The use of pulsed reactors for the evaluation of materials and components has been on the increase and pulsed reactors to handle large components are under consideration. Pulsed reactors currently operate at a 30 to 50 u sec pulse width and a neutron yield of 5 × 1016 fission/pulse; improved capability would move toward even smaller pulse widths and neutron yields in the 1017 fission/pulse range. The gamma phase U—10 Mo alloy with highly enriched uranium has been the fuel alloy used in most pulsed reactors. The fabrication of U—10 Mo alloy fuel plates for the new SPR-III reactor at Sandia Laboratories, Albuquerque, New Mexico, required a detailed review of all processing operations because of the highly enriched uranium and the related criticality considerations. It was necessary to cast the maximum allowable mass of highly enriched uranium (36 kg) in order to make a single fuel plate. The low carbon impurity level specified was obtained with the formulation of a new and highly successful composite coating material for graphite crucibles and molds. The plate distortions which occur in water quenching the alloy from the 950°C gamma phase to room temperature were eliminated by quenching between cold platens in a hydraulic press. Typical mechanical properties obtained on cast, heat treated plates were 930 MPa yield strength, 940 MPa tensile strength, 12.9% elongation in 25.4 mm, and 35.4% reduction in area.