The following progress report was compiled by the research and development division of the zirconium pilot plant. This report discusses two iodination and deposition runs that were completed as of August 20, 1951, as well as the third iodination run that uses a vaporizer condenser that condenses approximately 40 pounds of zirconium iodide.

This report covers the progress made on an intensive program to develop and evaluate UO2 as a possible fuel element for the PWR.

The following report presents neutron-flux measurements made with a concentric-cylinder element (Mark II) and includes axial, radial, and peripheral flux distributions.

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

Abstract: "The protection of thorium in hot water was studied. Copper electrocladding on thorium offers promising protection against hot water. The corrosion of thorium in 95 C water was reduced appreciably by a thorium phosphate film. The results of this abbreviated investigation offer a basis for the development of a method of protecting thorium at elevated temperatures in corrosive media."

The following report studies the dissolution of aluminum-canned thorium, providing results that suggest a dissolution cycle that permits the separation of the canned-slug components.

Abstract: "Aluminum electroplating was studied in a search for new methods of cladding uranium fuel elements. Uranium electroclad with 12 mils of aluminum over a 0.5-mil (or nickel plus copper) electroplate resisted corrosion for more than 100 hr in boiling water. This quality of protection was effected by hot pressing the electroclad uranium with 5.1 tons per sq in. for 5 min at 950 F. The electroclad uranium with hot-pressed samples paralleled those of later experiments with hot-pressed wrought aluminum claddings on uranium. In both cases, the uranium was electroplated with thin (0.5 mil) layers of metals to prevent aluminum-uranium diffusion, to aid bonding, and to assist in corrosion protection. This aluminum electroplating study helped to define the importance of the intermediate coating between the aluminum and the uranium, the effect of good bonds between the various layers, and the effects of hot pressing in protecting uranium with an aluminum cladding."

Abstract: "Aluminum-clad nickel-plated uranium is corrosion resistant in boiling water. Samples with intentional defects in the aluminum-nickel clodding layers, after testing for more than 300 hr. showed no sign of rapid failure. The study of electroplated metals on uranium for aluminum cladding has defined the effects of several processing variables on the corrosion resistance. The quality of the uranium and the quality of the aluminum-nickel bond were important. Heat treatment and vacuum outgassing of the nickel-plated uranium prior to aluminum cladding were beneficial, and minimizing the amount of air present in the hot-press assembly was desirable. Variation in the steps for electroplating on uranium did not affect the corrosion resistance of aluminum-clad uranium."

A report which describes a variety of methods for processing a low-grade sulfide concentrate from the Congo. This concentrate consists primarily of sulfides of cobalt, nickel, and iron, plus about 10 percent uranium, present principally as uraninite.

A report which intends to present an empirical formula, based on available experimental data, to correlate the thermal and electrical conductiviities of sirconium and sirconium alloys.

The following report focuses on research made to determine whether the service performance of UO₂ fuel-elements cores for the PWR can be improved by certain ceramic or metal additions.

From introduction: "This is the ninth monthly report, BMI-514, under Contract No. AT(30-1)-771 on "Zirconium Research and Development". The report covers the work period from September 15, 1950, to October 15, 1950. Work is continuing on the preparation of large-diameter zirconium crystal bars in the 16-inch-diameter de Boer unit. Crystal bars up to 1-5/16 inches in diameter and 8 feet long have been prepared in this unit."

Abstract: "Costs have been estimated for the production of uranium and pure thorium from monasite concentrates by a process involving (1) reaction of monasite with caustic soda, (2) dissolution of the hydrous oxides in hydrochloric acid, (3) separation from the bulk of the rare earths by hydroxide precipitation of thorium and uranium, and (4) purification by solvent extraction."

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.

From introduction: "At the request of WAPD, a study has been made of the effect of minor compositional variables on the corrosion behavior of uranium-molybdenum alloys in 650 F degassed water."

Abstract: "A quantitative method for the determination of individual rare earths in thorium down to a level of 0.05 ppm, is described. The procedure consists of a chromatographic cellulose-columns separation followed by a solution-type spectrographic determination. Values are given for the recovery of a number of rare earths using this combined procedure."

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

Abstract: The nonmetallic inclusions in both as-reduced and fabricated dingot uranium have been studied for comparison with those in ingot uranium. Special attention was paid to the hydride for the purpose of determining the amount and distribution in the various types of uranium. The types and distribution of other inclusions were also studied. It was found that the dingot uranium was of a higher quality than ingot uranium and was comparable to as-reduced derby uranium on the basis of over-all inclusion count. The hydrogen content in dingot uranium, however, was found to be appreciably higher than in either ingot or derby uranium.

From introduction: "This report summarizes the work done on a study of fused-salt systems in a search for new liquid fuels suitable for use in a nuclear power reactor."

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

"Centrifugal-casting techniques were investigated as a method of producing hollow cylindrical extrusion billets of aluminum-35 w/o uranium. Among the variables evaluated were melt temperature, mold and pouring-spout configurations, mold speed, and method of pouring. With the equipment employed it was found that the best castings were produced stilizing a pouring temperature of 2400 F, a heavy-walled steel cylinder rotating between 700 to 900 rpm for the mold and bottom-pouring technique employing a retractable pouring spout. Sound, nonporous billets 26 in. long and 5 in. in diameter were produced with a yield after machining of over 75 per cent of the original charge. The major losses occurred in the pouring spout-and-cup assembly. This loss is relatively unaffected by the casting length; and, therefore, coatings of greater length than 26 in. should results in even greater recoveries.

Abstract: "The effects of a number of ternary additions on the constitution, casting, and fabricating characteristics and the physical properties of aluminum-35 w/o uranium were investigated. Initial investigations were concerned with the effects of 3 w/o ternary additions on the microstructure and press-forging characteristics of the alloy. It was found that additions of this magnitude often introduced extrinsic phases in the alloy. At the 3 w/o level, additions of germanium, silicon, tin or zirconium inhibited the formation of UAl4 and thereby increased the content of the aluminum matrix in the alloy. It was also noted that these additions decreased the pressures required for extruding, and the tin addition also improved the homogeneity of cast shapes. Lead and palladium also improved the homogeneity of the cast material; however, neither of these was an effective inhibitor of UAl4 and free lead was detected in the alloy to which lead had been added at the ternary. From these studies it appears that tin and zirconium are as effective as silicon in enhancing the fabricating characteristics of aluminum-35 w/o uranium alloys, and may prove superior when evaluated on the bases of casting qualities and recycling characteristics."

Abstract: "A possible method of cooling a liquid-fuel reactor is by spraying liquid metal through the liquid fuel, and then circulating the liquid metal through a heat exchanger. To evaluate the effectiveness of this cooling method, a few simple experiments were made with mercury sprayed through water. On the basis of the results, it was concluded that this method was intrinsically a low-power-density method, which could not find application except where a low fissionable-material inventory was the dominating requirement in a low-power reactor. Even there, it is thought that a boiling homogeneous reactor might be superior. The results are reported, in spite of their probably lack of value in the reactor program, simply to make the record complete."

The following report describes work that was udertaken to determine whether a homogeneous breeder reactor using an alkili metal hydroxide solution is capable of breeding.