RITM-200 (РИТМ-200) is a Russian marine nuclear reactor plant made up of two compact pressurised-water reactors of 175 MW of thermal power each. On a ship the pair delivers 60 MW to the propellers through turbine-generators and electric motors. It was designed by OKBM Afrikantov (ОКБМ Африкантов), a design bureau of the Russian state nuclear corporation Rosatom, and powers the universal nuclear icebreakers of Project 22220 built at the Baltic Shipyard in St Petersburg: Arktika, which entered service in 2020 and which OKBM called "the world's most powerful icebreaker", Sibir, Ural and Yakutia, with three more under construction.[1][17][11][28] Versions of the design have been developed for floating nuclear power plants for Chukotka and for small land-based nuclear power plants, planned in Yakutia and under construction in Uzbekistan — the first export order for any small modular reactor.[32][34][36]

The RITM-200 is a product of Nizhny Novgorod — one of Russia's largest cities, standing where the Oka flows into the Volga, which from 1932 to 1990 was called Gorky. OKBM, founded there in 1945, has been the chief designer of the reactor plants of every Soviet and Russian nuclear icebreaker since the first one, the Lenin of 1959. It is the chief designer and complete supplier of the RITM-200, and at its own production base in the city it makes the reactor internals, the steam-generator cassettes and the refuelling equipment, while the reactor vessels are made at the ZiO-Podolsk plant near Moscow.[1][9][18][14]

Design

The RITM-200 is an integral reactor: the main equipment of the primary circuit, including the steam generators, is placed directly inside the casing of the steam-generating unit, instead of in separate vessels joined by pipes as in the first icebreaker reactors. Each reactor weighs 147.5 tonnes and is 7.3 metres high and 3.3 metres in diameter.[1][2] According to the 2018 statement of Rosatom's machine-building division, this made the plant twice as light, one and a half times more compact and 25 MW more powerful than the KLT-type plants of the previous icebreakers, and allowed the new ships to be built dual-draught; OKBM's general designer Vitaly Petrunin gave the figures as 1.7 times lighter, twice as compact and almost 20 per cent more powerful.[2][3]

A RITM-200 reactor is designed to operate for 40 years and needs refuelling once every seven years; Rosatom compares one fuel load to 540,000 tonnes of Arctic diesel fuel. The steam-generating unit keeps working when the ship rolls up to 45 degrees and pitches up to 15 degrees.[15][17][16] The fuel assemblies are made by the TVEL company at the Elemash plant.[14] On an icebreaker one RITM-200 unit produces about 30 MW of electricity after the ship's own needs; OKBM's chief designer of water-cooled reactor plants Yury Fadeev has said that, without changing the reactor, optimising its parameters could raise this to 50 MW, as he explained when OKBM began adapting the plant for land-based power stations.[6] The technical solutions of the RITM-200 are protected by eight inventions, four utility models, 21 computer programs and 96 items of production know-how held by OKBM.[1]

The Nizhny Novgorod chapter

Icebreaker reactors since 1959

OKBM — the Afrikantov Experimental Design Bureau of Mechanical Engineering (Опытное конструкторское бюро машиностроения им. И. И. Африкантова), named after its long-time chief designer and head Igor Afrikantov — was set up by a government decree in 1945 and stands on Burnakovsky Proyezd (Бурнаковский проезд) in Nizhny Novgorod.[9] Since 1955 it has been the designer, manufacturer and complete supplier of several generations of marine nuclear power plants, installed on nine nuclear icebreakers and on the nuclear-powered lighter carrier Sevmorput; by 2019 they had accumulated more than 400 reactor-years of operation.[10] The first, the OK-150, went into service on the icebreaker Lenin in 1959 — the world's first nuclear-powered surface ship; it was a "loop" plant, with the main equipment in separate casings joined by pipes, and in 1970 the Lenin received the new block-type OK-900.

