Small modular reactors, or SMRs, are nuclear power plants designed to be built in a factory, shipped by truck or rail, and assembled like Lego blocks on‑site. Each unit is much smaller than today’s gigawatt‑scale reactors—think tens to a few hundred megawatts—so utilities can add capacity in bite‑sized chunks instead of betting billions up front. Because the modules are standardized and mass‑produced, developers expect lower construction risk, tighter quality control, and faster schedules. Safety systems lean on passive physics—gravity, convection, and sealed coolant pools—rather than complex pumps, making the technology simpler and inherently safer.
In this report, we highlight the top small modular reactor stocks to watch in 2025, curated for pure-play exposure to this next-gen nuclear technology and its enabling supply chain.
Why SMRs, why now?
Two forces have converged as catalysts:
- First, electricity demand is spiking in places that can’t afford to fail. AI data centers are mushrooming worldwide, packing racks of hungry chips that have to run 24/7. The International Energy Agency projects that data‑center consumption will more than double to about 945 terawatt‑hours by 2030, with AI data centers driving most of that rise. Wind and solar are cheap but intermittent; batteries can stretch them only so far. Grid operators therefore need a clean, always‑on backbone—baseload power—to keep AI clusters humming when the sun sets or the wind stalls. SMRs slot neatly into that gap: compact enough to sit beside a tech campus, yet steady enough to guarantee five‑nines reliability without carbon emissions or local air pollution.
- Policy and geopolitics supply the second big push. Analysts now frame SMRs as a way to “neutralize Russia’s influence” on Europe via gas. Washington has moved just as aggressively: the U.S. Department of Energy’s Advanced Reactor Demonstration Program is pouring hundreds of millions of dollars into first‑of‑a‑kind SMR projects designed to reach the grid within seven years. The 2025 “One Big Beautiful Bill” added a 10 percent bonus tax credit for advanced nuclear plants built in former nuclear‑energy communities, a lever that can shave tens of millions off financing costs. With similar incentives in Canada, the U.K., and South Korea, the signal is clear: policymakers want reliable, low‑carbon power that doesn’t depend on volatile fuel imports. SMRs fit that brief—making today the most favorable policy environment nuclear innovators have enjoyed in decades.
In essence, small modular reactors promise nuclear’s reliability, at a fraction of the price and complexity, to previously inaccessible sites—all while solidifying invaluable energy sovereignty.
Pure-Play SMR Developers
Pure‑play SMR developers design, license, and sell factory‑built reactors. They trade like high‑growth tech stories—little revenue today, but huge optionality if they nail first‑of‑a‑kind builds. For investors hunting small modular reactor stocks with the highest torque, this segment offers the cleanest exposure to breakthroughs and stumbles. Expect more volatile prices that swing on regulatory rulings, pilot milestones, and funding headlines.
NuScale Power (NYSE: SMR)
HQ: USA; First U.S.-approved SMR design, backed by Fluor and nearing deployment.
NuScale Power has achieved a historic first: its 77 MWe VOYGR reactor is the first small modular reactor design ever approved by U.S. regulators. This gives NuScale a head start in turning the SMR concept into reality. Backed by engineering giant Fluor Corporation, the company is moving to build its first plant – a six-module SMR power station at Idaho National Laboratory – aiming to deliver power by 2029. Each VOYGR module is small but modular, so multiple units can be combined to scale up capacity to a utility’s needs. The company also pitches SMRs as ideal replacements for retiring coal plants, repurposing sites and preserving jobs while cutting emissions.
The thesis for NuScale lies in its pioneering status and the growing policy support for nuclear innovation. With governments streamlining approvals for new reactors, NuScale stands to benefit as a front-runner. Its NRC-certified design also gives it credibility to pursue projects abroad, as countries worldwide look to SMRs for clean energy. Key challenges remain, including financing and proving that its reactors can be built on time and on budget. However, if the SMR market expands as expected, NuScale’s first-mover advantage and strong partnerships could position it to capture significant market share in the coming decade.
Oklo Inc. (NYSE: OKLO)
HQ: USA; Microreactor startup targeting data centers with fast reactors and tech backing.
