Microreactors – FAQs

A microreactor is a small nuclear reactor that produces from roughly 1 to 50 megawatts that can operate independently from the electric grid.

Most of these small reactors are designed to be portable – many could be hauled by a semi tractor-trailer.

The 98 reactors operating at the nation’s 60 commercial nuclear power plants power plants operating in the U.S. generate from 1,775to 4,400 megawatts.

Microreactors are 100 to 1,000 times smaller than conventional nuclear reactors. Small modular reactors (SMRS) range from 50 to 300 megawatts.

Yes and no. In the 60s and 70s, U.S. military commissioned several mobile nuclear reactors including the “Sturgis,” a floating nuclear power station used to supply electricity to the Panama Canal Zone.


It supplied 10 megawatts of electricity from 1968-1975, located on a barge in Gatun Lake. The military decommissioned most of its microreactors by the early 1970s because oil was cheap, weakening demand for remote power sources.

Several organizations and companies are developing new designs equipped with advanced technologies such as sensors, electronics, safety systems and materials that did not exist 40 years ago. These advancements are expected to make the next generation of microreactors easier and less expensive to operate. This, in turn, could open new markets for these small, powerful, portable systems.

Fluctuating oil prices and the need to generate power in remote locations are helping to drive renewed interest in these very small nuclear reactors.

The U.S. Department of Defense is pursuing the concept as its military operations become more energy intensive and require portable, dense power sources. Remote, rural communities in the U.S., many of which fly or truck in diesel to run generators, are considering microreactors since they could generate power on site.

In addition, these new systems are expected to operate years without refueling – much like the nuclear reactors used to power the U.S. Navy’s nuclear submarines.

No. However, there are some microreactors operating outside the United States. For example, Russia has several microreactors, including a new system that is barge-mounted and producing heat and electricity for an arctic community across the Bering Strait from Alaska.

There are several. As noted above, one of the advantages is that a microreactor could generate a significant amount of power on site, eliminating the need to haul diesel fuel over long distances or to remote areas.
This is important for communities that rely on diesel to power their homes and businesses, for mining or exploration companies in remote areas, or even to restore power in areas hit by hurricanes or other natural disasters.
The new generation of microreactors under development is designed to be simple to use, easy to transport and set up, and go years without having to be refueled.
As the nation’s nuclear energy research laboratory, INL is working with developers, private industry, regulators, and others to develop, demonstrate, test, and validate this new generation of microreactors so they can be deployed.
As part of its research mission, INL is also helping to develop new fuels for microreactor designs, many of which require higher concentrations of uranium-235 than the fuel used in the current fleet of commercial reactors.
The anticipated time frame for demonstration of these modern microreactor systems is within the next seven years.
The 2019 National Defense Authorization Act (NDAA) requests a pilot program to construct a microreactor for energy resilience by 2027. Also, the Pentagon’s Strategic Capabilities Office is seeking proposals for a mobile microreactor demonstration.
The cost for these new generation microreactors is still uncertain, although it is anticipated that microreactors can be cost competitive for niche applications such as high-resilience needs, remote and geographically difficult locations, and disaster relief.
A recent report by the Nuclear Energy Institute: “Cost Competitiveness of Micro-Reactors for Remote Markets,” estimates the cost to generate electricity from the first microreactor will be between $0.14/kWh and $0.41/kWh. In some remote Alaskan areas that are dependent upon diesel generators, electricity prices are more than $1/kWh.
Future costs are estimated to decrease to between $0.09/kWh and $0.33/kWh. Costs are expected to decrease after demonstration, licensing and initial deployment and will depend on the location and type of owner, whether private or public.
The Nuclear Regulatory Commission oversees licensing. As very small microreactors evolve with safer construction materials, fuels and electronics, the regulatory process also needs modernization to recognize the new generation of small nuclear reactors.
The U.S. Department of Energy supports a new approach to licensing through the Licensing Modernization Project, a DOE cost-shared, industry-led effort to establish a technology-inclusive, risk-informed and performance-based approach for advanced reactor licensing.
Idaho National Laboratory