The following is a news release from the Idaho Environmental Coalition:
IDAHO FALLS, Idaho (KIFI) — Crews with the Idaho Cleanup Project (ICP) have completed the demolition of the high bay roof and walls of the Submarine 1st Generation Westinghouse (S1W) naval reactor prototype plant, using explosives to carry out this key phase of work. The effort, overseen by the U.S. Department of Energy Office of Environmental Management (EM) and ICP contractor Idaho Environmental Coalition (IEC), marks significant progress in reducing the footprint at the Naval Reactors Facility (NRF) located on the Idaho National Laboratory (INL) Site.
This carefully planned demolition followed extensive efforts that began in 2022 to safely remove contaminated and hazardous materials from the historic building. The ICP crew also removed the S1W’s defueled reactor vessel in March 2025, which was disposed of in a nearby on-site disposal facility in accordance with federal and state regulations.
The S1W demolition project has maintained an accelerated pace, completing work ahead of schedule and under budget.
Mike Swartz, IEC’s senior manager over demolition projects, commends the effort of these crews who worked hard to reach this significant milestone.
“This milestone represents the professionalism and dedication from every member of our team,” said Swartz. “Their ability to safely and efficiently execute complex work like this demolition will allow us to successfully complete our mission at NRF.”
While EM and IEC are responsible for managing demolition of the S1W and other historic reactor vessel prototypes at NRF, acting ICP Manager Nick Balsmeier recognizes the importance of an effective partnership with the U.S. Naval Nuclear Propulsion Program.
“I am incredibly proud of IEC and their team, and grateful for support from our partners at Naval Reactors,” said Balsmeier. “It is the collective effort that will allow DOE to continue meeting our cleanup commitments and enable a strong future at the INL Site.”
In the coming months, demolition crews will remove the remaining debris, recycling the material to the extent practicable. The project anticipates completing the S1W demolition project in Fall 2025.
The S1W reactor prototype plant, located at the INL Site’s Naval Reactors Facility, after construction was complete in 1951.
The S1W is a defueled naval nuclear propulsion plant prototype and supported the development of the USS Nautilus, which was launched in 1955 as the world’s first operational nuclear-powered submarine. S1W was built to simulate a submarine hull, with a nuclear reactor compartment surrounded by more than 300,000 gallons of water to mimic ocean-like conditions.
David Honabach, a former student and staff instructor at the S1W, reflected on the significant role the S1W and the Naval Reactors Facility played in proving a new technology that propelled the development of the U.S. nuclear navy fleet.
“When you go all the way back…you can look at the challenges that we had. And you could look at where we were as a nation and what we were trying to solve. For S1W…we were really trying to convince the military and the nation, as nuclear power technology was becoming available, how to convert from diesel to nuclear power. Proving that that was capable, proving that it could fit into a submarine hull,” said Honabach.
In addition to providing critical research and development, the S1W served as a training ground for thousands of prospective students. Honabach also provided insight into training and how the S1W developed a skilled and competent force of nuclear submarine operators.
“From the Navy side, it was really about the training of students. We recognized that there was a significant number of students that went before us. And we recognized the importance of being trained and qualified on a land-based prototype before we actually went, in our case, to a submarine,” he said. “We understood that that was absolutely critical in order to obtain our submarine warfare qualifications and to be able to be a productive crew member once you got to your first submarine.”
Honabach’s experience is recorded as part of a collection of oral histories archived in the Library of Congress and represents a broader effort by the Naval Reactors Program and the Idaho State Historic Preservation Office to memorialize the historic mission at NRF.
