Three microreactor designs selected for US test bed experiments

The awards have been made through the National Reactor Innovation Center (NRIC), which has developed the front-end engineering and experiment design (FEEED) process to help industry partners progress more quickly toward first-of-a-kind testing of advanced reactors. Assistant Secretary for Nuclear Energy Kathryn Huff said the FEEED process will bring Radiant's Kaleidos, Ultra Safe Nuclear Corporation's Pylon, and Westinghouse's eVinci reactor designs "one step closer to reality."

Westinghouse's eVinci microreactor is a heatpipe reactor producing up to 5 MWe of electricity that can also produce high temperature heat for industrial applications. Described by the company as "essentially a battery", the reactor could provide versatile power for a variety of applications such as remote communities, universities, mining operations, industrial centres, data centres, defence facilities, and even on the surface of the Moon. The funding will support planning for the deployment of a one-fifth scale test reactor version of the reactor, which Westinghouse said will enable design finalisation, testing and licensing of the technology.

"We appreciate the ongoing support from the Department of Energy and Idaho National Lab to further the development of this truly innovative reactor technology," said Jon Ball, president for eVinci Technologies at Westinghouse. "We are at an inflection point and are accelerating the commercialisation of our eVinci technology. NRIC's partnership will be a critical enabler to advance technology readiness and licensing."

Ultra Safe Nuclear Corporation's Pylon microreactor is a containerised system capable of producing 1.5-5 MWe with a lower mass than the company's Micro Modular Reactor (known as MMR) high-temperature gas-cooled reactor system. The system is designed to be easily transportable to off-grid locations both on Earth and in space: for terrestrial use, the system comprises separate nuclear heat supply system and balance-of-plant modules, each individually fitting within a standard 20 ft (6 m) container. "Demonstration of this technology will enable compact, low mass (10-ton class) nuclear systems and develop future markets to attract new classes of customers to the benefits of advanced nuclear technology," the company said on X (formerly Twitter).

Radiant envisages its Kaleidos reactor as an alternative to diesel generators (Image: Radiant)

California-based start-up Radiant Industries was set up in 2020 by former SpaceX engineers Doug Bernauer and Bob Urberger. The company is developing the Kaleidos high-temperature gas-cooled microreactor, which will be capable of generating up to 1.2MWe or 1.9 MW of thermal power for facility heating or water desalination, as a potential replacement for diesel generators. The electric power generator, cooling system, reactor, and shielding are all packaged in a single shipping container, facilitating rapid deployment. Radiant is targeting commercial unit production in 2028.

Repurposed dome

The test bed - Demonstration of Microreactor Experiments (DOME) - will repurpose the Experimental-Breeder Reactor-II containment structure at Idaho National Laboratory. This, the Department of Energy (DOE) says, will lessen the environmental footprint and save companies money in the testing process, as well as reducing overall project risk. It is one of two test beds being developed by the DOE: the Laboratory for Operation and Testing in the US test bed will host smaller reactor experiments to support the development of advanced reactors.

EBR-II's containment dome is being repurposed for the test bed facility (Image: DOE Office of Nuclear Energy)

EBR-II operated from 1964 to 1994, and was originally built to demonstrate a complete sodium-cooled breeder reactor power plant. It was later modified to test other reactor designs and to test materials and fuels for fast reactors, as well as generating power and heat for the site. While the reactor and much of its supporting equipment has been dismantled, the remaining 70-foot diameter, 80-foot high containment structure is particularly suited to host reactor demonstration and other nuclear projects.

Testing in DOME could begin as soon as 2026, DOE said.