Reactor high-temperature gas-cooled

The metal is a source of nuclear power. There is probably more energy available for use from thorium in the minerals of the earth s crust than from both uranium and fossil fuels. Any sizable demand from thorium as a nuclear fuel is still several years in the future. Work has been done in developing thorium cycle converter-reactor systems. Several prototypes, including the HTGR (high-temperature gas-cooled reactor) and MSRE (molten salt converter reactor experiment), have operated. While the HTGR reactors are efficient, they are not expected to become important commercially for many years because of certain operating difficulties. 

Coal can be processed to H2 by heat from a high temperature, gas-cooled reactor at a process efficiency of 60—70%. Process steps are coal hquefaction, hydrogasification of the Hquid, and steam reforming of gaseous products (179). 

Fig. 2. Fuel for high temperature gas-cooled reactor. Fissile material is coated with carbon and siHcon carbide, fertile material with carbon. Particles mixed...

As previously stated, uranium carbides are used as nuclear fuel (145). Two of the typical reactors fueled by uranium and mixed metal carbides are thermionic, which are continually being developed for space power and propulsion systems, and high temperature gas-cooled reactors (83,146,147). In order to be used as nuclear fuel, carbide microspheres are required. These microspheres have been fabricated by a carbothermic reduction of UO and elemental carbon to form UC (148,149). In addition to these uses, the carbides are also precursors for uranium nitride based fuels. 

Fluidized-bed CVD was developed in the late 1950s for a specific application the coating of nuclear-fuel particles for high temperature gas-cooled reactors. PI The particles are uranium-thorium carbide coated with pyrolytic carbon and silicon carbide for the purpose of containing the products of nuclear fission. The carbon is obtained from the decomposition of propane (C3H8) or propylene... 

Shiozawa, S., Development status on hydrogen production technology using high-temperature gas-cooled reactor at JAEA, Japan, ICAPP 06, Reno, NV, June 4-8,2006. 

Lackey, W.J., Stinton, D.P. and Seasc, J.D., Improved gas distribution for coating high-temperature gas-cooled reactor fuel particles, Nuclear Technology, 1977,35, 227 237. 

Hannon, D.P. and Scott, C.B., Properties influencing high-temperature gas-cooled reactor coated fuel particle performance, Nuclear Technology, 1977, 35, 343 352. 

HELP HEU HFO HFR HLW HREE HRL HT HTGR HWR Hydrological evaluation of landfill performance Highly enriched uranium Hydrous ferrous oxide or ferric hydroxide Hot fractured-rock High-level nuclear waste Heavy rare earth elements (Gd-Lu) Hard rock laboratory High temperature High-temperature gas-cooled reactor Heavy water reactor... 

An important parameter in the evaluation of the safety of a reactor system is the release of fission products from the fuel. The fuel in the high-temperature gas-cooled reactor (HTGR) consists of spherical particles (U, ThC2) that are coated with a material presenting a diffusion... 

In order, the following types of nuclearfission reactors are described in this section (1) light water reactors, (a) pressurized water reactors, (b) boiling-water reactors (2) high-temperature gas-cooled reactors (3) heavy water reactors and (4) fast breeder reactors. Military reactors are not described. 

The high-temperature gas-cooled reactor (HTGR) is a thermal reactor that produces desired steam conditions. Helium is used as the coolam. Graphite, with its superior high temperature properties, is used as the moderator and structural material. The fuel is a mixture of enriched uranium and thorium in the form of carbide particles clad with ceramic coatings. 

Fig. 18. General reactor arrangement of Fort St. Vrain high-temperature gas-cooled reactor. (GA Technologies)...

Takeda T, Kunitomi K, Horie T, Iwata K. Feasibility of the applicability of a diffusion-welded compact intermediate heat exchanger to next-generation high-temperature gas-cooled reactors. Nucl Eng Design, 1997 168 11-21. 

Takeda, T., Kunitomi, K., Horie, T., Iwata, K., Feasibility study on the applicability of a diffusion-welded compact intermediate heat exchanger to next-generation high temperature gas-cooled reactor, Nucl. Eng. Des. 1997, 168,11-21. Bier W., Keller W., Linder G., Seidel, D., Schubert, K., Martin, H., Gas-to-gas heat transfer in micro heat exchangers, Chem. Eng. Process. 1993, 32, 33-43. Schubert, K., Brandner J., Fichtner M., Linder G., Schygulla, U., Wenka, A., Microstructure devices for applications in thermal and chemical process engineering, Microscale Therm. Eng. 2001, 5,17-39. www.fzk.de, Forschungszentrum Karlsruhe, 17 July 2004. 

This is a relatively special technique which combines the principles of fluidized - bed heating and CVD. It is primarily used to coat powders of very fine size with suitable films for special applications. The most prominent application of this technique is in the coating of nuclear fuel particles used in high-temperature gas-cooled reactors (HTGR). A typical fluidized-bed CVD reactor is shown schematically in figure 13.4. 

Japanese industries including Toshiba, Mitsubishi Heavy Industries, Fuji Electric, Toyo Tanso, Nuclear Fuel Industries, etc., are developing the HTGR jointly with JAEA. The industrial and public information exchange is supported by the Japan Atomic Industrial Forum (JAIF), the Research Association of High-temperature Gas-cooled Reactor Plant (RAHP), etc. 

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