The RPI research reactor is licensed to operate at 1 MW power and has a peak flux of about 3.1 x 1013 n/cm2-s. The core was converted from a 93 percent enriched UAlx-aluminum dispersion fuel to 19.75 percent enriched uranium silicide (U3Si2)-aluminum dispersion fuel in 2007. The LEU fuel contains slightly more uranium-235 than the HEU fuel it replaced to ac­count for the increased neutron absorption by uranium-238.

The conversion goal for this reactor was to allow for 10 years of op­eration at acceptable neutron flux density levels using the same number or fewer fuel assemblies. A silicide fuel with the same fuel meat thickness as the original HEU fuel met this goal when the core contained 17 fuel assemblies. However, by increasing the thickness of the fuel meat by 0.1 millimeters, the conversion goal could be met using only 13 fuel assemblies, a savings of 4 assemblies. Additionally, by changing the locations of some of the beryllium reflector blocks, designers were able to increase neutron flux densities in key locations in the reactor core to better suit experimental needs.