The HEU Reactor Conversion subprogram supports the conversion of domestic and international civilian research reactors and isotope production facilities from the use of WMD-usable HEU fuel to LEU fuel.  These efforts result in permanent threat reduction because the use of WMD-usable HEU in the civilian fuel cycle is minimized or eliminated. This subprogram includes assisting reactor operators perform feasibility studies and safety analyses required for regulatory approval to convert, procuring LEU replacement fuels, developing and qualifying new high-density U-Mo LEU fuel to convert high performance reactors, and supporting the development of a U-Mo LEU fuel fabrication capability to produce the new high-density fuel.