The gas turbine-modular helium reactor (GT-MHR) is a promising power reactor for the next century. The project is based on experience gained from the operation of more than 50 gas-cooled reactors using CO 2 and helium coolant as well on as the latest advances in the implementation of the direct gas-turbine Brayton cycle.Five helium-cooled reactors, which were operated in the USA and Germany from 1960 to 1980, demonstrated their intrinsic properties that can meet the most stringent safety requirements. Experiments performed on the AVR (Germany) showed that reactors with a moderate energy intensity (up to 3-4 MW/cm 3) cool without the intervention of active systems and action by an operator. The operation of those five reactors (Dragon, Peach Bottom, Fort St. Vrain, THTR-300, AVR) also demonstrated that the refractory-coated particle fuel is capable of high burn-up.By 1990 the advances in the technology for gas turbine equipment, high-efficiency recuperators, and magnetic bearings made it possible to consider a reactor facility that would combine a safe modular gas-cooled reactor and an energy conversion system operating on the high-efficiency Brayton cycle.The international GT-MHR project under way now is characterized by: -greater safety than that of other reactor concepts, namely, meltdown of the fuel and the core as a whole cannot take place; -a high energy conversion factor; -competitiveness on the electricity generation market; -high radiation stability of the fuel, including discharged fuel, whereby it can be stored without further processing; and considerably lower environmental impact than that of other reactor facilities (50% smaller heat load on the environment and 75 % less heavy metals in the wastes).The GT-MHR can be used for effective consumption of weapons-grade plutonium with an attendant generation of electricity.The Reactor Facility (Fig. l). The facility incorporates a modular reactor with a high-efficiency gas-turbine system for thermal energy conversion, which are in two vessels and connected by a horizontal conduit. The reactor module is below ground in a cylindrical concrete vessel. It uses fuel microfueI elements with a multiple-layer coating, which retains fission products, containing fuel cores of fissile material surrounded by four ceramic layers. Closest to the core is a buffer layer of low-density pyrolytic carbon (-1 g/cm 3) acts as a collector of gaseous fission products. The next layers, a dense layer of pyrolytic carbon (7 = 1.8 g/cm 3) and a layer of silicon carbide, are barriers for retaining gaseous and volatile fission products. Comprehensive research on such fuel carried out in the United States, Germany, Japan, and Russia over the past 20 years has made it possible to develop a technology for producing such fuel. The outside diameter of the microfuel elements is -620 /.tm. The fuel particles are pressed into a cylindrical fuel compact of diameter -12.5 mm and height 50 mm. Synthetic graphite is used as the matrix. The microfuel elements occupy -15% of the volume of the fuel c...

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