Nuclear fuel ceramic fuels

In compound materials - in the ceramic sodium chloride, for instance - there are two (sometimes more) species of atoms, packed together. The crystal structures of such compounds can still be simple. Figure 5.8(a) shows that the ceramics NaCl, KCl and MgO, for example, also form a cubic structure. Naturally, when two species of atoms are not in the ratio 1 1, as in compounds like the nuclear fuel UO2 (a ceramic too) the structure is more complicated (it is shown in Fig. 5.8(b)), although this, too, has a cubic unit cell. 

Ceramics, including concrete, are useful especially in structures, reactors, as refractories in combustion of fuels, and as nuclear fuel. Porcelain insulators on transmission lines are an example of a specialized application of ceramics. 

Beryllium Oxide (Bromellite). BeO, mw 25.01, white amorph powd, mp 2530°, bp ca 3900°, d 3.01g/cc. Sol in coned acids and alkalies. V si sol in w. Prepn is by burning BeC03 at 900° in a Pt crucible to the oxide. It is used in nuclear reactor fuels and moderators as well as in powder metallurgy, ceramics, fuel cells and coatings (see above)... 

Nuclear fuels Government Research and development Produces ceramics... 

Feng, X., Einziger, R. E. Eschenbach, R. C. 1997. A direct single-step plasma arc - vitreous ceramic process for stabilizing spent nuclear fuels, sludges, and associated wastes. Materials Research Society Symposium Proceedings, 465, 25-32. 

Ball, C. I, Buykx, W. J. et al. 1989. Titanate ceramics for the stabilization of partially reprocessed nuclear fuel elements. Journal of the American Ceramic Society, 72, 404-414. 

Some properties of the ceramic fuels UO2 and UC are summarized in Table 11.5. UO2 is preferably used as nuclear fuel in all modem light-water reactors (LWR) of the boiling-water (BWR) as well as of the pressurized-water (PWR) type. The main advantages of UO2 are the high melting point and the resistance to H2, H2O, CO2 and radiation. The main disadvantage is the low thermal conductivity, which has to be compensated by application of thin fuel rods. 

The performance requirements for ceramic nuclear fuel elements include the following dimensional stability to high fuel burnups, fission product retention, corrosion resistance, high thermal performance, fabricability, economic advantage, inspectability, and chemical reprocessing and recycling. 

Brambilla, G. Caporali, G. Zambianchi, M. "Reprocessing Method of Ceramic Nuclear Fuels in Low-Melting Nitrate Molten Salts", U.S. Patent 3 981 960, 1976. 

Use Ceramics abrasive for glass polishing opacifi-er in photochromic glasses retarder of discoloration in glass, especially radiation shielding and color TV tubes catalyst enamels and ceramic coatings phosphors cathodes capacitors semiconductors refractory oxides diluent in nuclear fuels heat stabilizer (alumina catalyst). 

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