General Dynamics Electric Boat Corp., Groton, Connecticut, is awarded a $313,949,471 cost-plus-fixed-fee modification to previously awarded contract N00024-17-C-2117 for additional United Kingdom (UK) Strategic Weapon Support System kit manufacturing, and submarine industrial base development and expansion, as part of the Integrated Enterprise Plan supporting Columbia-class ballistic missile submarines and the nuclear shipbuilding enterprise (Virginia-class and Ford-class). The industrial base development work is for the furtherance of the Fiscal 2022 National Defense Authorization Act (Public Law 117-81) which authorized, and the Department of Defense Appropriations Act, 2022 (Public Law 117-103) which appropriated, additional funds for submarine industrial base development and expansion to ensure second- and third-tier contractors are able to meet increased production requirements. Work will be performed in Quonset Point, Rhode Island (96%); Newport News, Virginia (4%); and is expected to be completed by September 2029. This is a joint U.S. / UK program. No funding will be obligated at the time of award. This is a sole source award in accordance with Defense Federal Acquisition Regulation 6.302-1(a)(2)(iii) — only one responsible source and no other supplies or services will satisfy agency requirements. The Naval Sea Systems Command, Washington, D.C., is the contracting activity.