; 129 Stat. 1196) and submitted to the congressional defense committees on March 25, 2018, that the United States should not pursue research and development of an advanced naval nuclear fuel system based on low-enriched uranium, remains valid. (2) A determination by the Secretary of the Navy with respect to whether an advanced naval nuclear fuel system based on low-enriched uranium can be produced that would not reduce vessel capability, increase expense, or reduce operational availability as a result of refueling requirements. 3112. Prohibition on ARIES expansion before realization of 30 pit per year base capability Section 4219 of the Atomic Energy Defense Act ( 50 U.S.C. 2538a ) is amended by— (a) redesignating subsection (f) as subsection (g); and (b) inserting after subsection (e) the following new subsection (f): (f) Prohibition on ARIES expansion before realization of 30 pit per year base capability (1) In general Unless the Administrator certifies to the congressional defense committees that the base capability to produce 30 plutonium pits per year has been established at Los Alamos National Laboratory, the Advanced Recovery and Integrated Extraction System (commonly known as ARIES ) spaces at the Plutonium Facility at Technical Area 55 (commonly known as PF–4 ) may not be modified, including by installing additional equipment. (2) Exceptions Paragraph (1) shall not apply with respect to— (A) the planning and design of an additional ARIES capability