Deep Fission Proposes Revolutionary Underground Nuclear Reactor

Deep Fission, a pioneering company in the nuclear energy sector, has announced its ambitious plan to develop a new type of nuclear reactor designed for deep underground installation. Their proposed Deep Fission Borehole Reactor 1 (DFBR-1) aims to enhance safety and efficiency by placing pressurized water reactors (PWRs) a mile (1.6 kilometers) deep in boreholes.

The company asserts that burying the DFBR-1 at such depths can significantly improve safety. According to Deep Fission, the pressure at this depth would match the internal pressure of current PWRs, while a column of water would act as an additional safety measure. This innovative design reportedly eliminates the need for traditional concrete containment structures typically required for nuclear reactors.

Currently, the DFBR-1 is under pre-application review at the Nuclear Regulatory Commission (NRC), where the company has submitted a whitepaper outlining its regulatory engagement plans for the year 2025. Each borehole is designed to accommodate a single DFBR-1 microreactor with a thermal output of 45 megawatts (MWt). The reactor’s primary loop will be largely contained within the reactor module, which further enhances safety.

The steam generator will be located at the borehole’s base, necessitating the transport of steam to the surface to generate an estimated 15 megawatts of electrical power (MWe) via a steam turbine. Additionally, the design includes sampling tubes reaching down to the primary loop, along with ropes for the retrieval of fuel rods. These fuel rods will utilize low-enriched uranium, similar to conventional PWRs.

While Deep Fission’s approach could revolutionize nuclear power, the practicality of such a design remains uncertain. The company is striving to bring its first reactor online by 2026, competing with projects like TerraPower’s Natrium, which is already under construction and offers greater power per reactor alongside integrated grid-level storage solutions.

The growing interest in advanced nuclear technologies reflects a shift in the commercial power sector in the United States. This development signals a departure from traditional energy generation methods, opening new avenues for both innovation and energy security.

As the regulatory review progresses, the industry watches closely to see if Deep Fission’s innovative underground reactor will redefine the future of nuclear energy or if it will be seen as an overly ambitious concept.