Adwanced Water Reactor Progran. Seven reaction couples were studied for 60 days at 600 and 800-C:. graphite; lead with Zircaloy-2 amd stainless steel; amd graphite with Zircaloy-2. No reactions were observed at 600 C and only lead-Zircaloy-2 appeared to react at 8OO C. Fast Power Breeder Reactor Program. EBR-I Mark III core is being fabricated. Tests in Borax-rV on sheetu showed fracturing dependent on UO/sub 2/ content. Non-destructive testing development continued. Alloying with Ru showed no improvement in corrosion properties of U. Corrosion of M388 A1 alloy as affected by Vhosphate, pH, and flow rate were studied. Production, Trcatment, amd Properties of Materials. Plastic deformation and thermal conductivity of U single crystals was studied. Ihvestigation of recrystallization of alphaU without a texture change continued. Tests of French uranium are reported. Barrier layers of UO/sub 2/ were found in sputtering of Zr and U onto U, probably resulting from impurities in the argon used. Phase traasformations in the U-C system were studied, and gamma U lattice parameters for 900k C annealed amd water quenched U-Mo-Ru are given. Studies are also reported on the Zr corrosion mechanism and sintering of ceramic materials. (For preceding period see ANL5717.) (T.R.H.)

>Progress is reported in the extrusion of Cu-clad Zr billets into tubing, welding of Zr strip into tubing using a roder resistance welding tube mill, piercing of Zr billets into a base tube, the casting and fabrication of U-- Nb alloys, the rolling of Zircaloy sheet, the roll-cladding of Zircaloy to U--Nb alloys, the fabrication of plate type reactor fuel elements of U--Hb alloys roll bonded with Zircaloy, fabrication of a complete U/sup 235/--Zr fuel slug for the EBR, the fabrication of U-- Zr alloy rod into EBR fuel blanket slugs, the thermal cycling of U-- Zr rods following heat treatment, the fubrication of enriched U reactor fuses, the preparation and dimensional stability of U single crystals, twinning in U crystals, diffusion in Cu- U couples, the fabrication of U billets from electrolytic crystals, the preparation of U-- Zr and Hb--U alloys, effects of radiation on U, the effects of radiation on U-- Zr alloys, the corrosion of Al, Zr, and Nb-U alloys, and the effects of heat treatments on Hb-- U alloys. (C.H.)