Icebreaker "Lenin" - the world's first surface ship with a nuclear power plant

“Lenin” is a nuclear-powered icebreaker, the world’s first surface vessel with a nuclear power plant. The icebreaker was built in the Soviet Union to service the Northern Sea Route and ensure continuous navigation. It was handed over to the Ministry of the Maritime Fleet of the USSR on December 3, 1959. The project of the nuclear-powered ship was developed at TsKB-15 (now “Iceberg”) in 1953–1955 (project No. 92) after the decision to build a nuclear icebreaker was made on November 20, 1953, by the USSR Council of Ministers with the goal of escorting convoys along the Northern Sea Route for 6–8 months, and if necessary, for 12–14 months.

The chief designer was Doctor of Technical Sciences Vasily Ivanovich Neganov, and the nuclear power plant was designed under the leadership of Igor Ivanovich Afrikantov. The scientific supervisor of the work was Academician Alexandrov. Hull steel grades AK-27 and AK-28 were specially developed at the “Prometey” institute for icebreakers. Due to the novelty of the equipment, difficulties arose during the design of the engine room layout. It was decided to create a wooden mock-up of the engine room. This mock-up was used to work out the designers’ layout solutions, which was much easier and undoubtedly cheaper than making changes on the actual ship under construction.

The ship was laid down on July 17 or August 25, 1956, at the Admiralty Shipyards in Leningrad.

The ship’s turbines were produced by the Kirov Plant.

The main turbogenerators were made by the Kharkov Electromechanical Plant.

The propulsion electric motors were produced by the Leningrad “Electrosila” plant.

More than 500 enterprises of the Soviet Union created 76 new types of mechanisms and 150 new equipment models specifically for the nuclear-powered ship.

Launched on December 5, 1957. The nuclear power plant was installed in 1958–1959. On August 6, 1959, the nuclear reactor was physically started. On September 12, 1959, it departed from the Admiralty Shipyard for sea trials under the command of Ponomaryov (Western press cites the date as September 15). During construction and trials, many delegations and representatives from various countries visited the icebreaker, including British Prime Minister Harold Macmillan, U.S. Vice President Richard Nixon, and ministers from China.

The British studied the nuclear-powered ship carefully and attentively. “We are very grateful to you for this interesting day spent at your large shipyard,” they wrote in the shipyard’s guest book on May 21, 1957. “We are taking away much that belongs to the future.”

On December 5, 1957, the ship was launched. The completion of the icebreaker’s construction in September 1959 coincided with Nikita Khrushchev’s first visit to the USA. On September 14, Soviet newspapers published a message in which he responded to letters and telegrams sent to him regarding the trip. “Our trip to the USA,” Khrushchev wrote, “coincided with two great events: for the first time in history, a space rocket successfully flew to the Moon, sent from Earth by Soviet people, and the world’s first nuclear icebreaker ‘Lenin’ set sail... Our nuclear icebreaker ‘Lenin’ will break not only the ocean ice but also the ice of the ‘Cold War.’ It will pave the way to the minds and hearts of peoples, calling them to turn from the competition of states in the arms race to competition in the use of atomic energy for the benefit of mankind, to warm their souls and bodies, to create everything necessary that people need...”

On December 3, 1959, it was delivered to the Ministry of the Maritime Fleet. Since 1960, it was part of the Murmansk Shipping Company.

The nuclear icebreaker “Lenin” is a smooth-deck vessel with an elongated midship superstructure and two masts. At the stern, there is a takeoff and landing pad for ice reconnaissance helicopters. The nuclear steam-generating plant of the water-water type, located in the central part of the ship, produces steam for the turbines of four main turbogenerators, which supply direct current to three propulsion electric motors. These motors drive three specially strong propellers (two side and one central). There are two autonomous auxiliary power stations. Control of mechanisms, devices, and systems is remote. The crew was provided with good living conditions for long Arctic voyages.

Initially, the icebreaker was equipped with three OK-150 type reactors. In 1966, based on operational results, it was decided to replace the old three-reactor nuclear steam-generating plant with OK-150 reactors with a more advanced two-reactor plant with OK-900 reactors. The main reason was low maintainability. The old reactor plant was disposed of by flooding in the Tsivolki Bay on Novaya Zemlya after fuel unloading. The installation of the new plant was completed by 1970.

