June 30, 2026
Reactor goes hot, comments go hotter
Antares Achieves Criticality of Mark-0 Reactor
America’s tiny new reactor went live, and the comments instantly went full debate mode
TLDR: Antares hit a major early milestone by getting its tiny reactor running in a controlled way, a big step toward future military and commercial power systems. Commenters were split between cheering an on-time win, arguing over nuclear versus renewables, and making jokes about “nuclear autotune.”
America just got a flashy nuclear milestone: Antares says its Mark-0 microreactor reached its first controlled nuclear reaction at Idaho National Laboratory, making it the first private company to pull this off under a U.S. Department of Energy test program for next-generation reactors. In plain English: a very small reactor just cleared a huge early hurdle, with the government, a national lab, a fuel maker, and even the U.S. Army all watching closely because they want portable power on military bases by 2028.
But the real fireworks were in the comments. One camp was pure applause, cheering that a hard engineering project actually happened on schedule for once. “Congrats” and “awesome milestone” energy was strong, with a side of disbelief that a nuclear project didn’t immediately become synonymous with delay. Another camp went straight into Wait, what kind of reactor is this actually? detective mode, poking at the fuel design and wondering why certain buzzwords weren’t being used more loudly.
Then came the classic internet split: nuclear vs. renewables. One commenter basically asked the question haunting every energy thread online: should we go all-in on wind, solar, and giant batteries, or bankroll futuristic nuclear too? The answer from the vibe of the thread was basically: yes, and also please stop making this simple. And because no comment section can resist a joke, one user dropped “nuclear autotune,” instantly giving the whole announcement the kind of weird meme energy only the internet can provide.
Key Points
- •Antares said its Mark-0 microreactor achieved initial criticality at Idaho National Laboratory under DOE authorization.
- •The company described the event as the first time a private company has brought an advanced reactor to criticality under the DOE Reactor Pilot Program.
- •The demonstration involved DOE, Idaho National Laboratory, BWXT, and support from the U.S. Army.
- •Mark-0 used TRISO fuel fabricated by BWXT and is intended to validate reactor physics parameters while supplying data to Project Pele.
- •The article says the demonstration and licensing pathway support a goal of deploying electricity-producing microreactors at U.S. military installations by September 30, 2028.