Very high temperature reactor applications

Furthermore, industrial prospects for high temperature electrochemical or thermochemical processes and the temperature involved, together with non-hydrogen related applications of process heat, will impact the development strategy of high or very high temperature reactors. 

The PBMR, the GT-MHR, the GTHTR300 (Annex XVI) and the AHTR (Annex XXVI) target a very high temperature reactor option, which could make them competitive in future markets of non-electric applications, such as hydrogen production. 

Graphite (Chapter 14), SiCf/SiC (Chapter 12), and C/C composites (Chapter 13) for gas-cooled fast reactor (GFR), very-high-temperature reactor (VHTR), and fusion applications ... 

T. Shibata, J. Sumita, T. Makita, Research and developments on C/C composite for very high temperature reactor (VHTR) application, Ceram. Nucl. Appl. 30 (10) (2009). 

Based on the type of thermal destruction process selected, there are several different commercial designs and configurations of the reactor that have been utilized for a particular application. Some of the most commonly used technologies include rotary kilns, starved air incinerators, fluidized beds, mass-bum incinerators, electrically heated reactors, microwave reactors, plasma, and other high-temperature thermal destruction systems. Recent advances include gasification and very high temperature steam reforming. 

Many applications of novolacs are found in the electronics industry. Examples include microchip module packaging, circuit board adhesives, and photoresists for microchip etching. These applications are very sensitive to trace metal contamination. Therefore the applicable novolacs have stringent metal-content specifications, often in the low ppb range. Low level restrictions may also be applied to free phenol, acid, moisture, and other monomers. There is often a strong interaction between the monomers and catalysts chosen and attainment of low metals levels. These requirements, in combination with the high temperature requirements mentioned above, often dictate special materials be used for reactor vessel construction. Whereas many resoles can be processed in mild steel reactors, novolacs require special alloys (e.g. Inconel ), titanium, or glass for contact surfaces. These materials are very expensive and most have associated maintenance problems as well. 

Carbide-based cermets have particles of carbides of tungsten, chromium, and titanium. Tungsten carbide in a cobalt matrix is used in machine parts requiring very high hardness such as wire-drawing dies, valves, etc. Chromium carbide in a cobalt matrix has high corrosion and abrasion resistance it also has a coefficient of thermal expansion close to that of steel, so is well-suited for use in valves. Titanium carbide in either a nickel or a cobalt matrix is often used in high-temperature applications such as turbine parts. Cermets are also used as nuclear reactor fuel elements and control rods. Fuel elements can be uranium oxide particles in stainless steel ceramic, whereas boron carbide in stainless steel is used for control rods. 

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