The Department of Energy (DOE) has unveiled three nuclear microreactor developers—Westinghouse, Radiant Nuclear, and Ultra Safe Nuclear Corp. (USNC)—that will design the first experiments at Idaho National Laboratory’s (INL’s) new Demonstration of Microreactor Experiments (DOME) test bed.

The microreactor developers will receive a combined $3.9 million to further their microreactor designs through a front-end engineering and experiment design (FEEED) process spearheaded by the National Reactor Innovation Center (NRIC), the DOE’s 2020-launched program designed to speed up demonstration and deployment of advanced nuclear energy. 

“The FEEED process supports developers in planning for the design, fabrication, construction, and testing of fueled reactor experiments,” the DOE’s Office of Nuclear Energy said on Oct. 23. Testing at DOME could start “as early as 2026,” it noted. 

An eVinci Nuclear Test Reactor

Westinghouse is poised to test its eVinci reactor (Figure 1), a portable microreactor concept of up to 5-MWe that it is readying for the market by 2027 and would be suited to decentralization” or resiliency applications. Westinghouse told POWER its test reactor will be “one-fifth scale representation” of an actual eVinci microreactor.

The eVinci microreactor has very few moving parts, working "essentially as a battery, providing the versatility for power systems ranging from several kilowatts to 5 MW of electricity, delivered 24 hours a day, 7 days a week for eight-plus years without refueling," Westinghouse says. "It can also produce high temperature heat suitable for industrial applications including alternative fuel production such as hydrogen, and has the flexibility to balance renewable output." The technology is 100% factory built and assembled before it is shipped in a container to any location. Courtesy: Westinghouse
1. The eVinci microreactor has very few moving parts, working “essentially as a battery, providing the versatility for power systems ranging from several kilowatts to 5 MW of electricity, delivered 24 hours a day, 7 days a week for eight-plus years without refueling,” Westinghouse says. “It can also produce high temperature heat suitable for industrial applications including alternative fuel production such as hydrogen, and has the flexibility to balance renewable output.” The technology is 100% factory built and assembled before it is shipped in a container to any location. Courtesy: Westinghouse

DOME “will enable design finalization, testing, and licensing of the technology utilizing INL’s National Reactor Innovation Center DOME test bed facility,” it said. During the FEEED contract phase, the eVinci team is slated to work with NRIC/INL to create an “End-to-End Reactor Test Program” plan and schedule for placing the test reactor in the INL facility, it noted.

Jon Ball, president for eVinci Technologies at Westinghouse, noted the opportunity marks a key pillar to support commercialization of Westinghouse’s flagship microreactor design. “We are at an inflection point and are accelerating the commercialization of our eVinci technology.  NRIC’s partnership will be a critical enabler to advance technology readiness and licensing,” he said.

USNC Will Test Derivative of ’10-Ton-Class’ Pylon Microreactor

USNC will test Pylon D1, a derivative of its Pylon nuclear system architecture that the Seattle-based company is developing for research, transportable, and space applications. “As a 10-ton class microreactor, the Pylon architecture builds on Ultra Safe’s Micro-Modular Reactor (MMR) and Fully Ceramic Microencapsulated (FCM) [TRISO] fuel technologies to be more easily transportable and capable of safely generating electrical and thermal power anywhere,” Wesley Deason, Pylon Program manager at USNC, told POWER.

The Pylon D1 Demonstration System, slated for DOME testing, contains “a small HTGR that utilizes FCM nuclear fuel, metal hydride neutron moderator, and graphite control drums,” he noted. “Pylon D1 uses helium as the working fluid to transfer the fission generated heat from the reactor via the primary coolant loop to a secondary gas loop (helium, air, supercritical CO2, and other gases are currently under trade) for rejection into the surrounding environment.” 

The test will allow USNC “to validate to our customers the promises of our technology including licensability, performance, operations, safety, and cost,” Deason added. “USNC’s strategy for enabling early demonstration relies on limiting scope to demonstrate only the Pylon D1 primary loop and by using commercially available 9.9% enriched uranium FCM TRISO fuel,” he noted. 

But the demonstration may also have broader benefits, he suggested.  “Demonstration will provide proof that USNC’s advanced nuclear technology—including additively manufactured FCM nuclear fuel and encapsulated solid metal hydride neutron moderators—can be safely incorporated within an operating 1-MWth nuclear reactor with 1000 K outlet temperatures,” he said. Enabling higher core temperatures and “an order of higher power density”—will serve to improve the performance of other USNC technologies, including the MMR, he suggested. That, in turn, willl support the development of future markets and attracting a “broader class of customers” to USNC, he said.

“The demonstration is focused solely on reaching reactor power and temperature goals, without the expense, design, and safety analysis complexity of a coupled power generation balance of plant,” Deason said. That’s why the opportunity to test on “significant infrastructure” is especially lucrative. “

The largest of these are items such as the development of an entire confinement structure, a National Environmental Policy Act (NEPA) environmental assessment, and nuclear regulator interactions,” he said. 

Radiant Poised to Test Kaleidos Battery

El Segundo, California–based Radiant Industries will test its Kaleidos Battery microreactor design (Figure 2), the DOE said. Radiant, a company founded in 2019 by former SpaceX engineers, has been developing a 1.2-MWe HTGR design, which will use TRISO fuel, a helium coolant, and a graphite moderator. The company says the 1-MWe 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,” it notes. 

2. Radiant’s microreactor will be the first portable zero-emissions power source that works anywhere, offering a clean and resilient energy alternative to fossil fuels for commercial and military applications. Courtesy: Radiant

The DOE’s announcement on Monday marks the first awards under NRIC for the DOME test bed. A final design for the new test bed was completed in September 2022, and long-lead procurement efforts began in December 2022.

DOME can host microreactors up to 20 MWth that use high-assay low-enriched uranium (HALEU) fuels. It will allow “safety-significant confinement for reactors to go critical for the first time,” NRIC has said. It will repurpose the Experimental-Breeder Reactor-II (EBR-II) containment structure, an effort intended to “speed up microreactor development” while lessening “the environmental footprint, saving companies money in the testing process, and reducing overall project risk,” the agency noted.

The DOE is also developing the Laboratory for Operation and Testing in the U.S. (LOTUS), a separate test bed that will “host smaller reactor experiments to support the development of advanced reactors,” the DOE said.

—Sonal Patel is a POWER senior associate editor (@sonalcpatel, @POWERmagazine).

Editor’s Note: This is a developing story that is actively being updated. As this story continues to unfold, POWER magazine remains dedicated to delivering comprehensive updates. Please check back for further details as they become available.