The icebreaker had good icebreaking capability. In the first six years of operation alone, it covered over 82,000 nautical miles and independently escorted more than 400 vessels. Over its entire service life, it traveled 654,000 miles, including 563,600 miles in ice. In June 1971, the icebreaker “Lenin” became the second surface vessel (after the icebreaking steamer “A. Sibiryakov” in 1932) to pass north of the Severnaya Zemlya archipelago. The voyage started in Murmansk and ended in Pevek. This prepared the expedition of the icebreaker “Arktika” to the North Pole in 1977.

Ultimately, the icebreaker “Lenin” served for 30 years and was decommissioned in 1989 and placed in permanent mooring in Murmansk. Currently, a museum operates on the icebreaker, and work is underway to expand the exhibition.

Nuclear incidents on the icebreaker:

In February 1965, during scheduled maintenance of the main circulation pumps of the first circuit of reactor No. 2, due to operator error, water circulation through the active zone was briefly stopped, leading to overheating. Different sources describe this as melting with destruction of technological channels, partial damage to about 60% of fuel assemblies, or serious mechanical damage to some fuel assemblies, including detachment of parts of structures found during spent nuclear fuel unloading. Ninety-five spent fuel assemblies were reloaded into storage casks at the “Lepse” floating technical base. The remaining 124 spent fuel assemblies (about 60% of the fuel) were unloaded together with the shielding assembly and compensating grid, placed in a special cylindrical container filled with a hardening radiation-resistant preservative and sealed with a welded stainless steel lid. A cylindrical pontoon was built for it, into which a special stainless steel caisson was welded. After two years of shore storage, the container was inserted into the caisson, and the remaining free space was concreted. The pontoon with the container of spent nuclear fuel was then sunk in Tsivolki Bay on the eastern coast of the Novaya Zemlya archipelago.

Approximately around September 1965 or somewhat later, during the navigation season, a leak was discovered in the first circuit of reactor No. 3. One of the two steam generators of the operational reactor failed after only three thousand hours of operation due to a faulty stainless steel insert jacket, which was supposed to protect the inner surface of the body from corrosion for several decades. This steam generator developed a first circuit leak into the second circuit. As a result, the second steam generator could only provide half the reactor’s rated power until the end of the navigation season.

In early 1966, due to violation of welding technology, a major fire broke out in the apparatus room on the icebreaker, destroying cable routes. The consequences of the fire were eliminated with great difficulty, and the steam generator on the third reactor was replaced.

By the end of the 1965 navigation season, a coolant leak was detected on the same reactor. The first circuit leak was located on a “non-isolatable” section of the pipeline.

“The second accident on the icebreaker occurred in 1967. After the scheduled loading of fresh nuclear fuel into one of the icebreaker’s nuclear power plant reactors, a leak was detected from the third circuit pipelines (the cooling circuit for the first circuit equipment). To determine the leak location, it was necessary to dismantle the biological shielding in the reactor compartment.

The shielding was made as a solid concrete casting with metal shavings and was not disassemblable, so the work was carried out using jackhammers. This caused new serious mechanical damage to the reactor plant equipment. It soon became clear that the problem could not be fixed this way.”

Thus, ten years after launching, eight years after commissioning, and several Arctic navigation seasons, the nuclear power plant of the icebreaker “Lenin,” initially consisting of three reactors, had deteriorated so badly that designers, engineers, and consulted scientists decided to get rid of it in the simplest way — by making a hole in the ship’s bottom and dumping and sinking the reactor compartment through it.

Manually dismantling the units and mechanisms subject to replacement, including the current hull of one of the reactors, radiation-contaminated pipelines, and steam generators, would have meant overexposing personnel and prolonging repair and restoration work for a long time. Therefore, another method was chosen — “free unloading through the bottom.” The operation was secret and only became known recently.

As stated in the “Bellona” report, “The unsuccessful repair operation of the cooling system was one of the reasons for the decision to completely replace the icebreaker ‘Lenin’s’ nuclear power plant. It was necessary to remove the entire reactor compartment, including steam generators and pumps, weighing about 3,500 tons.”

