Correlation of a number of physical and chemical properties of 12 different UO/sub 2/ powders was continued. The UO/sub 2/ powders were studied by means of infrared absorption measurements, oxidation temperatures as determined by hot stage microscopy techniques, and B. E. T. surface area measurements. Additional pellets were prepared to study ceramic performance. (M.C.G.)

The lifetime of a B/sub 4/C-in-tubes'' control rod may be limited by either nuclear worth depreciation or internal gas pressure buildup as helium is formed and released from the B/sub 4/C particles. Nuclear life is enhanced by thin tube walls for any given O.D. of tubing and by high B/sub 4/C density, but the time to failure from gas pressure buildup is increased by the opposite. The optimum B/sub 4/C density and tube wall thickness were calculated for maximum control rod life, using several release fractions of generated helium and a number of allowable cladding stress values. It was estimated that lifetimes of l0 or more years for B/sub 4/C-in-tubes control systems are achievable through the proper selection of tubing material and B/sub 4/C density values. The B/sub 4/C densities required for maximum lifetimes are in a range that can be obtained by vibratory compaction followed by swaging. (auth)

S>An inline densimeter was fabricated and tested in the laboratory. When operated in a range of 1.000 to 1.200 g/cc, an accuracy of plus or minus 0.2% in the mid-point of the range was easily achieved. The instrument also measures pulse amplitude and pulse frequency when used on a pulsating flow. A long life with high reliability is expected because of the simple all-welded construction and highly reliable electronic system. (auth)

Tables are presented for conversions from photon vacuum wavelength to photon energy and vice versa. The ranges covered are 500 to 12,000 angstroms and 1.000 to 26 electron volts. (D.L.C.)