Nine samples of ThO/sub 2/ -UO/sub 2/ prepared as part of the solgel process development studies showed no consistent effects from small variations in several process parameters. The reaction of methane and copper oxide was studied. Engineering studies of the continuous dissolution of simulated U-Zr-Sn fuels in 6.5 M NH4F, 0.6-1.0 M NH/sub 4/NO/sub 3/, 0.1 M H/sub 2/O/sub 2/ were continued in modified 6-in.-dia. equipment. A total of 1642 kg of U from NaK bonded SRE Core I fuel rods wad dejacketed to date/su Initial operability tests of the 250 ton prototype shear unit showed a number of minor modifications are warranted. Center tube temperatures measured in a vertical 64 tube electrically heated simulated fuel element bundle were very near those previously obtained in the horizontal position. A 304 SS tube containing eutectic NaK was dissolved by HF in fused saIt at a tube wall penetration rate of approximates 2 mils/hr. Partial differential equations were derived from the concentration of unreacted UF/sub 6/ as a function of time and position in a sphere of NaF during sorption of UF/sub 6/. Calcium nitrate solution was added directly to the pot calciner during Purex feeding to give smoother operation of themore » feeding system. (auth) « less