One of the reactors on the damaged OK-150 installation had already been loaded with fresh fuel. It was decided to extract all fuel assemblies to send the fresh nuclear fuel back to the manufacturer. However, the internal and external surfaces of the assemblies had significant levels of radioactive contamination, so all fuel assemblies had to be completely disassembled into parts to extract the fuel elements (36 elements per assembly). After that, the elements containing unirradiated nuclear fuel were decontaminated in chemical solutions, carefully wiped, and sent to the manufacturer.

Spent nuclear fuel was also unloaded from the other two reactors to the “Lepse” floating base. The internal cavities of the icebreaker’s reactor plant were filled with a hardening furfural-based composition. Necessary cuts were made on the ship’s hull and around the reactor plant, and “Lenin” was towed to Tsivolki Bay (Novaya Zemlya archipelago).

There, final preparations for sinking the reactor plant were made: explosive charges were placed at the crossbeams holding the entire structure. After detonation, the structure separated from the icebreaker’s hull and sank (the bay’s depth did not exceed 40–50 meters).”

Preliminary dismantling work on the hull and bottom of the ship continued from September 8 to 19, 1967. The icebreaker was positioned over the reactor compartment’s burial site.

This was preceded by delicate and hazardous work by diving specialists. Using special equipment, they cut a 60-meter perimeter in the icebreaker’s bottom under the reactors in two days. Then it was sealed with foam rubber and tarpaulin, allowing water to be pumped out of the central compartment and cutting of bulkheads to begin.

According to the article “How the ‘Heart’ Was Cut Out of ‘Lenin,’” “The middle part of the longitudinal strength bulkheads was cut manually, the lower part with a remotely controlled device. Cutting the lower part of the strength bulkhead was the most critical moment before detonating the charges, as the compartment was held in the hull by the upper parts of four bulkheads about 2.3 m high each, intended for detonation by shaped charges. If there were internal cracks in any of the crossbeams, its strength could be compromised, and the 3,700-ton compartment could jam in the hull due to skewing. Therefore, upper and lower supports preventing skewing were installed, along with a special release device guiding the compartment as it exited the hull... At the moment of the shaped charge detonation, only emergency rescue teams and the commission overseeing the compartment’s unloading remained on the icebreaker.”

As recorded in the watch log of the nuclear icebreaker “Lenin,” “September 19, 1967. 22:27. Explosion carried out. The compartment went underwater. Emergency teams began inspecting their posts.”

After the charges were detonated and the reactor compartment separated, the icebreaker surfaced, reducing its draft by about 2–2.5 meters.

The immobilized icebreaker was towed with all precautions from Novaya Zemlya to the Kola Bay. On September 26, 1967, “Lenin” arrived at port, and on October 5, it was docked at SRZ-35 in the settlement of Roslyakovo. By mid-November, the icebreaker’s bottom was restored, and a few days later, the installation of overboard fittings according to the new design was completed. Then it was prepared for a sea passage and safely towed through the Barents Sea to the White Sea — to the “Zvezdochka” ship repair plant in Severodvinsk. There it was moored at the enterprise’s berth for installation of the new OK-900 type reactor plant and its servicing systems.

Within two years, by April 1970, modernization work was mostly completed. To fit the new nuclear power plant (now with two reactors instead of the previous three) into the existing hull, 204 of the 675 compartments of the icebreaker had to be “redesigned.” During this work, 6,200 units of new equipment were installed, including over thirty prototype models — that is, equipment installed for the first time.

22 April 1970, on the 100th anniversary of the “leader of the world proletariat,” whose name the icebreaker bore, both reactors of the new plant were brought to power. Comprehensive tests of the OK-900 plant were conducted at the shipyard, and in May 1970, the updated icebreaker with its transplanted energy “heart” went to sea for sea trials. A month later, the acceptance certificate was signed, and on June 21, 1970, the nuclear-powered ship “Lenin” resumed service in the Arctic.

Sources:

https://www.gov.spb.ru/gov/otrasl/arkt/news/172806/

https://ru.wikipedia.org/wiki/Lenin_(nuclear_icebreaker)

https://histrf.ru/read/articles/devyat-faktov-iz-istorii-atomnogo-ledokola-lenin