Oklo Inc. is a Silicon Valley-backed microreactor pioneer aiming to make nuclear power ultra-small and accessible. The startup, famously backed by OpenAI’s Sam Altman, initially proposed a 1.5 MW mini-reactor, but after a regulatory setback it unveiled a larger 75 MW fast-reactor design tailored for energy-hungry data centers. Oklo plans to deploy its first unit by 2027–2028, potentially at Idaho National Lab, to prove how a compact reactor can directly power high-tech facilities. The company has amassed tentative agreements totaling about 14 GW for future projects, including a 12 GW partnership with a major data center operator – an enormous vote of customer interest for an unbuilt technology.
Oklo aims to plug nuclear into the booming demand for constant, carbon-free power in the digital economy. By focusing on modular reactors that can be factory-built and installed on commercial sites, Oklo aims to sidestep the huge costs and delays of traditional plants. The U.S. government’s push to streamline reactor licensing could smooth Oklo’s path after its earlier license attempt was denied. This company is still pre-revenue and faces significant execution risk, but if it delivers, Oklo could become a leading supplier of off-grid nuclear generators for tech and remote industries – a potentially massive growth market.
NANO Nuclear Energy (NASDAQ: NNE)
HQ: USA; Early-stage microreactor firm focused on off-grid and frontier energy markets.
Nano Nuclear Energy is an early-stage company developing portable microreactors to bring nuclear energy to remote areas. Though still pre-revenue, NANO has drawn attention for its ambitious vision: reactors small enough to fit in a shipping container but capable of powering isolated communities, military bases, or disaster zones. The company has signed cooperative agreements to test its microreactor prototypes at Idaho National Laboratory under a new Department of Energy program. It’s also exploring deployments in places like West Africa – recently partnering with Togo’s government – and even integrating reactors with off-grid agriculture projects.
NANO Nuclear is a speculative bet on a potentially transformative niche: ultra-small reactors for markets that big power plants can’t reach. The company’s microreactors, named Zeus and Odin, aim to be factory-built and easily transported, lowering the barriers to clean energy in remote or developing regions. This positions NANO to benefit from government initiatives to use miniature reactors for energy security in off-grid locations. If microreactors become a critical piece of the future energy puzzle, NANO could reap outsized rewards. However, as a tiny pre-revenue firm, it faces considerable technological and regulatory hurdles.
Critical Enablers & Suppliers
Critical enablers sit behind the curtain, supplying the advanced fuel, metallurgy, and precision components that every SMR needs. Their markets already exist—defense reactors, isotope production—but they gain fresh upside from the SMR build‑out. These small modular reactor stocks are the picks-and-shovels plays: they profit whether one or many reactor designs win. Growth depends on policy support for domestic fuel cycles and large‑scale manufacturing.
Centrus Energy (NYSE: LEU)
HQ: USA; Sole U.S. supplier of HALEU fuel, critical for advanced SMRs.
Centrus Energy occupies a pivotal role in the SMR ecosystem as the only U.S. company currently licensed to produce the advanced fuel many next-gen reactors require. Most new designs – especially advanced and micro reactors – need high-assay low-enriched uranium (HALEU) fuel enriched to around 20% U-235, which was previously only available from Russia. Centrus recently delivered the first batches of U.S.-produced HALEU under a Department of Energy contract. It is now ramping up its enrichment facility in Ohio with government backing to supply this critical fuel domestically. With Washington prioritizing a home-grown nuclear fuel cycle for energy security, Centrus stands to benefit from funding and fast-tracked licensing to expand production.
Rather than betting on a particular reactor design, owning Centrus is a bet that many reactor projects will move forward, all of which will need fuel. If the SMR and advanced reactor market grows as projected, demand for HALEU could skyrocket, putting Centrus in a favorable position as a near-monopoly U.S. supplier. The company’s fortunes are tightly linked to government policy and the pace of reactor deployments. In the meantime, Centrus’s established enrichment business and long-term contracts provide a foundation as it pursues the emerging HALEU market.
Lightbridge Corp (NASDAQ: LTBR)
HQ: USA; Developer of high-efficiency metallic fuel for next-gen reactors.
