The following progress reports continues the investigation of the HCl-acetone process for extracting uranium, discovering that it is applicable to most Western ores, yielding high uranium recoveries. The economics of the process have been improved by substitution of sulfuric acid for part of the hydrochloric acid requirements.

The following report describes the welding characteristics of several high-strength stainless steels that were considered for use as a pressure vessel to operate at high pressures at 800 F.

The following report follows the studies of electroplating on uranium and concurrent metallurgical clodding.

A report about a method for fabricating 30-in long stainless steel UO2 fuel sheet and the properties of the fabricated sheet were investigated.

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.

A report which covers an investigation of techniques for producing hot-dip Al-Si coatings on uranium sheet. Also, the study is concerned with the effects of time and temperature of dipping on the intermetallic zone and its ductility.

A report which investigated the effects of a number of elements on the workability, hardness, and high-temperature strength of zirconium were investigated.

Abstract: "Stainless steel-clad fuel sheet 0.020 in. thick with a 0.008-in. core of stainless steel plus UO2 was produced by roll cladding a powder metal compact. The effects of processing variables, core-matrix composition, quantity of oxide, and oxide particle size on the properties of the sheet were investigated. The strength and ductility of the core decreased sharply as the quantity of oxide in the core increased from 20 to 40 w/o. Over the range of matrix compositions investigated the particle size of the oxide had little affect on the core strength. In cores containing 21 w/o of oxide. 18 w/o chromium, 82 w/o iron matrix prepared from the elemental metal powders had the highest strength and ductility, but this matrix was susceptible to cracking during thermal cycling. As elemental 18 w/o chromium, 9 w/o nickel, 73 w/o iron matrix was the most satisfactory from the standpoint of fabrication and over-all characteristics of the resulting sheet."

A report about the effects upon the fuel plate temperatures of introducing channel spacers into the proposed curved plate subassembly for the super critical water reactor.

A report pertaining to heat-transfer characteristics , the supercritical water reactor, and flat fuel plates separated by cylindrical spacers perpendicular to the plates.