In studies of the fabrication of fuel subassemblies for the supercritical-water reactor, the limited ductility of stainless steel-UO₂ fuel sheet made the fabrication of corrugated-flat-plate-type subassemblies impractical. A fabricable MTR-type assembly, 5/8 in. square and 30 in. long, was developed. Methods for edge cladding fuel sheet were developed and a brazing alloy, GE-75, was found to be corrosion resistant in supercritical water.

From introduction: "This report covers the development of nondestructive techniques for measuring quantitatively: (1) thickness of electrodeposited-nickel diffusion barriers, and (2) thickness of aluminum cladding on flat-plate fuel elements."

Abstract: In one of the final stages of the process at the Mallinckrodt Uranium Refining Center, a 45 per cent nitric acid solution at about 170 F is used to pickle the calcined magnesium fluoride scale off the uranium derbies. The increase in the fluoride-ion content of the bath tends to promote corrosion of the Type 347 stainless tanks. This attack becomes excessive if 0.3 g/liter of fluoride ion or more is present. It was found that if aluminum ion is added to the solution the corrosiveness of the bath can be controlled. Two or three times as much aluminum ion as fluoride ion present is found satisfactory at 170 F. Indications are that the tying up of the fluoride-ion by the complexion [AlF6]8 is responsible for the corrosion control.

Abstract: "Four brazing methods and one other joining process were evaluated for the joining of aluminum spacer fins to flat-plate aluminum-clad fuel elements. None of these methods appear completely suitable for use in a mass-production operation. Furnace brazing and salt-bath brazing were most promising. However, the mechanical problems involved in the application of either process deter their recommendation. Resistance brazing and torch-brazing were proven impractical. The great difference in mass between the two pieces being joined prevents the use of either the resistance or torch method. Pressure bonding is not applicable because of the excessive deformation of parts being joined."

A report about the corrosion tendencies of 64 metallic elements, nonmetallic elements, and carbides evaluated by means of thermodynamic methods.

Abstract: "Thirty-four uranium ingots containing controlled amounts of carbon, nitrogen, and Mgl2 slag were cast, rolled, and examined to investigate the relation between these impurities and the quality of the rolled rod. Carbon in concentrations up to 1400 ppm and nitrogen up to 170 ppm, either singly or in combination, had no significant effect on the number of defects observed in the rolled rod. The quality of the rods, however decreased with increasing amount of slag necessary to cause observable differences in the rod could not be detected on analysis, but was visible in the microstructure."

A report intended to aid in the evaluation of solid-state bonding techniques for cladding natural-uranium fuel-element cores with aluminum, tensile specimens which are 1/4 in. in diameter and 3 in. long.

From abstract: "The feasibility of casting a bare, radiator-type fuel element of the uranium-chromium eutectic alloy (5 w/o chromium) was investigated."

From Abstract: "The heat treatment and mechanical properties of four zirconium alloys...were investigated. Tensile, hardness, Jominy end-quench, and metallographic data constitute the basis for much of the report. Other data reported include the results of high-temperature creep, tensile, hardness, cold rolling, thermal-cycling, and dynamic-modulus tests." A connection is made between the behavior of these four alloys and more alloys in the zirconium-uranium system.

Abstract: "Blacosolv, trichloroethylene, is used in degreasing uranium metal. Tests were made under possible industrial conditions to determine whether a hazardous reaction between uranium and Blacosolv could occur. Temperature-rise measurements showed that there was no reaction of the metal, in various states of subdivision, with Blacosolv at temperatures up to 850 F. However, a reaction was observed in tests under which the finely divided metal, wet with solvent, was subjected to a severe impact."

From abstract: "The composition of vapors from aqueous nitric acid solutions boiling at 200 mm mercury total pressure is established for solutions containing between - and 67.5 w/o nitric acid. The volatility characteristics of low concentrations of chloride in the same concentration range of nitric acid have been measured in solutions boiling at 200 mm mercury. The effects of chloride concentration and pressure of boiling are evaluated. A spectrophotometric method of the determination of chloride in nitric acid solutions is described."

Report discussing reaction of hydrogen with uranium in a range of temperatures and pressures. Experimental materials, methods and results are included.

From introduction: "Centrifugal casting appeared to be the only method by which the intricate shape could be produced in a cold mold. With this in mind, a program was initiated for the purpose of determining the feasibility of centrifugally casting plates of uranium-5 w.o chromium and uranium-2 w/o zirconium."

The following report discusses the development of methods for sealing the ends of metallic-cored fuel rods.

Report discussing the redetermination of liquids for aluminum alloys containing 13 to 25 w/o uranium by metallographic examination, thermal analyses, and electrical resistance measurements. In addition, phase diagrams and a method for producing sound, homogeneous aluminum 16 w/o uranium alloy sleeve castings are presented.

Report presenting a study that evaluates various types of refractories for use in a refractory-lined vessel that would be used for continuous reduction of uranium tetrafluoride to uranium metal.

Report discussing experiments on the interaction of neutron-absorber materials and metal matrix materials used in the fabrication of control rods, such as "boron, cadmium, and some of the rare-earth elements such as gadolinium and europium...In order to evaluate the reactions that might occur during fabrication and use, experiments were carried out in which combinations of the various control materials were heated in intimate contact with the several matrices at elevated temperatures."

Abstract: "The effects of nitrogen, slag, and hydrogen additions on the surface quality of rolled uranium rod were studied. The addition of 400 ppm of nitrogen resulted in severe striations. Slag inclusions elongated during rolling and produced short open seams in the etched surface. The effects of 9 to 10 ppm of hydrogen were obscured by defects in the original costings. These defects were caused by oxide films entrapped in the ingot."

This report follows investigations of methods for sealing the ends of stainless steel-uranium oxide fuel pins with the objective to develop an end-capping method that would give consistently good-quality closures in production.

Abstract: "The heat-treatment behavior of zirconium alloys containing 7 to 70 w/o uranium is described. The effect of oxygen contamination on the structure and hardness of these alloys is outlined. It is shown that in the initial stages pf transformation of beta zirconium-uranium solid solution into the low-temperature phases a potent hardening reaction occurs in alloys containing 20 to 70 w/o uranium. In this reaction the hardness may rise from 200 DPH characteristic of retained beta to values in excess of 400 DPH. Practical heat treatments have been developed which produce relatively soft alloys. The microstructures and hardnesses produces by these treatments are shown."

This report discusses studies revealing the tensile properties, hot hardness, and heat treatment characteristics of uranium alloys with added aluminum or zirconium.

This report studies ammonium dichromate and the conditions it needs to be under in order to precipitate and be isolated from an aqueous system.

Report discussing the progress of research projects at Battelle Memorial Institute relating to civilian applications during August 1956.

This report discusses a study regarding the properties of uranium with added chromium, silicon, or titanium. This study was conducted in order to evaluate the effects of alloying on the mechanical properties of base metal.