10 Listed Companies Developing Small Modular Reactors (SMRs)

NuScale Power (SMR)

HQ 🇺🇸 United States · Market cap $3.9B · Yahoo Finance ↗ · Investor Relations ↗

NuScale is the only company in the world with an NRC-certified SMR design.⁶

NuScale Power Corp (SMR) received Standard Design Approval for its original 50 MWe module in 2020, followed by Design Certification for that design in 2023. The United States Nuclear Regulatory Commission issued Standard Design Approval for the uprated 77 MWe module in May 2025. Founded in 2007 by researchers from Oregon State University who developed the original reactor concept, the company has spent nearly two decades developing its VOYGR pressurized water reactor.⁶

Each NuScale Power Module (NPM) generates 77 MWe and is designed for factory fabrication and truck delivery to site. A single VOYGR plant can house up to 12 modules for a combined output of 924 MWe. The design uses natural circulation cooling and passive safety systems, meaning the reactor can shut down and self-cool indefinitely without operator intervention, AC or DC power, or additional water.⁶

NuScale’s commercial pipeline centers on two major programs. RoPower Nuclear, a joint venture between Romania’s Nuclearelectrica and Nova Power & Gas, is planning a six-module VOYGR plant at the Doicesti Power Station site, though the project timeline has slipped to a projected 2033 commercial operation date.⁷ In the United States, ENTRA1 Energy is NuScale’s exclusive global commercialization partner and is in negotiations with the Tennessee Valley Authority (TVA) to deploy up to six 12-module plants totaling approximately 6 GW of capacity, with a first plant targeted for power delivery by 2030.⁸

NuScale’s 2025 Annual Report warns: “We have incurred significant losses since inception, we expect to incur losses in the future, and we may not be able to achieve or maintain profitability.”⁹

NuScale reported a loss from operations of $689.6 million USD for fiscal year 2025, up sharply from $138.7 million in fiscal 2024, driven primarily by a $507.4 million milestone contribution payment under its partnership agreement with ENTRA1 Energy expensed through general and administrative costs. The company has not yet generated revenue from module deliveries. NuScale holds 781 patents granted or pending across 21 countries and has assembled a supply chain including Doosan Enerbility for heavy components, Framatome for fuel, and Paragon Energy Solutions for monitoring and protection systems.⁹

Oklo Inc. (OKLO)

HQ 🇺🇸 United States · Market cap $8.4B · Yahoo Finance ↗ · Investor Relations ↗

Oklo Inc (OKLO) is developing the Aurora, a compact fast neutron reactor capable of generating 15 to 100+ MWe. The design uses metallic fuel and is intended to operate with high-assay low-enriched uranium (HALEU) or recycled nuclear fuel. Any cost or waste advantage will depend on licensing, fuel availability, recycling capability and commercial operation.¹⁰

The company operates across three business segments: Oklo Power (reactor development and deployment), Oklo Fuel (fuel recycling and supply), and Oklo Isotopes (radioisotope production, following its February 2025 acquisition of Atomic Alchemy). Oklo completed groundbreaking for its first Aurora powerhouse at Idaho National Laboratory and targets initial deployment in 2028.¹¹

In August 2026, Oklo’s Groves isotope test reactor in Texas reached first criticality a little over 11 months after groundbreaking: the first reactor the company has built and operated, constructed on private land with private capital under the Department of Energy’s Reactor Pilot Program.

Oklo’s customer pipeline includes some of the largest names in technology. Meta Platforms has signed a prepayment agreement for a 1.2 GW campus in Ohio, with initial capacity of 150 MW targeted for approximately 2030. Other announced customers include Equinix, Diamondback Energy, Switch (with a 12 GW Master Power Agreement), and Prometheus Hyperscale.

The company’s regulatory pathway involves a combined license application with the NRC. An Operational Testing Authorization (OTA) has been signed with the Department of Energy, the Nuclear Safety Design Assessment (NSDA) has been approved, and in the second quarter of 2026 the DOE approved the preliminary documented safety analysis (PDSA) for Aurora-INL, allowing final design and construction to advance. Kiewit serves as lead construction contractor, while Siemens Energy has been contracted for the power conversion system.

Oklo reported total operating expenses of $139.3 million USD in fiscal 2025, up from $52.8 million in fiscal 2024.

