11 Listed Companies Developing Small Modular Reactors (SMRs)

NuScale Power (SMR)

HQ 🇺🇸 United States · Market cap $3.8B · Yahoo Finance ↗ · Investor Relations ↗

NuScale is the only company in the world with an NRC-certified SMR design — the 12-module, 50 MWe US600.⁶

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. The certified US600 plant design combines twelve 50 MWe modules, while the US460 design approved in 2025 pairs six 77 MWe modules — and Standard Design Approval is a preliminary step short of full design certification. 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, though a 12-module plant of 77 MWe units sits outside the approved US460 configuration and would need further NRC approval. 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 Fluor, the prime contractor, completed front-end engineering and design phase 2 on the project in late 2025, and NuScale said on its second-quarter 2026 earnings call that the project had moved into a pre-EPC phase running up to a final notice to proceed, which chief executive John Hopkins put at “probably another year from now.” Nuclearelectrica cautioned in July 2026 that mandatory conditions attached to the project’s February 2026 investment decision remained unresolved. 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; the collaboration is non-binding and no firm module order has been signed.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, and second-quarter 2026 revenue was $0.1 million against $8.1 million a year earlier, the drop reflecting the end of the Fluor FEED work on RoPower. It closed June 2026 with $1.9 billion of cash, cash equivalents and short- and long-term investments. NuScale holds 513 issued patents and a further 268 pending applications 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 $7.5B · 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 $5.0B · 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 meters compared to 16 kilometers 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 (licensed under a 40-year NRC Special Nuclear Material License issued in February 2026 — the first US license for a Category II fuel fabrication facility dedicated to advanced-reactor fuel) 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; the NRC’s environmental review concluded with a finding of no significant impact in May 2026, while the safety review continues. 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

In August 2026 the fuel supply chain behind the Xe-100 moved onto contract. X-Energy signed long-term HALEU enrichment services agreements with Centrus Energy and General Matter, and agreed to invest up to $8 million in milestone-based payments to expand SGL Carbon’s nuclear-grade graphite production at Chedde, France — an agreement the companies state would double the site’s NBG-18 capacity by 2030. The Department of Energy also notified X-Energy on August 12, 2026 that its ARDP cooperative agreement will receive up to an additional $1.0 billion under the program’s 50/50 cost-share terms, taking the DOE’s total commitment to up to $2.115 billion, of which $547 million had been reimbursed to June 30, 2026.⁵³

X-Energy reported $54.6 million of revenue and grant income for Q2 2026, up from $21.5 million in Q2 2025 and driven principally by engineering and design services under the ARDP, against operating expenses of $164.6 million that included $33.5 million of non-cash equity compensation tied to IPO grants. Cash, equivalents and investments were approximately $1.9 billion at June 30, 2026, with no debt. First commercial Xe-100 delivery is targeted for the early 2030s.⁵³ For a full breakdown of the IPO terms, ownership structure and key risks, see our X-Energy IPO Preview.

Terrestrial Energy (IMSR)

HQ 🇨🇦 Canada · Market cap $540M · 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 In June 2026, the company signed ground lease and research agreements giving it exclusive access to approximately 77 acres at RELLIS for the planned commercial IMSR plant, and site characterization work is intended to support a future NRC construction permit application.⁵¹ Terrestrial Energy also announced a collaboration with Riot Platforms in May 2026 to develop nuclear-powered data center projects, a program targeting up to 4 GW of IMSR capacity; the company put the indicative capacity of its full project pipeline at 7.8 GW in August 2026.⁵²

The Canadian Nuclear Safety Commission (CNSC) completed its Vendor Design Review in April 2023 and declared no fundamental barriers to licensing the IMSR design. That review is a voluntary pre-licensing assessment rather than a design certification or plant license, and it identified further design work to complete. 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 NRC has approved two IMSR topical reports, principal design criteria in 2025 and the postulated initiating events methodology in May 2026, and the company is developing a pilot reactor (Project TETRA) and a pilot fuel salt production facility (Project TEFLA) under Other Transaction Agreements with the U.S. Department of Energy.⁵¹ The company targets first commercial IMSR operations in the early 2030s.

