"A series of glass compositions containing uranium oxide was investigated to determine fiberizability and physical properties of resultant fibers. The basic properties to be determined were the maximum U/sub 3/O/sub 8/ content in a fiberizable glass and the maximum service temperature of the fibers. Glasses containing 60 wt% U/sub 3/O/sib 8/ were fiberizable; the fibers had strengths of 100,000 psi at 1600 deg F. Fiber-forming equipment was installed at Moun Laboratory to produce glass fibers containing PuO/sub 2/. Fibers were successfully formed in the first trials. For additional work a series of base glasses were provided affording a wider range of both PuO/sub 2/ solubility and physical properties."