Lightbridge Corp is a nuclear technology firm working on next-generation reactor fuel. Its specialty is a metallic nuclear fuel design intended to boost the efficiency and safety of reactors compared to today’s uranium oxide fuel. The idea is to allow reactors to run at higher power or longer cycles, potentially generating more electricity from the same reactor hardware. This innovation could be especially valuable for SMRs and advanced reactors looking to maximize output in a small footprint. Although still in R&D with no commercial revenue, Lightbridge has directly felt the tailwinds from recent pro-nuclear policy.
The case for Lightbridge hinges on the nuclear industry’s need for better fuel as advanced reactors emerge. Governments are now funding fuel innovation (including recycling and high-burnup fuels) to support the new wave of reactors. Lightbridge’s technology could become an enabling piece of that puzzle, offering plant operators more power per reactor and safety benefits. However, the path to market for a new fuel is long – requiring years of testing and regulatory approval – and Lightbridge will likely need partnerships with major fuel manufacturers. Thus, Lightbridge is a high-risk, high-upside bet on a critical piece of the SMR supply chain; if its fuel proves out, it could secure licensing deals globally.
BWX Technologies (NYSE: BWXT)
HQ: USA; Defense-grade nuclear supplier building SMRs and specialty fuels.
BWX Technologies is a powerhouse in nuclear engineering and manufacturing and could be a major winner of the SMR age. BWXT has decades of experience building reactors for U.S. Navy submarines and carriers, and it leverages that precision manufacturing capability for emerging reactor projects. The company is already contracted to build a prototype microreactor for the Pentagon and is a leading producer of advanced nuclear fuel like TRISO pebbles – fuel needed for certain SMRs and space reactors. With the U.S. pushing to revive domestic nuclear manufacturing, BWXT’s extensive facilities and expertise in reactor components position it as a critical enabler for the SMR rollout.
For investors, BWXT offers a blend of steady business and growth potential. Its defense and naval reactor segments provide a stable revenue base, while the expansion of SMRs and advanced reactors could drive new orders for BWXT’s reactors and fuel services. Many new reactor ventures may rely on BWXT to build parts of their designs or supply specialty fuel, making BWXT an “arms dealer” in a nuclear renaissance. The company’s involvement across multiple SMR projects and government programs spreads out risk compared to betting on a single reactor developer. While not as flashy as a pure-play startup, BWXT provides exposure to the SMR theme with the cushion of an established, profitable enterprise.
Diversified Industrials with SMR Programs
Big industrial names with SMR programs bring balance‑sheet heft, global sales channels, and operating know‑how. Their share prices hinge on turbines, jet engines, or EPC contracts today, yet they are quietly incubating reactors that could reshape their futures. For investors, these small modular reactor stocks offer a steadier ride: downside is cushioned by diversified earnings, while successful first deployments could unlock a new profit stream. Think of them as blue‑chip gateways to next‑gen nuclear.
GE Vernova (NYSE: GEV)
HQ: USA; Global energy player deploying its SMR with international partners.
GE Vernova, General Electric’s energy spinoff, is a diversified giant with a key stake in the SMR race through its nuclear division. GE Hitachi Nuclear Energy (part of GE Vernova) has developed the BWRX-300, a 300 MWe small modular reactor that is one of the furthest-advanced SMR designs. GE’s partner Ontario Power Generation is already building the first grid-scale SMR based on this design, slated to be online by 2028 in Canada. This project at Darlington will be a crucial proof of concept: a successful deployment can demonstrate the BWRX-300’s benefits to other countries looking for reliable mid-sized nuclear plants. GE Vernova’s nuclear business also draws on decades of experience with boiling water reactors and an established supply chain, which should help in commercializing the SMR.
For investors, GE Vernova offers exposure to SMRs in a balanced way. It’s not a pure nuclear play – the company also makes wind turbines, gas turbines, and grid equipment – so there’s more stability but less direct SMR upside. Still, the BWRX-300 could become a growth driver if orders materialize in the U.S., Europe, and Asia after the Canadian launch. GE Vernova’s global reach and industrial scale give it an edge in ramping up SMR production to meet demand.
Rolls-Royce Holdings (LSE: RR)
HQ: UK; Aerospace firm developing a modular 470 MW SMR with UK backing.
