U.S. Army finished dismantling Cold War nuclear plant

The U.S. Army Corps of Engineers has finished dismantling the SM-1 nuclear power plant at Fort Belvoir, Virginia, the Army’s first nuclear reactor and the first facility in the country to send nuclear-generated electricity into the commercial power grid. The Corps’ Baltimore District completed the last field work this year, closing out a project that began mobilizing crews in 2021.

The job involved clearing non-radioactive hazards, safely removing and disposing of radioactive materials and equipment, tearing down the plant’s structures, hauling away debris, and restoring the site. What was once a working reactor is now a graded, seeded plot of land. Planning for the teardown dates back to 2014, and the Corps received its formal decommissioning permit in 2020 before field crews arrived the following year.

“This team set out to execute a complex mission methodically, protect the installation and the National Capital Region through every phase, and deliver a lasting result worthy of the Army’s trust,” said Col. Francis B. Pera, Baltimore District commander and district engineer. “It’s a credit to the health physicists, engineers, project managers, field personnel, and contractor workforce who executed this mission day after day.”

SM-1 traces back to 1954, when the Army launched its Nuclear Power Program and tasked the American Locomotive Company with building a small reactor at its Corps of Engineers headquarters in Fort Belvoir. The reactor reached criticality, the point where a nuclear chain reaction becomes self-sustaining, on April 8, 1957, and began feeding power into the commercial grid months before Pennsylvania’s much larger Shippingport reactor came online that December. SM-1 produced only a modest 1.5 megawatts of electricity from roughly 10 megawatts of reactor heat, but it also doubled as a training site, teaching reactor operations to personnel from the Army, Navy and Air Force. The plant ran until 1973, when it was shut down and placed in long-term storage rather than torn down right away.

Members of the U.S. Army Corps of Engineers (USACE) team involved in the decommissioning and dismantlement of the former SM-1 Nuclear Power Plant at Fort Belvoir, Virginia, stand for a photograph with the original 1957 building marker from the plant during a project close-out ceremony marking the completion of all field activities associated with the site, Sept. 9, 2026. Photo by Thomas Deaton

The Corps awarded a roughly $68 million contract in August 2020 to a joint venture of APTIM and AECOM to carry out the decommissioning work. Baltimore District leaned on expertise it had already built up dismantling a related Army reactor, the MH-1A, which sat aboard a converted cargo ship called the STURGIS. That floating power plant was tested at Fort Belvoir before it was sent to the Panama Canal Zone in the 1960s to supply electricity there, and the Corps completed its own decommissioning in 2019.

The timing lands on a symbolic bookend for Army nuclear power. As the Corps closes the book on SM-1, the reactor that opened the Army’s nuclear era nearly 70 years ago, the service has separately launched a new push to put small nuclear reactors back on its bases. Under a program called Janus, launched in October 2025 through the Defense Innovation Unit, the Army has paired commercial reactor companies with five host installations, including Fort Benning, Georgia, where a company called Radiant Industries is set to install three one-megawatt microreactors. The Army has said it is targeting 2028 for the first Janus reactors to come online.

The Army says the completed SM-1 project now gives it a full picture of a nuclear plant’s life span, from construction through decades of operation to final teardown, a body of experience it says will help inform this next generation of reactors as they move from installation through years of service and eventual retirement of their own.