Nuclear deepwater submarines

By Dmitry Kornev 

In 1965, the Ministry of the Defence of the USSR established a special department named the Main Directorate for Deep Sea Research to initiate the development and servicing of deepwater vehicles. In 1976, as a sort of a cosmonaut corps, the Minister of Defence of the USSR ordered to establish a hydronaut team and a task-oriented training center in Leningrad to operate underwater vehicles. 

Project 09787 BS-64 “Podmoskovie” nuclear submarine is making its way back home after its first sortie for sea trials. Severodvinsk, 25th November 2016


In June 1979, the 29th Red Banner North Sea Fleet separate submarine brigade was formed at Olenya Guba, a naval base in Russia, for maintenance and operation of underwater vehicles and their carriers. To make sorties, hydronaut crews travelled to the North Sea naval bases, received there vehicles from maintenance crews to make a sortie, and then returned the equipment.

The “Arkhipelag” (Archipelago) and “Seliger” bathyscaphes became the first Russian naval underwater vehicles, which allowed to gain invaluable experience in works with different objects on the seabed.

The first nuclear deepwater station

Actually, even before operating the Seliger-class underwater vehicles, developers knew their disadvantages. First of all, the operational area for such submersibles is narrowed by communication with the carrier submarine. Secondly, there was restrained sea endurance in terms of energy sources and crew life support system resources. Thirdly, they had extremely poor maneuverability. These factors inspired developers to create an autonomous modification of the Seliger-class bathyscaphes by installing a nuclear reactor on the vehicle, increasing its overall dimensions, and by enhancing the life support system resources, speed and maneuver performance. No doubt, a new type of the underwater vehicle was meant to be more autonomous and capable of accomplishing different types of missions on the World’s ocean bed.

Thus, in 1970s a new deepwater system development project (Project 1851) was launched. The system included the “Nelma” nuclear deepwater station (NDS) (Project 18510) and nuclear carrier submarine (Project 675N).

At that time, a new modification of the carrier submarine was developed (Project 675) under Project 675N (“Nositel” (Carrier)).

On 25th September 1981, Leningrad Admiralty Association (now – “Admiralty Shipyards” JSC) laid down the flagship nuclear deepwater station AS-23 (Project 18510 “Nelma”). Two years after laying-down, on 29th September 1983, the top secret mini-submarine was set afloat, opening the phase of retrofit and testing. Probably, as far back as 1984, western intelligence services spotted the new deepwater vehicle in Leningrad and named it X-RAY. In 1986, Project 1851 complex reached the final phase of testing: the first underwater docking between NDS and a carrier submarine was completed. The complex with NDS AS-23 was officially approved and put into service by the USSR Navy on 30th December 1986.

One of the questions that arise immediately: how can a nuclear power plant be installed inside so very small submersible? For the basic design of Project 18510 NDS, it was proposed to use a lightweight power plant similar to those installed in spacecraft. The nuclear reactor was supposed to be installed inside a capsule without a special heavy biological shield. Seawater was meant to be such a shield, i.e. the reactor compartment was made as an individual unit of the pressure-proof hull, which was separated from the inhabited pressure-proof hull by the seawater space inside the external lightweight hull of NDS.

The distinctive feature and the main drawback of the first nuclear deepwater station was that it had the structure similar to the Seliger-class bathyscaphes. Actually, a new type of subs was designed as submersibles similar to tethered bathyscaphes, but without the tether. These subs also featured quite large sizes, onboard small-size nuclear power plants and advanced main and auxiliary propellers or propeller screws. The location of the access hatch in NDS was similar to the first underwater vehicle “Arkhipelag” – in the upper section of the hull, without a deck-house and a barrier. The crew was meant to be transferred from NDS through a special transfer module of the carrier submarine. The emergency exit was available after surfacing similarly to the procedure for “Arkhipelag”. In service, the structure of NDS AS-23 was redeveloped: the station was equipped with a barrier that ensured safer exit to the NDS deck in case of surfacing. This was the final version of NDS (Project 18510 “Nelma”) as we know it now.