Terra Innovatum (NKLR)

HQ 🇬🇧 United Kingdom · Market cap $623M · 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 $171B · Yahoo Finance ↗ · Investor Relations ↗

Rolls-Royce Holdings plc (RR.L) is developing its SMR through Rolls-Royce SMR Ltd, 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 first tranche triggered a change of control on 4 March 2025, since when Rolls-Royce Holdings has equity-accounted its stake rather than consolidating Rolls-Royce SMR Ltd as a subsidiary; the holding is reported within the group’s All Other Businesses category.⁵⁴

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 and remains in progress; the UK regulators’ July 2026 update scheduled the Step 3 public consultation for February 2027, taking the assessment beyond its originally planned August 2026 completion. Rolls-Royce SMR also received the first regulatory justification approval for an SMR design in the United Kingdom, granted in March 2026 — a decision separate from the GDA and from site licensing.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 In April 2026, GBE-N converted that selection into a firm contract with Rolls-Royce SMR to design and build the first three Wylfa units — a program of at least 1.4 GW — enabling site-specific design work and orders for critical components, though the contract is not an operating license and nuclear construction has not begun.

Reporting its 2026 half-year results in July 2026, Rolls-Royce said the GBE-N contract in the United Kingdom and the CEZ Group contract in the Czech Republic had both entered their execution phase and were generating revenues and profits for Rolls-Royce SMR. In the same period Rolls-Royce SMR was selected by Videberg Kraft to supply three SMRs in Sweden, and in July 2026 signed a memorandum of understanding with CEZ and the Czech government covering preparation of two further Czech sites. Management restated a target of commissioning two reactors per year by the mid-2030s, rising to eight per year at maturity, and said it was accelerating research into advanced modular reactors under agreements with nuclear authorities in the United Kingdom and Japan.⁵⁴

GE Vernova (GEV)

HQ 🇺🇸 United States · Market cap $243B · 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 (OPG) — the project’s owner, licensee and intended operator — plans four BWRX-300 units at the Darlington New Nuclear Project site in Ontario. The Canadian Nuclear Safety Commission (CNSC) granted OPG a license to construct the first unit in April 2025, and Ontario approved that first unit in May 2025. In March 2026 the CNSC removed the first regulatory hold point, authorizing reactor-building foundation and civil works, and now classifies Unit 1 as under construction; OPG has also applied for a 20-year operating license for the unit, an application still under review. The three additional units remain subject to further construction 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. The US pipeline advanced in the second quarter of 2026, when GE Vernova secured two further technology selections under early work agreements for its SMR in the United States, though it disclosed no customer names, contract values or timelines.⁵⁶ 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 The nuclear business is still small within that: Nuclear Power revenue was $817 million in the second quarter of 2026 and $1,575 million in the half, against $649 million a year earlier.⁵⁶

Cameco Corp (CCJ)

HQ 🇨🇦 Canada · Market cap $44B · 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 Cameco’s shares trade primarily on the Toronto Stock Exchange as CCO, with a New York listing as CCJ, and its SMR exposure is indirect: Westinghouse, not Cameco, develops the reactors, while Cameco’s own core business remains uranium mining, conversion and fuel services.

