The practical use of atomic energy for civilian and military purposes in the Soviet Union began with the launching of research reactor F-1 in December 1946. The reactor is graphite moderated and is fueled with 50 tonnes of natural uranium. Its operational range extends from 25 kW to 4 MW. This reactor is still operating today and is used as a reference source for neutron fluxes.

There have been a total of 80 research reactors constructed by the Soviet Union, including the following 15 reactors that were constructed in foreign countries:

• VVR-S (2-10 MW power): Constructed in East Germany, Czecho­slovakia, Romania, Poland, Hungary, and Egypt between 1957 and 1961.

• IRT-2000 (2-10 MW): Constructed in China, Bulgaria, North Ko­rea, and Iraq between 1961 and 1967.

• TBP-C (10 MW): Constructed in China in 1959.

• RA (10 MW): Constructed in Yugoslavia in 1959.

• IRT-10000 (10 MW): Constructed in Libya in 1981.

• MARIA (30 MW): Constructed in Poland in 1974.

• IVV-9 (0.5 MW): Constructed in Vietnam in 1983.

Eleven research reactors besides F-1 have been constructed at the Kurchatov Institute:

• RFT: Channel graphite reactor; initial power 10 MW, later up­graded to 20 MW; began operations in 1957 and was partially demolished in 1962.

• VVR-2: Pool-type reactor; initial power 0.3 MW, later upgraded to 3 MW; began operations in 1954 and was dismantled in 1983.

• IRT: Pool-type reactor; initial power 2 MW, later upgraded to 5 MW; began operation in 1957 and was dismantled in 1979.

• MR: Channel-type reactor immersed in a pool; initial power of 20 MW, later upgraded to 50 MW; began operation in 1963 and was shut down in 1993.

• Chamomile: High-temperature neutron thermoionic converter; 0.1 MW; began operation in 1964 and was shut down in 1996.

• Hydra: Homogeneous pulse reactor; 0.01 MW (30 mega Joules per pulse); began operations in 1972 and is currently operational.

• Yenisei: High-temperature neutron thermoionic converter; 0.1 MW; began operation in 1973 and was dismantled in 1986.

• IR-8: Pool-type reactor; 8 MW; began operation in 1981 and is currently operational (Figure 2-9).

• Argus: Homogeneous reactor; 0.02 MW; began operations in 1981 and is currently operational.

• Gamma: Cabinet water-cooled reactor; 0.125 MW; began opera­tion in 1982 and is currently operational.

• OR (referred to as OP-M in Table 1-2 in Chapter 1): Pool-type reactor; 0.3 MW; began operation in 1989 and is currently operational.

These reactors created an experimental base for nuclear and materials re­search at the Kurchatov Institute.

The remainder of this presentation focused on the characteristics of the MR and IR-8 reactors at the Kurchatov Institute and activities at a branch institute in Sosnony Bory (Leningrad region).

MR was equipped with 10 experimental loops, each of which func­tioned as a small prototype power reactor. Several coolants were used in these loops, including pressurized water, steam-water mixtures, helium, carbon dioxide, and liquid lead bismuth. The neutron flux density in the reflector was 5 x 1014 n/cm2-s. This reactor was used to work out the struc­ture of active zones of nuclear reactors and test 400 fuel assemblies and more than 8,000 fuel rods for VVER, RBMK, ACT, high-temperature, and naval reactors.

IR-8 has a compact core with an effective reflector that provides for large thermal neutron densities of 2.3 x 1014 n/cm2-s. The core contains 12

experimental channels in a horizontal orientation. This reactor is used to carry out fundamental research in nuclear physics, solid state physics and superconductivity, and other experiments.

The Scientific Research Technological Institute (NITI), a branch of the Kurchatov Institute, was created in Sosnovy Bor in 1964. It has a full-scale prototype submarine reactor.