Historical information concerning the development of high-temperature gas-cooled reactors in the USA and Russia is presented. The reactor facilities MHTGR (USA), , VGM (Russia), GT-MGR (Russia, USA), and at the Fort St. Vrain nuclear power plant (USA) are described. The US programs for developing innovative high-temperature nuclear reactor technologies are examined. It is shown that the Russian and US technological developments for the fuel, reactor system, energy conversion system, and fission-product transport are similar.Analysis of world energy consumption with limited resources for conventional power generation shows that intensive economic development is impossible without the establishment of large-scale nuclear power capable of supplying the energy required for a substantial part of the growth in energy needs. At the present time, the largest amount of fuel-energy resources, including the most expensive and scarce -oil and gas, is used for producing heat with diverse potentials, approximately three times more than for electricity production [1, 2]. The expansion of nuclear power into high-temperature industrial production, where the scarcity of fossil fuel is even more acutely felt than in the production of electricity, can be attained by bringing high-temperature gas-cooled reactors (HTGR) which are capable of generating high-potential heat, into the nuclear power system. HTGR Development in the USA and Russia. HTGR use fuel with specific qualities as compared with other types of reactors; it contains spherical fuel pellets or fuel blocks containing fuel compacts. The foundation of the fuel composition is microfuel containing a spherical kernel with ceramic multilayer coatings, which are the main barriers for confining fission products. The first US facility with an experimental reactor, developed by the General Atomics Company, was introduced in 1967 at the Peach Bottom 115 MW(t) nuclear power plant. The objective was to demonstrate the possibilities of using HTGR for commercial production of electricity with high-temperature steam and to obtain the experience required for developing a more powerful nuclear power plant. The problem of developing a reactor with high fuel burnup (75 MW·days/kg) was posed at the same time. Thirty-three fuel modifications, including the fuel rods at the Fort St. Vrain nuclear power plant, were tested [3].The pilot nuclear power plant at Fort St. Vrain with a high-temperature gas-cooled reactor was put into operation in 1976. The main equipment in the first loop of the facility consisted of a 842 MW(t) reactor with a core comprised of prismatic fuel assemblies, steam-generators, and axial gas blowers with steam-turbine drive placed beneath the core in a vessel

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