Half of global energy demand is consumed for heating and cooling, and most of it still depends on fossil fuels. Transitioning this demand to clean, dependable nuclear power offers one of the largest decarbonization opportunities available.
Yet, conventional nuclear power has long been defined by high costs, complex construction, and slow deployment timelines. A new generation of companies is working to change that. By simplifying reactor designs, modularizing construction, and integrating advanced digital systems, these innovators are making nuclear energy faster to build, safer to operate, and more affordable to deploy.
This article highlights five startups redefining what modern fission can achieve. From compact modular reactors for data centers and district heating to AI systems that optimize plant operations, these companies are unlocking nuclear’s potential to deliver reliable, carbon-free energy at scale.
Valar Atomics (USA)
Valar Atomics is developing small modular reactors (SMRs) to deliver clean, high-temperature energy for data centers, industrial facilities, and synthetic fuel production. Led by CEO Isaiah Taylor, the 25-year-old founder heads a team of 35 nuclear experts working to make nuclear energy scalable, affordable, and central to industrial decarbonization.
The company is on a mission to scale nuclear energy beyond the grid by developing modular, factory-built systems that can be rapidly deployed at industrial sites.
Its helium-cooled, high-temperature gas reactor design operates at up to 900°C, three times the temperature of conventional nuclear reactors, enabling applications beyond electricity generation. By standardizing reactor design and manufacturing, Valar aims to overcome the cost and complexity barriers that have historically slowed nuclear deployment. Its “gigasite” model envisions hundreds of modular reactors installed off-grid to provide continuous, low-carbon power and heat for data centers and heavy industry.
Valar Atomics raised $19 million in Seed funding in February 2025 to build its first test reactor, the Ward 250, at the Utah San Rafael Energy Lab under the U.S. Department of Energy’s Nuclear Reactor Pilot Program.
Nuclearn (USA)
Nuclearn is a US-based software company that applies artificial intelligence to modernize nuclear power plant operations. The company builds an integrated machine learning platform that automates repetitive and compliance-heavy processes unique to nuclear facilities.
Its platform includes pre-trained tools that support outage preparation, maintenance planning, documentation, and reporting. These solutions integrate directly with existing plant workflows, reducing manual effort and improving data accuracy. Nuclearn’s software is already in use across more than 65 nuclear reactors worldwide, helping operators streamline operations and lower costs.
The company originated at the Palo Verde Nuclear Generating Station, where its founders began automating routine plant tasks using data science and AI models. That experience shaped Nuclearn’s approach to developing secure, adaptable software tailored to the sector’s strict regulatory and safety standards.
In 2025, Nuclearn raised $10.5 million in Series A funding to scale its automation platform and expand adoption across the global nuclear fleet.
TerraPower (USA)
TerraPower is a US-based nuclear innovation company founded by Bill Gates and other visionaries to accelerate the development of advanced nuclear technologies. The company aims to deliver safe, affordable, and carbon-free energy while strengthening global energy security and supporting industrial decarbonization.
Its core technology, the Natrium® system, integrates a 345-MW sodium fast reactor with a molten salt-based thermal energy storage system. The configuration allows heat generation and electricity production to operate independently, enabling flexible power output and improved grid stability. The molten salt storage provides gigawatt-scale capacity, offering a resilient and cost-effective alternative to conventional grid batteries.
The Natrium design maintains constant thermal power, achieving higher capacity factors and supporting renewable integration. Embedded digital controls coordinate reactor performance, heat exchange, and storage dispatch, while passive safety systems ensure operational integrity.
Beyond power generation, TerraPower develops radioisotope production technologies that support medical applications, including targeted cancer therapies.
In 2025, the company closed a $650 million Series C funding round to help continue development of an advanced reactor project under construction in Wyoming.
Steady Energy (Finland)
Steady Energy develops compact small modular reactors (SMRs) for clean district heating and industrial applications. The company emerged from research conducted at Finland’s Technical Research Centre (VTT) in 2020, where the LDR-50 reactor was first conceived.
The LDR-50 is a 50-MW low-temperature, low-pressure light water reactor designed specifically for producing heat rather than electricity. Its simplified design ensures safety, reliability, and affordability while operating at significantly lower pressures than conventional reactors. The compact system enables installation near urban centers, supplying emission-free heat directly to district networks.
Steady Energy’s modular plants can also support desalination, industrial steam generation, and cooling. Each unit delivers consistent zero-carbon thermal energy for up to 60 years with minimal maintenance downtime. At an estimated cost of €100 million per reactor, the system offers competitive economics for utilities and municipalities.
Steady Energy raised $36 million in Series B funding in July 2025 to accelerate construction of its first pilot plant in Helsinki and advance toward commercial deployment. The company estimates potential CO₂ reductions exceeding 60 million tonnes by decarbonizing district heating networks across Finland, Sweden, and Poland.
Saltfoss Energy (Denmark)
Saltfoss Energy builds Compact Molten Salt Reactors (CMSRs) for clean power, desalination, and industrial energy needs. Founded in 2014 in Copenhagen by a team of physicists, the company focuses on reducing CO₂ emissions through safe, scalable nuclear technology.
Its CMSRs uses molten fluoride salt as both fuel and coolant. In the event of a leak, the salt solidifies, containing radioactive materials without external intervention. After each fuel cycle, short-lived fission products are removed, and the remaining salt is recycled into new fuel.
Saltfoss deploys its CMSRs on floating power barges, providing 200–800 MW of clean electricity that can power desalination plants, district heating, and cooling. The system’s high outlet temperature supports hydrogen, synthetic fuel, and fertilizer production. Each modular unit can operate for up to 24 years, offering flexible deployment in coastal or industrial locations.
Saltfoss raised $27.9 million in late-stage venture funding in February 2025 to advance commercial deployment. The company also partnered with Samsung Heavy Industries to develop floating nuclear power plants based on its CMSR design.
What’s next for startups in nuclear fission?
For nuclear power to play a larger role in addressing climate change, new reactor designs must be safer, simpler, and more secure. The startups featured here are redefining what advanced fission can deliver pairing modern engineering with modular, cost-efficient construction to unlock nuclear’s full potential.
Their innovations rely on passive safety systems, factory manufacturing, and digital optimization to reduce risk, speed up deployment, and lower cost. By combining carbon-free electricity with reliable heat and steam generation, these systems can decarbonize power, industry, and urban heating simultaneously.
The success of this new generation of reactors will depend on sustained investment, continuous innovation to overcome long-standing barriers that affect its large-scale deployment.
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