Abstract: "Refinement of grain size of the base uranium-chromium eutectic alloy (uranium-5 w/o chromium) by ternary additions is discussed. Thirteen additions to the base alloy were investigated, and three additions were found to exhibit worthwhile grain-refinement tendencies. The three alloys, uranium-5 w/o chromium-0.2 w.o molybdenum, uranium-5 w/o chromium-0.2 w/o germanium, and uranium-5 w/o chromium-0.2 w/o niobium, were heat treated to produce final grain-size structures of between 0.015 and 0.033 mm."

The following report discusses an equation derived by which the maximum allowable concentration in the atmosphere of a beta-omitting isotope for which lung damage is the limiting consideration can be calculated.

This is the third of a series of reports describing the phases of a study of the wear and galling of autoclavedZircaloy-2 by various bearing surface materials. The first report (1) showed that increasing contact area between the autoclaved Zircaloy-2 surfaces will not prevent scratching. It also showed that metals softer than Zircaloy-2 in general do not scratch it. The second report (2) described how eight metals and alloys were wear-tested on autoclaved Zircaloy-2 as prospects for fuel element support-bearing surface materials.

Two 500-kw fused-fluoride-to-Nak heat exchangers, two 500-kw NaK-to-air radiators, and a 20-tube high-velocity heat exchanger were fabricated for a heat-exchanger development program. A construction procedure, utilizing both inert-arc-welding and high temperature dry-hydrogen brazing, was used successfully on all of the units. The tube-to-header joints were welded and back-brazed; the manifold joints were inert-arc-welded with full penetration; and the tube-to-fin joints were brazed. A detailed description of the fabrication of each type of component is discussed and a cost analysis of the 500-kw units is presented.

Progress report of the Oak Ridge National Laboratory Analytical Chemistry Division providing updates on various projects, experiments, and other work in ionic analyses, analytical instrumentation, radiochemical analyses, activation analyses, spectrochemical analyses, inorganic preparations, optical and electron microscopy.