Sodium-Cooled Fast Reactors

Afrikantov OKBM JSC commenced the work in the area of fast reactors in 1960 with designing BN-350, a first pilot power reactor, in Shevchenko (now, Aktau, the Republic of Kazakhstan).

BN-350, the world’s first pilot fast-neutron power reactor


The BN-350 reactor was developed on the basis of the experience in creating and operating the BR-5 experimental reactor, which was constructed on the premises of the Institute of Physics and Power Engineering (IPPE, Obninsk, Kaluga region, Russia) in 1959, and on the basis of the experience in developing of the BOR-60 research reactor that was commissioned at RIAR in 1969 (formerly Melekess, which is now Dimitrovgrad, Ulyanovsk region, Russia). All the power reactors were developed with the scientific guidance provided by IPPE. The reactor achieved its first criticality in 1973, and it was decommissioned in 1999.

 The operation of the BN-350 power unit verified that high-power sodium-cooled fast reactors are reliable and safe. The long-time reactor operation made it possible to collect substantial information on the operability of the reactor core, equipment, and safety systems, which provided a reliable basis for the development of the subsequent sodium-cooled fast reactors.

BN-600 is operating successfully for more than 35 years

The 600 MWe unit with the BN-600 reactor (Beloyarsk NPP, Unit 3, Zarechny, Sverdlovsk region, Russia) is the key plant that demonstrates the achieved results and the possibilities for further improvement of fast reactors.
In this design, a fundamental decision was made for the primary circuit to switch over from the loop-type layout to an integral layout, where all the primary circuit equipment is placed inside the reactor vessel. It allowed the safety and reliability of reactor operation to be enhanced. Unit 3 achieved its first criticality in April of 1980. BN-600 is the world’s only reactor that has a commercial power level and has been in commercial operation for nearly 40 years. Throughout the long time in operation, the capacity factor of the power unit was maintained at a stably high level—in the 75–80% range. Unplanned losses were less than 2.2%. No long-lived gas-aerosol radionuclides are released to the environment. Presently, the release of the inert radioactive gasses is negligibly small—less than 1% of the permissible release according to the sanitary norms.

In the course of operation, Unit 3 demonstrates high operating performance thus successfully solving the set task—validating the reliability and safety of sodium-cooled fast reactors at a commercial level. Three times BN-600 has been recognized as the best among the power units of Russia in terms of reliability and safety performance.

In April of 2010, the reactor exhausted its design service life of 30 years. The reactor plant structure had preserved sufficient operability, which allowed a license to be obtained for extending the operation life by 10 years with prospects for further extension.

While being the chief designer of the BN-600 reactor, Afrikantov OKBM JSC supervises the reactor operation at the Beloyarsk NPP with solving, jointly with the Beloyarsk NPP and other organizations, the matters of ensuring the reliable and safe reactor operation throughout its entire lifecycle.

In 2018, Afrikantov OKBM JSC employees were awarded with an RF Government Prize in the sphere of science and technology for their paper entitled “Enhancing the Operating Efficiency and Radiation Safety of the BN-600 Reactor Plant; Using the Gained Experience for the Prospective Designs of the Sodium-Cooled Fast Reactor Plants”.



BN-800, a baseline design to mature the technologies for closing the nuclear fuel cycle

  In 1983, the Company developed a BN-800 design for the 830 MWe power unit. In 1984, activities commenced to construct two BN-800 reactors—at the Beloyarsk NPP and at the new South Ural NPP.

  The subsequent delay in the construction of the reactors was used to update the design in order to improve the technical and economic characteristics and to further enhance the safety level. Note that the thermal power was increased by 42%, and respectively the electric power was brought to 880 MW practically in the same overall dimensions of the BN-600 reactor vessel. The construction activities on BN-800 were recommenced in 2006, and in 2015, the reactor achieved its first criticality in Beloyarsk NPP, Unit 4.


Thanks to the gained experience and the created production facilities, Afrikantov OKBM JSC, while functioning as a complete supplier, ensured that reactor plant equipment manufacturing and deliveries were organized with the significant part of equipment manufactured by the Company itself.

