-water designs. Many advanced reactors are small, and small light-water reactors like the BWRX-300 are SMRs built on conventional fuel. See our SMR stocks guide for that side.

This article is for informational purposes only, not investment advice.