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Liquid Sodium Reactor Powered USS Seawolf Was Part of First Nuclear Task Force

If the atomic powered USS Nautilus (SSN 571) revolutionized submarine warfare, then the follow-on USS Seawolf (SSN 575) was intended to revolutionize nuclear propulsion.

To achieve greater efficacy and power density, the Navy built Seawolf with a liquid metal (sodium) cooled nuclear reactor.

Seawolf was built by the Electric Boat Division of General Dynamics in Groton, Conn., and commissioned on March 30, 1957. She was the U.S. Navy’s second nuclear submarine.

Seawolf (SSN 575)

The Seawolf (SSN 575) readies for launching at Electric Boat, Groton, Conn., July 21, 1955. U.S. Navy photo

To achieve greater efficacy and power density, the Navy built Seawolf with a liquid metal (sodium) cooled nuclear reactor. Nautilus used pressurized water and saturated steam, while Seawolf’s reactor was more compact, and employed superheated steam.

The liquid sodium idea may have seemed like a good idea in theory, but it was unsuccessful in practice. In fact, the Navy was quick to deep-six the concept. Literally.

The liquid sodium idea may have seemed like a good idea in theory, but it was unsuccessful in practice. In fact, the Navy was quick to deep-six the concept. Literally.

USS Seawolf (SSN 575)

The USS Seawolf (SSN 575), under way in the 1960s. The Seawolf‘s S2G reactor was replaced with an S2W pressurized water reactor in 1958. The carrier in the far background might be the USS Essex (CVA 09). U.S. Navy photo

In 1958, Seawolf entered the Electric Boat shipyard to have her S2G reactor replaced with the same S2W pressurized water reactor as Nautilus.

In 1958, Seawolf entered the Electric Boat shipyard to have her S2G reactor replaced with the same S2W pressurized water reactor as Nautilus.

The Navy ordered three S2W reactors from Westinghouse; one for Nautilus, one as a land-based training prototype, and a spare. Likewise, the Navy ordered three S2Gs from GE. The “spare” S2W was installed on Seawolf in the conversion.

USS Seawolf (SSN 575)

USS Seawolf (SSN 575) under way. In 1963, Seawolf operated as part of the world’s first nuclear task force. U.S. Navy photo

This presented a new problem. How do you dispose of a radioactive reactor? The Navy’s solution: encase the “hot” S2G containment vessel, which was made of stainless steel, take it to sea, and dump it overboard.

In 1963, Seawolf operated as part of the world’s first nuclear task force with the aircraft carrier USS Enterprise (CVAN 65), guided missile cruiser Long Beach (CGN 9), and guided missile frigate Bainbridge (DLGN 25).

In 1963, Seawolf operated as part of the world’s first nuclear task force with the aircraft carrier USS Enterprise (CVAN 65), guided missile cruiser Long Beach (CGN 9), and guided missile frigate Bainbridge (DLGN 25).

USS Seawolf (SSN 575)

USS Seawolf (SSN 575) receives her new “special projects” hull section at Mare Island, Calif., June 2, 1971. Later in her career, Seawolf became a “special project platform.” U.S. Navy photo

Later in her career she would be modified as a “special project platform.”

She would serve the fleet until 1987, when she was decommissioned.

She would serve the fleet until 1987, when she was decommissioned.

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Capt. Edward H. Lundquist, U.S. Navy (Ret.) is a senior-level communications professional with more than...