On July 1st, the Department of Energy (DOE) announced microreactor developer Deployable Energy had achieved criticality on their Unity reactor design at Idaho National Labs (INL).
CRITICALITY NUMBER THREE! 🎉
— Office of Nuclear Energy | US Department of Energy (@GovNuclear) July 1, 2026
On June 30, 2026, at around 11:55 PM MDT, @DeployableE’s Unity microreactor achieved initial criticality at @INL. It is the third nuclear test reactor this year to go critical under @ENERGY authorization.
Congratulations to Deployable Energy on… pic.twitter.com/TaIKbtnNTx
This is the third privately developed and funded reactor to have obtained the nuclear milestone of sustaining a chain reaction of fissioning uranium atoms inside of a reactor core.
Executive Order 14301, “Reforming Nuclear Reactor Testing at the Department of Energy”, was the starting point. The executive order contained, among many other things, a goal for the DOE to start up a reactor testing program that enabled rapid iterati
