He served on "pigboats" (diesel SSK's). As for the USS Seawolf, that liquid sodium reactor was a causality waiting to happen.
"Detached from Pomfret on 1 February 1951, Carter was assigned as Engineering Officer for the precommissioning detail for USS K-1 (SSK 1). K-1, the first postwar submarine built, was under construction by Electric Boat Division, General Dynamics Corporation, Groton, Connecticut. After K-1's commissioning on 10 November 1951, Carter served as Executive Officer, Engineering Officer, and Electronics Repair Officer. During this tour he also qualified for command of a submarine.
When Admiral Hyman G. Rickover (then a captain) started his program to create nuclear powered submarines, Carter wanted to join the program and was interviewed by Rickover. On 1 June 1952, Carter was promoted to Lieutenant. Selected by Rickover, Carter was detached on 16 October 1952 from K-1 for duty with the U. S. Atomic Energy Commission, Division of Reactor Development in Schenectady, New York. From 3 November 1952 to 1 March 1953, he served on temporary duty with the Naval Reactors Branch, U. S. Atomic Energy Commission, Washington, DC to assist "in the design and development of nuclear propulsion plants for naval vessels."
From 1 March to 8 October, Carter was preparing to become the engineering officer for the nuclear power plant to be placed in USS Seawolf (SSN 575), one of the first submarines to operate on atomic power. He assisted in setting up training for the enlisted men who would serve on Seawolf. During this time his father became very sick and died in July 1953. After his father's death in 1953, Carter resigned from the Navy to return to Georgia to manage the family interests. Carter was honorably discharged on 9 October 1953 at Headquarters, Third Naval District in New York City. On 7 December 1961, he transferred to the retired reserve with the rank of Lieutenant at his own request."
http://www.history.navy.mil/faqs/faq60-14.htm