Rolls-Royce is best known for jet engines, but it’s now at the forefront of Britain’s push into SMRs. In 2025, the UK government selected Rolls-Royce to build the country’s first SMRs and pledged £2.5 billion to kickstart the program. The company’s SMR division is designing a 470 MW modular reactor, aiming to have its initial units operating in Britain by the mid-2030s. Its experience making nuclear reactors for Royal Navy submarines lends credibility to its design, and factory-built components should bring economies of scale. If the UK rollout succeeds, it could open a big global market.
For Rolls-Royce, the SMR venture represents a potentially transformative new business on the horizon. The company’s core aerospace and defense segments provide stability, while SMRs offer a growth avenue aligned with global decarbonization goals. Rolls has already said it expects the SMR unit to grow “materially,” and winning the UK contract validates its approach against competitors. There are still risks around regulatory approvals and cost control, while revenue from SMRs won’t flow until later this decade. However, the upside is significant if Rolls-Royce captures a first-mover advantage in exporting SMRs worldwide by leveraging its home market as a springboard.
Fluor Corporation (NYSE: FLR)
HQ: USA; Engineering giant and majority owner of NuScale.
Fluor Corporation is a global engineering firm that has made itself a key player in SMRs by backing one of the leading developers. Fluor is the majority owner of NuScale Power – holding roughly a 60% stake – and has helped fund NuScale’s SMR through its development. This could pay off if NuScale’s reactors are widely deployed, as Fluor would benefit both as a major shareholder and as the likely contractor building NuScale plants. Beyond NuScale, Fluor stands to gain from any broader nuclear resurgence: the company’s expertise in managing complex energy projects makes it a prime contender to construct new SMR deployments for utilities and governments.
Fluor offers a way to tap into SMR growth through a well-established industrial name. Its core business spans oil & gas, infrastructure, and government work, so Fluor isn’t dependent solely on nuclear. At the same time, the NuScale stake gives it upside exposure to one of the most advanced SMR technologies. If NuScale’s first projects make progress and industry confidence in SMRs grows, Fluor’s equity stake and nuclear construction segment could appreciate substantially. Execution will be critical, but Fluor’s long track record with mega-projects lends confidence.
Private Companies to Watch
Some of the most daring SMR work happens off the public exchanges. Venture‑backed players supported by billionaires and strategic investors are racing to prove radical reactor concepts before tapping capital markets. Though not publicly traded yet, their breakthroughs and supplier alliances serve as bellwethers for the sector’s health. Early customers, fuel contracts, or DOE milestones often ripple into the valuations of listed peers and hint at future IPOs.
TerraPower
HQ: USA; Bill Gates–backed firm building the sodium-cooled Natrium SMR.
TerraPower is among the most high-profile advanced nuclear startups – in part because it was founded by Microsoft co-founder Bill Gates. TerraPower’s flagship design is the Natrium reactor, a 345 MWe sodium-cooled fast reactor with an innovative molten salt energy storage system. This allows the reactor to load-follow like a giant battery, an attractive feature for grids with lots of renewables. TerraPower, in partnership with GE Hitachi, won a major U.S. Department of Energy award to build a Natrium demonstration plant at a retiring coal site in Wyoming, aiming for operation around 2030. If successful, it will be one of the first Gen-IV reactors to deliver electricity to the grid.
TerraPower embodies the long-term, high-upside potential of SMRs. TerraPower’s success would validate advanced reactor economics and the viability of alternatives to traditional reactors. It has already prompted efforts to expand the fuel supply chain (for example, producing the HALEU fuel its design needs). Thus, watching TerraPower is key – its milestones (or setbacks) will likely influence sentiment toward nuclear innovation. If TerraPower eventually IPOs or seeks public funding, it could offer a unique chance to invest in a company at the forefront of reinventing nuclear energy on a grand scale.
X-energy
HQ: USA; Xe-100 developer with major backing from DOE and Big Tech.
X-energy is a private leader in advanced SMRs, focused on its Xe-100 reactor – an 80 MWe high-temperature gas reactor fueled by durable TRISO pebbles. X-energy was one of two companies (with TerraPower) to win a major DOE award under the Advanced Reactor Demonstration Program. It is working with Energy Northwest to build a four-unit (320 MWe total) Xe-100 plant in Washington state by the late 2020s. X-energy is also partnering with industry – for example, it plans to deploy a reactor at a Dow chemical site by the early 2030s. In 2023, Amazon invested in X-energy and announced plans to help deploy up to 5 GW of its reactors by 2035, starting with the Washington project. These partnerships signal strong market demand for X-energy’s carbon-free power solution.
