Hydraulic tests were made on the Hallam Prototype Free-Surface Sodium Pump to determine the net positive suction head (NPSH) required at various sodium flow rates. Pump performance data were also collected. The results indicate that an NPSH of 22 ft sodium is required at the design flow rate of 7200 gpm at approximates 1000 deg F, agreeing with computed values, and that the pump is designed with a safety margin of slightly over l0%. (D.L.C.)

Concrete mix design criteria, based on existing theories of proportioning and specifically oriented toward the solution of radiation shielding problems, were developed. Effects of aggregate gradation, cement-to- aggregate ratio, and water content were examined. A barytes concrete, designed according to these criteria, was thoroughly investigated in the Lid Tank Shielding Facility. Relative effectivenesses of dry aggregates, aggregates plus cement, and cured concrete were compared through thermal-neutron flux, fast- neutron dose, and gamma-ray dose measurements behind slab configurations. Attenuation was measured for the aggregate, the aggregate plus cement, and for the barytes concrete. Comparison with attenuations calculated on the basis of removal cross sections for the measured chemical compositions showed satisfactory agreement. (auth)