Development of NDS. “Paltus” and “Kashalots” class submarines

In the course of development of the NDS prototype (Project 18510) designers found out some appropriate selected solutions. On 26th December 1984, Leningrad Admiralty Association (now – “Admiralty Shipyards” JSC) laid down NDS AS-21, which became the flagship station of the series production Project 18511 “Paltus”. The new NDS had large overall dimensions, enhanced performance and a new carrier (Project 09774) based on Project 667А nuclear missile submarine. The carrier sub was refitted at Shipreparing Center “Zvyozdochka” in Severodvinsk since 1983.

At least two nuclear stations were expected to be built under the “Paltus” project: flagship AS-21 and the first standard model AS-35. By the end of 1995, these plans were completed. In April 1991, NDS AS-21 (Project 18511) was identified by western intelligence services for the first time, and the project was named “Paltus” – probably, they had already known the real codename of the project through other sources.

While developing carried NDSs, Project 1910 named “Kashalot” was launched to build larger and more autonomous nuclear deepwater stations, which, in fact, were designed as full-featured nuclear submarines with long sea endurance. These subs may operate at a long distance from their bases.

The new NDS was designed according to the above-mentioned Decree of the USSR Council of Ministers issued in 1972, the task being assigned to the TsKB “Volna” of the USSR Ministry of Shipbuilding Industry. E.S. Korsukov was the chief designer of the project; S.M. Bavilin, developer of the “Nelma” project, the deputy designer. Later, according to the order of the Minister of Shipbuilding Industry, a special design team led by Yu.M. Konovalov was formed for designing Project 1910 NDS. In 1979, the 1st and 2nd crews of the flagship NDS Class 1 AS-13 (Project 1910) were included in the hydronaut team.

Class 1 NDS (the “Kashalot” project) was planned to be built as small series, including the flagship NDS and two standard models. The standard models have been built by Leningrad Admiralty Association (“Admiralty Shipyards” JSC) since 1977. The series flagship AS-13 was set afloat on 25th November 1982. On 31th December 1986, it was accepted by the Navy for field testing after completing factory and state tests (started in 1983). The series consisting of three stations was completed on 16th December 1994, and the third NDS was supplied to the Navy. The NATO repowering name for Project 1910 NDS is Uniform.

The depth of submersion of the first gen NDSs is believed to be not less than 1,000 m. This depth is a few times higher than the depth of submersion of standard-type submarines, but, for example, the “Komsomolets” submarine, composed of titanium, built at the same time and probably featuring the similar structure, was able to submerge at the similar depth.

No public data on the operation of complexes with deepwater stations is available through open media sources, and we can only speculate on possible application of the new type of underwater vehicles. NDS may be delivered to the operational area by means of nuclear carrier subs and then may independently conduct search and reconnaissance operations on the seabed. Of course, such submersibles should be equipped with tools for bottom sampling and for lifting object onboard. Like some civil submersibles for similar applications, NDSs should be fitted with observation and surveillance equipment, manipulators and remotely controlled equipment for handling objects.

The purpose of such stations is believed to be operations with their own and foreign objects fallen onto the seabed if such objects may provide valuable data. No doubt, such submersibles are able to carry out reconnaissance operations to detect cable and other communications on the seabed and to disrupt them.

In addition, NDSs may be used for search-and-rescue operations. It is known that in the period from 13th to 19th August 2000, NDS AS-15 (Project 1910) took part in an operation intended for search and observation of the “Kursk” submarine lying on the seabed. The data collected by NDS were likely to be the first valid information about the condition of the “Kursk” submarine.


Development of the materials science along with gained experience in building and service of nuclear deepwater stations should seamlessly lead to the next breakthrough stage in their development, i.e. to building submersibles able to operate deeper and to accomplish various missions. Such underwater vehicles should combine the performance of Project 1910 nuclear deepwater stations and the depth of submersion demonstrated by the best research bathyscaphes available at that time.

In the late 1980s, the task force led by S.M. Bavilin at the Marine Engineering Bureau “Malakhit” prepared the basic design of the complex (Project 10830) which included a nuclear deepwater station (Project 10831) with a polyspherical pressure-proof hull. Based on the above-mentioned Decree of the USSR Council of Ministers, development efforts were undertaken to refine the technology for manufacturing a polyspherical pressure-proof hull and monoblock units of the lightweight filler, and to develop equipment for such a station as well. The complex had to include the nuclear carrier sub BS-136 “Orenburg” (Project 09786).

