S3W reactor

The S3W reactor is a naval reactor used by the United States Navy to provide electricity generation and propulsion on warships. The S3W designation stands for:


 * S = Submarine platform
 * 3 = Third generation core designed by the contractor
 * W = Westinghouse was the contracted designer

This nuclear reactor was a variant of the Submarine Fleet Reactor (SFR), an advance on the pressurized water reactor (PWR) plant design employed on the USS Nautilus (SSN-571). The S3W plant utilized horizontal U-tube steam generators. This concept developed into vertical U-tube steam generators in the S5W reactor plant, and is in common use today on commercial PWR power plants.

The USS Halibut (SSGN-587) and the four Skate class boats were built with S3W reactors: USS Skate (SSN-578), USS Swordfish (SSN-579) , USS Sargo (SSN-583) , and USS Seadragon (SSN-584). USS Swordfish (SSN-579) and  USS Seadragon (SSN-584)  had the S3W reactor installed in the S4W reactor plant, which was an alternate arrangement of the same components.