Deep Fission

Endeavour and Deep Fission are partnering to scale low-cost, inherently safe nuclear power for data center applications.

With over 40 patent-protected inventions, Deep Fission’s pioneering small modular reactor (SMR) capsules dramatically reduce costs and safety concerns while delivering a breakthrough in energy density. The Deep Fission solution leverages the natural geological advantages of deep underground placement – robust containment and constant pressure – making the reactors inherently safe.

Endeavour’s sustainable engineering expertise complements Deep Fission's cutting-edge solution, creating a solid foundation for driving the rapid commercialization of these advanced nuclear reactors.

Endeavour and Deep Fission have committed to co-developing 2 gigawatts (GW) of nuclear energy to power Endeavour’s expanding portfolio of Edged data centers, with the first reactors expected to be operational in 2029.

Press Release

FAQs

What is “inherently safe” about Deep Fission technology?

Deep Fission’s design uses mature pressurized water reactor (PWR) technology, the most common nuclear technology worldwide (more than 65% of U.S. commercial reactors are PWRs). In PWR designs, high-pressure water serves as a moderator that stabilizes the nuclear reaction. At borehole depths of 1 mile below the Earth’s surface, the Deep Fission reactor is naturally pressurized to the 160 atmospheres needed for PWR operation by fail-safe gravitational forces. This eliminates the cost and complexity of massive pressure containment vessels that are required when nuclear plants are built on the surface, and it eliminates the risk of depressurization due to power outage, extreme weather events or other accidental or intentional disturbances. PWR systems have an additional layer of safety provided by reactor control rods, which are held in place above the reactor core by electromagnets. It the event of a power failure, the electromagnets cease operation and the control rods naturally fall into place in the reactor, which stops the nuclear chain reaction and causes the reactor to safely shut down.

Deep Fission facilities are isolated far from surface populations and well below groundwater aquifers (which range from a few meters to a few hundred meters). The only part of the Deep Fission system that reaches the surface is non-radioactive steam, which rises through piping, passes through steam generators and is returned to the borehole in a continuous closed loop.

How does Deep Fission reduce the high costs and long delays of conventional nuclear power systems?

Speed, cost and safety are closely linked in nuclear power. Conventional surface nuclear projects take decades to build and cost tens of billions of dollars to start producing power because they require layers upon layers of engineering to keep nearby communities safe in the event of natural disasters, wars and material failure. By making the technology inherently safe and isolating it under billions of tons of rock, Deep Fission’s subsurface reactors can dramatically increase the speed to market and reduce the cost of energy. Many novel reactor designs and enriched fuel systems face long regulatory analysis and permitting delays. Deep Fission uses mature PWR reactor technology and standard domestically-produced fuels that are familiar to regulators and have robust supply chains. The advanced drilling technology that Deep Fission uses is well established in the oil and geothermal energy industries.

What is your development timeline?

Deep Fission is well along the regulatory review process. The U.S. Nuclear Regulatory Commission has reviewed the conceptual design and issued a Regulatory Engagement Plan. Deep Fission expects to submit site-specific engineered designs and environmental impact studies in 2026. The first U.S. reactors are expected to begin operation in 2029. Endeavour and Deep Fission are also engaged with other nuclear regulatory agencies and may begin international operations before 2029.

What do you do with waste and spent fuel?

Deep Fission’s sister company, Deep Isolation, is the world’s premier nuclear waste handling solution.

Who is behind this project?

Deep Fission was founded by the father-daughter team of Richard Muller, Ph.D. and Liz Muller, who previously founded Berkeley Earth, a pioneering climate data company, and Deep Isolation, a leader in nuclear waste mangement solutions. Endeavour was founded by data center industry veteran Jakob Carnemark, who also founded Skanska Mission Critical and Aligned Data Centers before launching Endeavour and the Edged data center platform.

