Executive Order 14301 set an ambitious goal for at least three test reactors to achieve criticality by July 4. Two private companies participating in the Department of Energy’s Reactor Pilot Program—Antares and Valar Atomics—reached this stage earlier in June, and Deployable Energy—participating in the DOE's Nuclear Energy Launch Pad—became the third last week.

In the last few weeks, reports indicated that Aalo would be next, reaching criticality at Idaho National Laboratory with a low-enriched uranium–fueled, sodium-cooled reactor on or near the target date set forth by President Trump’s EO 14301. In the early hours of July 4, Aalo’s critical test reactor—a full-scale zero-power version of its planned 10-MWe Aalo-X—did just that, becoming the fourth DOE-authorized reactor to hit the milestone.

Commonwealth Fusion Systems, headquartered in Devens, Mass., has been selected by the U.K. Atomic Energy Authority as the first international partner for the agency’s Lithium Breeding Tritium Innovation (LIBRTI) program. LIBRTI is a U.K. government initiative with the goal of demonstrating the feasibility of fusion power plant–relevant fuel technologies.

The UKAEA is creating a first-of-a-kind technology facility, called the LIBRTI Facility, at its Culham Campus. It will house a test bed made of a 14-MeV neutron source in a shielded blockhouse. This structure will be surrounded by rooms for the assembly and disassembly of multiton breeder blanket prototypes.

In the latest twist in a long-term, multistep contracting arrangement with the Department of Energy, Centrus Energy has signed a contract to finalize terms of a $900 million DOE task order to expand production capacity for high-assay low-enriched uranium at its American Centrifuge Plant in Piketon, Ohio. The expansion is part of Centrus’s multibillion-dollar capacity expansion that also includes low-enriched uranium.

The new DOE award allows the company to transition its HALEU production cascade to a commercial-scale operation at Piketon. The contract also includes options for as much $170 million in HALEU purchases for DOE missions, for a total contract value of $1.07 billion. Those options are subject to the discretion of DOE.

Realta Fusion announced it has achieved direct energy conversion at the Wisconsin HTS Axisymmetric Mirror (WHAM), powering a lightbulb using electricity extracted from charged particles emitted by the plasma.

This process, called direct energy conversion (DEC), was theorized by Richard Post, a physicist at Lawrence Livermore National Laboratory, and has been demonstrated experimentally a few times, the earliest being the “Venetian blind” converter in the 1970s.

On May 23, 2025, President Trump signed Executive Order 14301, “Reforming Nuclear Reactor Testing at the DOE,” which instructed the Department of Energy to create a Reactor Pilot Program (RPP)—a new system in which companies could pursue DOE authorization to build and test their first-of-a-kind nuclear technologies. EO 14301 set an ambitious goal for that program: three reactors achieving criticality by July 4, 2026.

A proposed rule from the Nuclear Regulatory Commission would update radiation protection regulations and remove “as low as reasonably achievable” (ALARA) language without changing specific radiation exposure limits that are based on the linear no-threshold (LNT) model of low-dose radiation health effects. A second proposed rule would reform reactor licensing, safety oversight, and siting practices with changes the agency said are the most significant in years.

The NRC unveiled the two proposed rules on July 1 and published them in the ADAMS public document library the same day. The rules have not, at this writing, been published in the Federal Register, but once they are, each rule will be open for public comment for 45 days.

Researchers from the University of Manchester, the U.K. National Nuclear Laboratory, and Clemson University have studied using crushed concrete at legacy nuclear facilities as a long-term sink for strontium-90, a radioactive contaminant found at many such sites. Their research has been published in the American Chemical Society journal ACS ES&T Water.

Ahead of the July 4 deadline set by President Trump in Executive Order 14301, the nuclear community has been following the developments of the Department of Energy’s Reactor Pilot Program, in which companies have been pursuing DOE authorization to build and test their first-of-a-kind nuclear technologies. The EO set an ambitious goal of three reactors achieving criticality by July 4, 2026.

