The stability and corrosion resistance of thorium exposed to eutectic NaK were investigated. Satisfactory results on thorium tube or rod fabrication by means of extrusion were obtained. Rolling and swaging thorium presented no difficulty but drawing proved unsuccessful. Strainhardening values of iodide thorium were about half of those of Ames thorium. The fubrication of unanium tubing by extrusion was successful in the alpha but not in the gamma nange. By increasing the extrusion ratio, an increaae in the strength of the STA410! fiber texiure with respect to that of the STA010! component and an increase in sharpness of both resulted. Static corrosion tests using a two-component system was initiated. The characteristics of a plate which is to be fabricated into a fuel element tube were determined and methods for fabrication of such a plate are discussed. (See also ORNL-910(Del).) (C.J.G.) Preliminary investigations on SAP (sintered aluminum powder) alloys are reported. The mechanical properties of SAP at elevated temperatures are oniy slightly altered by prolonged heating. Its structaral stability is not effected by temperatures at 450 deg C and lower temperatures, blistering starts at 520 deg C and fissures appear in thin walled SAP 930 tubes at temperatures higher than 500 …

Advanced Water Reactor Program. The second fuel loading for the EBWR is planned as ThO/sub 2/--UO/sub 2/. Some properties of ThO/sub 2/-- UO/sub 2/ systems are presented. Fast Power Breeder Reactor Program. The development of casting techniques for EBR-1, Mark III extrusion billet cores are described. The investigation of methods for the remote refabrication of irradiated reactor fuels was undertaken with the objective of designing, constructing, and testing techniques and equipment for the refabrication of EBR-II fuels. Advanced Engineering and Development. From observations amd photographs made during disassembly operations, and from chemical, metallographic, and density measurements, it was possible to reconstruct the probable physical structure of the core after the meltdown of the EBR-1 core. A boiling experiment was performed to give preliminary information as to whether thermal decomposition or volatility would complicate the use of H/sub 3/PO/sub 4/ solution in boiling reactors. Due to the possible use of Mg as a cladding material a few preliminary corrosion tests were made with distilled water. Cylindrical, NaK-filled Zr irradiation capsules, which suddenly broke open during decanning operations following irradiation, were examined in an effort to determine the role of irradiation in these unexpected failures. Production, Treatment, and Properties of Materials. Elastic …

A study was made of fiber-texture type of preferred orientation in extruded Al rods and brass sheeting. Experiments to purify Zr by the zone- melting techniques were studied. Several transformation products of the decomposition of the BETA eutectoid of the Ag--Zr system were identified. The tempering of the martensitic structure of a hypoeutectoid Ag-- Zr was studied. Metallurgical treatments for the recovery of U from spent stainless steel fuel elements were investigated. Physical properties and radiation stability of the Si-- SiC fuel element material were investigated. The development and fabrication of a uniform fuel-bearing sandwich plate were continued. Methods of welding stainless steel were studied. An evaluation study was made of brazing alloys on the basis of corrosion resistance, neutron economy, flow temperature, availability, and cost. (C.H.)

3 9 8 4 3 3 3 6 9 6 5 5 have been started on possible urania-ceramic fuels with magnesia, alumina, zirconia, magnesia-- zirconia and calcia--zirconia. Mixtures of 45 magnesia--45 zirconia and 9 magnesia--81 zirconia by weight appeared to give good preliminary promise. Work on ThO/sub 2/--10 wt.% UO/sub 2/ has centered about improvement in density of pellets and elimination of cracking and open porosity. Efforts to increase the percentage of urania in thoria--urania have met with considerable success up to 70 wt.% urania in air-firing tests. Some attempts have been made to prepare UC by reaction of UO/sub 2/ with carbon, but so far an incomplete reaction has resulted. As to metal fuels, a sample of U--3 wt.% Ti--1.5 wt.% Nb has shown good corrosion resistance in 245 deg C water, slightly better than the EBWR fuel alloy. Fast Power Breeder Program. An improvement of the average yield of EBR- IItype fuel pin injection castings has been attained, reaching over 90% as compared with yields of 50 to 60% in the recent past. The uranium-plutonium- fissium alloys proposed for the fuel of EBR-II are being given further examination. The thermal conductivity of U-- 20 wt.% Pu--10 wt.% Fs …