FAQs

Supporting gigawatt-scale projects

Deep Fission SMR capsules (15MW each) can deliver high power density in a small footprint, enabling 150MW in a quarter acre and 1.5GW of clean energy generation in just 3 acres. The Deep Fission system eliminates the need for massive containment and pumping infrastructure. The U.S. Nuclear Regulatory Commission has not yet ruled on buffer zone requirements for SMRs, but we do not expect our inherently safe subsurface system to require any footprint restrictions beyond the standard fence line.

An “inherently safe” technology

The Deep Fission system leverages mature pressurized water reactor (PWR) technology, the most common nuclear technology worldwide (more than 65% of U.S. commercial reactors). PWR designs use high-pressure water, which serves as a moderator that enables power production using ordinary low-enriched uranium dioxide fuel pellets. Deep Fission reactor capsules operate at depths of 1 mile underground where they are naturally pressurized by gravitational forces. This eliminates the cost and complexity of massive pressure containment vessels that are required when nuclear plants are built on the surface and reduces the risk of losing pressure due to power outage, extreme weather events or other accidental or intentional disturbances.

Deep Fission reactor capsules are isolated far from surface populations and below groundwater aquifers (which range from a depth of a few meters to a few hundred meters). The only part of the Deep Fission system that reaches the surface is clean steam, which rises through piping, passes through steam generators and is returned to the borehole in a continuous closed loop.

Avoiding the high costs and delays of conventional nuclear

Speed, cost and safety are closely linked in nuclear power. Conventional surface nuclear projects take decades to build and cost tens of billions of dollars to start producing power because they require layers upon layers of engineered construction to keep nearby communities safe in the event of natural disasters, wars and material failure. By making the technology inherently safe and isolating it under billions of tons of rock, Deep Fission’s technology can dramatically increase the speed to market and reduce the cost of energy. Many novel reactor designs and enriched fuel systems face long regulatory analysis and permitting delays. Deep Fission uses mature PWR reactor technology and standard domestically-produced fuels that are familiar to regulators and have robust supply chains. The advanced drilling technology that Deep Fission uses is well established in the oil and geothermal energy industries.

Our development timeline

Deep Fission is currently in pre-application engagement with the U.S. Nuclear Regulatory Commission (NRC). The NRC has reviewed the conceptual design white paper. Deep Fission expects to submit site-specific applications in 2026. The first U.S. reactors are expected to begin operation in 2029. Endeavour and Deep Fission are also engaged with other nuclear regulatory agencies and may begin international operations before 2029.

Responsibly managing waste and spent fuel

Deep borehole burial is a thoroughly researched and established technology for the disposal of nuclear waste, with customers around the world committed to using this technology. Deep Fission co-founders also launched Deep Isolation, the leading innovator in this field with 80 patents on the technology. Deep Fission’s SMR capsule design shares the safety benefits of deep borehole waste disposal during a reactor’s operational life and introduces the opportunity to never bring nuclear waste to the surface, where it could potentially put humans and the environment at risk.

Who is behind this project?

Deep Fission was founded by the father-daughter team of Richard Muller, Ph.D. and Liz Muller, who previously founded Berkeley Earth, a pioneering climate science company, and Deep Isolation, a leader in nuclear waste management solutions. Endeavour was founded by data center industry veteran Jakob Carnemark, who also founded Skanska Mission Critical and Aligned Data Centers before launching Endeavour and the Edged data center platform.

Deep Fission

Deep Fission is revolutionizing the energy landscape with innovative technology that places small modular reactor capsules a mile underground. The team of leading scientists, engineers, and visionaries is driven by a shared commitment to advancing safe, reliable, and affordable low-carbon energy solutions.

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Endeavour

Endeavour is a sustainable infrastructure company, specializing in data center development, waterless cooling, microgrids, and renewable energy technologies for enterprise, cloud and hyperscale users. Its Edged data center platform is a gigawatt-scale global network of ultra-efficient, waterless data centers.

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