; (2) will not result in exceeding the low-rate initial production quantity approved in the Littoral Combat Ship acquisition strategy in effect as of the date of the certification; and (3) is necessary to maintain a full and open competition for the Guided Missile Frigate (FFG(X)) with a single source award in fiscal year 2020. (c) Definition The term revision five of the Littoral Combat Ship acquisition strategy means the fifth revision of the Littoral Combat Ship acquisition strategy approved by the Under Secretary of Defense for Acquisition and Sustainment on March 26, 2018. 127. Nuclear refueling of aircraft carriers (a) Authorization To procure nuclear refueling materials Pursuant to section 7314a of title 10, United States Code, as added by section 1014 of this Act, the Secretary of the Navy may procure naval nuclear reactor power units and associated reactor components for the following aircraft carriers: (1) U.S.S. John C. Stennis (CVN–74). (2) U.S.S. Harry S. Truman (CVN–75). (3) U.S.S. Ronald Reagan (CVN–76). (4) U.S.S. George H.W. Bush (CVN–77). (b) Condition for out-year payments Any contract entered into under subsection (a) shall provide that any obligation of the United States to make a payment under the contract for a fiscal year after fiscal year 2019 is subject to availability of appropriations for that purpose for that later fiscal year. 128. Limitation on funding for Amphibious Assault Vehicle Product Improvement Program Not more than 75 percent of the funds authorized by this Act or otherwise made available for the Marine Corps for fiscal year 2019 for the Amphibious Assault Vehicle Product Improvement Program (AAV PIP) may be obligated or expended until the Secretary of Defense has submitted to the congressional defense committees— (1) the report required under subsection (b) of section 1041