Though still private (a planned SPAC listing was canceled in 2023), X-energy has attracted significant funding from corporate and government sources. It is a relatively mature SMR venture with a clear path to commercial operation. The pebble-bed design offers inherent safety (TRISO fuel that cannot melt). X-energy is also building a fuel fabrication facility to supply its reactors. If it meets its schedule, it could be among the first next-gen nuclear companies to generate revenue from a working plant. An eventual IPO could give investors access to this frontrunner. In the meantime, X-energy’s progress serves as a barometer for confidence in the SMR industry.
Kairos Power
HQ: USA; SMR developer of Hermes, the first NRC-approved molten salt test reactor.
Kairos Power is a nuclear startup taking an iterative, Silicon Valley–style approach to SMR development. Its Hermes demonstration unit in Oak Ridge, Tennessee is slated to start up by 2027 using a novel fluoride-salt coolant. This will test Kairos’s design on a small scale before scaling to a planned ~140 MWe commercial SMR. The design uses TRISO pebble fuel and low-pressure molten salt cooling, a combination promising high safety and efficient heat transfer. The NRC has already granted Kairos a construction permit for Hermes, a first for any Gen-IV reactor. Google is among the companies partnering with Kairos to explore its reactors for data center power needs.
While still private and pre-revenue, Kairos’s “build-test-learn” philosophy makes it unique among SMR ventures. It aims to de-risk its technology with prototypes (much like SpaceX does with rockets) before building full-scale plants. If its demonstrations succeed, Kairos could leap forward in the race to commercialize Gen-IV reactors. One major challenge is securing HALEU fuel, which is in limited supply today. Nonetheless, the company’s momentum and strong backers suggest it could become a major SMR contender.
Holtec International
HQ: USA; Veteran nuclear firm developing the SMR-160 for global markets.
Holtec International built its name designing nuclear spent fuel storage systems, and now it’s developing its own reactor: the SMR-160. True to its name, SMR-160 is a 160 MWe pressurized water reactor – essentially a smaller, simplified version of a conventional reactor with an emphasis on passive safety. Holtec largely self-funded the reactor’s R&D for a decade and recently received a DOE grant to support final design work. The company is targeting both U.S. and international markets. In 2023, Holtec signed an agreement with Ukraine’s Energoatom to potentially build up to 20 SMR-160 units in Ukraine, with the first unit aimed for 2029.
Holtec’s pitch is a smaller reactor that utilities or industrial firms can adopt with less financial risk than a full-scale plant. The company’s long nuclear engineering experience (from plant decommissioning to fuel handling) lends credibility to its plans. If SMR-160 wins deployment at a site, either in the U.S. or abroad, it would validate Holtec’s bet and potentially lead to broader adoption. While not publicly traded, Holtec’s progress bears watching; the company could eventually seek outside investors or partners if demand grows.
Westinghouse Electric Company
HQ: USA; Legacy nuclear firm launching a modular version of its proven reactor.
Westinghouse Electric Company is a storied name in nuclear energy adapting its technology to the SMR era. Now privately held (co-owned by Brookfield and Cameco), Westinghouse in 2023 unveiled the AP300, essentially a 300 MWe small modular version of its proven AP1000 reactor. By leveraging an already licensed design, Westinghouse aims to secure U.S. NRC certification by 2027 and have the first AP300 operating by the early 2030s. The AP300 uses the same fuel, safety features, and supply chain as the larger AP1000, giving it a reassuring pedigree for utilities. Westinghouse is pitching the AP300 globally for mid-sized power needs, and it’s also developing a microreactor (the 5 MWe “eVinci”) for remote sites.
There’s no publicly traded play for Westinghouse’s SMR endeavors (except indirectly via part-owner Cameco), but its progress matters for the whole sector. For example, the AP300’s success could directly benefit its owners and suppliers (like Cameco for fuel). More broadly, Westinghouse’s pivot shows that industry giants are also adapting to the new demand for small reactors. A future IPO or sale of Westinghouse is possible if its SMR business booms.