Nuclear submarines, unlike diesel-electric boats, can be used underwater. They are larger and require a greater infrastructure. They are usually required to be overhauled on site for two years before they can resume their service. They require storage for used fuel.
Nuclear submarines typically use highly enriched uranium (HEU) as their fuel. HEU, one of the most harmful metals on earth, is also one of the most dangerous. It is also one of the simplest materials to work with. HEU is not required to be replaced throughout the life of a submarine. It is possible for poisons in fuel to build up. This could cause fuel efficiency to drop. Some poisons can be removed by burning.
Nuclear submarines have used several types of reactors. Some of the earliest were PWRs, which were built by Westinghouse. Rolls-Royce further developed these PWRs. They were designed for Royal Navy submarines. They are built to last between 30-40 years.
Later, lead-bismuth cooled reactors became available. These were later used to make submarines. These designs were tested on the K-27 which was an experimental precursor to the Alfa class. However, the experimental reactors were found to have problems, and the submarine was laid up at Gremikha Bay.
In the 1960s long-range antisubmarine rockets were created. These were submerged to launch the missiles, and were designed to be able to hit targets in far away regions. They had a striking range of about 2,500 miles.
There have been over 100 nuclear submarines that the United States has used. The US Virginia-class submarines usually have HEU. HEU is used on the US's other submarines such as the Virginia-class, Skipjack and Dreadnought. A burnable poison can be added to the core to extend its life. Only the US and Britain use HEU to power their naval reactors.
The United States has been involved with Australia and the UK in security alliances over the past few years. The alliance is designed to counter China. These three countries share a common point of view in security matters. In order to develop a security alliance, they have signed a new security pact. This agreement will allow Australia become the seventh world-class nuclear-powered submarine. It will also give Australia the opportunity to receive US technology.
Australia will end its multi-billion-dollar submarine contract with France and enter into a new security agreement with the United States of America and the United Kingdom. This deal will enable Australia to become the second country to receive US nuclear submarine technology.
Australia will receive diesel-powered subs that are complementary to the US's nuke submarines. These submarines are able to operate in tandem with the US/UK, since Australia has no domestic nuclear power sector. It is anticipated that the subs' majority of work will be done overseas.