What does TerraPower’s $650m fundraise mean for next-gen nuclear rivals like X-energy and Kairos Power?

TerraPower’s $650 million capital raise in June 2025 has not only fortified its lead in the advanced nuclear sector but also raised competitive pressure for other U.S.-based next-generation reactor developers—especially X-energy and Kairos Power. While all three companies benefit from strong federal backing and private investment, their divergent strategies, technology platforms, and licensing timelines are shaping a dynamic new race to commercialize clean nuclear energy in the 2030s.

With its Natrium sodium-cooled fast reactor on track for first deployment in Wyoming, TerraPower’s fundraising success signals both investor confidence and growing alignment between energy infrastructure and the compute sector—particularly as firms like NVIDIA and Amazon deepen exposure to AI-powered data centers demanding reliable, carbon-free power. But how do TerraPower’s advantages compare to its nearest peers, and can competitors keep pace?

How does TerraPower’s $650 million raise compare with X-energy’s funding momentum and institutional investor sentiment?

TerraPower’s June 2025 raise included strategic investors like NVentures (NVIDIA’s venture arm) and HD Hyundai, pushing its total private funding to well over $1.4 billion. That total puts it alongside X-energy, which closed a $700 million Series C round earlier this year led by Amazon’s Climate Pledge Fund, along with investors such as Ares Management, Segra Capital, Jane Street, and Emerson Collective.

Institutional sentiment around both companies reflects confidence in their distinct reactor designs—TerraPower’s Natrium and X-energy’s Xe-100. While TerraPower’s funding was driven by utility-scale storage-linked output and project-specific momentum at the Kemmerer site, X-energy’s capital came with offtake potential in mind: the Xe-100 is being evaluated for use at Dow’s Seadrift facility in Texas and a planned 12-unit deployment in Washington state.

The difference in investor profiles is notable. TerraPower’s backers skew industrial and tech-centric, while X-energy’s funding was built around climate funds, asset managers, and customer-aligned partners. Analysts say this divergence highlights different risk tolerances and deployment strategies—but both are seen as sectoral leaders.

How do regulatory timelines and deployment strategies differ among TerraPower, X-energy, and Kairos Power?

TerraPower began non-nuclear construction of the Kemmerer, Wyoming Natrium plant in 2024 and submitted its NRC Part 50 construction permit application in early 2024. Full nuclear construction is expected to begin by 2026, pending approval, with commercial operations targeted for 2030. This project is supported by a $2 billion federal cost-share under the U.S. Department of Energy’s Advanced Reactor Demonstration Program (ARDP).

X-energy is pursuing an accelerated NRC pathway for its Xe-100 high-temperature gas-cooled reactor, and aims to begin operation of its Texas deployment with Dow by the end of the decade. It is also building out its TRISO-X fuel facility in Oak Ridge, Tennessee, with plans to produce high-assay low-enriched uranium (HALEU) to power its reactor fleet.

Kairos Power, while earlier in terms of commercial deployment, has already received an NRC construction permit for its 35 MWt Hermes test reactor in Tennessee. Backed by $303 million in ARDP funding, Kairos is taking an iterative approach, focusing on demonstration-scale success before scaling to commercial sizes. Analysts see its strategy as de-risked but slower, and highly dependent on experimental validation.

The three firms’ timelines reflect fundamentally different philosophies. TerraPower is targeting a high-capacity, utility-scale reactor from day one. X-energy is banking on modularity and earlier commercialization through industrial partnerships. Kairos Power is prioritizing low-risk iteration to perfect its fluoride salt-cooled reactor technology.

What technical differentiators define Natrium, Xe-100, and KP-FHR designs in the advanced reactor space?

TerraPower’s Natrium combines a 345 MWe sodium fast reactor with a molten salt thermal energy storage system, enabling dispatchable output up to 500 MWe. This gives it a unique ability to pair with renewable energy, supporting flexible grid integration.

X-energy’s Xe-100 is a high-temperature gas-cooled reactor delivering 80 MWe per module, designed to be grouped in standard four-unit installations (320 MWe total). It uses TRISO fuel, known for high safety margins and containment strength at extreme temperatures.

Kairos Power’s KP-FHR technology is a low-pressure, high-temperature fluoride salt-cooled reactor using TRISO fuel. The system emphasizes passive safety and compact size, targeting a smaller industrial and distributed energy market.

From a commercial perspective, TerraPower leads in utility-scale deployment and flexible energy storage. X-energy is better suited for modular industrial integration and rapid replication. Kairos Power is focused on thermally efficient, non-electric applications with potential for process heat in hydrogen and chemical sectors.

How does each company’s funding and public-private partnership structure impact its ability to scale?

TerraPower’s strategy is built on a blend of DOE funding, utility partnership (via PacifiCorp), and industrial co-investment. The company’s ability to secure new capital from NVIDIA and Hyundai signals growing tech-industry convergence on nuclear as a long-term power solution.

X-energy’s funding model has heavily incorporated private capital alongside federal support. Amazon’s backing brings a built-in offtake scenario, while Dow offers siting and infrastructure synergies for early deployment. X-energy is also the furthest along among its peers in vertically integrating its fuel supply chain, thanks to TRISO-X.

Kairos Power’s approach is deeply integrated with federal research agencies and national labs. Its milestone-based ARDP award is designed to support an experimental learning curve before commercialization. The startup has not yet announced major strategic investors from tech or industrial sectors, but its risk-controlled approach may appeal to government and utility partners seeking pilot-phase reliability.

Investors broadly perceive TerraPower as the most ambitious in scale, X-energy as the most modular and PPA-ready, and Kairos Power as the most methodical and technically cautious.

How does the HALEU fuel supply constraint affect each player’s commercial timeline?

All three companies require HALEU fuel—uranium enriched between 5% and 20% U-235—for their reactor types. The U.S. does not currently have sufficient commercial-scale HALEU production, creating a supply bottleneck that impacts every next-gen reactor developer.

TerraPower’s own deployment was delayed from 2028 to 2030 due to HALEU constraints following the collapse of Russian imports after 2022. The company has since announced partnerships with ASP Isotopes to address enrichment capability domestically.

X-energy, through its TRISO-X fuel arm, is actively building its own HALEU production capacity in Oak Ridge, making it the furthest ahead in vertical fuel integration. That internal capability could give X-energy a deployment advantage in the event of prolonged market-wide shortages.

Kairos Power does not yet produce its own fuel and is dependent on national programs like DOE’s Centrus pilot or future commercial enrichment efforts.

Analysts suggest that early leadership in HALEU availability could tilt the competitive field—particularly if domestic supply remains constrained past 2027.

Are advanced nuclear developers competing or creating differentiated niches within a growing clean energy sector?

Rather than true competition, many experts believe TerraPower, X-energy, and Kairos Power are occupying different lanes of a broadening clean energy transformation. Natrium targets large, dispatchable grid support; Xe-100 focuses on modular carbon-free industrial integration; KP-FHR is tailored for thermal process applications and compact use cases.

Still, comparisons persist, particularly as capital flows remain finite. With over $2 billion raised across the three firms since 2022, private equity, government, and climate funds are increasingly treating them as parallel bets on different delivery models. Sentiment from analysts is that all three could succeed—but only if each can deliver first-of-a-kind performance on time and within budget.