Project 705

Project 705

Ship data country  Soviet Union Shipyard Admiralty Shipyard 196 in Leningrad Shipyard 402 in Severodvinsk Construction period 1968 to 1975 Decommissioning 1983 to 1997 Units built 7th

Ship dimensions and crew length 81.4 m (705) 79.6 (705 K) m ( Lüa ) width 10.0 m Draft Max. 7.6 m (705) 9.6 (705 K) m displacement surfaced: 2300 t (705) 2280 t (705 K) submerged: 3180 t (705) 3610 t (705 K)   crew 32 men

Machine system machine 1 × OK-550 - nuclear reactor 155  MW th (705) 1 × BM-40A core reactor 155 MW th (705 K) 2 × electric maneuvering drives with 100  kW each propeller 1 × five-leaf (main drive) 2 × double-leaf (maneuvering drive)

Mission data submarine Diving depth, normal 320 to 350 m Immersion depth, max. 400 to 600 m Top speed submerged 41.0 kn Top speed surfaced 14.0 kn

Armament 6 × torpedo tubes ∅ 533 mm Ammunition: 20 torpedoes and cruise missiles

Project 705 Lira (NATO designation Alfa class ) was a class of nuclear-powered submarines of the Soviet Union , seven of which were built between 1968 and 1972. Planned for attack and interception tasks, they should evade enemy defensive measures by increasing their depth and speed. Because of the use of various new technologies, this class is considered to be one of the most groundbreaking projects in Cold War submarine building .

planning

A Project 705 on May 23, 1984

The idea of ​​building a small and very fast military submarine goes back to 1959. The first design study was drawn up in April 1960 and the planning and construction permits were issued by the Soviet leadership in 1961, with the developers being granted an unusually high degree of planning freedom.

The prospect of working on a project that went far beyond the technical conventions of the previous submarine construction motivated numerous well-known Soviet scientists to collaborate.

The decision was made to build a submarine that would intercept enemy submarines as they left their bases and that would also have the ability to attack land-based targets with cruise missiles . The real innovation should lie in a previously unattained speed and diving depth. Using a single high-performance reactor driving a single shaft and the highest level of automation possible at the time, the size of the boat was reduced to just 3000 tons.

After the original plans included only twelve crew members, whose number should be sufficient to carry out short missions, the leadership of the Navy stepped in and increased the number. The degree of automation that was originally planned could not be fully achieved, and longer missions with failures among the crew had to be considered. In the end, 32 seafarers provided the standard crew for Project 705.

The low mass of the boats and the low-resistance shape of the outer shell, in combination with the drive, allowed maximum speed. An increase in the possible diving depth was also favored by the low mass of the boats: A high-strength titanium alloy could be used for the relatively small surface area of ​​the pressure hull . For this purpose, new production processes had to be developed under the direction of Igor Gorynin , because machining titanium is more complex than machining steel . The titanium alloy is light, pressure-resistant and has a low magnetic signature . Russian sources give the diving depth a maximum of 460 meters, while in the west it was initially assumed to be more than 800 meters.

The finished pressure hull was divided into six compartments, which were separated from each other by transverse bulkheads . The partitioning of the third compartment differed from the others because it was not vertical, but rather convex , in order to give the compartment the best possible resistance to water pressure - even if the neighboring compartments were already full of water. The command center, the mess with twelve seats and most of the accommodation were located here.

Another innovation was the escape capsule in the tower of the submarines. In an emergency, it could accommodate the entire crew, was locked, then part of the tower shell broke loose from the boat and floated to the surface.

Command center

While with older submarines a large part of the data relevant to the ship's command had to be reported to the control center via an on-board intercom , this data was brought together in the command center for the first time in Project 705. A large number of analog measuring devices were built in, as well as some black and white television screens showing certain analog measuring devices in real time, which were permanently filmed by cameras in other parts of the submarines. Studies had been carried out on the processes on board submarines and, in Project 705, attempts had been made to accommodate the soldiers who were on duty in the headquarters so that workflows and communication were as smooth as possible: the commander sat in the back of the headquarters the center, and all workstations were mounted along the outer walls. The more important a system was, the closer its station was to the commandant's seat.

A system for automatic control of the radiation level ("Alfa"), an early navigation system ("Sog"), a long-range communication system and a control and control system for the reactor unit of the boat were combined in the control center.

The control of the boats had also been supplemented by automatic systems: A control system for the automatic trim and one for stabilization in the event of depth changes supported the crew.

drive

The energy supply for the main drive of Project 705 was one of the core problems that the developers had to solve. The limited space in the small submarines forced them to find an unconventional solution: The submarines were powered by an OK-550 nuclear reactor (three steam generators and coolant pumps) with an output of 155  MWt, which was cooled with liquid metal (a lead-bismuth alloy ) and a turbo-electric drive on a shaft . Some submarines of the class received a different reactor model with the BM-40A (two coolant pumps and steam generator) and the identifier Project 705K to distinguish them . Both reactor types used around 200 kg of highly enriched uranium as nuclear fuel . The reactors had a service life of around seven years.

