The DOME test bed is now open at Idaho National Laboratory. (Photo: INL)
On Wednesday, Idaho National Laboratory announced that the National Reactor Innovation Center’s Demonstration of Microreactor Experiments (DOME) test bed is now “open for business.”
With DOME’s opening, microreactor developers will soon be able to test, demonstrate, and validate their reactor designs. Rian Bahran, the Department of Energy’s deputy assistant secretary for nuclear reactors, called this “essential infrastructure” a “testament to our commitment to a robust nuclear future” and a key tool for “accelerating the development and deployment” of new energy technologies.
The background: In 2017, the Nuclear Energy Innovation Capabilities Act was signed into law. Among other reforms to the DOE, the act authorized the creation of NRIC, which it envisioned as a program “to enable the testing and demonstration of reactor concepts to be proposed and funded, in whole or in part, by the private sector.”
Since its founding, NRIC has pursued numerous projects and programs to achieve this goal. Plans for DOME in particular began to be discussed with the public in late 2022 and early 2023. The foundation of those plans included the repurposing of the dome of the Experimental Breeder Reactor-II. EBR-II was a 20-MWe reactor that entered operation at INL (then called Argonne West) in 1964 and shut down in 1994. DOME reuses EBR-II’s distinctive dome for the containment of new reactor demonstrations.
According to INL, DOME will host reactors rated at up to 20 MWt that use fuels with uranium enriched to less than 20 percent U-235—though “other reactor designs and fuel types can be considered if their design analyses are bounded by the DOME safety posture,” according to an INL fact sheet. Applications to test at DOME opened in May 2025. At the time, NRIC clarified that both private industry and government agencies could apply to test at DOME, provided they are able to foot the bill for testing.
Who’s first? NRIC is currently preparing for DOME’s inaugural fueled experiment, which is slated to take place later this year. That experiment will focus on Radiant Industries’ Kaleidos Demonstration Unit, a 1-MW microreactor that is TRISO fueled and helium cooled.
NRIC first awarded funding to Radiant (along with Westinghouse and the now-defunct Ultra Safe Nuclear) to develop an experiment for DOME in 2023. In 2024, Radiant raised $100 million in funding to be used primarily to complete its microreactor ahead of the test.
Quotable: “With the information gathered from their testing at DOME, reactor developers will turn pioneering ideas into validated technologies to advance nuclear energy. We are extremely proud to offer this capability and cannot wait to see the impact it has on the nuclear industry,” said NRIC director Brad Tomer.
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