X-Energy, Inc. (XE)

HQ 🇺🇸 United States · Market cap $5.8B · Yahoo Finance ↗

At its initial gross size of $1.02 billion, X-Energy’s April 2026 Nasdaq offering was the largest IPO by an advanced nuclear developer to date.³

X-Energy, Inc. (XE) is developing the Xe-100, a Generation IV pebble-bed high-temperature gas-cooled reactor (HTGR) producing 80 MWe per unit (200 MWt), designed for deployment in a standard four-reactor configuration generating 320 MWe per plant. X-Energy priced its upsized Nasdaq IPO on April 23, 2026, at $23 per share, above the $16 to $19 target range. Shares began trading on April 24, and the offering closed on April 27 after the underwriters exercised their over-allotment option.³¹² Founded in 2009 by Dr. Kamal “Kam” Ghaffarian, X-Energy employs around 916 staff, of whom over 400 hold advanced degrees, led by Chief Executive Officer J. Clay Sell, a former U.S. Deputy Secretary of Energy.³

The Xe-100 uses helium coolant and graphite moderation, operating at 565°C, high enough for both electricity generation and industrial process heat applications such as chemical manufacturing. The design relies on passive safety physics: in a loss-of-cooling scenario, the negative temperature coefficient slows fission and heat dissipates without operator intervention, enabling an emergency planning zone of just 400 metres compared to 16 kilometres for conventional large reactors. X-Energy’s wholly owned subsidiary TRISO-X manufactures the proprietary tri-structural isotropic coated particle pebble fuel required by the Xe-100, using HALEU enriched to 15.5%. The TX-1 fuel fabrication facility in Oak Ridge, Tennessee (the first Category II nuclear fuel facility licensed in the United States, following an NRC Special Nuclear Material License issued in February 2026) is under construction and targeted for completion in the first half of 2028.

X-Energy’s announced pipeline includes a Dow project, Amazon options and a non-binding joint development agreement with Centrica. Dow’s subsidiary Long Mott Energy filed a Construction Permit Application with the NRC in March 2025 for a four-reactor Xe-100 plant at its Seadrift, Texas facility under the U.S. Department of Energy’s Advanced Reactor Demonstration Program, with permit receipt targeted for Q1 2027. Amazon holds options for more than 5 GWe of Xe-100 capacity through 2039, beginning with an Energy Northwest project in central Washington. Centrica’s agreement covers a potential UK fleet of approximately 6 GWe, represented by 76 reactors, with Hartlepool identified as the preferred site for a first project of up to 12 reactors. Together, the announced Dow, Amazon and Centrica opportunities exceed 11 GWe, but they comprise different types of arrangements and remain subject to approvals and final investment decisions.³

X-Energy generated $109.1 million in total revenues and grant income in fiscal year 2025, principally from services work and ARDP cost-share reimbursements, against a net loss of $389.8 million. The company entered its IPO with approximately $1.03 billion in combined cash and investments. First commercial Xe-100 delivery is targeted for the early 2030s.³ For a full breakdown of the IPO terms, ownership structure, financial performance and key risks, see our X-Energy IPO Preview.

Terrestrial Energy (IMSR)

HQ 🇨🇦 Canada · Market cap $615M · Yahoo Finance ↗ · Investor Relations ↗

Terrestrial Energy Inc (IMSR) is developing the Integral Molten Salt Reactor (IMSR), a Generation IV reactor that uses liquid fluoride salt as a coolant and fuel carrier. The company began trading on the NASDAQ following completion of its business combination with HCM II Acquisition Corp.¹³

The IMSR plant consists of two reactor units for a combined output of 390 MWe. It operates at 585°C, which enables thermal efficiency of approximately 44%, significantly higher than the roughly 30% efficiency of conventional light-water reactors. The sealed core unit is designed to be replaced entirely at the end of its seven-year service life. The reactor uses standard assay low-enriched uranium, avoiding the HALEU supply chain constraints faced by some competitors.¹⁴

In February 2025, the Texas A&M University System selected Terrestrial Energy’s IMSR for siting at its RELLIS campus following a competitive Request for Proposals process.¹⁵

The Canadian Nuclear Safety Commission (CNSC) completed its Vendor Design Review in April 2023 and declared no fundamental barriers to licensing the IMSR design. Terrestrial Energy’s engagement with the United States NRC commenced in 2016 and includes a joint CNSC-NRC review under a Memorandum of Cooperation. The company targets first commercial IMSR operations in the early 2030s.

