The submarines to be maintained are those that home port at the U.S. Naval Submarine Base in Groton, Conn.
"Under the contract, Electric Boat will continue to operate the Nuclear Regional Maintenance Department at the submarine base," Electric Boat said. "The company will provide project management, planning, training and nuclear services to support maintenance, modernization and repairs."
About 25 Electric Boat employees are assigned to the NRMD but the workforce can be augmented temporarily by as many as 100 others.
The contract modification is worth $25 million and is the second to an existing award worth as much as $164 million over five years.
Earlier this month the company received a $9.5 contract modification to perform maintenance and modernization work on the USS Hartford (SSN-768), a Los Angeles class attack submarine. The modification covered included conducting "a dry-docking selected restricted availability."