Summary. At the time this project was initiated, all brazing had been confined to small retorts of ten cubic feet capacity or less. Larger assemblies were scheduled which required retorts of over 100 cubic feet capacity. Hydrogen atmospheres had given the best results, however, there was considerable reluctance to use hydrogen in these large retorts from a safety standpoint. It was thought that thru the use of PMC 2252, an argon - 2 1/2% hydrogen gas atmosphere which in non-explosive, sufficient cleaning action might be attoined without the inherent hazards encountered with hydrogen. An investigation of the argon - 2 1/2% hydrogen gas as a brazing atomosphoer

Technical report of an investigation to determine a suitable material for sintering and casting of braze rings. Braze rings afford an excellent means of preplacing braze alloy on tube to head joints of radiators, heat exchangers, and similar applications. A cast ring is especially desirable because of its increased strength. Previous efforts at casting had used welding grade carbon blocks with the desired ring cavities machined into their surface. Conclusion: Stackpole grade 331 electro-graphite provided the best results of the materials investigation. It is hard and more readily machinable with conventional tools than other grades. Carbon, in general, proved to be more satisfactory especially due its ease and speed of fabrication.

Technical report describing the process to determine the fusion welding characteristics of Haynes Alloy #25 as applied to TLJ-100530, Corrosion Loops. Hayes Stellite Alloy #25 is a cobalt-base alloy for corrosion resistant high temperature applications. This material, when welded by the inert gas shielded tungsten arc method, produces sound ductile joints. Material thicknesses greater than 12 gauge require standard joint preparations, a V joint being preferred up to 1/4 inch and a U joint for greater thicknesses. Welding heat should be kept to a minimum followed by fast cooling. The molten metal is very fluid and may present difficulties when position welding.

Uranium carbide shows promise as a fuel material for reactors operating at relatively high temperatures based on its high melting point, high uranium density and high thermal conductivity. Before refined reactor designs can be made, however, good quantitative data on the thermal conductivity at temperatures in excess of 1000C is required. This technical report presents data gathered as part of a continuing study aimed at determining the thermal conductivity of refractory uranium fuels as a function of temperature, density and composition over the temperature range 1000-2200C. At the inception of this program it was felt that an absolute method capable of achieving high temperatures was necessary and that the difficulties encountered in fabricating the large complex specimens needed were justified. The steady state radial heat flow method and apparatus of Rasor and McClelland were therefore chosen. The technical report discusses the experimental equipment and presents results of measurements on three specimens of UC over a temperature range 900 to 1600C. An analysis of the data is made with respect to other physical properties of the material and the measured conductivities are compared with the work of other investigators.

The use of uranium mononitride as a nuclear fuel is being considered for a number of high temperature applications. In comparison with the most often applied high temperature fuels, UO2 and UC, one finds that UN has a combination of the high melting point of UO2 and the thermal conductivity and high uranium density of UC. However, interest in UN is often dampened by qualitative indications of its low thermal stability and by lack of experimental thermodynamic data. Is is the purpose of this study, therefore, to provide a quantitative measure of the thermal stability of UN and to establish some of its thermodynamic properties.

This technical report is a summary of short time strength data for CS1830 series Cb-1Zr material. The data are presented as a function of fabrication history or the amount of cold work received during fabrication. Three fabrication categories were considered for comparison: forgings and extrusions; bar, plate, rod and pipe; and sheet and tubing. Forgings and extrusions having received no cold work showed the highest strength over the entire temperature range 68F to 2800F; bar, plate, rod and pipe received moderate cold work and showed lower strength than forgings and extrusions but higher strength than sheet and tubing in the temperature range 2000F to 2800F.

Abstract. Some recent analysis of certain Lid Tank fast neutron dose rates measured in oil and water indicates that there are some basic inconsistencies with reported oxygen and carbon removal cross sections and the reported data. These inconsistencies may be explained in several ways: (1) The reported carbon removal cross section is wrong. (2) The reported oil composition is wrong. (3) The reported oxygen removal cross section is wrong since it is based on an assumed rather than a measured oil composition. (4) Some of the experimental data are wrong. It is not possible to determine which of the above is most likely on the basis of analysis alone but the possibilities are pointed out and, based on the assumption that all the experimental data are correct, it appears most likely that the oil composition assumed in ORNL 2197 was in error.