Staff at the Nuclear Regulatory Commission have recommended the agency issue a construction permit to the Tennessee Valley Authority for its plans to construct a GE Vernova Hitachi Nuclear Energy (GVH) BWRX-300 reactor at the Clinch River site in Tennessee, according to the safety evaluation report published as part of the construction permit application process.

The recommendation to the commissioners is a boon for the project, which proposes constructing a 300-MWe boiling water reactor in Oak Ridge, Tenn. The June report—available in the NRC ADAMS library—presents the NRC staff’s review of TVA’s 2025 application and any additional information staff received through April of this year.

NASA has announced that it will release a solicitation related to lunar surface power this month and that it is considering sending a rover powered by a radioisotope thermoelectric generator (RTG) to the moon.

The American Museum of Science and Energy recently hosted national technical director of Oak Ridge National Laboratory and American Nuclear Society member Paul Cantonwine on its podcast, AMSEcast. There, Cantonwine discussed the creation of the nuclear navy and the life of Admiral Hyman George Rickover.

Updates from utility companies in Colorado and Arizona, nuclear legislation and discussions, and the potential Duane Arnold restart were among the news items in the month of June at the local and state levels.

Last week, Canadian nuclear and engineering company AtkinsRéalis announced that it has formally submitted a notice of intent to the Nuclear Regulatory Commission “to begin the licensing process” for its CANDU reactor technology in the United States.

Completing an international commitment between the two countries, the United Kingdom’s Nuclear Transport Solutions (NTS) delivered the third and final shipment of vitrified high-level radioactive waste to Germany, the U.K. Nuclear Decommissioning Authority (NDA) announced last week.

New calculations by scientists at Lawrence Livermore National Laboratory suggest that changing the polarization of the National Ignition Facility’s lasers could reduce backscatter, an effect that can make an optic unusable after a single shot.

For just over a year, President Trump’s Executive Order 14301, “Reforming Nuclear Reactor Testing at the Department of Energy,” has loomed large because it pegged a stretch goal to a significant date: July 4, 2026. Will there be at least three participants in the Department of Energy’s Reactor Pilot Program whose reactors achieve criticality by Saturday’s deadline?

Continuing its breakneck pace of introducing new rules and proposals, the Nuclear Regulatory Commission last week announced that it was proposing to amend its regulations under 10 CFR Part 61 governing the land disposal of low-level radioactive waste.

The proposed rule, which introduces a new risk-informed framework for LLW disposal in which sites can develop waste acceptance criteria based on site-specific characteristics, is one of several rules the NRC is seeking to finalize and issue in response to Executive Order 14300, “Ordering the Reform of the Nuclear Regulatory Commission.”

Holtec president Rick Springman (left) and EDF CFO Rob Guyler pose with the signed joint proposal for deployment of Holtec’s SMR-300 at Cottam. (Photo: Holtec)

Jupiter, Fla.–headquartered Holtec International has announced that it and London-based EDF Energy have jointly submitted a proposal to the government of the United Kingdom for deployment of Holtec’s SMR-300 small modular reactors at Cottam, Nottinghamshire. Holtec International and EDF Energy have established a joint venture to advance development of the proposed SMR project at the site in England’s East Midlands, which hosts a gas-fired power plant and previously hosted a coal plant.

In 2019, a familiar landmark at Idaho National Laboratory was scheduled for demolition. Though striking for both its physical presence and its significance to nuclear history, the containment dome that once housed Experimental Breeder Reactor-II sat unused—that is, until INL realized its potential as a reactor testing facility.

The Department of Energy’s Gateway for Accelerated Innovation in Nuclear has recently awarded four third-round fiscal year 2026 vouchers to support the development of innovative nuclear technologies. Each company will get access to specific capabilities and expertise in the DOE’s national laboratory complex—in this round of awards Idaho National Laboratory, Oak Ridge National Laboratory, and Sandia National Laboratories are named—and will be responsible for a minimum 20 percent cost share, which can be an in-kind contribution.