WASHINGTON, June 21, 2026, 18:05 EDT
Key takeaways
- The U.S. Department of Energy announced two advanced-reactor criticality demonstrations in 14 days, with Antares’ Mark-0 on June 4 and Valar Atomics’ Ward 250 on June 18. Neither reactor is making electricity yet.
- Defense is where early demand looks most solid right now: Army microreactor plans, Project Pele, Janus, Eielson Air Force Base and other military projects are moving small nuclear out of the “future grid option” bucket and into national-security planning. The National Interest
- Talk of Gulf SMRs is turning concrete. Regional news outlets are asking if SMRs could give the Gulf an energy edge. Kuwait and the IAEA have looked at ways to fit SMRs into the region. Nuclear-safety coordination has picked up after the Barakah drone incident.
Modular nuclear reactors crossed from policy to hardware this week. The U.S. Department of Energy said Valar Atomics’ Ward 250 reactor reached zero-power fueled criticality at the Utah San Rafael Energy Lab on June 18, joining Antares’ Mark-0, which did the same at Idaho National Laboratory on June 4 through the DOE’s Reactor Pilot Program. This step shifts the nuclear energy debate beyond clean power for data centers. Now it’s about where resilient electricity lands first: military bases, remote sites, industrial hubs, and Gulf states looking at similar security needs.
Speed is the difference from yesterday. Valar’s trial didn’t involve a commercial power launch; here, “criticality” means a working nuclear chain reaction, not putting electricity on the grid. But POWER Magazine said Ward 250 became the first DOE-authorized reactor built outside a national laboratory to reach this point. DOE says several advanced reactors could hit criticality by July 4. That’s pushed the story out of white paper territory and onto a real production timeline. POWER Magazine
There was one line that stood out from the event. Valar co-founder Isaiah Taylor said, “Nine months ago, this was an empty site,” during the Utah demo. That sums up the Discover pitch, but the main news is more limited: the reactor worked at zero power. The next challenge is seeing if these machines can go beyond a controlled reaction to steady power, all while handling military rules, regulators and the fuel supply. The Department of Energy’s Energy.gov
The Pentagon is driving this round of nuclear activity. National Interest reported U.S. Army reactor program chief Jeff Waksman said the Army has set aside more than $2 billion over five years for new reactor projects. Waksman summed up the next challenge: “Next, we need a microreactor to generate electrons.” The National Interest
Project Pele is catching the military’s eye. The prototype, built as a 1.5 MWe transportable microreactor and running on TRISO fuel, fits inside four 20-foot containers and can move by C-17. That output won’t run a city, but it could make a difference for a base cut off from steady diesel or grid power. Diesel supply lines can be a problem; National Interest points to a 2018 Army study finding 52% of casualties in Iraq tied to land-transport missions, including fuel convoys.
Information gain: Near-term demand in defense is clearer than most reporting suggests. DOE and EIA list nine Army sites under Janus review, and analysts usually cite 1–20 MW for installation microreactors. That translates to about 9–180 MW if each site gets one unit—not counting Eielson, Project Pele, or possible Navy buys. It’s small compared to the U.S. nuclear fleet of 98 GW, but enough for standardizing parts, logging run data and straining the HALEU supply chain before big civilian SMR builds.
That piece connects the defense angle to the AI story. OilPrice called SMRs a national-security play, pointing out that AI, chips, advanced manufacturing and military work all need steady power, not just more intermittent supply. DOE followed with $94 million in cost-shared awards in May for advanced light-water SMRs—deployment projects including licensing, supply chain, and site work.
Regulators are getting swept up in the push, too. The U.S. Nuclear Regulatory Commission has sped up small-reactor licensing reforms after a White House order pushing for faster design sign-offs, according to Reuters. “A bridge for data sharing between federal agencies while preserving the NRC’s independent oversight,” said Rita Baranwal, chief nuclear officer at Radiant Industries. Yasir Arafat at Idaho National Laboratory called it more simply: “This rule turns that data into something the NRC can formally credit.” Reuters
The Gulf push on SMRs is being driven by a mix of energy advantage and worries about infrastructure security. GDNonline is now asking if SMRs could be the Gulf’s next energy advantage, while Kuwait Times said last year that Kuwait’s scientific-research institute and the IAEA were looking at how SMRs might fit the region, considering technical, economic, environmental, social and political factors. In a separate move, IAEA chief Rafael Mariano Grossi ramped up Gulf outreach after the May drone attack at the UAE’s Barakah nuclear plant, putting nuclear safety, emergency plans and advanced-reactor talks all into the regional spotlight.
Policy momentum could get ahead of what’s possible with the current reactor fleet. Zero-power criticality matters, but it’s not the same as making electricity for the grid. HALEU fuel is still in short supply, and new fuel plans are running into security debates. Earlier this month, Reuters said a U.S. plan to use surplus plutonium set off alarms among nonproliferation experts. “This is weapons-usable plutonium,” Ross Matzkin-Bridger told Reuters. Rep. Bill Foster said his “brain goes on high alert” when weapons-grade material comes up in these discussions over civilian fuel. Industry and government officials say rules, NRC checks and federal programs can keep things safe, but proving it gets harder as test reactors move to actual bases or industry. Reuters
The small reactor contest is at an awkward stage. Big Tech is driving much of the demand. The military looks set to be the first steady buyer. In the Gulf, political signaling is at work. The next thing to watch is if DOE’s push, due before July 4, gets another key criticality win, and if later programs can deliver actual, reliable power.