The lead-bismuth cooling liquid had a melting point of 124 ° C with a boiling point of 1679 ° C and was therefore able to dissipate much more heat from the reactor than water cooling could, with the same amount, so that the reactor complex could be much smaller and saved around 300 tons of water displacement during planning compared to a conventional reactor model. At the same time, the cooling circuits of the reactors therefore had to be constantly heated to over 124 ° C with the aid of steam generators in order to prevent the coolant from solidifying.

Two OK-7K steam generators each generated 15,000 kW from the steam from the reactor and transferred around 40,000  PS (29,420  kW ) to the shaft of the submarine. This accelerated the boats of the class for a short sprint up to 45 knots. 41 kn could be maintained in continuous operation. That was significantly faster than all NATO anti -submarine torpedoes could move, and thus a clear tactical advantage.

In addition, a 500 kW auxiliary diesel generator was available for the alternative energy supply in an emergency .

Until then, the electronic systems of Soviet submarines had a mains frequency of 50  Hz for alternating current . In Project 705, the frequency was changed to 400 Hz / 380  volts , so that smaller transformers could be used, which saved additional space in the narrow pressure hull.

As a maneuvering drive, each submarine of the class had two small electric motors with 100 kW each on the outer edges of the rear depth rudder. Each of these drives operated a small two-bladed propeller, with which the angle of attack of the blades could be automatically adjusted. The reactors were used on submarines between 1968 and 1997. The fuel rods were removed from the reactors between 1997 and 2007 and transferred to long-term storage facilities.

Armament

Project 705 with sensors extended in 1983. From left to right: Periscope, radar sensor, communication antenna and radar warning device are extended.

The ships had six torpedo tubes with a diameter of 533 mm, which, in addition to conventional torpedoes, could also launch anti-submarine missiles. SET-65 and SAET-60 torpedoes and RPK-2 “Wijuga” missiles were carried along . Sea mines of the types PMR-1 or PMR-2 could also be deposited via the torpedo tubes. A total of either 20 torpedoes and missiles or 24 mines were stored in the torpedo room.

The weapons were automatically lifted on loading arms in front of the torpedo tubes and then pushed into the respective tube by a hydraulic ramming device.

Sensors

The boats in projects 705 and 705K received a sonar system for use under water , which NATO code-named “Squid-Arm” (German: Kalmar -Fangarm). The system, actually MGK "Океан" (German: Ocean), consisted of a main sonar phalanx in the lower part of the submarine nose, with an integrated "Енисей" passive sonar (German: Jenissei) and a high-frequency sonar to warn of ice and mines . It was also suitable for fire control.

For use on the water surface, the boats had a retractable radar device with the code name "Чибис" (German: Kiebitz ), which worked in the X-band , combined with a radar warning system . This system was called "Squid-Head" (German: Kalmar-Kopf) by NATO and was able to locate the direction and intensity of intercepted radar signals. The commander had an observation / attack periscope of the "Signal" type.

rating

Tactical assessment and impact

assessment

Project 705 was a class of submarines with good performance; In addition to the unique top speed, the boats also had good maneuverability, which enabled them, for example, to turn 180 ° at a speed of 40 kn in just 42 seconds.

The class had one major disadvantage: the submarines were extremely fast, but they made a lot of noise under full load and were therefore easy to locate. The great depth might have been a significant advantage when using sonar, as Project 705 could use more thermal layers than potential opponents. However, this advantage only arose at low speeds.

Effects

The American secret services learned about the construction of the new class of submarines and the use of titanium in their construction through satellite monitoring of the shipyards.

The mere existence of submarines with such performance values ​​in the Soviet Navy primarily put pressure on the Americans and British, who in turn were forced to start research programs to counter this new threat to their submarines with ballistic missiles . They did not want to build their own boats with similar capabilities, as the enormous costs of submarines with titanium hulls could not be justified. That is why they started the development of appropriate weapon systems, which only years later led to the Spearfish , the Mark 48 Model 4 and finally the Mark 50 torpedo . At first, however, the appearance of the Alfa class caused a certain perplexity and dubious proposals, such as the dropping of atomic bombs that were to be detonated underwater in order to stop Project 705 in the event of a war.