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. Cameco’s Q4 2025 investor presentation put the AP300 licensing timeline at 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 That has since moved out. At its Q2 2026 results Cameco gave a construction period of roughly 40 months per unit and first commercial operation potentially in the mid-to-late 2030s, with $0.8 billion to $1.2 billion of spending remaining to finalize the design and an nth-of-a-kind two-unit overnight capital cost of approximately $6 billion to $8 billion. About 80% of the supply chain is common with the AP1000, and more than 30 units are in origination.⁵⁵

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. That interest is conditional: it vests only if the Department of Commerce arranges at least $80 billion of investment in US nuclear projects before January 2029, a condition management confirmed was unchanged as of its Q2 2026 call.⁵⁵

Westinghouse’s New Build segment (covering AP1000 and AP300) generated approximately $800 million USD in revenue in 2025, representing 16% of total Westinghouse revenue; that revenue reflects AP1000 work, as no AP300 has been ordered or built. 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 $965M · 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, The design draws on the HTGR lineage of earlier programs including Dragon, Fort St. Vrain, AVR, and China’s HTR-PM, though KRONOS itself has yet to be built or operated.³²

On March 31, 2026, The Grainger College of Engineering at the University of Illinois Urbana-Champaign — the license applicant — submitted a Construction Permit Application to the US Nuclear Regulatory Commission for the proposed KRONOS MMR on its campus, a unit that would be licensed as a non-power research reactor with NANO Nuclear as technology supplier. 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. A separate operating license would be required before the unit could run; 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, an application that remains in the licensing process. 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, with its latest quarterly filing describing four principal business lines: its nuclear reactor business led by KRONOS, a nuclear fuel supply chain business, a nuclear fuel transportation business, and nuclear consultation and technical services. Its fuel subsidiaries include HALEU Energy Fuel Inc (developing a domestic HALEU fabrication pipeline) and Advanced Fuel Transportation Inc (AFT), which holds an exclusive license for a patented high-capacity HALEU fuel transportation basket developed with US national laboratories. LIS Technologies, a strategic affiliate outside the consolidated group, uses laser isotope separation for uranium enrichment; it received a Key Radioactive Material License in early 2026 and announced its own plans to invest USD 1.38 billion in a commercial enrichment facility in Oak Ridge, Tennessee.³⁴

Commercially, the company completed a feasibility study with BaRupOn during the quarter ended June 30, 2026 evaluating a phased deployment of up to 1 GW of KRONOS MMR capacity at a data center and manufacturing campus, and has signed MOUs with DS Dansuk (South Korea), Ameresco, Supermicro and others covering deployment, manufacturing localization, EPC integration and AI data center platforms. In May 2026 its Advanced Fuel Transportation subsidiary acquired Secured Transportation Services, a nuclear logistics and transportation operator, for total consideration of USD 10.3 million; the business contributed USD 0.2 million of revenue between closing on May 22 and June 30, 2026, the company’s first revenue. As of June 30, 2026 NANO Nuclear held cash, cash equivalents and short-term investments of USD 580 million, after approximately USD 26 million of net at-the-market proceeds during the quarter and an oversubscribed private placement in October 2025 that raised approximately USD 400 million gross. Operating expenses for the quarter ended June 30, 2026 were USD 15.9 million and the net loss was USD 10.1 million.⁵⁷

Deep Fission (FISN)

HQ 🇺🇸 United States · Market cap $396M · 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 program whose next stage includes a commercial-scale-diameter, non-nuclear borehole and installation testing.³⁷ The company is advancing a second, near full-scale proof-of-concept well and targets completing that phase of work by the end of 2026. On August 6, 2026 the DOE conditionally approved Deep Fission’s Nuclear Safety Design Agreement for the Gravity Reactor, allowing it to move to the next stage of the Reactor Pilot Program review with submission of a Preliminary Documented Safety Analysis.⁴⁸⁴⁹ Subject to further DOE authorization, the company intends to demonstrate the Gravity Reactor and apply to the NRC for a commercial license in 2027, with conversion of the same pilot reactor to commercial operation subject to separate NRC licensing.⁴⁴⁹

