Baltic Shipyard has brought the starboard RITM-200 reactor aboard the nuclear-powered icebreaker Chukotka to minimum controlled power, beginning the physical start-up phase for one half of the vessel’s reactor plant. The Russian shipbuilder reported the achievement on 19 October, before further international reporting on 26 October. The milestone confirms a controlled reaction in one reactor; the vessel is still undergoing tests and is not yet in service.
The Project 22220 icebreaker is being completed in St Petersburg with two RITM-200 pressurised water reactors. Each is specified at 175MW of thermal output, supplying heat to the ship’s steam and power-generation arrangements that ultimately drive its electric propulsion equipment. During start-up, engineers reached the lowest controllable power level and checked instruments connected with reactor control, monitoring and protection.
Preparation for physical start-up included months of commissioning, checks on emergency protection equipment and the loading of nuclear fuel. Bringing a reactor to a stable low-power condition permits further verification of the systems that regulate its operation. It does not establish that the second unit has started or that the complete shipboard electrical and mechanical installations can yet meet propulsion demands.
The two reactors have a combined nominal thermal rating of 350MW. That figure is heat generated in their nuclear cores, not the electrical output available for propeller motors after conversion losses and auxiliary demands. Assessing the vessel’s propulsion capability therefore requires separate figures for steam generation, generators, motors and mechanical systems rather than treating reactor thermal power as shaft or electric power.
RITM-200 units are compact marine reactors designed for the loads and limited space aboard an icebreaker. The shipbuilder reports each unit weighs more than 147 tonnes, stands about 7.3 metres high and measures 3.3 metres in diameter. The design is specified to cope with substantial vessel motion, including roll and pitch limits; these are design requirements, not a claim that Chukotka has already completed trials under those conditions.
The first low-power start-up establishes a controlled operating state from which instrument response and protective functions can be assessed. Further tests must examine how the two reactor units and their support systems behave together, including the interfaces between controls, steam generation and the rest of the nuclear installation. The shipyard says integrated plant testing will follow physical start-up of both reactors.
Project 22220 vessels are designed with a variable draught so that they can escort cargo through deep Arctic waters and navigate shallower approaches to river ports. Ballast arrangements change the depth at which the hull sits, while a powerful icebreaking bow and propulsion plant support passage through thick ice. Chukotka is approximately 173 metres long and 34 metres wide, with a stated maximum icebreaking capability of about three metres.
The Chukotka keel was laid in December 2020, and the hull was launched in November 2024. Other Project 22220 vessels, including Arktika, Sibir, Ural and Yakutia, have entered service, giving shipbuilders operating experience with the compact twin-reactor arrangement. Nevertheless, commissioning records from other ships cannot substitute for tests of installed instruments, cables, cooling circuits and protection arrangements on Chukotka itself. The ship is undergoing mooring trials before later factory sea trials, which will test systems in the conditions associated with navigation and propulsion.
Building the reactor plant involves a network of specialised suppliers. Afrikantov OKBM is responsible for the reactor design and associated systems, while ZiO-Podolsk manufactures major pressure equipment. The Chukotka milestone concerns installation and commissioning of equipment already aboard the ship, rather than a fresh reactor procurement contract. Each vessel still requires its own testing even when related ships use the same reactor design.
Mooring trials permit plant checks while the vessel remains alongside; sea trials introduce sustained propulsion loads, vessel movement and more demanding interaction between onboard systems. Bringing one reactor to minimum controlled power is therefore an intermediate step between completing equipment installation and demonstrating a functioning propulsion system at sea. The shipbuilder has not reported completion of those later tests.
Baltic Shipyard’s next announced tasks are physical start-up of the second RITM-200 reactor and integrated tests of the nuclear power installation, followed by further vessel trials. The 19 October result establishes the starboard unit’s initial controlled operation but does not establish the completion of propulsion commissioning or a new operational handover date.
