A significant portion of the cost of nuclear reactors comes from the size of the infrastructure required to build them. These reactors need massive amounts of reinforced concrete to withstand extreme pressures—sometimes as high as 160 times atmospheric pressure—and to resist damage from natural events or human threats. To address these challenges, physicist Richard A. Muller and his daughter, Liz Muller, have founded Deep Fission Inc. Their goal is to reduce the need for large above-ground structures by using the natural stability of underground environments. The idea is to drill a 1.6-kilometer-deep well, fill it with water, and place a pressurized water reactor inside. At this depth, the natural pressure is ideal for reactor operation, and the surrounding rock could provide natural protection against risks. Each of these reactors would produce 15 megawatts of electricity, and by clustering 100 of them at a single site, the company aims to generate up to 1,500 megawatts of power—enough to supply a medium-sized city. Deep Fission's concept relies on existing technologies that have been widely tested and used in other industries. The pressurized water reactor is the same type that powers most of France's nuclear power plants. Deep drilling techniques are common in the oil and gas industry, and heat exchange systems are used in geothermal energy projects. According to Elizabeth Muller, the company's general director, these proven technologies could allow for electricity at a cost of between 5 and 7 cents per kilowatt-hour—among the lowest in the market. This cost efficiency, combined with the potential for faster deployment, makes the project attractive for industries that require large amounts of power, such as data centers, which consume vast amounts of electricity due to the rise of artificial intelligence. Despite the promise of the technology, several challenges remain before commercial deployment can begin. Maintaining and monitoring a reactor located 1.6 kilometers underground is unprecedented and could pose logistical and technical difficulties. Refueling would also require bringing the reactor to the surface, which adds complexity. Additionally, there are concerns about how to manage and protect groundwater in the surrounding area from potential contamination. These issues need to be addressed to ensure the safety and viability of the project. Despite these hurdles, Deep Fission is moving forward. The company has raised approximately $122 million, including $30 million from a recent public offering. It has already conducted tests on the equipment needed to lower and retrieve the reactor casing for its full-scale reactors. The company has partnered with Endeavour Energy to develop 2 gigawatts of nuclear power, with the first reactors expected to be operational around 2029. Currently, testing is underway in Parsons, Kansas, where the company has begun drilling three wells to gather geological and hydrological data before any nuclear demonstration. This data will be crucial in determining the feasibility of the project and ensuring its safe implementation.