The {sup 235}U content in fuel tubes (g{sup 235}U/ft) is directly proportional to the {sup 235}U concentration (g{sup 235}U/cc) in the U-Al core alloy. In order to prepare enriched uranium metal, aluminum, and U-Al scrap for U-Al production melts, the overall alloy composition (wt % U-Al) must be calculated for the desired {sup 235}U concentration (g{sup 235}U/cc) and uranium enrichment (*wt % {sup 235}U). This memorandum documents an alternative equation for calculation of U-Al alloy casting compositions in Building 321-M. This equation confirms the results of another, undocumented equation that has been used in the past.