Megawatt-level nuclear battery chosen for second-ever reactor test at 100-foot-tall DOME

A Houston startup will test an experimental “nuclear battery” in the Idaho desert next year, marking a key milestone for next-generation clean energy.

The US Department of Energy selected Deployable Energy to run trials at the Idaho National Laboratory in 2027. The firm will test its microreactor inside the Demonstration of Microreactor Experiments facility, known as DOME.

Deployable Energy is only the second company chosen to use the testbed. Nuclear developer Radiant carried out the inaugural test there earlier this year.

Unlike traditional atomic plants, which require massive containment structures and produce gigawatts of electricity, microreactors are compact and portable. Deployable Energy’s prototype, called the Nuclear Unity Battery, is designed to generate one megawatt of electric power (1 MWe).

Specific technical configuration

The machine uses a specific technical configuration: light water moderates the nuclear reaction, while circulating helium gas cools the system.

“The test builds on the company’s earlier work achieving zero-power criticality through Nuclear Energy Launch Pad and will provide an opportunity to evaluate system performance, integration, controls, safety and operational procedures at increased scale,” noted INL.

Officials view these demonstrations as essential for modernizing the power grid.

“Testing at facilities like DOME is how we move these technologies closer to deployment,” said Chimi Zacot, acting deputy assistant secretary for Nuclear Reactors at the energy department. He added that the initiative supports the goal of providing affordable, reliable electricity across the country.

Meeting technical benchmarks

Deployable Energy won its slot following a competitive application window in July 2026. The testing campaign is entirely self-funded by the company.

However, access to the site is not guaranteed. To keep its schedule on track, the firm must hit strict benchmarks for technical readiness, fuel procurement, and regulatory clearances.

“The company must meet specific milestones throughout the process to maintain its allotted time in DOME and ensure efficient use of the test bed,” highlighted the lab.

National Reactor Innovation Center (NRIC) director Brad Tomer noted that interest from commercial developers remains high.

“We have a strong pipeline of companies interested in the DOME,” Tomer said, calling the momentum vital as developers push toward commercial markets.

Practical engineering solution

The test site itself represents a practical engineering solution. Located at the laboratory’s Materials and Fuels Complex, DOME officially opened in April 2026 as the world’s first facility designed specifically to run fueled microreactor tests producing up to 20 megawatts of thermal energy.

Instead of building a new shell, engineers repurposed an empty structure: the containment dome of Experimental Breeder Reactor-II. The building measures 80 feet (24 meters) wide and 100 feet tall.

By reusing an existing, reinforced building, researchers avoided years of construction. The facility provides private innovators with pre-built safety barriers and monitoring instruments, dramatically reducing the capital needed to collect real performance data. That data is critical, as developers must eventually satisfy strict federal regulators before any commercial reactor can connect to the public grid.

Source: https://interestingengineering.com/energy/megawatt-level-nuclear-battery-dome