EM Set to Demolish Second Submarine Reactor Prototype in Idaho

Mark Brown, left, manager of Idaho Cleanup Project, and Gil Pratt, manager of the Naval Reactors Idaho Branch Office, stand with a plaque commemorating the 30-year operational history of the Submarine 5th Generation General Electric prototype.

IDAHO FALLS, Idaho - A U.S. Department of Energy Office of Environmental Management (EM) team is set to decommission and demolish (D&D) a second submarine reactor prototype at the Idaho National Laboratory (INL) Site's Naval Reactors Facility (NRF).

The Submarine 5th Generation General Electric (S5G) prototype is a defueled land-based reactor vessel that served as an important training ground for prospective U.S. Navy submariners. D&D plans at S5G are consistent with a 2019 agreement between EM and the U.S. Office of Naval Reactors that created a path for EM's current D&D efforts at the Submarine 1st Generation Westinghouse (S1W) and Aircraft Carrier 1st Generation Westinghouse (A1W) legacy prototypes at NRF.

A ceremony commemorating the transfer of the defueled S5G prototype from Naval Reactors to EM was held on Oct. 30 at NRF. Jeff Avery, EM principal deputy assistant secretary, attended the ceremony and commended the efforts of EM crews in Idaho.

Representatives of the U.S. Department of Energy Office of Environmental Management headquarters, Idaho Cleanup Project, Naval Nuclear Laboratory, Naval Reactors Laboratory Field Office-Idaho Branch Office, Shoshone-Bannock Tribe and others pose for a photo during a tour of the Submarine 5th Generation General Electric prototype last week.

Representatives of the U.S. Department of Energy Office of Environmental Management headquarters, Idaho Cleanup Project, Naval Nuclear Laboratory, Naval Reactors Laboratory Field Office-Idaho Branch Office, Shoshone-Bannock Tribe and others tour the Submarine 5th Generation General Electric prototype last week.

Idaho Cleanup Project Manager Mark Brown said the EM team is excited to continue its close partnership with Naval Reactors.

"Our cleanup contractor, Idaho Environmental Coalition LLC (IEC), has a well-trained and motivated workforce that has demonstrated huge progress in safely demolishing the first NRF submarine prototype, S1W," Brown said. "This same workforce will maintain demolition momentum at the S5G prototype."

Gil Pratt, Naval Reactors Idaho Branch Office manager, values EM's expertise and partnership in the D&D projects at NRF. He also recognizes the significant place the S5G prototype has in Naval Reactors history.

"S5G was a testbed for multiple technologies that are still used today, ensuring our submarine fleet can operate anywhere, anytime, virtually undetected," said Pratt. "Naval Reactors is preserving the legacy of S5G through oral histories, written records and artifacts from the prototype."

During operations decades ago, the Submarine 5th Generation General Electric prototype was placed inside a basin and submerged in thousands of gallons of water to mimic ocean-like conditions.

The Submarine 5th Generation General Electric prototype was constructed in a below-ground basin, unlike the Submarine 1st Generation Westinghouse and Aircraft Carrier 1st Generation Westinghouse prototypes.

Constructed in 1965, the S5G prototype was built to simulate the operations of a nuclear reactor within a submarine. During operations, it was submerged in thousands of gallons of water to mimic ocean-like conditions. The prototype also was used to train nearly 12,000 naval officers and enlisted personnel to operate the propulsion plants of nuclear-powered submarines. The prototype was shut down in 1995 and its reactor vessel was defueled in 1999.

EM, with concurrence from the U.S. Environmental Protection Agency and the state of Idaho, has released an engineering evaluation and cost analysis on the final end state for D&D of the S5G prototype. The public can comment on the documents through Nov. 14. Click here for more information.

D&D of the S5G prototype warranted an evaluation separate from the S1W and A1W prototypes because the S5G prototype was constructed belowground, unlike the other two.

Following the public comment period, a memorandum will be prepared to document the final end-state decision for the S5G prototype. Four alternatives are detailed in the evaluation and analysis. EM anticipates signing that memorandum next year.

-Contributor: Carter Harrison