PROGRESS RELATING TO CIVILIAN APPLICATIONS DURING FEBRUARY 1959

Measurements of the thermal conductivity of unirradiated U and UO/sub 2/ were completed. An evaluation is being made of the creep properties of annealed and 15% cold-worked Zircaloy-2 at elevated temperatures in order to determine the suitability of Zircaloy-2 for process tubing in the NPR. Single crystals of highpurity Mo are being grown for irradiation studies. Research to identify factors affecting irradiation-induced volume changes sn graphite by means of sink- float density measurements was continued. Hollow cylindrical tubes of Al-U alloys clad inside and outside with Al are being developed. A radiometric method for the determination of Ca is under study. An investigation of the mechanism of solidification of U metal in cylindrical graphite molds was continued. A study to evaluate arc spraying as a method for coating Ni with Ca is reported. Work on the valence effects of Y/sub 2/O/sub 3/, CaO, and La/sub 2/O/sub 3/ additions to UO/sub 2/ was continued. The investigation of the structure of U--Zr alloy hydrides for potential use in fueled moderators is nearing completion. The changes in mechanical properties of AISI Type 347 stainless steel as the result of exposure to a fast-neutron flux is being investigated. Corrosion data are presented for commercial-purity Nb-base alloys. Data are presented on the creep behavior of high-purity Nb and Nb-base alloys. Work was continued on the development of Nb-U alloys. lmprovement of the irradiation-damage resistance and of the corrosion resistance of Th-U alloys is being sought by means of alloying and process control. The gas-pressure-bonding technique is being investigated as a method for cladding cermet and ceramic-type fuels with Mo and Nb. The hightemperature irradiation behavior of dispersion fuel elements consisting of 24 wt.% UN and UC dispersed in stainless steel is being evaluated. An investigation of the mechanism and kinetics of solid-state bonding of metals by the application of heat and pressure is in progress. Fatigue studies of Inconel and INOR-8 were continued. A fundamental study of the reactions of N2 with Nb is being made. An investigation of the constitution of U-Nb alloys is in progress. A study of post irradiation fission-gas release from UO/sub 2/-graphite spheres at elevated temperatures was started. Mean linear-thermal-expansion coefficients for irradiated Th-11 wt.% U specimens are reported. The compatibility of Ta and Ta alloys with Pu is being investigated. A flat-plate Zircaloy-2-clad fuel element containing compartmented UO/sub 2/ is being considered for Core 2 of the PWR. The postirradiatson examination of UO/sub 2/ samples was completed. Techniques are betng studied for fabricating graphite --matrix bodies containing 20 vol.% of fuel compound in the form of UC or UC/sub 2/. (For preceding period see BMI- I315.) (W.L.H.