Terra Innovatum (NKLR)

HQ 🇬🇧 United Kingdom · Market cap $665M · Yahoo Finance ↗ · Investor Relations ↗

Terra Innovatum Global N.V. (NKLR) is developing the SOLO, a helium gas-cooled micro-modular reactor designed to generate 1 MWe (5 MWt). At 1 MWe, it is smaller than the other designs covered here. It uses a thermally moderated, gas-cooled core with low-enriched uranium below 5% and conventional zircaloy-clad UO2 fuel rods. The current design targets 15 years of operation without refuelling and a potential 45-year life through core swaps; the company says a future HALEU configuration could operate for up to 45 years without refuelling.¹⁶¹⁷

In March 2026, the United States NRC formally docketed Terra Innovatum’s SOLO topical reports, initiating the formal review and approval process. The NRC determined that the submissions contained sufficient technical information to begin detailed safety and design evaluation. Earlier in 2026, the company completed the Phenomena Identification and Ranking Table (PIRT), a key pre-licensing milestone, and NRC Safety Evaluations of the topical reports are anticipated by October 2026.¹⁸

Terra Innovatum’s latest SEC prospectus targets commercial deployment of the SOLO in 2028. The company’s proposed first site is Rock City Industrial Park in Valmeyer, Illinois, where it plans to supply behind-the-meter power. The site owner has an option to order up to 50 reactors, subject to definitive agreements and regulatory approvals.¹⁷

In February 2026, Terra Innovatum announced completion of its full end-to-end supply chain for the SOLO reactor, including nuclear-grade graphite and other critical components. The company also appointed Kathy Williams, former Framatome CEO and CFO, to its leadership team in March 2026.¹⁹²⁰

Rolls-Royce Holdings (RR.L)

HQ 🇬🇧 United Kingdom · Market cap $172B · Yahoo Finance ↗ · Investor Relations ↗

Rolls-Royce Holdings plc (RR.L) is developing its SMR through Rolls-Royce SMR Ltd, a subsidiary initially backed by Rolls-Royce Group, BNF Resources (the Perrodo family), the Qatar Investment Authority, and Constellation Energy. Czech utility CEZ Group agreed to acquire a 20% stake in October 2024, with the transaction completing in two tranches: approximately 11% in March 2025 and the full 20% by July 2025, diluting the original shareholders’ positions accordingly.²¹²²

The Rolls-Royce SMR is a 470 MWe pressurized water reactor designed for a 10-acre footprint and at least 60 years of operation. The company targets a 500-day on-site construction period within a total four-year build cycle (two years site preparation plus two years construction and commissioning). It received approximately £210 million in United Kingdom government funding and an initial £195 million in private investment from Rolls-Royce Group, BNF Resources, and the Qatar Investment Authority in 2021, with total private investment later growing to approximately £280 million as additional investors participated.²²

The design is undergoing the United Kingdom’s Generic Design Assessment (GDA), a multi-step regulatory process. Step 1 (Initiation) was completed in April 2023, Step 2 (Fundamental Assessment) in July 2024, and Step 3 (Detailed Assessment) commenced in July 2024 with planned completion by August 2026. Rolls-Royce SMR also received the first regulatory justification approval for an SMR design in the United Kingdom.²³

In November 2025, the United Kingdom government selected the Wylfa nuclear site on the island of Anglesey, North Wales, to host at least three Rolls-Royce SMRs, with potential capacity for up to eight units. The Welsh Government described the project as an initial investment of £2.5 billion. Great British Energy Nuclear (GBE-N) will begin site activity in 2026, with the government targeting power delivery to the grid from the mid-2030s.²⁴

GE Vernova (GEV)

HQ 🇺🇸 United States · Market cap $277B · Yahoo Finance ↗ · Investor Relations ↗

GE Vernova Inc (GEV) is developing the BWRX-300 through GE Vernova Hitachi Nuclear Energy, a joint venture between GE Vernova and Hitachi Ltd. The BWRX-300 is a 300 MWe boiling water reactor (BWR) that simplifies the traditional BWR design by eliminating recirculation pumps, jet pumps, and associated piping, achieving what the company describes as approximately one-tenth the size and complexity of a conventional BWR.²⁵

