Oklo vs NuScale: Two Nuclear Power Startups Compared

• Short answer
• Reactor design and size compared
• Regulatory status
• Business model and backers
• The risks for each
• Verdict: which fits which situation

Short answer

Oklo and NuScale both build small nuclear reactors, but their plans are very different. Oklo designs tiny "Aurora" powerhouses. It wants to own and run them, then sell the power directly to customers.

NuScale Power takes the opposite path. It makes larger reactor modules called VOYGR and licenses the design to others. NuScale is the only US small modular reactor (SMR) with full design approval from the Nuclear Regulatory Commission (NRC).

So one sells electricity. The other sells reactors. That single choice shapes almost everything else about each company.

This matters because AI needs huge, steady power. Data centers want clean electricity that never stops. Both firms pitch nuclear power as the answer.

Both trade on public stock markets. Neither has a working commercial plant yet. People often search "Oklo vs NuScale stock," but this page compares the companies, not their shares. It is not investment advice.

Oklo has also stacked up large early orders. Its deals and letters of intent add up to well over 10,000 megawatts of future demand. But these are mostly promises, not signed and finished plants.

Reactor design and size compared

The reactors differ in size, coolant, and how many units you need. Oklo's units are small microreactors. NuScale's modules are larger and grouped into big plants.

Oklo uses a fast reactor cooled by liquid metal. NuScale uses a mini light-water reactor, the same basic type as today's big plants. That makes NuScale's design more familiar to regulators.

Oklo Aurora

• Type: a liquid-metal-cooled fast reactor, not a standard water-cooled design.
• Size: Oklo scaled its Aurora powerhouse up to about 75 megawatts of electricity in 2025.
• History: its earliest design was tiny, near 1.5 megawatts, but the company kept growing it.
• Fuel: designed to run on both fresh fuel and recycled nuclear fuel.
• Running: each powerhouse is meant to operate for years with little refueling.

NuScale VOYGR

• Type: a shrunken version of a normal light-water reactor.
• Size: its certified module makes 50 MWe, and an uprated version makes 77 MWe.
• Plants: one VOYGR plant can hold up to 12 modules for large output.
• Example: a six-module plant would produce about 462 MWe.

Why the size gap matters

Size changes how each firm serves a data center. A single Oklo powerhouse could sit beside a mid-size site. A large AI campus might need several units or one full NuScale plant.

Oklo says its bigger 75 MW design lets it serve large buyers with fewer builds. NuScale says stacking modules gives utilities flexible output. Both claims are still unproven at commercial scale.

The two firms also plan to build in different ways. NuScale wants factory-built modules shipped to a site and assembled. Oklo wants compact powerhouses set up near the customer. Both hope factory work can cut cost and time.

In short, Oklo bets on many small, self-run units. NuScale bets on stacking modules into one large station. Learn more in our guide to whether small modular reactors are safe.

Regulatory status

NuScale is further along with US regulators than Oklo. NuScale holds design approvals that Oklo does not yet have.

Design approval is a big deal in nuclear power. It means regulators accept that a reactor design is safe to build. Without it, no plant can move forward.

The NRC certified NuScale's 50 MWe module design in January 2023. That made it the first SMR design certified in the United States. In May 2025, the NRC gave Standard Design Approval to NuScale's uprated 77 MWe design.

Still, a certified design is not the same as a finished plant. NuScale needs owners to build and pay for real reactors. Approval clears the design, but not the money or the site.

Oklo's harder road

Oklo's path has been bumpier. In January 2022, the NRC denied Oklo's combined license application for its first Aurora plant.

The NRC said Oklo left large information gaps. It cited weak detail on possible accidents and on safety systems. The denial was "without prejudice," so Oklo could try again.

Oklo has been rebuilding its application since then. In May 2026, the NRC approved a key design-criteria report for the Aurora plant in Idaho. That was real progress, but it is not full approval.

