Nuclear powered submarines (SSN) are not required to defend Australia. They are only needed to attack other countries near their coast.
The likely target countries for these nuclear-powered submarines to attack are China and Russia. Both are surrounded by shallow waters filled with sophisticated sensor systems which will expose large submarines however they are powered. China and Russia will continue to have far more powerful militaries than us and so any attempt to blockade their ports will result in decisive retaliation.
SSN could be useful in deterring a blockade of Australia by China, but China could still blockade Australia using long-range anti-ship missiles and its own nuclear submarines. And Australia won’t have the SSN’s for a decade or more.
As per previous posts, advanced diesel fuel cell submarines (SSK) operating from ports around Australia are a far more efficient way to defend our nation. This capability is far cheaper and quicker to build, and conventional submarines are quieter and harder to find. Large nuclear submarines will be hard to operate in the shallow Timor and Arafura Seas.
The main advantage of nuclear power is that a submarine can be faster and larger than fuel-cell submarines. Endurance is still limited by food supplies and so is not much greater than a fuel-cell submarine. The larger and faster a submarine is the easier it is to detect – all other technology being equal. SSN’s emit heat which is more detectable in shallow waters.
If SSN’s are to be built in Australia, they should be an exact copy of an existing proven design – not another bespoke design which always blows out the cost.
Presumably the reactor and other propulsion systems would be shipped in from the USA or UK. Note the reactors (S9G?) will use weapons grade Highly Enriched Uranium (HEU) fuel so the reactor does not have to be refuelled for the life of the submarine – up to 30 years.
The only positive from today’s revelations is that this is potentially a step up from the bizarre idea to try and build bespoke long-range diesel submarines for $90 billion – but only if a proven design is used.
Large areas of the Arafura Sea and Timor Straight are too shallow to permit an SSN to operate submerged. (Google maps)
- USS Virginia SSN (Wikipedia)
- Benefits of small, quiet conventional subs over nuclear (ASPI, Hans J. Ohff, July 2017)
- Virginia vs. Astute SSN (Naval Technology, Talal Husseini, April 2019)
- The Feasibility of Ending Highly Enriched Uranium (HEU) Fuel Use in the U.S. Navy (Arms Control Organisation, November 2016)