A PWR that is placed one mile underground in a borehole. The small footprint for the reactor means that it is possible to have 10s of them on a single site for large data centres or power plants. The power output per reactor is between 300 MWe and 1.5 GWe. It uses Low Enriched Uranium (LEU) with four standard pressurized water reactor (PWR) fuel assemblies cooled by water. There is geological isolation at depth naturally that provides operational pressures, enhances safety, and protects the public; no large, above-ground containment structures needed.