Ontario Power Generation plans four BWRX-300 units at the Darlington New Nuclear Project site in Ontario. The Canadian Nuclear Safety Commission granted a licence to construct the first unit in April 2025, and Ontario approved that first unit in May 2025. The three additional units remain subject to regulatory approvals; if all four are built, their combined capacity would be 1.2 GW.²⁶²⁷

Early site preparation work has been completed, with key components including the reactor pressure vessel currently in manufacturing. A tunnel boring machine arrived from Germany for assembly in early 2026. OPG expects the first unit to come online by the end of 2030, drawing on more than 7,000 lessons learned from the Darlington refurbishment project completed in early 2026.²⁸²⁷

Beyond Canada, GE Vernova Hitachi has signed a Generic Design Agreement with OSGE in Poland in February 2026 and is exploring BWRX-300 deployment in Southeast Asia. For GEV shareholders, the BWRX-300 program represents one component within a diversified power equipment business that generated $38.1 billion in total revenue in fiscal year 2025.²⁹

Cameco Corp (CCJ)

HQ 🇨🇦 Canada · Market cap $43B · Yahoo Finance ↗ · Investor Relations ↗

Cameco Corp (CCJ) holds a 49% ownership stake in Westinghouse Electric Company, the nuclear technology provider developing two SMR designs: the AP300, a 300 MWe-class pressurized water reactor rated at 330 MWe, and the eVinci microreactor. Brookfield holds the remaining 51%. Cameco acquired its stake as part of a joint acquisition that closed in 2023. The Westinghouse stake adds reactor-technology exposure to Cameco’s uranium mining and nuclear fuel businesses.³⁰

The AP300 is derived from Westinghouse’s AP1000 technology, of which six units are currently operating (two at Plant Vogtle in the United States, four in China) with four additional AP1000 units under construction in China. According to Cameco’s Q4 2025 investor presentation, the AP300 licensing timeline runs from 2022 to 2027, followed by project preparation from 2027 to 2030 and a 36-month construction period, placing the first unit ready for construction around 2030 and first commercial operation around 2033.³¹

Westinghouse has agreements or Memorandums of Understanding in place with Great British Nuclear, Ukraine, and Slovakia for AP300 deployment, with additional sites under consideration in the United States, Canada, and Europe. In the United Kingdom, Community Nuclear Power is planning four AP300 units at Teesside.

On October 27, 2025, Cameco, Brookfield, and the United States Department of Commerce announced a strategic partnership with an $80 billion USD aggregate investment value to facilitate financing and approvals for new Westinghouse AP1000 reactors in the United States. The structure includes a participation interest where the United States Government receives 20% of cash distributions from Westinghouse exceeding $17.5 billion USD.

Westinghouse’s New Build segment (covering AP1000 and AP300) generated approximately $800 million USD in revenue in 2025, representing 16% of total Westinghouse revenue. The core business (outage services, long-term operations, nuclear fuel) generated approximately $4.3 billion USD.

Nano Nuclear Energy (NNE)

HQ 🇺🇸 United States · Market cap $1.0B · Yahoo Finance ↗ · Investor Relations ↗

NANO Nuclear Energy Inc (NNE) is developing the KRONOS MMR™, a 45 MWt (15 MWe) stationary high-temperature gas-cooled reactor (HTGR) using helium coolant and Fully Ceramic Microencapsulated (FCM) fuel, which incorporates TRISO particles in a silicon carbide matrix. The company acquired the KRONOS technology along with the portable LOKI MMR™ from Ultra Safe Nuclear Corporation in early 2025, inheriting a design platform with a high technology readiness level built on decades of prior HTGR operating history spanning programmes including Dragon, Fort St. Vrain, AVR, and China’s HTR-PM.³²

On March 31, 2026, The Grainger College of Engineering at the University of Illinois Urbana-Champaign submitted a Construction Permit Application to the US Nuclear Regulatory Commission for the proposed KRONOS MMR prototype on its campus. The NRC accepted the application for review on May 18 and subsequently set target dates of May 2027 for the final environmental assessment and September 2027 for the final safety evaluation. NANO Nuclear expects initial construction activities to begin in the second half of 2027, subject to regulatory approvals.²³³

In Canada, NANO Nuclear is pursuing regulatory approval through the Canadian Nuclear Safety Commission (CNSC), where the KRONOS MMR was the first microreactor to enter the Phase 1 pre-licensing process. The company’s acquisition of Global First Power (rebranded True North Nuclear) provides an existing Canadian licensing application for a KRONOS MMR demonstration project at Chalk River, Ontario. The company also plans a reduced-scale non-nuclear engineering demonstration unit at its Oak Brook, Illinois technical facility to support engineering validation ahead of nuclear construction.

