TechSSN-AUKUS, new generation nuclear submarine

SSN‑AUKUS, new generation nuclear submarine

HMS Ambush - Astute-class submarine
HMS Ambush - Astute-class submarine
Images source: © Public domain
4:52 PM EDT, October 6, 2023

AUKUS, an agreement made by Australia, the United Kingdom, and the United States, transforms previous declarations into concrete actions. An example of this is the decision to develop a new generation submarine by the BAE Systems corporation. What do we know about it and what will its capabilities be?

The AUKUS alliance, also referred to as the Pacific Triad, was formed amidst an international scandal. This resulted from the Australian authorities breaking an agreement made in 2016, under which Australia was supposed to order 12-16 submarines from France.

The plans assumed that for Australia's needs, the French company DCNS (now Naval Group) would redesign the Barracuda type nuclear submarines used by France and build a new version, equipped with conventional propulsion.

The budget for this ambitious program was set at 64 billion Australian dollars (approx. 42 billion dollars), and Australia's withdrawal caused an unfavorable reaction from France. However, breaking the agreement does not mean that Canberra is giving up on new ships. Units capable of threatening China's fleet will be built under the AUKUS agreement, and instead of a conventional power system, they will be equipped with a nuclear propulsion system.

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This means that Australia, which currently does not have any nuclear energy infrastructure (though it possesses 38 percent of global uranium resources and is trying to quickly train the necessary staff) - will be joining the exclusive club of six countries that are currently building and operating nuclear submarines.

Initially, this will be possible thanks to the three "interim" Virginia-class submarines acquired in the United States. Ultimately, the Australian navy is to operate eight future SSN-AUKUS submarines. Plans assume this will happen after the year 2040.

Part of the name of new units - SSN - is their brief description. SSN (Submersible Ship Nuclear) is a "hunter" nuclear-powered submarine, whose main objective is to combat enemy ships, also those underwater. Optionally - and this option will be used in the case of Australian ships - SSN class units can be equipped with cruise missiles for strikes on land targets.

AUKUS SSN Submarines

Information about the new submarines is - for now - very fragmented. Although Australia is making efforts for the greatest possible participation of its industry in the construction of new units, the main contractors will be British corporations BAE Systems and Babcock International.

The work will not be started from scratch - the new type of ships is supposed to be based on the British Defiance type, which is an evolution of the currently used Astute type ships. The new vessels are also supposed to draw from solutions applied to American Virginia-class units.

Preliminary technical data is provided by Sławomir Lipiecki from the magazine "Nowa Technika Wojskowa". The new ships will have a hull length of 364 feet and a width of 46.6 feet. They are expected to displace 9,000 tons and have a double-hull structure, allowing operation at depths exceeding 2,952 feet.

An important characteristic is to be corrosion resistance - the risk of corrosion should not occur until after 25 years of service. The ships are to be equipped with a nuclear propulsion with a core life estimated at 42 years and will not require fuel rod replacements during operation.

In addition to the nuclear propulsion, the units will also receive a backup drive in the form of two diesel engines, as well as an emergency APU system capable of maintaining the operation of the ship's systems in case of power cut off.

The propulsion is meant to provide the ability for stealth operations at speeds around 23-28 miles per hour, and at the same time offer the possibility of developing very high speed underwater, reaching 46 miles per hour (officially: above 34 miles per hour). The submarines will be armed - besides torpedoes - with UGM-109E Tomahawk Block V cruise missiles.

"AUKUS and the Polish matter"

In mid-2023, after many years of suspension, the Polish authorities returned to the Orka program. This program assumes the modernization of the Polish submarine fleet, and essentially replacing its outdated remnants, which is currently the only submarine ORP Orzeł.

The words of the head of the Polish Ministry of National Defense have become the basis for media speculation about Poland's intention to acquire nuclear-powered submarines. However, in the context of Poland's needs and the specificity of the Baltic Sea, which is the main area of operation for the Polish Navy, such a solution seems highly unlikely.

Significant competitors are manufacturers of conventional submarines equipped with air-independent propulsion.

Pros and Cons of Nuclear Submarines

Nuclear submarines are built and operated by six countries. These are China, France, India, Russia, the United States, and the United Kingdom. These countries have common characteristics.

This is a developed nuclear energy sector, ensuring scientific and technical support, but also related activities such as storing or processing used fuel. The second characteristic is a long coastline and access to the open ocean.

It is precisely these oceanic conditions that allow for the advantages of nuclear submarines. Often cited as their key advantage is the ability to stay submerged for a long time. Equally important is another characteristic - the ability not only to develop, but above all to maintain a high underwater speed for a long time.

This feature is of less significance on small bodies of water, but crucial when moving ships over distances measured in thousands of miles - the Royal Australian Navy is, among others, facing such challenges.

At the same time, nuclear submarines are not without flaws: they are louder than those with conventional propulsion, and the need to properly silence various mechanisms forces a large hull size. For this reason, nuclear submarines - even those that do not carry powerful intercontinental missiles - usually have larger sizes than their conventional counterparts.

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