From introduction: This is the final report on uranium carbide studies sponsored by the United States Atomic Energy Commission and performed by United Nuclear Corporation at its New Haven Research Laboratories during the period from May 1959 to January 1964. The work was part of the Commission's Fuel Cycle Development Program aimed at lowering the cost of nuclear power by improving fuel cycle technology. At the inception of this program in 1959, some work was in progress on uranium carbide. Little was known of making a satisfactory fuel in quantity or of how it would perform either in-pile or out-of-pile. The United Nuclear program was designed with no specific reactor in mind and was aimed at furnishing information over a broad spectrum.