They were followed by the OK-900A for the Arktika class, the KLT-40 for the Sevmorput and the KLT-40M for the Taymyr and Vaygach. In 1996 OKBM put into service a test-stand prototype of a nuclear steam-supply plant with an integral-type reactor, the layout later used in the RITM-200.[1][9] OKBM also designed the two KLT-40S plants of the floating nuclear power plant Akademik Lomonosov, and the reactor cores both of that plant and of the new Arktika.[13][4]

From project to series

Vitaly Petrunin, OKBM's first deputy director general and general designer, defended the RITM-200 project before the scientific and technical council of Rosatom in 2009; ten years later the reactors were in series production for Atomflot, the operator of Russia's nuclear icebreakers. In his words, RITM-200 was the first marine reactor plant manufactured entirely within Rosatom's machine-building division, Atomenergomash, with OKBM as chief designer and complete supplier and with ZiO-Podolsk mastering the reactor vessels "from scratch".[3]

The work in Nizhny Novgorod covers the reactor's interior and its servicing. OKBM is the designer, complete supplier and manufacturer of the reactor in-vessel internals of the RITM-200 and of its successor, the RITM-400.[18][19] For a reactor of the Sibir, for example, it produced the twelve steam-generator "cassettes", weighing almost one and a half tonnes each, which ZiO-Podolsk fitted into the reactor body.[14] In the first half of 2018 alone it shipped large power equipment for the RITM-200 to ZiO-Podolsk.[8] OKBM also developed and makes the equipment for the first loading of the reactor cores and the refuelling complex: the first-loading equipment passed its acceptance tests on an OKBM test stand in 2017, and the digital control system of the refuelling complex was developed and is made by another Nizhny Novgorod enterprise, the Sedakov Research Institute of Measuring Systems.[7] In 2025 OKBM made the first reactor-plant component in the Russian nuclear industry to be produced by 3D printing: a terminal box of the RITM-200's pump equipment, for which the Russian Maritime Register of Shipping issued its first such certificate in Russia.[37]

Since 2008 the bureau's director and general designer has been Dmitry Zverev, a graduate of the Gorky Polytechnic Institute who joined OKBM in 1984.[5] In 2019 the bureau signed the contract with the Baltic Shipyard to supply RITM-200 plants for the fourth and fifth icebreakers.[17] For 2020, Rosatom's "Person of the Year" awards gave a special prize to the project "Reloading the Northern Sea Route" for a historic record of cargo traffic on the route, and OKBM was named among its participants.[12]

Project 22220 icebreakers

The Project 22220 (LK-60Ya) icebreakers were designed by the Iceberg Central Design Bureau in 2009 and are built at the Baltic Shipyard in St Petersburg for Atomflot. They are dual-draught (8.55 or 10.5 m), so that they can work both in Arctic waters and in the mouths of polar rivers, are 34 m wide and can break ice 3 m thick; each carries two RITM-200 reactors.[20][17] The Sibir, for example, is 173.3 m long, makes 22 knots in open water and has a crew of 54.[1]

  • Arktika: keel laid on 5 November 2013, launched on 16 June 2016, entered service on 21 October 2020; it left Murmansk on its first working voyage on 14 November 2020.[20][11][21]
  • Sibir: keel laid on 26 May 2015, launched on 22 September 2017, accepted by Atomflot on 24 December 2021.[20][22]
  • Ural: keel laid on 25 July 2016, launched on 25 May 2019, state flag raised on 22 November 2022.[20][23]
  • Yakutia: keel laid on 26 May 2020, launched on 22 November 2022, state flag raised on 28 December 2024.[39][40][24]
  • Chukotka: keel laid on 16 December 2020, launched on 6 November 2024, completion planned for 2026.[26][25]
  • Leningrad: keel laid on 26 January 2024; its two RITM-200 reactors were installed by August 2026, and launching is planned before the end of 2026.[26][19][27]
  • Stalingrad: keel laid on 18 November 2025, launching planned for 2028.[26][38]

By September 2026 sixteen RITM reactors had been produced, and eight of them were in operation on the Arktika, Sibir, Ural and Yakutia.[28]

