; and (2) final results of test programs of engineering development models or prototypes for critical systems specified by the Senior Technical Authority pursuant to section 8669b of title 10, United States Code, as added by section 1017 of this Act, in their final form, fit, and function and in a realistic environment, which shall include a land-based engineering site if the propulsion system will utilize integrated electric power technology, including electric drive propulsion. (b) Limitation The Secretary of the Navy may not release a detail design or construction request for proposals or obligate funds from the Shipbuilding and Conversion, Navy account for the next new class of Navy large surface combatants until the class of Navy large surface combatants receives Milestone B approval and the milestone decision authority notifies the congressional defense committees, in writing, of the actions taken to comply with the requirements under subsection (a). (c) Definitions In this section: (1) The term Milestone B approval has the meaning given the term in section 2366(e)(7) of title 10, United States Code. (2) The term milestone decision authority means the official within the Department of Defense designated with the overall responsibility and authority for acquisition decisions for the program, including authority to approve entry of the program into the next phase of the acquisition process. (3) The term large surface combatants means Navy surface ships that are designed primarily to engage in attacks against airborne, surface, subsurface, and shore targets, excluding frigates and littoral combat ships. 128. Refueling and complex overhauls of the U.S.S. John C. Stennis and U.S.S. Harry S. Truman (a) Refueling and complex overhaul The Secretary of the Navy shall carry out the nuclear refueling and complex overhaul of the U.S.S. John C. Stennis (CVN–74) and U.S.S. Harry S. Truman (CVN–75). (b) Use of incremental funding With respect to any contract entered into under subsection (a) for the nuclear refueling and