Deep Fission’s commercial pipeline is preliminary and entirely non-binding. On June 24, 2026 the company said it had signed letters of intent with data centers, co-developers, industrial parks and strategic partners representing up to 18.5 GW of potential generation capacity, while stating that the LOIs “do not contain commitments to purchase electricity, finance projects, construct facilities, grant exclusivity, or deploy a specified number of reactors” and that either party may terminate without penalty.⁵⁰ The largest named relationship within that pipeline is the January 2025 partnership with sustainable data-center developer Endeavour, aimed at powering Endeavour’s Edged AI data centers and governed by a non-binding term sheet entered in November 2024, contemplating 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.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 alongside a concurrent $30 million private placement, raised a further $80 million privately in February 2026, and then completed a traditional Nasdaq IPO in June 2026, selling 2.5 million shares at $16.00 to raise $40.0 million gross and $34.3 million net.^3843949

The first results Deep Fission filed as a listed company put a number on how much more capital the plan needs. Its Form 10-Q for the quarter ended June 30, 2026 reported a net loss of $52.4 million for the first half of 2026 against $6.9 million a year earlier, with $93.0 million of cash and cash equivalents at the period end, and management concluded there is substantial doubt about the company’s ability to continue as a going concern for the following twelve months absent additional financing or material changes to the operating plan.⁴⁹

Hadron Energy (HDRN)

HQ 🇺🇸 United States · Market cap $141M · Yahoo Finance ↗ · Investor Relations ↗

Hadron Energy, Inc (HDRN) is developing the Hadron Halo, a 10 MWe Generation III+ pressurized light-water micro-modular reactor designed to be factory-fabricated, shipped by standard heavy-haul truck, rail or barge, and installed on a footprint of under one acre. The company builds its case on proven light-water technology rather than novel reactor physics: LEU+ fuel enriched to 5-10% uranium-235, chosen over HALEU or TRISO to avoid their longer lead times and NRC review, off-the-shelf nuclear-qualified pumps, valves and control systems, and an integral primary loop that houses the core, coolant pumps, steam generator and pressurizer inside one reactor pressure vessel. Its August 2026 investor materials quote 45 MWth of thermal output and a six-year LEU fueling cycle, revised from the 35 MWth and sealed 10-year core described in its listing documents.⁴³⁴⁷

The planned business model is energy-as-a-service rather than reactor sales: Hadron intends to own and operate its units and sell power under long-term PPAs at a target price of $0.15 per kWh, initially behind-the-meter or off-grid for data centers, industrial sites, remote communities and defense installations. In June 2026 the company announced that NRC staff had issued a final safety evaluation finding Revision 3 of its Quality Assurance Program Description topical report acceptable for referencing in future license applications — a first for a light-water microreactor, by the company’s account. A 10 CFR Part 52 manufacturing license and concurrent combined license submission is targeted for 2027-2028, with a first-of-a-kind unit in 2030 and at least 50 units per year from a planned US factory by 2035. H1 2026 supply agreements cover uranium conversion (ConverDyn), instrumentation and control (Paragon Energy Solutions) and a training simulator (GSE Solutions), but no license application has been filed, no factory site has been selected, and every customer commitment disclosed to date — including an April 2026 Smartland Energy MOU covering up to five potential deployments from the early 2030s — is non-binding.^43444547

Hadron listed through a de-SPAC with GigCapital7 Corp. in May 2026 after roughly 84% of public shares were redeemed. Its FY2025 and Q1 2026 accounts flagged substantial doubt about its ability to continue as a going concern; the first post-closing quarterly report, filed August 12, 2026, stated the trust proceeds had alleviated that doubt, with cash of $22.2 million at June 30, 2026 against the company’s own estimate of roughly $100 million of R&D spending through 2030 — so substantial further funding will be needed before commercialization. Insiders held 77% of the shares at closing, with founder-CEO Samuel Gibson at 61%, and the stock has traded well below the SPAC reference price since listing. In August 2026 Hadron appointed Eric Williams, previously chief operating officer of TerraPower, as EVP of Engineering. It remains pre-revenue with no binding customer, and its shares offer highly speculative exposure to microreactor development.⁴⁴⁴⁵⁴⁶

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 programs. 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 programs.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 license 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.