Oxidized Pellets

By contrast, uranium fuels for lightwater reactors fall between these extremes. A typical pressurized water reactor (PWR) fuel element begins life at an enrichment of about 3.2% and is discharged at a bum-up of about 30 x 10 MW-d/t, at which time it contains about 0.8 wt % and about 1.0 wt % total plutonium. Boiling water reactor (BWR) fuel is lower in both initial enrichment and bum-up. The uranium in LWR fuel is present as oxide pellets, clad in zirconium alloy tubes about 4.6 m long. The tubes are assembled in arrays that are held in place by spacers and end-fittings. 

AH operating facilities shear the spent fuel elements into segments several centimeters long to expose the oxide pellets to nitric acid for dissolution. This operation is often referred to as chop-leach. The design and operation of the shear is of primary importance because (/) the shear can be the production botdeneck, and (2) the shear is the point at which tritium and fission gases are released. 

The fifth component is the stmcture, a material selected for weak absorption for neutrons, and having adequate strength and resistance to corrosion. In thermal reactors, uranium oxide pellets are held and supported by metal tubes, called the cladding. The cladding is composed of zirconium, in the form of an alloy called Zircaloy. Some early reactors used aluminum fast reactors use stainless steel. Additional hardware is required to hold the bundles of fuel rods within a fuel assembly and to support the assembhes that are inserted and removed from the reactor core. Stainless steel is commonly used for such hardware. If the reactor is operated at high temperature and pressure, a thick-walled steel reactor vessel is needed. 

Aluminum oxide pellets impregnated with potassium permanganate. 

EARS [Enhanced acid regeneration system] A process for recovering hydrochloric acid from the ERMS ilmenite beneficiation process. It may be used also for recovering waste pickle liquor. The acid liquor containing ferrous chloride is evaporated at low temperature to form iron chloride pellets, which are fed to a pyrohydrolysis reactor. This generates hydrochloric acid and iron oxide pellets, which can be used for steel production or disposed of as inert landfill. Developed by E. A. Walpole at the University of Newcastle, Australia, from the early 1990s and piloted by Austpac Gold (now Austpac Resources). 

The straight-chain 1- and 2-butenes can be converted into more butadiene when they are preheated in a furnace, mixed with steam as a diluent to minimize carbon formation, and passed through a reactor with a bed of iron oxide pellets. The material is cooled and purified by fractional distillation or extraction with solvents such as furfural, acetonitrile, dimethylformamide (DMF), and N-methylpyrrolidone (NMP). The conjugated n system of butadiene is attracted to these polar solvents more than the other C4 compounds. Extractive distillation is used, where the C4 compounds other than butadiene are distilled while the butadiene is complexed with the solvent. The solvent and butadiene pass from the bottom of the column and are then separated by distillation. 

Figure 14. Uptake of Mo03 by solid oxide pellets 0.62 cm. in diameter...

A- Solid Electrolyte B, C- Oxide Pellets D- Platinum Foils E- Alumina Crucibel F, G- Alumina Tubes H, K- Platinum Leads L- Silica Tube M- Resistance Furnace N- Glass T-Piece R Spring... 

Nuclear fuel rods consist of uranium oxide pellets contained in zirconium alloy or steel tubes. As the fission process proceeds, uranium is used up and fission products accumulate. A lot of these fission products are good neutron absorbers and reduce the efficiency of the fission process (by absorbing neutrons before they reach uranium atoms) so that the rods are removed for reprocessing before all the content has undergone fission. Fission of a atom produces two lighter atoms of approximate relative atomic masses around 90-100 and 130-140, with the main fission products being the intensely radioactive and short lived I (fi 8 d), °La, Pr, Zr, Ru, and Nb, and longer-lived... 

Rotary multitray dryer pulverized coal, pectin, penicillin, zinc sulfide, waste slude, pyrophoric zinc powder, zinc oxide pellets, calcium carbonate, boric acid, fragile cereal products, calcium chloride flakes, caffein, Inorganic fluorides, crystals melting near 100°F, prilled pitch, electronic grade phosphors, and solvent-wet organic solids... 

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