BN-800 is designed to ensure that elements of the closed nuclear fuel cycle are tried out in order to switch over to a new technology platform. The transition to the closed nuclear fuel cycle will allow a number of important problems to be solved:

  • involve into the nuclear fuel cycle the plutonium generated by irradiating in nuclear reactors uranium-238, which is the basic isotope of natural uranium, thus broadening the reactor fleet by many times for the nuclear power industry;

  • ensure a transition to the two-component nuclear power industry that will be efficiently using both the mastered reactors and newly commissioned fast neutron reactors;

  • minimize radioactive wastes through ensuring that long-lived isotopes contained in the wastes are burned up.

  • In 2016, the power unit achieved the design power and was switched over to commercial operation. Since that time, BN-800 became the world’s most powerful operating fast power reactor.

    BN-1200, a prospect of developing the fast reactor area

    The development and implementation of BN-350, BN-600, and BN-800 allowed the effective design, engineering, and production infrastructure to be created, which became a basis for the further progress in the SFR technology through developing a BN-1200 commercial project.

    BN-1200 optimally combines reference and new engineering solutions and has a safety level that conforms to the requirements for Generation IV plants and a higher economic efficiency compared to the SFR plants of the previous generations.

    Afrikantov OKBM JSC is a chief designer of the BN-1200 reactor plant. The Company ensures that the required R&D activities are coordinated and that optimal solutions are effectively developed for the reactor plant and the power unit.

    In 2016, as part of the BN-1200 basic design, the major research and design activities, the development of the detailed design of the reactor plant were completed.

    The BN-1200 design documentation underwent an industry-wide review. The results from the review generally confirmed the designers’ conclusions that the BN-1200 design conforms to the requirements in the Technical Assignment—the technical and economic characteristics of the BN-1200 reactor plant are comparable with those of the VVER reactor plant.

    Presently, the work on BN-1200 is in progress to improve its competitive ability vs. modern NPPs and vs. traditional and renewable power sources. Regarding the equipment and system layout in the reactor building, new engineering solutions are being reviewed, which allow the technical and economic characteristics to be significantly enhanced. R&D work is in progress to validate the new design solutions.

    If implemented, the work package planned under the Project R&D Work Program will make it possible to create a serial commercial power unit that meets the competitive ability requirements vs. energy sources of various types in order to ensure that the Russia’s Nuclear Energy Development Strategy is implemented in terms of developing a two-component system based on the VVER and SFR technologies.

    History of the Sodium-Cooled Fast Reactors in Russia

    география ру бн_EN.jpg

    The Table below shows how the basic technical characteristics of the BN sodium-cooled fast reactors evolved as soon as their designs were developed and the operating experience was accumulated.





    Rated thermal power, MW



    Not less than 2,800

    Gross electric power, MW 



    Not less than 1,220

    Fuel type

    uranium dioxide (UO2)

    uranium and plutonium dioxide (UPuO2)

    uranium and plutonium dioxide /

    uranium and plutonium nitride (UPuO2/UPuN)

    Efficiency factor, gross/net, %

    42.5 / 40

    41.9 / 38.8

    43.5 / 40.7

     Afrikantov OKBM JSC akes and active part in international cooperation on fast reactors. The Company developed a detailed design for the reactor plant and was a chief contractor for developing and manufacturing the main equipment for the China Experimental Fast Reactor (CEFR).  

    Presently, Afrikantov OKBM JSC  has signed a number of contracts for the activities under the CFR600 Fast Reactor Project in the People’s Republic of China.

    Options of possible mutually advantageous cooperation on fast reactors with other foreign partners showing their great interest in development of large fast neutron reactor plants are considered.

    The engineering solutions underlying the sodium-cooled fast reactor plants are legaly protected, and today Afrikantov OKBM JSC has the rights to:

    1. In the BN-800 reactor plant design:

    • 2 utility models,

    • 108 production secrets (know-hows).

    2. In the BN-1200 design:

    • 5 utility models,

    • 14 computer programs,

    • 1 database,

    • 99 production secrets (know-hows).


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