Oklo still plans to file a full combined license application. A win there would let it build and run the first Aurora unit. It targets late 2027 or 2028 for that plant, though such dates often slip.

Timelines matter as much as approvals here. NuScale has spent more than a decade in review to reach this point. Oklo has moved faster but from a weaker start. Speed and proof pull in opposite directions.

Business model and backers

The two companies raise money and pick partners in very different ways. Their backers hint at who each firm serves.

Both are public, which is why people search "oklo vs nuscale stock." Oklo trades on the New York Stock Exchange as OKLO. NuScale trades on the Nasdaq as SMR.

Oklo

• Model: build, own, and operate reactors, then sell power under long contracts.
• Public listing: Oklo went public in May 2024 by merging with AltC Acquisition Corp.
• Key figure: OpenAI chief Sam Altman chaired AltC and helped take Oklo public.
• Big deal: in December 2024, Oklo signed a roughly 12-gigawatt power agreement with data-center firm Switch.
• Pipeline: Oklo also signed letters of intent with Equinix, Diamondback Energy, and Prometheus Hyperscale.

NuScale

• Model: license its reactor design and supply modules to plant owners.
• Main backer: engineering giant Fluor has invested more than $600 million since 2011.
• Sales partner: a firm called ENTRA1 now handles global sales of NuScale plants.
• Setback: its flagship US project with UAMPS was cancelled in November 2023.

The UAMPS plan would have built a six-module plant in Idaho. It ended after it could not sign up enough buyers. NuScale now points to a plant planned in Romania and a large draft deal with US utility TVA.

NuScale's clearest live project now sits in Romania. Its partner plans a six-module plant at a former coal site in Doicesti. Early engineering work there is finished, and local approvals have moved ahead.

The two models split the cost in different ways. Oklo must raise huge sums up front to fund and keep each plant. NuScale spreads that cost to buyers, but it needs willing customers to sign on.

The risks for each

Both companies face real risks, and neither is a sure bet. This is not investment advice, just an honest look at the hazards.

Oklo's risks

• It has no NRC license yet and once failed a full review.
• It reports no revenue and no operating plant as of mid-2026.
• Its first plant is not due until late 2027 or 2028.
• Owning and running many reactors ties up huge amounts of cash.
• Much of its value rests on hopes about AI power demand.

NuScale's risks

• Its first big US project was cancelled over weak demand.
• It has spent years and lots of money with few plants built.
• Rising costs have scared off some past buyers.
• It leans on partners like Fluor and ENTRA1 to win deals.
• Rivals like GE Hitachi and Holtec chase the same customers.

Both share some risks too. Nuclear projects often run late and over budget. Public support can also shift if costs or safety fears rise. For the wider picture, see our guide to the nuclear companies powering AI.

Verdict: which fits which situation

NuScale is further along on paper, while Oklo has bolder deals and bigger risk. Neither is the automatic winner. The right pick depends on what you value most.

Who NuScale may suit

NuScale fits people who value regulatory progress. It owns the only US-certified SMR design. Its larger modules aim at utilities and national grids.

But it moves slowly and has lost a major project. Its story is steadier, not flashier.

Who Oklo may suit

Oklo fits people drawn to the AI-power theme. It has huge data-center deals and a famous backer. It also carries more risk, since it lacks a license and revenue.

It is worth noting a third name here. TerraPower, backed by Bill Gates, is building its own larger reactor. It competes with both firms for the same future customers.

How to compare them fairly

Judge each firm by clear milestones, not headlines. Watch for licenses, cash, and real plants under construction. The company with the best press is not always the one furthest ahead.

Also weigh who each company serves. Oklo chases private data-center buyers who want fast, on-site power. NuScale courts utilities and governments that plan decades ahead. Different buyers reward different strengths, so there is no single winner.

To see why AI is driving all this, read our pillar on nuclear data centers and our explainer on what Oklo is. You can also map the boom on our data center map and track power strain on our AI grid impact page.