NANO Nuclear frames itself as a vertically integrated advanced nuclear company across five business lines: microreactor development, nuclear fuel fabrication, nuclear fuel transportation, nuclear space applications, and nuclear consulting. Its fuel subsidiaries include HALEU Energy Fuel Inc (developing a domestic HALEU fabrication pipeline) and Advanced Fuel Transportation Inc (AFT), which holds an exclusive licence for a patented high-capacity HALEU fuel transportation basket developed with US national laboratories. Strategic affiliate LIS Technologies, which uses laser isotope separation for uranium enrichment, received a Key Radioactive Material License in early 2026 and announced plans to invest USD 1.38 billion in a commercial enrichment facility in Oak Ridge, Tennessee.³⁴

Commercially, the company has signed a feasibility study agreement with BaRupOn to evaluate deploying KRONOS MMR reactors to provide up to 1 GW of power to a data centre and manufacturing campus, and MOUs with DS Dansuk (South Korea), Ameresco, and others covering deployment, manufacturing localization, and EPC integration. As of December 31, 2025, NANO Nuclear held cash and cash equivalents of USD 577.5 million following an oversubscribed private placement in October 2025 that raised approximately USD 400 million gross (approximately USD 379 million net of fees). Operating cash burn for Q1 FY2026 (quarter ended December 31, 2025) was USD 4.0 million, with a net loss from operations of USD 11.6 million for the quarter.³⁵

Deep Fission (FISN)

HQ 🇺🇸 United States · Market cap $503M · Yahoo Finance ↗ · Investor Relations ↗

Deep Fission, Inc (FISN) is developing the Gravity Nuclear Reactor™, a small modular pressurized water reactor designed to operate roughly one mile underground at the bottom of a 30- to 50-inch-diameter vertical borehole. Its initial 2×2 fuel-assembly configuration targets up to approximately 8 MWe per reactor, with a later 3×3 configuration targeting up to approximately 15 MWe. The design uses conventional PWR fuel and control principles; at depth, the hydrostatic pressure of the mile-deep water column (roughly 160 atmospheres) is intended to support reactor operating pressure and primary cooling, while the surrounding geology provides structural confinement and shielding. The company says this approach reduces reliance on the large forged pressure vessels and above-ground containment structures of surface plants, and targets delivered power at 5 to 7 cents per kWh.⁴³⁶

The company was founded in 2023 by chief executive Elizabeth Muller and her father, Berkeley physicist Richard Muller, the team behind spent-fuel disposal company Deep Isolation, with which Deep Fission holds a memorandum of understanding on used-fuel management. Deep Fission was selected for the US Department of Energy’s Reactor Pilot Program and holds a long-term lease on approximately 100 acres at the Great Plains Industrial Park in Parsons, Kansas, where it has drilled a data-acquisition well gathering data at depths of up to 6,000 feet. A non-nuclear prototype reactor canister arrived at the Kansas site on July 7, 2026, as part of a proof-of-concept programme whose next stage includes a commercial-scale-diameter, non-nuclear borehole and installation testing.³⁷ Subject to DOE authorization, the company intends to demonstrate the Gravity Reactor and apply to the NRC for a commercial license in the first half of 2027, converting the same pilot reactor to commercial operation.⁴

Deep Fission’s commercial pipeline is preliminary. Its publicly announced January 2025 partnership with sustainable data-centre developer Endeavour, aimed at powering Endeavour’s Edged AI data centres, is governed by a non-binding term sheet entered in November 2024: the framework contemplates potential deployments of up to 1.5 GW at a single location, within a broader potential co-development framework of up to 2 GW across multiple projects, and creates no commitments to purchase electricity, finance projects, construct facilities, grant exclusivity, or deploy a specified number of reactors.⁴³⁶

