Kaleidos Has Left the Building

Radiant's Reactor Is En Route to The INL DOME

August 12, 2026

August 13th, 2026 – Kaleidos, Radiant's 1 MWe transportable microreactor, has departed Radiant's El Segundo, California facility and is en route to Idaho National Laboratory (INL), where it will undergo the most rigorous microreactor test campaign in the country and the industry’s only full-power, full-scale test.

This shipment marks the start of the next chapter in Radiant's industry-leading testing campaign at INL's DOME (Demonstration of Microreactor Experiments) facility. We said we’d make a microreactor that is transportable by land, sea and air. We did. Kaleidos is traveling more than 1,000 miles on a trailer bed. At the DOME, we will begin rigorous testing on the same reactor model that will be delivered to military and commercial customers. This is a critical milestone in moving from concept to customer by 2028.

A Company of Onlys

• Only Reactor in the DOME. INL's DOME facility was updated for microreactor testing. Following a competitive selection process, the Department of Energy awarded Radiant exclusive access to the facility for a full year. Kaleidos will be the first reactor in DOME to go critical and reach full power in decades.
• Only Full-Scale, Full-Power Operations. No other reactor developer is running a full-scale, full-power, extended-duration test in 2026. While others are proving basic physics with sub-scale, simplified test articles, Radiant is testing the same unit that will ship to commercial and military customers.
• Only Commercial Microreactor Scheduled for Military Deployment by 2028. Radiant signed an agreement with the U.S. Air Force and is on track to deliver America's first commercial microreactor to a military installation, Buckley Space Force Base, by 2028. That’s less than 18 months from now.
• Only End-to-End Solution. Radiant’s eighty acre campus in Oak Ridge, Tennessee, will house its fueling and manufacturing facilities. The NRC license application is already under accelerated review, and construction is well underway. The facility is tracking to be commissioned in January 2027.

Kaleidos leaving the factory floor is the physical, visible proof point of all four.

Why this shipment matters

Testing our full commercial reactor – through all five phases, generating full heat and power and running 150 continuous hours without operator assistance. That’s the milestone. Going critical alone doesn't generate any meaningful power. That’s why it’s called zero-power critical; it proves basic neutron physics, nothing more. Radiant's test campaign at the DOME is built around a harder, more consequential goal: proving that Kaleidos works as a commercial product.

The unit now on its way to Idaho isn't a simplified stand-in. Kaleidos is the same design, at the same scale, with the same commercial fuel load, that will roll off the production line at Radiant's R-50 factory in Oak Ridge and ship to customers. Every phase of testing it undergoes, from criticality to 1 MWe thermal operation, to full power, and a capstone 150-hour continuous run without operator intervention, generates data that feeds directly into Radiant's NRC license application and de-risks manufacturing and deployment at commercial scale.

Radiant chose this harder path intentionally. Performing sub-scale, zero-power criticality experiments would have been faster on paper, but it wouldn’t have moved the ball forward when it comes to proving out the full commercial capabilities required to move from concept to manufacturing at scale. Radiant didn't shortcut that process; the company built its plan around full-scale, full-power testing from the start.

What's Next

Kaleidos will arrive at INL and take residence inside the DOME, where fresh, TRISO fuel – purpose built to our specifications, will be loaded under U.S. Department of Energy and INL oversight. From there, the reactor will progress through Radiant's five-phase test campaign, culminating in a minimum 150-hour continuous run at full power without operator assistance, targeted for the third quarter of 2026, a crucial milestone in proving commercial readiness.

In parallel, Radiant's Part 70 license application, the only one of its kind currently under NRC review, remains on an accelerated eight-month timeline, targeting approval by the fourth quarter of 2026.

Radiant’s testing campaign will ensure we deliver Kaleidos to Buckley Space Force Base by 2028, marking the first commercial microreactor at a U.S. military installation.

Each of these milestones builds toward the same destination: manufacturing the world's only transportable, mass-produced nuclear microreactors. This is the technology that will define the next era of nuclear energy.