Beyond the icebreakers

RITM-400. An enlarged version designed by OKBM, with a thermal power of 315 MW per reactor, was developed for the still larger icebreaker Rossiya, the first of Project 10510 ("Lider"), which is being built at the Zvezda shipyard; with two RITM-400 reactors it will have 120 MW at the propellers. ZiO-Podolsk completed the second of its two reactors, named "Dobrynya Nikitich" and "Ilya Muromets", in September 2025, and OKBM has been making equipment for the ship's nuclear power plant under its own contract with Zvezda.[1][19][29][4]

Floating power units. In 2021 Rosatom committed to supply the Baimskaya copper-mining project in Chukotka, in the far north-east of Russia, from three floating nuclear power plants, each with a pair of reactors of the RITM-200M type rated at 55 MW of electricity, and a fourth plant held in reserve for refuelling and repairs. The barges are being built at a shipyard in China. The upgraded reactors, called RITM-200S, have a thermal power of 198 MW each and need refuelling about every five years. The first reactor unit for these plants, rated at 58 MW of electricity, was completed at ZiO-Podolsk in May 2026, and the second in September 2026.[30][31][32][28]

Land-based plants. On 5 September 2019 Rosatom and the government of Yakutia signed an agreement on cooperation in building small nuclear power plants based on the RITM-200 developed by OKBM, and in 2020 Rosatom named the village of Ust-Kuyga as its site.[33][35] The land version, RITM-200N, has a thermal power of 190 MW, gives 55 MW of electricity gross, needs refuelling every six years and is designed for a service life of 60 years. A siting licence for the first unit was issued in April 2023; in 2024 the project was changed to two units of 110 MW in total, with the first planned to start in 2030.[34][41] Construction began first in Uzbekistan: a contract signed in May 2024, and changed in 2025, provides for two such units next to two large VVER-1000 reactors in the Jizzakh region. A construction licence for the first unit was issued on 4 June 2026 and first concrete followed; World Nuclear News described the project as featuring the first export order for any small modular reactor.[36]

