An S2G was the initial power plant of
USS Seawolf (SSN-575). This was one of three
sodium cooled reactors (the core was moderated) ordered for the
Seawolf program at the same time as three PWR units were ordered to support the
USS Nautilus (SSN-571) program; In each case, one reactor was land-based for training and research, one intended for installation on a submarine, and one spare. The land-based unit corresponding to S2G was
S1G reactor. The reactor core was
beryllium-
moderated. Persistent superheater problems on
Seawolf caused the superheaters to be bypassed, resulting in mediocre performance. This and concern for the dangers posed by liquid
sodium coolant led to the PWR type being selected instead as the standard US naval reactor type, and the S2G on
Seawolf was replaced by the spare
S2Wa reactor from the
Nautilus program. The
Atomic Energy Commission historians' account of the naval sodium-cooled reactor experience was: ==References==