Reactors

In particular, the reactor cooled with a liquid alloy was initially considered in the Soviet Union to be an elegant solution for several weak points that could occur in the otherwise used light water reactors :

• The high boiling point of the coolant, in combination with the low pressure in the primary cooling circuit, made explosions with subsequent release of radioactivity, which could occur when normal cooling water evaporated, extremely unlikely.
• The solidification of the coolant at temperatures below 125 ° C ensured that a possible leak in the cooling circuit closed automatically as soon as the coolant came into contact with the cold ambient air. A loss of the entire coolant due to a leak could thus be almost ruled out.
• No release of ²¹⁰ Po isotopes through escaping steam.
• No release of significant amounts of unstable iodine isotopes .

disposal

Since Project 705 was the only class of ships in the Soviet Union with LMC reactors (Liquid Metal Coolant), there were very few facilities for defueling the reactors and even fewer for treating "frozen" reactors with solidified coolant. The collapse of the Soviet Union in 1991 worsened the situation, so that two reactors with solidified coolant in particular could not be disposed of because the necessary systems were not available or were no longer operational.

First, in the 1990s, the Americans initiated various covert operations to secure highly enriched uranium (including those for reactors of the OK-550 and BM-40A types) from deposits on former Soviet Union territory that did not belong to Russia , and to Oak Ridge to prevent spread to terrorist groups and third countries that could have used them for nuclear weapons production.

Because of the highly enriched uranium in the reactors from three Project 705 submarines, international aid programs were finally initiated to bring the work to a conclusion. Since the last unloading of a reactor from a Project 705 boat took place in 1992, financial support from international partners and extensive planning work were necessary before the fuel rods were removed from the last three Project 705 reactors in Gremicha between 2005 and 2007 and put into a storage facility could be transferred.

units

K-64

The boat was laid down on June 2, 1968 in Leningrad . After being launched in April 1969, it was subjected to numerous tests in October 1970 in Severodvinsk .

On July 4, 1971, after a closure failed, super-hot steam was released in the reactor compartment. After a test drive and repeated tests in Severodvinsk, the boat was put into service on December 31, 1971. After a failure of the coolant circuit of the reactor in February 1972, the boat was decommissioned after a damage assessment. The coolant had solidified and the repair seemed too costly. The bow section of K-64 was cut off and in 1978 it was examined whether it could be set up on land for training purposes. The reactor compartment was sealed and temporarily stored. The bow section was also scrapped after a commission found that numerous systems were inoperable as a result of illegal cannibalization after the long layover.

K-432

The boat was laid down in Severodvinsk on November 12, 1968 and was part of Project 705K. After delays caused by the investigation into the accident on K-64, K-432 was launched on November 3, 1977. She took part in numerous exercises and missions and was decommissioned on April 19, 1990. After the fuel rods were removed from the reactor, it was scrapped in 1996.

K-493

The boat was laid down in Severodvinsk on February 21, 1972 and was part of Project 705K. After delays incurred in investigating the K-64 accident, K-493 was launched on December 21, 1980. It entered service in 1981 and participated in numerous exercises and missions. In 1984, the fresh air treatment system failed during an operation and the team had to complete the mission with CO ₂ filters from the emergency equipment. In 1985 there was another defect and radioactivity was released in the engine room. On April 19, 1990, K-493 was decommissioned and scrapped in 1996.

K-316

The boat was laid down on April 26, 1969 in Leningrad. K-316 was not launched until July 1974, following delays incurred in investigating the K-64 accident. It was subjected to numerous tests in Severodvinsk in October 1977. During a test drive, the control system malfunctioned and the machine could not be throttled to below 40 knots. It was finally put into service in October 1978. After participating in numerous missions, she was decommissioned on April 19, 1990 and scrapped in 1996.

According to American sources, the K-316 was the boat whose reactor froze in 1982 after the cooling system heater failed, and not, as according to Russian sources, K-123.

K-373

The boat was laid down on June 26, 1972 in Leningrad. After being launched in April 1978, it was subjected to final tests in Severodvinsk in 1979. After numerous missions, it was decommissioned in April 1990. However, there was evidence that the boat had not yet been scrapped in 2001.

K-463

→ Main article : K-463

The boat was laid down on June 26, 1975 in Leningrad. After being launched in April 1981, it was subjected to numerous tests in Severodvinsk and put into service on December 30, 1981. After participating in several exercises and operations as part of the standby fleet, K-463 was decommissioned on April 19, 1990. The boat was scrapped near Severodvinsk and the sealed reactor compartment was first towed to Sajda Bay for interim storage.

K-123

→ Main article : K-123

The boat was laid down in Severodvinsk on December 29, 1967 and was part of Project 705K. After delays caused by investigating the accident on K-64, K-123 was launched on April 9, 1976. After the final inspection, it entered service on December 12, 1977. On March 15, 1982, one of the steam generators that kept the reactor coolant in a liquid state failed. The repair efforts failed and on March 18, the generators failed on the high seas, so that the lead-bismuth alloy used for cooling solidified and made the entire reactor unusable. The boat had to be brought in. It was laid up and, after a decontamination phase of one year, provided with a new reactor compartment in December 1983 and launched again in November 1989. It was decommissioned on July 31, 1996. The fuel rods were removed from the reactor in 2006 and the boat was scrapped. The reactor compartment was sealed and towed to Sajda Bay for interim storage.

