A nuclear-powered submarine is capable of remaining deep submerged for a limited period of time only by the capabilities of the crew on board. It uses an electric motor powered by a nuclear fission reactor which, in addition to autonomy, determines the higher speed compared to conventional propulsions. It can therefore cover greater distances in less time, and be less detectable by the opponent’s radars, elements from which the ability to penetrate the opponent’s defenses derives. For these reasons, nuclear-powered submarines are considered by the great powers to be among the most relevant assets of force projection.
In 1955, between Florida and Connecticut, the first nuclear-powered submarine in history was submerged in the sea: the Nautilus. The studies had begun about eight years earlier, when the US Navy saw the possibility of increasing the capabilities of the submarine fleet by resorting to nuclear power. Since then, capabilities have greatly improved, fueled by the competition between the US and the USSR and the need for mutual deterrence (including nuclear).
Experts now divide nuclear-powered submarines into three categories: Ssbn, Ssn and Ssgn. The former are submarines used for launching nuclear ballistic missiles, an important part of the triad on which the capability of the great powers is based, and a central element of the stability guaranteed by the “second strike capabiliy”. The latter are attack submarines, the real “sharks” of the confrontation on the seas, devoid of nuclear weapons, with the main task of rapidly attacking the enemy naval forces (surface and non-surface) and defending their own; over time they have also been equipped with land attack capabilities. The Ssgns represent an intermediate category, with cruise missile launching capabilities.
The agreement announced by Joe Biden , Boris Johnsonand Scott Morrison is about the second category. The joint statement speaks of “nuclear-powered submarines”, subsequently specifying that “Australia remains committed to fulfilling all its obligations as a non-nuclear state”. The initial commitment, over a period of 18 months, will identify “an optimal path to provide this capability” to the Australian Navy, leveraging “the expertise of the United States and the United Kingdom”, building on “the submarine programs of the two countries to implement service an Australian capacity as soon as possible ”.
This program should allow Australia to join the small club of countries with nuclear-powered submarines, a capability currently only owned by the United States, Russia, the United Kingdom, China, France and India. For the USA, the current class of reference is Virginia, with about twenty units currently in service and another fifteen with purchase already defined, as part of a program of at least sixty units with an operational life of about thirty years. They will replace the Los Angeles class units (about thirty), already entering the decommissioning phase, alongside the Seawolf class submarines, limited to three units. Meanwhile, however, the United States is also thinking about the next generation of attack submarines, Ssn (X).
The second fleet of nuclear-powered attack submarines and the Russian one, with about 17 units currently in service, at least according to the numbers of the Nuclear Threat Initiative. These are Akula-class units, which entered service in the 1980s with anti-submarine and anti-ship capabilities. Over time they will be replaced by the Yasen class (in service since 2013) which, although categorized as Ssgn (given the significant missile launching capacity, including the hypersonic Zircon carriers), aims to replace the Akula and Antey submarines (these used as Ssgn). It also remains to understand how the new Belgorod nuclear-powered submarine, launched in 2019, will be categorized, the first capable of carrying the strategic Poseidon torpedoes, also nuclear-powered. The Poseidon would be configured as a sort of drone (or small submarine) capable of traveling in depth and at high speeds, carrying nuclear or conventional warheads. The Belgorod submarine carrying them (rumored up to six) could enter service this year.
As for China, the Nuclear Threat Initiative talks about six Shang-class nuclear-powered attack submarines, as part of a rapidly expanding fleet (like the entire naval component of the People’s Liberation Army). Similar numbers for the great dissatisfaction with the Aukus agreement, France, which deploys seven Rubis-class attack submarines in active service, entered into service starting from the 1980s, after the more determined start of ballistic launch capacity. Paris has however already launched the Barracuda class, with the first unit (Suffren) commissioned last year. This class had been chosen by Australia to replace the six Collins class submarines, based on the Swedish Vastergotland class and powered by a diesel-electric system.
The United Kingdom instead ranks the Astute class in the NHS category, still being completed to replace the Trafalgar class (seven united in all). The first element of the new category was declared fully operational in 2010. Shutting down the club is India, equipped with its Russian-supplied Chakra-II, Akula-class nuclear-powered attack submarine. This is a real ten-year lease that began in 2012. According to Indian media, New Delhi is currently trying to extend it and is in the process of negotiating with Moscow for a second unit.