By 1990, the technical and design projects of the station were developed and approved. Moreover, both projects were developed along with the modeling of equipment layout inside spherical compartments of the submarine. In 1991, with almost completed sections of the NDS pressure-proof hull, technical project 10830 was revised concerning customized auxiliary equipment to be installed in the fore part of NDS. The reworked technical project of the complex (Project 10830/1083К) was represented and reviewed in May 1992.

The new deepwater station featured a pressure-proof hull made of several intersectional titanium spheres. Due to this structure, the submersible was unofficially named “Losharik” in the process of building. Later, this name stuck to it and is still used nowadays. The space between the spheres and a lightweight external housing was filled with a new porous material, which provided the desired combination of structural strength and positive buoyancy, similarly to the Consul-class bathyscaphes and other types of deepwater vehicles. One of the spheres contained the unique nuclear power plant.

NDS that belongs to the project is able to operate autonomously like large NDSs (Project 1910) or may be used together with a nuclear carrier sub. The depth of submersion of the new NDS exceeds the operating depth of Project 18511 and Project 1910 NDSs and may be over 2,000 m. Some sources report even 6,000 m.

As far back as 1988, Production Association “Sevmash” (Severodvinsk) started design works preparation for the production of a new NDS under the project. Among other reasons, such efforts were needed to master a new technology for manufacturing titanium spheres of large diameters: Soviet specialists did not have any experience in such applications. The flagship NDS AS-12 (factory No. 01210) was laid down in “secret” shop No. 42 at “Sevmash” on 16th July 1990. In the mid-1990s, the building of the station was frozen due to insufficient funds and resumed only in 2000. The station was set afloat in the presence of Commander-in-Chief of the Russian Navy V. Kuroedov on 5th August 2003.

In 2004–2007, under the command of Captain A.I. Oparin the factory, state and deepwater tests of the special-purpose experimental submarine have been held in the White Sea, Barents Sea, Norwegian Sea, and Greenland Sea. In 2006, Project 10831 NDS was transferred to the Navy for field testing; in 2008, NDS was put into service by the Russian Navy. In May 2010, some media sources reported that specialists of JSC Shipreparing Center “Zvyozdochka”, JSC Central Design Bureau for Marine Engineering “Rubin”, JSC Marine Engineering Bureau “Malakhit” and Federal State unitary Enterprise “Central Research Institute of Structural Materials “Prometey” received the national award for “experimental deepwater station state order 1083К”.

Longer range, deeper waters, larger scope

At the turn of millennium, Project 09787 was launched to develop a new carrier submarine based on the nuclear submarine (Project 677BDRМ). The new carrier was developed as an auxiliary element for the BS-136 “Orenburg” carrier submarine. Probably, development of the modernization program for nuclear deepwater stations and carriers was started at that time. In 2004, a contract was signed to develop an equipment complex for the carrier submarine “Podmoskovie” (Project 09787 BS-64). In 2008, Shipreparing Center “Zvyozdochka” began works to upgrade the submarine. “Losharik” was meant to become the main load to be carried by the new submarine.

At the same time, they started to restore technical readiness and upgrade nuclear deepwater stations (Projects 10511 and 1910) not used then by the Russian Navy. The set of technical equipment for special missions is likely to be expanded.

Moreover, in 2009 Russia’s Ministry of Defence and the Central Design Bureau for Marine Engineering “Rubin” signed a contract for developing a project to modify the unfinished submarine tender “Belgorod” (Project 949А) into a special-purpose nuclear research submarine. Nearly no information on the project is currently available, but we know that this new special-purpose submarine is expected to be the multirole mothership for a massive fleet of manned and unmanned underwater vehicles. On 20th December 2012, Production Association “Sevmash” (Severodvinsk) laid down the special-purpose submarine “Belgorod” under Project 09852 KS-139. The new submarine is expected to be put into service by 2020.

Many years of efforts applied by developers, engineers, the whole industry and the Ministry of Defence allowed to form and equip a new branch of armed forces – the deepwater special operations forces, which include some large nuclear carrier submarines, carrier submarines for small-size bathyscaphes and unmanned underwater vehicles, plus the fleet of nuclear deepwater stations and a wide range of various auxiliary underwater equipment. For now, this is Russia’s top priority in the field of naval research and development.


New defence order. Strategy | 05 | 2018

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