Abstract: A pressurized water reactor nuclear fuel element has a tubular cladding container formed from zirconium or a zirconium alloy material without a protective coating or liner therefor, the cladding material containing less than 4 percent of alloying elements, including an oxygen content of less than 600 parts per million. The cladding contains a sealed nuclear fuel and a pressurized helium atmosphere which fills the gap between the fuel material and the inner wall of the cladding, the helium pressurized to between 150 to 500 pounds per square inch.

Abstract: Apparatus such as a nuclear fuel sub-assembly for use in a liquid alkali metal environment has bearing surfaces (4) coated with alumina or aluminide particles to reduce wear, fretting and friction. The particles are deposited by plasma or detonation gun using a nickel chromium alloy as a metallic bond.

Abstract: A nuclear fuel cladding tube composed of a single zirconium base alloy is provided preferably with a cold worked and stress relieved microstructure throughout. The cladding is characterized by excellent aqueous corrosion resistance as well as excellent resistance to PCI crack propagation. The alloy is selected from a group of zirconium base alloys containing tin, iron, chromium, and/or nickel and low levels of impurities.

Abstract: Cladding tube of a zirconium alloy especially for a nuclear reactor fuel rod, characterized by the feature that the geometric mean of the grain diameters in the zirconium alloy is smaller than or equal to 3 .mu.m.

Abstract: A method of producing cladding tube comprises a step of temperature-gradient annealing in which the inner surface of the tube is heated to a temperature higher than the recrystallization temperature thereof, while the outer surface of the tube is cooled, after the tube has been hot-extruded. The temperature-gradient annealing is effected while a temperature gradient is maintained between the inner surface and the outer surface of the cladding tube. While keeping the inner surface at a temperature higher than the recrystallization temperature, and the outer surface at a temperature lower than the recrystallization temperature. The cladding tube is obtained with the outer surface which has an excellent resistance to nodular corrosion and a soft inner surface which has an excellent resistance to stress corrosion cracking.

Abstract: It has been found that modifying standard Zircaloy alloy processing techniques by limiting the working and annealing temperatures utilized after conventional beta treatment results in Zircaloy alloy product having superior high temperature steam corrosion resistance.

Abstract: A metallic composite material and nuclear components such as fuel cladding, rod guide thimbles, grids and channels made therefrom. The metallic composite material comprises 90-60 volume percent of a metal matrix of zirconium or a zirconium alloy containing homogeneously incorporated, throughout the matrix, 10-40 volume percent of silicon carbide whiskers.

Abstract: Fiber reinforced hollow film forming material microspheres 17 made from a fiber and film forming material composition are described. The fiber reinforced hollow microspheres 17 are used to make shaped and molded articles and to make insulation materials. The fibers can be made from ceramic materials, glass, metal, metal glass and plastic. The reinforcing fibers can be one-half to five microns in diameter and five to one hundred microns in length.

Abstract: A hydride blister-resistant nuclear fuel rod cladding has a tubular cladding formed from a zirconium-based alloy which has a thin nickel base film, of a thickness of about 0.01 to 5 microns distributed over between 1-40 percent of the area of the internal surface of the tubular cladding. The dispersed nickel base film provides multiple sites for hydride transport from the interior of the nuclear fuel rod and prevents localized hydride transport and resulting hydride blistering.

Abstract: The invention discloses a metal-actinide mononitride composition with dimensional stability in extended nuclear reactor operations, with a method of operation at surface temperatures in excess of 1700.degree. C. The preferred embodiment and operating method uses a mononitride of uranium and a metal selected from the group consisting of titanium or yttrium. Parameters for determination of the metal element to stabilize the fuel are disclosed.

Abstract: A nuclear fuel assembly suitable for use in fast breeders. The fuel assembly has a wrapper tube and a plurality of fuel elements contained in the wrapper tube, each fuel element having a clad tube. The wrapper tube is made of a material which exhibits a larger rate of swelling by neutron irradiation than the material of the clad tube. For instance, the wrapper tube is made of an austenitic stainless steel, and the clad tube is made of an austenitic Ni alloy having a high Ni content. According to this arrangement, it is possible to avoid undesirable contact between the clad tube and the wrapper tube in the last period of the life time of the nuclear fuel.

Abstract: It has been found that modifying standard Zircaloy alloy processing techniques by limiting the working and annealing temperatures utilized after conventional beta treatment results in Zircaloy alloy product having superior high temperature steam corrosion resistance.

Abstract: Precipitation hardening, austenitic type superalloys are described. These alloys contain 0.5 to 1.5 weight percent silicon in combination with about 0.05 to 0.5 weight percent of a post irradiation ductility enhancing agent selected from the group of hafnium, yttrium, lanthanum and scandium, alone or in combination with each other. In addition, when hafnium or yttrium are selected, reductions in irradiation induced swelling have been noted.

Abstract: An aluminide coating for a fuel cladding tube for LMFBRs (liquid metal fast breeder reactors) such as those using liquid sodium as a heat transfer agent. The coating comprises a mixture of nickel-aluminum intermetallic phases and presents good corrosion resistance to liquid sodium at temperatures up to 700.degree. C. while additionally presenting a barrier to outward diffusion of .sup.54 Mn.

Abstract: A method for compressing gases in a contained volume consisting of hollow glass microspheres is described. The gases are compressed under high pressure and can be easily handled and stored. The gases to be compressed and contained in the microspheres are used as blowing gases to blow the microspheres.The metal vapor deposited coating can be reflective of or transparent to visible light.The hollow glass microspheres can be made to contain a thin transparent or reflective metal coating deposited on the inner wall surface of the microspheres by adding to the blowing gas small dispersed metal particles and/or gases of organo metal compounds and decomposing the organo metal compounds.The hollow glass microspheres can be made in the form of filamented glass microspheres with a thin glass filament connecting adjacent glass microspheres.

Abstract: The invention is concerned with providing substrates with coatings obtainable from sols, for example to protect the substrate (such as in nuclear reactors or hydrocarbon cracking plant) or to provide a carrier for catalytically active material.Hitherto, coatings obtained from sols have had a high porosity and high surface area so that they have not been entirely satisfactory for the above applications.In the invention, dense, low-porosity coatings are provided by contacting the substrate with a sol of refractory material (e.g. CeO.sub.2 or SiO.sub.2) convertible to a gel of density at least 40% of the theoretical density of the refractory material, and converting the sol to the gel. Optionally, the gel may be converted to a ceramic coating by firing.