GROTON — The defense industry continues to be a cornerstone of Connecticut manufacturing, as nuclear submarine maker General Dynamics’ Electric Boat division plans to expand its Groton headquarters.

The $31.5 million project will allow the company to add up to 200 new workers to its 8,700-strong workforce. The state’s Department of Economic & Community Development (DECD) will aid the expansion with a $10 million loan, which is completely forgivable if it hires those 200 new employees within 24 months.

The company expands to accommodate increased hiring and industry demands. The U.S. Navy awarded Electric Boat a $17.6 billion contract in April to construct the next order of Virginia-class submarines.