Alloying zirconium

The Idaho Chemical Processing Plant is a versatile, multipurpose facility used for recovering highly enriched uranium from a variety of fuels in naval propulsion, research, and test reactors. Materials processed [Al] include aluminum-alloyed, zirconium-alloyed, stainless steel-based, and graphite-based fuels. The West Valley plant, although designed primarily for low-enriched uranium fuel from power reactors, also processed plutonium-enriched and thorium-based fuels. It is the only U.S. plant to have reprocessed fuel from commercial nuclear power plants. 

Early Work. The irradiated fuel, upon discharge from the reactor, comprises the residual unbumt fuel, its protective cladding of magnesium alloy, zirconium or stainless steels, and fission products. The fission process yields over 70 fission product elements, while some of the excess neutrons produced from the fission reaction are captured by the uranium isotopes to yield a range of hew elements—neptunium, plutonium, americium, and curium. Neutrons are captured also by the cladding materials and yield a further variety of radioactive isotopes. To utilize the residual uranium and plutonium in further reactor cycles, it is necessary to remove the fission products and transuranic elements and it is usual to separate the uranium and plutonium this is the reprocessing operation. 

Fuel clad material (multiple choice magnesium alloy, stainless steel, zirconium alloy, zirconium-magnesium alloy, carbide compound) 2 ... 

Fuel clad material - the material of the tube containing the fuel pellets or rods. Basically, there are three types of cladding - magnesium alloys (e.g. Magnox), stainless steel, or various zirconium alloys. HTGR reactors use fuel particles coated with pyrolitic carbon and silicon carbide in two layers. Data providers should choose the appropriate option from the multiple-choice menu magnesium alloy, stainless steel, zirconium alloy, zirconium-magnesium alloy, carbide compound. 

Dust explosions can occur with a large variety of solids that have been ground to a finely divided state. Many metal dusts, particularly those of magnesium and its alloys, zirconium, titanium, and aluminum, can burn explosively in air. In the case of aluminum, for example, the reaction is as follows ... 

Austenitic stainless steel, titanium and its alloys, zirconium and Cr—Co alloys are found to be the metallic materials of choice for joint prostheses. The first two materials... 

Of all the corrosion-resistant metals and alloys, zirconium is among the most resistant to crevice corrosion. In low-pH chloride solutions or chlorine gas, for example, zirconium is not subject to crevice corrosion. This resistance can be attributed to zirconium s excellent corrosion resistance in HCl solutions. 

Compared to stainless alloys, zirconium is lower in density, higher in thermal conductivity, and lower in coefficient of thermal expansion. 

Environment Alnminmn aHo Carbon steels C(qq er alloys Nickel alloys Austenitic Stainless Steds Duplex Martensitic Titanium alloys Zirconium alloys... 

Aqueous media and marine corrosion. Zirconium has excellent corrosion resistance to seawater, fresh water, brackish water, and other polluted water streams and is a material of choice for heat exchangers, condensers, and other equipment handling these media, where it can replace titanium-palladium alloys. Unlike titanium and its alloys, zirconium is highly resistant to crevice corrosion. With their high corrosion resistance to pressurized water and steam, low neutron absorption (with low hafiiium content), good mechanical strength, and ductility, at nuclear reactor service temperatures, and their ability to remain stable even after extensive radiation, zirconium alloys are used extensively in fuel cladding, fuel channels, and pressure tubes for... 

Reactor-grade zirconium is essentially free of hafnium. Zircaloy(R) is an important alloy developed specifically for nuclear applications. Zirconium is exceptionally resistant to corrosion by many common acids and alkalis, by sea water, and by other agents. Alloyed with zinc, zirconium becomes magnetic at temperatures below 35oK. 

Small amounts of yttrium (0.1 to 0.2%) can be used to reduce the grain size in chromium, molybdenum, zirconium, and titanium, and to increase strength of aluminum and magnesium alloys. 

Analyses of alloys or ores for hafnium by plasma emission atomic absorption spectroscopy, optical emission spectroscopy (qv), mass spectrometry (qv), x-ray spectroscopy (see X-ray technology), and neutron activation are possible without prior separation of hafnium (19). Alternatively, the combined hafnium and zirconium content can be separated from the sample by fusing the sample with sodium hydroxide, separating silica if present, and precipitating with mandelic acid from a dilute hydrochloric acid solution (20). The precipitate is ignited to oxide which is analy2ed by x-ray or emission spectroscopy to determine the relative proportion of each oxide. 

R. K. McGeary, inM Symposium on Zirconium and Zirconium Alloys, American Society for Testing and Materials, Philadelphia, 1953, p. 168. 

Nitrogen and carbon are the most potent solutes to obtain high strength in refractory metals (55). Particulady effective ate carbides and carbonitrides of hafnium in tungsten, niobium, and tantalum alloys, and carbides of titanium and zirconium in molybdenum alloys. 

An important iadustrial use of NaH involves its in situ formation ia molten NaOH or ia fused eutectic salt baths. At concentrations of 1—2% NaH, these compositions are powerful reducing systems for metal salts and oxides (5). They have been used industrially for descaling metals such as high alloy steels, titanium, zirconium, etc. 

The abihty of magnesium metal to reduce oxides of other metals can be exploited to produce metals such as zirconium, titanium [7440-32-6] and uranium [7440-61-1] (see ZiRCONiUMAND ZIRCONIUM COMPOUNDS Titaniumand titanium alloys Uraniumand uranium compounds). These reactions are... 

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