U.S. Navy taps portable reactor to power Indiana base

The U.S. Navy has selected Radiant to install its Kaleidos nuclear microreactor at Naval Weapons Station Crane in Indiana, putting a commercial company in charge of the service’s first shore-based advanced reactor, which the Department of War wants running no later than September 2028.

Radiant announced the selection on Oct. 20, about six weeks after the Department of War named Crane as the site for the Navy’s first microreactor without saying which vendor would build it.

Kaleidos is a factory-built reactor that produces 1 megawatt of electricity and is designed to be moved by truck, ship or aircraft and set up at a customer’s site without cooling water, major excavation or extensive construction. Each unit runs for up to five years before it needs refueling, over a planned service life of 20 years, and at Crane it is meant to keep power flowing to the base independently of the regional grid, which matters for an installation where the Naval Surface Warfare Center, Crane Division, works on microelectronics, high-voltage systems and weapons.

The reactor will be installed under the U.S. Army’s Janus Program, the Pentagon effort to put commercially owned and operated microreactors on military bases so they can keep critical facilities running through grid outages. Before it reaches Crane, the project still has to move through design refinement, prototype testing, environmental review, site preparation and coordination with the Nuclear Regulatory Commission, with technical support from the Naval Nuclear Propulsion Program, the organization that runs the reactors on the Navy’s carriers and submarines.

“The Janus Program was built from day one to deliver real, reliable hardware and systems to solve energy resilience challenges across all of the Services,” said Dr. Jeff Waksman, Principal Deputy Assistant Secretary of the Army for Installations, Energy and Environment. “We are excited to partner with the Navy to place a Janus reactor at NWS Crane, and by doing so to deliver the state of Indiana its first advanced microreactor.”

Crane is the second military base Radiant has lined up this year under Janus. In August, the U.S. Army awarded contracts worth up to $2.2 billion to five reactor makers, with Radiant receiving the largest share, up to $750 million to deploy 15 Kaleidos units by 2030, as we reported, starting with three reactors at Fort Benning in Georgia that will back up Lawson Army Airfield and other critical facilities, we reported in September. The company also has a deal with the Defense Innovation Unit and the Department of the Air Force to deliver a Kaleidos unit by 2028, and it now says it is the only nuclear company working with the U.S. Army, U.S. Navy and U.S. Air Force at once.

“Our installations are foundational warfighting platforms and ensuring their resilience is essential to supporting the Fleet,” said Vice Adm. Brad Collins, Commander, Navy Installations Command. “By investing in advanced capabilities like this microreactor at Crane, we are providing our Shore infrastructure with the resources needed to sustain the mission and empower our warfighters.”

Radiant has not yet proven the design at full scale, and the reactor is now going through a year-long test campaign at the Idaho National Laboratory’s DOME facility, where the Department of Energy gave the company exclusive access after a competitive selection. The company says the test uses the same reactor design and the same type of fresh fuel that will go to military customers, running at full power for an extended period to show the performance and reliability needed before deployment.

The Navy brings decades of reactor experience to the project, since the Naval Nuclear Propulsion Program, founded in 1948, has logged more than 7,500 reactor-years of operation and over 171 million miles under nuclear power without a reactor accident.