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The status of work on the development of a 1200 MW sodium-cooled reactor facility for serial construction is presented. The general characteristics of the facility and the power-generating unit as well as the objectives which must be attained as a result of the design are presented. The design of the power-generating group is based on solutions some of which have been checked during the operation of sodium-cooled reactors in Russia and some have been validated by the appropriate research and development work performed for BN-800. At the same time, new solutions are used which are aimed at improving the technical-economic indicators and increasing the level of safety. Additional R&D work will be needed to validate them.The nuclear future of Russia and most other countries developing nuclear power involves fast reactors and a closed fuel cycle. Thus far only sodium-cooled fast reactors are ready for commercial adoption on a wide scale. In our country, we have more than 50 years of experience in developing and successfully operating such reactors: BR-5 (1959) → BR-10 (1973-2002) → BOR-60 (1969 -in operation) → BN-350 (1973-1998) → BN-600 (1980 -in operation) → BN-800 (under construction). A design of an advanced power-generating unit with a sodium-cooled BN-1200 reactor as the foundation for the initial step in the serial construction of reactors of this type is under development.Target Indicators of Reactor Facility and Power-Generating Unit Design. The development of a power-generating unit must meet the following requirements set for new-generation reactors and nuclear power plants:1) competitiveness with advanced power-generating unit based on reactors of a different type and power-generating units operating on fossil fuel;2) safety increased to a level that makes it unnecessary to take measures to protect the general public outside the borders of the nuclear power plant site for any possible accidents;3) attainment of breeding ratios from 1.2 (stage 1) to 1.3-1.35 (stage 2) using mixed oxide fuel and 1.45 with nitride fuel; 4) reducing the construction time for serially built power-generating units to 48 months; and 5) possibility of introducing a series of reactors in 2-3 years after the startup of the main power-generating unit.

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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