Evidence and references

Remarks

1. ↑ The number was increased again later when the boats were in service and reached over 40 men for some boats.
2. ↑ According to American publications from the Cold War, an Alfa could be heard under full load in 1980 in the North Sea as far as Bermuda , as described in The threat inside the Soviet military machine by Andrew Cockburn, 1984, ISBN 0394723791 , p. 426.

Individual evidence

1. ↑ ^{a b} J. Apalkow: Корабли ВМФ СССР. Многоцелевые ПЛ и ПЛ спецназначания. P. 25.
2. ↑ deepstorm.ru, Project 705 , viewed June 5, 2011
3. ↑ Project 705 on atrinaflot.narod.ru, viewed on June 5, 2011 ( Memento from August 31, 2011 in the Internet Archive )
4. ^ ^{A b c d} Norman Polmar, Kenneth J. Moore: Cold War submarines: the design and construction of US and Soviet submarines, 1945-2001. Pp. 142 and following.
5. ^ Stan Zimmerman: Submarine Technology for the 21st Century. P. 129.
6. ↑ Article on the technology of the command center of WA Sobakin at legion.wplus.net, viewed June 6, 2011
7. ^ Peter Lobner: Marine Nuclear Power 1939-2018. Lyncean Group, 2018. pp. 91–92.
8. ↑ ^{a b} legion.wplus.net, viewed on June 5, 2001
9. ^ Norman Friedman: The Naval Institute guide to world naval weapons systems, 1997-1998. P. 605.
10. ^ The New Encyclopaedia Britannica. Volume 29, p. 607.
11. ↑ Hearings before and special reports made by Committee on Armed Services of the House of Representatives on subjects affecting the naval and military establishments, Committee on Armed Services, Procurement and Military Nuclear Systems Subcommittee, United States, Congress, 1980, statement by Admiral Rickover , P. 26.
12. ^ JR Hill: The Oxford illustrated history of the Royal Navy. P. 421.
13. ↑ PDF on iaea.org, Sources of Radioactive contamination by Thomas Nilsen, Igor Kudrik, Alexandr Nikitin, 1996, pp. 34 and 35.
14. ^ John M. Shields, William C. Potter, Dismantling the Cold War: US and NIS Perspectives on the Nunn-Lugar Cooperative Threat Reduction Program. P. 345 and following.
15. ↑ Major achievements and current state of activities under the Russian Program for Comprehensive NPS Dismantlement and Remediation of Radioactively Contaminated Sites, Viktor Akhunov, iaea.org, 2007, viewed on June 6, 2011 (PDF file; 439 kB)
16. ↑ K-316 at Deepstorm.ru, viewed August 3, 2013
17. ↑ Alfa class Attack Submarine (Nuclear Powered )
18. ↑ K-373 at deepstorm.ru, viewed June 5, 2011

literature

• J. Apalkow: Корабли ВМФ СССР. Многоцелевые ПЛ и ПЛ спецназначания. (For example: Ships of the USSR - multipurpose submarines and special submarines. ) Saint Petersburg, 2003, ISBN 5-8172-0069-4 (Russian).
• Alexander Antonov, Walerie Marinin, Nikolai Walujew: Soviet-Russian nuclear submarines. Berlin 1998.
• Norman Polmar, Kenneth J. Moore: Cold War submarines: the design and construction of US and Soviet submarines. Brassey's Verlag, 2004, ISBN 978-1-57488-594-1 (English).
• Stan Zimmerman: Submarine Technology for the 21st Century. Trafford Publishing, 2006, ISBN 978-1552123300 .
• Norman Friedman: The Naval Institute guide to world naval weapons systems, 1997–1998. US Naval Institute Press, 1997, ISBN 9781557502681 .
• JR Hill: The Oxford illustrated history of the Royal Navy. Oxford University Press, 2002, ISBN 978-0198605270 .
• Norman Polmar, Kenneth J. Moore: Cold War submarines: the design and construction of US and Soviet submarines, 1945-2001. Free Press, 2003, ISBN 978-1574885941 .
• John M. Shields, William C. Potter: Dismantling the Cold War: US and NIS Perspectives on the Nunn-Lugar Cooperative Threat Reduction Program. The MIT Press, 1997, ISBN 978-0262691987 .

Web links

• Project 705 at deepstorm.ru (Russian)
• Project 705 at legion.wplus.net (Russian)
• Alfa class (English)