Microreactors are the smallest class of advanced nuclear reactors, designed to produce 1 to 20 megawatts of thermal or electrical power in a self-contained, transportable package. Unlike larger SMRs intended for grid-scale power, microreactors target niche but high-value applications: remote communities dependent on expensive diesel generators, military forward operating bases, mining operations, disaster relief, and space exploration.
Several companies are developing microreactors with diverse designs. Westinghouse's eVinci uses heat pipes and TRISO fuel to produce up to 5 MW of electricity with no on-site refueling for 8+ years. Ultra Safe Nuclear Corporation (USNC) is developing its Micro Modular Reactor (MMR) with a gas-cooled design. Oklo, which went public via SPAC, is pursuing its Aurora fast-spectrum microreactor. The U.S. Department of Defense's Project Pele has contracted with BWXT to build a transportable microreactor prototype for military applications, reflecting national security interest in the technology.
The appeal of microreactors lies in their potential for factory production, truck-transportable size, and autonomous operation with minimal staffing. Challenges include achieving economical costs at small scale (where nuclear's fixed costs are harder to amortize), securing regulatory approval through the NRC's adapted licensing frameworks, and building the HALEU fuel supply chain that many designs require. The first operational microreactors are expected to begin deployment in the late 2020s. For deeper coverage, see DeepTechIntel's nuclear section.