The Very-High-Temperature Reactor (VHTR) is a graphite-moderated, helium-cooled reactor with a thermal neutron spectrum.The VHTR is designed to be a high-efficiency system, which can supply electricity and process heat to a broad spectrum of high-temperature and energy-intensive processes. The reference reactor is a 600 MWth core connected to an intermediate heat exchanger to deliver process heat. The reactor core can be a prismatic block core or a pebble-bed core according to the fuel particles assembly. Fuel particles are coated with successive material layers, high temperature resistant, then formed either into fuel compacts embedded in graphite block for the prismatic block-type core reactor, or formed into graphite coated pebbles. The reactor supplies heat with core outlet temperatures up to 1,000 degrees Celsius, which enables such applications as hydrogen production or process heat for the petrochemical industry. As a nuclear heat application, hydrogen can be efficiently produced from only heat and water by using thermochemical iodine-sulfur process, or high temperature electrolysis process or with additional natural gas by applying the steam reformer technology. Thus, the VHTR offers a high-efficiency electricity production and a broad range of process heat applications, while retaining the desirable safety characteristics in normal as well as off-normal events. Solutions to adequate waste management will be developed. The basic technology for the VHTR has been well established in former High Temperature Gas Reactors plants, such as the US Fort Saint Vrain and Peach Bottom prototypes, and the German AVR and THTR prototypes. The technology is being advanced through near- or medium-term projects lead by several plant vendors and national laboratories, such as: PBMR, GT-HTR300C, ANTARES, NHDD, GT-MHR and NGNP in South Africa, Japan, France, Republic of Korea and the United States. Experimental reactors: HTTR (Japan, 30 MWth) and HTR-10 (China, 10 MWth) support the advanced concept development, and the cogeneration of electricity and nuclear heat application.
This diagram illustrates a schematic concept of the reactor system and does not represent the reference design. Source: http://www.ne.doe.gov/genIV/documents/gen_iv_roadmap.pdf Advantages and challengesThe VHTR offers the potential for the cogeneration of electricity and hydrogen, alongside process heat applications. As the basic technology for VHTR systems has already been established in high temperature gas reactor plants, the design is an evolutionary development. However, the system’s aim of operating above 1000°C presents significant challenges in terms of fuel and materials development, as well as safety under transient conditions. GIF progress in 2007With the signing of a VHTR system arrangement by seven GIF members in November 2006, a system research plan has been put in place setting out the VHTR medium-term R&D projects to be pursued. Currently project arrangements to study the following areas are in the final stages of negotiation: the development and validation of materials to be used in VHTR systems; fuels and fuel cycle issues for VHTR systems; and the use of VHTR systems to produce hydrogen. The overall aim of these research efforts is to define the system's baseline concepts by 2010 and to optimize their design and operating features by 2015. Recent VHTR research papers and linksOh, C. (2007), Power Cycle and Stress Analyses for High Temperature Gas-Cooled Reactor, 2007 International Congress on Advances in Nuclear Power Plants (ICAPP 2007). Sterbentz, J. W. (2007) Low-Enriched Very High Temperature Reactor Core Design, 2007 International Congress on Advances in Nuclear Power Plants (ICAPP 2007). R. B. Vilim (2007), Interface Design Studies for the Production of Hydrogen Using the VHTR Coupled to the HTSE Process, 2007 International Congress on Advances in Nuclear Power Plants (ICAPP 2007). Billot, P., Hittner, D. and Vasseur, P. (2006) Outlines of the French R&D Program for the development of High and Very High Temperature Reactor, Third International Topical Meeting on High Temperature Reactor Technology, 1-4 October 2006, Johannesburg, South Africa. Fütterer, M. et al, (2006) Irradiation Results of AVR Fuel Pebbles at Increased Temperature and Burn-Up in the HFR Petten, Third International Topical Meeting on High Temperature Reactor Technology, 1-4 October 2006, Johannesburg, South Africa. Greyvenstein, R., Correia, M. and Kriel, W. (2006) South Africa's opportunity to maximize the role of nuclear power in a global hydrogen economy, Third International Topical Meeting on High Temperature Reactor Technology, 1-4 October 2006, Johannesburg, South Africa. Hittner, D. et al (2006), RAPHAEL, A European Project for the development of HTR/VHTR technology for industrial process heat supply and cogeneration, Third International Topical Meeting on High Temperature Reactor Technology, 1-4 October 2006, Johannesburg, South Africa. Hu, S., Liang, X., Wei, L., (2006) Commissioning and Operation experience and safety experiment at HTR-10, Third International Topical Meeting on High Temperature Reactor Technology, 1-4 October 2006, Johannesburg, South Africa. Lee, Y-W., Park, J-Y., Kim, YK., Jeong, BG. Kim, YM. (2006), Development of HTGR coated particle fuel technology in Korea, Third International Topical Meeting on High Temperature Reactor Technology, 1-4 October 2006, Johannesburg, South Africa. Takamatsu, K., Nakagawa, S. Takeda, T. (2006), Development of core dynamics analysis of coolant flow reduction tests of HTTR, Third International Topical Meeting on High Temperature Reactor Technology, 1-4 October 2006, Johannesburg, South Africa. P. V. Tsvetkov (2006) Coupled Hybrid Monte Carlo - Deterministic Analysis of VHTR Configurations with Advanced Actinide Fuels, Paper ICAPP-6400, 2006 International Congress on Advances in Nuclear Power Plants (ICAPP'06). Kim, T.K., Taiwo, T.A., Hill, R.N., and Stillman, (2005), Spent Nuclear Fuel Characterization for the VHTR, Paper 67, GLOBAL 2005, Tsukuba, Japan, 9-13 October 2005. Related linksVHTR System Arrangement signatories HTR-10 10MW High Temperature Gas-Cooled Reactor Project RAPHAEL Project
ANTARES
HTTR Project
PBMR Project
DOE Nuclear Energy Research Initiative VHTR Program Plan (pdf, 1 mb). E-mail contact: [email protected] |
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