150624-N-AT895-212 GROTON, Conn. (June 24, 2015) Chief of Naval Operations (CNO) Adm. Jonathan Greenert delivers remarks during a dedication ceremony for NR-1, the Navy's deep sea research nuclear submarine, at the Submarine Force Library and Museum. NR-1 was in service for 39 years and was the Navy’s only nuclear- powered, deep-diving ocean engineering and research submarine. (U.S. Navy photo by Mass Communication Specialist 1st Class Nathan Laird/Released)