Ceramic nuclear fuels vaporization

The present review will cover the phase equilibria of these ceramic nuclear fuels at high temperatures, and a summary will be given on their nonstoichiometric region, defect structure and thermodynamic data. In addition, diffusion and vaporization processes will be taken as representative phenomena eharacteristic of these materials at high temperatures, and these phenomena also will be reviewed in their relation to nonstoichiometry. 

Chemical Vapor Deposition (CVD) is a technique of deposition of a solid on a heated substrate, from gaseous precursors. It has been used for many years to produce wear resistant coatings, coatings for nuclear fuels, thin films for electronic circuits ceramic fibers, etc. .. When the CVD technique is used to impregnate ratiier large amounts of matrix materials in fibrous preforms, it is called chemical vapor impregnation or infiltration... 

Boron-carbon-nitride ceramic is deposited on iron-based sliding parts by chemical vapor deposition (CVD) it is used as rotary compressor shafts, in order to improve the wear resistance [1 to 5]. Such B-C-N coatings have also been applied to dynamic pressure air bearings [6]. In gas-cooled nuclear reactors, °B-enriched B-C-N can be deposited by CVD in the fluid channels of the fuel elements for permanent deactivation in case of an emergency [7]. Radiofrequency or microwave-enhanced CVD is employed in order to deposit a diamond carbon and (3-BN superlattice structure [8]. 

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