Absolute calibration of neutron yields from a polonium nitrate- fluorocarbon interface gave 8 neutrons/min, sq cm, mc/ml. In two Fluorox fluidized bed reactor runs UF/sub 6/ recoveries of 47 and 70% theoretical were attained. Washing and descaling operations for Loop P-1 have been completed. Preliminary studies of ThO/sub 2/ classification by hydroclones showed that particles as small as 0.5 micron could be classified. Continuous, self- sustaining operation of the Darex dissolver, stripper, and reflux condenser was maintained during a 48-hr period. Uranium losses to the sublimate were less than 0.1% in a 24 hr Zircex run. A 32 hr dissolution run was completed in which a fuel element fabricated of Zircaloy-3 was dissolved in a NaF-ZrF/sub 4/ fused salt. (auth)