See also

Sources

  1. OKBM Afrikantov — "Reactor plants for nuclear icebreakers and other ships" (in Russian; archived copy, January 2022)
  2. OKBM Afrikantov — "Atomenergomash has completed production of RITM-200 reactor plants for three new-generation icebreakers", 16 October 2018 (in Russian; archived copy)
  3. OKBM Afrikantov — "Prospects for the use of RITM-generation reactors", interview with Vitaly Petrunin, 2019 (in Russian; archived copy)
  4. OKBM Afrikantov — "OKBM Afrikantov, the flagship of Russian reactor building", interview with Dmitry Zverev, 2020 (in Russian; archived copy)
  5. OKBM Afrikantov — "Director general and general designer Dmitry Zverev celebrates his 60th birthday", 30 August 2021 (in Russian; archived copy)
  6. OKBM Afrikantov — "RITM-200 will be brought ashore", interview with Yury Fadeev, 2018 (in Russian; archived copy)
  7. OKBM Afrikantov — "OKBM Afrikantov will create a refuelling complex for new-generation icebreakers", 21 March 2018 (in Russian; archived copy)
  8. OKBM Afrikantov — "OKBM Afrikantov has shipped more than 300 tonnes of equipment", 13 August 2018 (in Russian; archived copy)
  9. OKBM Afrikantov — "Chronology" (in Russian; archived copy, September 2025)
  10. OKBM Afrikantov — "Russia's nuclear icebreaker fleet celebrates its 60th anniversary", 3 December 2019 (in Russian; archived copy)
  11. OKBM Afrikantov — "The world's most powerful icebreaker Arktika has joined Russia's nuclear fleet", 23 October 2020 (in Russian; archived copy)
  12. OKBM Afrikantov — "OKBM Afrikantov staff named Rosatom's Person of the Year", 28 May 2021 (in Russian; archived copy)
  13. OKBM Afrikantov — "OKBM Afrikantov staff receive a Russian Government prize for the nuclear plant of the floating power unit", 8 November 2021 (in Russian; archived copy)
  14. World Nuclear News — "Russia charts 40 years of icebreaker progress", 15 August 2017 (archive)
  15. World Nuclear News — "Russia speeds up manufacture of icebreaker reactor", 26 April 2017 (archive)
  16. World Nuclear News — "Ural icebreaker passes construction milestone", 1 August 2018 (archive)
  17. World Nuclear News — "Russia plans next two nuclear icebreakers", 30 October 2019 (archive)
  18. Atom Media (Rosatom) — "Rosatom's machine builders have manufactured the first RITM-200 reactor unit for the nuclear icebreaker Leningrad", 14 May 2026 (archive)
  19. World Nuclear News — "Reactors installed on nuclear-powered icebreaker Leningrad", 24 August 2026 (archive)
  20. Baltic Shipyard — "Projects": universal nuclear icebreakers of Project 22220 (in Russian) (archive)
  21. World Nuclear News — "Arktika icebreaker completes first mission", 24 November 2020 (archive)
  22. World Nuclear News — "Nuclear icebreaker Sibir enters service", 6 January 2022 (archive)
  23. Strana Rosatom — "The flag raised on the Ural", 23 November 2022 (in Russian) (archive)
  24. Atom Media (Rosatom) — "The state flag raised on the nuclear icebreaker Yakutia", 28 December 2024 (in Russian) (archive)
  25. Baltic Shipyard — launch of the nuclear icebreaker Chukotka, 6 November 2024 (in Russian) (archive)
  26. Strana Rosatom — "From a ship to an icebreaker": the Baltic Shipyard at 170, chronology, 25 May 2026 (in Russian)
  27. Baltic Shipyard — news about the nuclear icebreaker Leningrad, 9 October 2026 (in Russian) (archive)
  28. World Nuclear News — "Second reactor manufactured for floating nuclear plant", 24 September 2026 (archive)
  29. Atom Media (Rosatom) — "Rosatom's machine builders have completed the second RITM-400 for the nuclear icebreaker Rossiya", 8 September 2025 (archive)
  30. World Nuclear News — "Russia commits to further floating nuclear power plants", 27 July 2021 (archive)
  31. World Nuclear News — "Nuclear fuel development completed for RITM-200S floating units", 20 December 2022 (archive)
  32. World Nuclear News — "First RITM-200C reactor unit manufactured for floating power plant", 27 May 2026 (archive)
  33. OKBM Afrikantov — "Rosatom and the government of Yakutia have signed an agreement on cooperation in small nuclear power plants", 5 September 2019 (in Russian; archived copy)
  34. International Atomic Energy Agency — D. V. Shchekin, I. O. Bykh, I. V. Yurina (OKBM Afrikantov), "Characteristics and status of the first-of-a-kind land-based small nuclear power plant project with the RITM-200N reactor plant", poster, IAEA conference on small modular reactors, 2024
  35. World Nuclear News — "Rosatom plans first land-based SMR for Russian Far East", 11 November 2020 (archive)
  36. World Nuclear News — "Ceremony to mark first concrete for Uzbekistan SMR", 5 June 2026 (archive)
  37. Atom Media (Rosatom) — "Rosatom introduces 3D printing of RITM-200 equipment components", November 2025; Russian version (archive)
  38. World Nuclear News — "Keel laid for the Stalingrad nuclear icebreaker", 20 November 2025 (archive)
  39. OKBM Afrikantov — "Technical keel-laying of the third serial universal nuclear icebreaker Yakutia", 26 May 2020 (in Russian; archived copy)
  40. Baltic Shipyard — "The nuclear icebreaker Yakutia sets off for Murmansk", 7 April 2025 (in Russian) (archive)
  41. International Atomic Energy Agency — T. Bogdanova (Rostekhnadzor), contribution to the IAEA conference on small modular reactors, 2024, on the licensing of the Yakutia small nuclear power plant (archived copy)