Deep Fission’s route to the public market was unusual. Legacy Deep Fission listed via a September 2025 reverse merger with shell company Surfside, while the combined company separately completed a concurrent $30 million private placement; a further $80 million private placement followed in February 2026. It then priced a traditional Nasdaq IPO on June 17, 2026, selling 2.5 million shares at $16.00 after terms were reduced from a preliminary proposal of 6 million shares at $24 to $26; trading began June 18 and the offering closed June 22, raising $40.0 million gross (approximately $32.9 million net).³⁸⁴³⁹ At $16.00, the roughly 60.3 million post-offering shares implied a market capitalization of about $965 million. The company, its directors and officers, and certain shareholders are subject to 180-day underwriter lock-ups running from the June 17 prospectus; other holders have different or no lock-up terms. Deep Fission is pre-revenue, and per its prospectus the pilot program and commercial deployments are not fully funded and will require substantial additional capital.⁴

Risks

NuScale’s experience shows how difficult licensing and deployment schedules are to predict. The company holds the only NRC-certified SMR design, yet its proposed commercial deployments have repeatedly moved further out. Regulators in the United States, Canada and the United Kingdom are reviewing several SMR applications, and developers’ stated timetables remain subject to revision.⁶²³²⁶²

Commercial SMR and MMR deployments have not yet generated meaningful revenue for any company covered here. NuScale, Oklo, Terrestrial Energy, Terra Innovatum and NANO Nuclear continue to report operating losses while funding their reactor programmes. GE Vernova and Rolls-Royce can support development from diversified businesses. Cameco receives revenue through Westinghouse’s existing reactor-services operations, although the AP300 remains under development.^{101729303592140}

The AP1000 units at Plant Vogtle demonstrate the financial consequences of nuclear construction risk. The project experienced years of delays and billions of dollars in cost overruns, which contributed to Westinghouse’s 2017 bankruptcy. SMR developers expect factory fabrication and modular construction to improve delivery, but this has not been demonstrated at commercial scale.⁴¹

Fuel availability could also limit deployment. Oklo’s Aurora and NANO Nuclear’s KRONOS require high-assay low-enriched uranium (HALEU), for which commercial supply remains limited. Oklo is working with Centrus Energy, while NANO Nuclear has established HALEU Energy Fuel and a separate fuel-transportation subsidiary. These initiatives have yet to demonstrate supply at the scale required by multiple advanced-reactor programmes.¹⁰³⁴⁴²

SMRs must compete for capital with natural-gas generation, renewable projects paired with battery storage and conventional large reactors. Nuclear siting also faces public opposition in some jurisdictions. A serious incident elsewhere in the industry could affect regulatory decisions and public support for SMR deployment.

Conclusion

These ten companies represent the listed universe of SMR and MMR developers as of mid-2026, spanning reactor types from proven pressurized water technology to experimental molten salt, fast reactor, and high-temperature gas-cooled designs. They range from pre-revenue startups like Oklo, Terra Innovatum, and NANO Nuclear to diversified industrial conglomerates like GE Vernova and Rolls-Royce, offering varying degrees of reactor-specific exposure.

Among the grid-scale projects, GE Vernova and OPG’s first BWRX-300 at Darlington is closest to commercial operation, with one unit under construction and grid connection targeted by the end of 2030.²⁶²⁷ NuScale holds the only NRC-certified SMR design, although its proposed US deployments do not yet have a contracted construction timetable.⁶

The smaller designs are pursuing earlier stated deployment dates. Terra Innovatum’s latest SEC prospectus targets commercial deployment of its 1 MWe SOLO in 2028.¹⁷ The University of Illinois submitted the construction-permit application for NANO Nuclear’s 15 MWe KRONOS MMR on March 31, 2026.² Deep Fission plans to use the DOE Reactor Pilot Program pathway and targets an NRC licence application in the first half of 2027 for a design initially configured at up to approximately 8 MWe.⁴ These remain developer schedules rather than demonstrated construction timelines.

The first Western SMR or MMR deployments to enter commercial operation will provide evidence on capital cost, construction time and operating performance. Until then, schedules and economics remain developer targets rather than demonstrated outcomes.