Is the Kaleidos reactor approved?

The developer is engaging a regulator but has not submitted an application. Regulatory reference: DOE demonstration agreement, National Reactor Innovation Center, Idaho National Laboratory.

Kaleidos

Pre-application HALEU dependency

Output

1MWe

Kaleidos is a helium-cooled reactor design rated at 1 MWe. The developer is engaging a regulator but has not submitted an application. It requires HALEU fuel.

What would have to be true

Radiant would need to enter NRC licensing to sell power commercially — a DOE demonstration on a national laboratory site is not a commercial licence. It would also need a HALEU TRISO supply that does not yet exist at volume. The engineering claim is credible; the schedule depends almost entirely on fuel.

Designed from the outset to fit a standard shipping container, sized to replace diesel generators at remote sites, disaster areas and military bases. At 1.2 MWe it is roughly a thousandth of a large reactor — the point is not scale but transportability and the fact that diesel is the incumbent it has to beat, not grid power.

Regulatory position

Tier	Pre-application
Regulator	US Department of Energy authorisation pathway
Application type	DOE demonstration at the National Reactor Innovation Center
Docket / reference	DOE demonstration agreement, National Reactor Innovation Center, Idaho National Laboratory
Application date	—
Review phase	Fuelled demonstration planned at a DOE site; no NRC licence application
Decision expected	not stated

Design

Coolant	Helium
Reactor family	High-temperature gas reactor (HTGR)
Electrical output	1MWe
Thermal output	not disclosed
Fuel	TRISO
Enrichment	HALEUUp to 19.75% U-235
First site	Idaho National Laboratory
Offtakers	none announced

Fuel supply for this design

This design needs HALEU — uranium enriched above 5% and below 20%. That is not the fuel any commercial Western power reactor uses today, and it is the single most common reason an advanced reactor timeline slips. Every Western facility that can make it or turn it into fuel:

Facility	Capacity	Status
TRISO-X Fuel Facility (TX-1), Oak Ridge	not disclosed	construction
American Centrifuge Plant, Piketon	900kg HALEU/yr	operating
Nuclear Fuel Services, Erwin	not disclosed	operating
Savannah River Site HEU downblending	3,100kg HALEU total	operating
BWXT TRISO facility, Gillette	not disclosed	planned
Urenco Capenhurst HALEU line	not disclosed	planned

Sources

US Department of Energy, National Reactor Innovation Center · retrieved 2026-09-06