Nuclear Regulatory Commission Advances New Microreactor Policies

The U.S. Nuclear Regulatory Commission announced in June that it is moving forward to advance new uses of factory-built microreactors by accepting three policies recommended by staff.

Microreactors are small modular reactors that generate nuclear energy for particular uses, such as to create a power supply for a company or generate energy an isolated community. This use of nuclear energy could also provide emergency power reserves.

This unique application of nuclear energy would serve non-conventional nuclear markets, such as the power-hungry data centers fueling the AI boom, and they differ from the current electric utilities facilities providing nuclear power among the energy mix for its customer base.

“These very small reactors could be built, loaded with fuel, and tested at factories before being shipped to operating sites, and would generate about 1% or less of the power of a current large reactor,” NRC stated.

The NRC revealed this key development in a short June 18 public notice called “NRC Advances Factory-Built Microreactor Policy.” The agency briefly described its three new federal policies.

The new NRC policies are:

A factory-fabricated microreactor loaded with fuel may be excluded from being “in operation” if it has features to prevent a nuclear chain reaction.
A microreactor designed with features to prevent a chain reaction may be loaded with fuel at a factory if it is done under an NRC license enabling fuel possession.
NRC staff may apply nonpower reactor regulations to okay a microreactor to be tested at a factory before being shipped to an operating site.

Furthermore, the NRC also directed its staff “to continue other microreactor-related activities, such as engaging with” the U.S. Department of Energy, as well as the U.S. Department Defense “to build and operate microreactors on DOE/DOD sites or as part of critical national security infrastructure.”

The NRC announcement referred to a June 17 memo from Dr. Mirela Gavrilas, NRC executive director for operations, to Tomas Herrera, acting NRC secretary.

The memo stated NRC staff should explore additional recommendations by stakeholders, such as using existing National Oceanic and Atmospheric Administration and National Weather Service meteorology and weather information to support analyses and design bases. In addition, the memo advises NRC staff to proactively develop a comprehensive regulatory framework, and microreactor manufacturers licensing options, that combine the activities of a microreactor applicant (for factory fabrication, operational testing, fuel loading and microreactor transportation) in a single federal license.

“Such a framework could clarify the appropriate use of using license conditions or technical specifications to address unique technical considerations such as the need for features to preclude criticality while the microreactor is in transit,” the memo added.

DOE Microreactor Program

The DOE has a microreactor program to examine new technologies to create, test and deploy very small, transportable reactors to provide decentralized energy and heat for civilian, industrial and defense uses. DOE is looking into different type of microreactor reactor designs—such as gas, heat-pipe-cooled, liquid-metal and molten-salt.

Microreactors would be able to operate for up to a decade or even longer. Another feature is the ability they could be transported quickly to provide power to specific locations in emergencies.

The DOE’s microreactor program is being spearheaded by its Idaho Falls-based Idaho National Laboratory. In February, INL hailed reaching a milestone with the Battelle Energy Alliance to start developing a primary coolant system for a Microreactor Applications Research Validation and Evaluation Project microreactor. The MARVEL is a sodium-potassium-cooled reactor designed to produce 85 kilowatts of thermal energy.

“It will be one of the lab’s first new reactors in nearly 50 years,” the INL team stated in a press release. “MARVEL will help developers demonstrate microreactor applications and evaluate systems for new microreactor technologies. The primary coolant system manages the heat produced in the reactor core and will be the most complex fabrication of the MARVEL project.”