Nuclear power really hit its stride in the 1950s. In the post-war period, there was a rush to develop peaceful uses for splitting the atom, beyond its application as a weapon of war. Soon enough, nuclear reactors were hooking up to power grids and helping propel ships and submarines around the globe.
Eventually, this led to an obvious idea—what if a ship with a reactor could serve as a floating nuclear power station? That question would be answered in the mid-1960s, with an American project of some strategic importance.
Whatever Floats Your Boat
You might think that the first floating nuclear power plant would have been a US or Soviet navy project, but you’d be quite wrong. Instead, it was actually the US Army which was responsible for achieving this feat. The project began as part of the US Army Nuclear Power Program, which was intended to develop small reactors that could be deployed to remote regions to supply electricity. One of the results of that program was MH-1A, the nuclear reactor abord the vessel otherwise known as the USS Sturgis.
The control room for the MH-1A nuclear reactor. Credit: US Army, public domain
The contract for the Sturgis’ reactor was awarded to Martin Marietta in 1961. Termed the MH-1A, standing for Mobile, High Power, the reactor was a pressurized water unit running on low-enriched uranium, built inside a 350-ton containment vessel. Nameplate capacity was a healthy 10 megawatts. The ship itself was not a clean-sheet design; instead, it was built out of a converted Liberty Ship left over from World War II. The former cargo vessel was formerly known as the SS Charles H. Cugle. As part of its conversion, it had its propulsion system removed, since it was intended to operate from fixed moorings or anchorage for extended periods of time. It was deemed uneconomical to otherwise maintain the capacity for independent propulsion.
The MH-1A reactor was installed in the Sturgis while it was moored at Gunston Cove, near the Fort Belvoir facility that hosted the Army’s very first nuclear reactor, the SM-1. The reactor first went critical in January 1967, and was accepted into Army service six months later in July. The Sturgis would remain at Gunston Cove for the following 11 months, where it supplied electricity to Fort Belvoir in lieu of any required operational use.
The USS Sturgis, pictured at its station supplying power to the Canal Zone. Credit: US Army, public domain
The Sturgis did not have to wait long to be called into service. It was initially considered for deployment in the Vietnam theatre, but instead, it would wind up serving in Central America—but not for entirely unrelated reasons. In 1968, the Panama Canal was
facing somewhat of a crisis. The dry season led to water shortages, with authorities forced to ration what was ran through the Gatun Hydroelectric Station for local energy needs, and what was used to run the locks to allow ships to transit the Panama Canal. To aid in keeping the canal open, the US Army deployed both the Sturgis, as well as the Andrew J. Weber, a diesel-powered power barge of some 20 MW capacity. The two ships were hooked up to support the power needs of the Canal Zone, in turn freeing up water resources for the locks of the Panama Canal. This allowed the passage of an additional 15 ships through the canal per day. The deployment wasn’t entirely altruistic, of course. Keeping traffic flowing through the canal was undoubtedly an aid to US logistics during the Vietnam War, with much materiel passing through this route during the conflict. The Sturgis ultimately stayed on station until 1975, eventually being replaced by Hitachi turbine generators instead.
The reactor core of the MH-1A. Credit: US Army, public domain
Beyond its trip to Panama, the Sturgis didn’t have much else to do. It was retired from service in 1976, since the Army Reactor Program had been ended and its generation capacity had been replaced with more practical solutions at the canal. It returned to the US in 1977, where its fuel was removed at Fort Belvoir. It was then moored as part of the James River Reserve Fleet for long-term storage. Eventually, a $35 million contract was awarded in 2014 to decommission and dispose of the reactor, with the rest of the ship then to be scrapped as per usual shipbreaking practices. The process was completed by 2019, and the world’s first floating nuclear power station was no more.
The story of the Sturgis is rather a strange one. Military planners conceived that a floating nuclear power plant could be incredibly useful, and not long after it was completed, they found the perfect application for it. Once that application was no longer important, the ship was mothballed in short order.
Russia launched the Akademik Lomonsov in 2019, with a pair of KLT-40S nuclear reactors putting out a total of 70 MW of electricity. The ship currently supplies electricity and thermal energy to the town of Pevek, Russia. Credit: Elena Didier, CC BY-SA 4.0
Since then, the world hasn’t seen a whole lot of floating nuclear power stations. Russian efforts netted a single nuclear-powered barge in 2019, but plans to produce more have not yet come to fruition. Ultimately, it seems hard enough for our modern civilization to put together new reactors for use on land, let alone portable floating units that can be deployed at will. It seems like there just isn’t quite enough demand to justify their existence in greater numbers than one at a time.
Featured image: “MH-1A, STURGIS Nuclear Barge”, US Army Corps of Engineers
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