"A series of high urania-content glasses were fiberized and examined for high-temperature strength properties. One glass, RX360 containing 60% U/sub 3/O/ sub 8/ by weight, had better high-temperature tensile properties than any glass previously reported. It was observed that many of the glasses studied separated into immiscible phases and that the fiberizable glass phase had lower U/sub 3/O/ sub 8/ content than the base compositions. A physical analysis of crystal structures of the devitrification products from the nuclear fuel glasses indicated that most of the crystals consisted of uranium oxide in a reduced state. By adding O/sub 2/ to molten glass, it was possible to eliminate most of this devitrification. By elimination of crystals, the fiberizing of the glass was more uniform and the glasses produced had more consistent physical properties."

"Properly designed and fitted respirators have been effective devices for reducing the inhalation of toxic aerosols. The degree of protection afforded by these devices has not been quantitatively measured under actual work conditions except by bioassay or other elaborate techniques. This report describes a new quantitative technique for evaluating over-all respiratory performance under conditions comparable to exposure to highly toxic radioactive materials such as plutonium and non-radioactive materials such as beryllium."