The nuclear technology behind the Australian Aukus submarine deal



Australia’s decision to tear up its $ 90 billion deal with France for 12 diesel-powered submarines, and opt instead to build nuclear-powered ships with Britain and the United States , is a historic moment for Asia-Pacific geopolitics and the global defense industry.

The new submarines will perform much better than the initially planned fleet and could represent a boon for defense contractors in the UK and America.

Propulsion: diesel vs nuclear

The main difference between the French-built submarines and the new submarines on offer is the propulsion technology they will use. French ships – based on that country’s nuclear-powered Barracuda class – were to have electric motors charged by diesel engines.

One of the advantages is that diesel-electric submarines tend to be smaller and can run quietly by turning off the diesel engine and relying on battery power. One downside, however, is that boats have to resurface regularly to run their diesel engines so that the batteries can be recharged – an operation known as ‘sniffing’.

Nuclear-powered submarines, on the other hand, are built for endurance. They have a reactor that generates electricity that powers the electric motors and drives the propeller; alternatively, the heat from the reactor is used to create steam which turns the turbines.

Australia initially opted for diesel-electric submarines to replace its own fleet of conventionally powered Collins-class boats.

Defending Australia’s decision this week, Scott Morrison, the Australian Prime Minister, said he told French President Emmanuel Macron in June that there were “very real issues as to whether a capability under- conventional navy â€would meet Australia’s strategic security needs in the Indo-Pacific.

Choosing to go nuclear, however, will not be without challenges given Australia’s lack of critical infrastructure.

“All of the nuclear infrastructure you need is very expensive – the people, the safety devices and the mooring facilities, to name a few,†said Trevor Taylor of Royal United Services. Institute, a British think tank.

Stealth and detection

The biggest advantage of nuclear powered submarines is that they can stay submerged and remain stealthy for much longer. Conventionally powered vessels do not have the same range without exposing themselves to detection when returning to the surface. Nuclear powered submarines can carry enough fuel for up to 30 years of operation and only need to return to port for maintenance and supply.

Nuclear-powered submarines are “the most complex machines humans make, even more so than the space shuttle,” according to a defense expert. “You have a nuclear reactor in the back, high explosives in the front and in the middle, a hotel, where people live, and it all goes underwater for months at a time.”

It is not yet clear what type of design Canberra will choose. However, it is likely to be based on either the British Astute submarines, built by BAE Systems, or the US Navy equivalent, the Virginia class, built by the US General Dynamics Electric Boat and Newport News Shipbuilding. .

One of the key questions will be how much of the silent operation and sonar technology of their fleets the British and Americans are going to give to the Australians.

Weapon capacity

Australia will also significantly increase its weapons capabilities under the tripartite agreement.

Richard Fontaine, head of the Center for a New American Security, said Australia would deploy conventional missiles on the submarines, which had larger payloads than the weapons that would have been on French ships.

The decision to acquire Tomahawk missiles – which can be fired from ships or submarines – also marks a major addition to Australia’s capabilities.

“The Tomahawks transform a Navy surface vessel into a strategic asset that can target military installations ashore thousands of miles away. This new payload will significantly improve the conventional strike power of the Australian Navy, â€said Eric Sayers, defense expert at the American Enterprise Institute.

Sayers said the move was part of Canberra’s trend towards adopting joint ammunition with the United States, including anti-ship weapons such as the MK48 torpedo and LRASM, a missile that can be launched from a F-18 fighter plane.

The Tomahawks would give Australia more capabilities to strike targets in China in any conflict, which is important because the United States and its allies would have less military means off the Chinese coast than the Chinese military.

“The Tomahawk opens the door to long-range strikes against ground targets, such as the destruction of integrated air and missile defense systems or aircraft hangars,” Sayers said.

US Virginia-class nuclear submarine

Virginia class submarine

Who will build the new submarines?

UK Prime Minister Boris Johnson may have spoken of the potential impact on UK industry, but defense executives said it was too early to say what the deal could mean for contractors. country.

Nonetheless, there should be some advantages.

Sash Tusa, analyst at Agency Partners, said that a “defense equipment program of more than $ 50 billion, even spread over, say, 20 years, should produce winners, especially since Australia is linked to the United States and the United Kingdom. It does not have a nuclear industry of its own and will therefore require many decades of significant support, including direct nuclear fuel supplies. “

BAE, which builds submarines for the Royal Navy at its Barrow-in-Furness site in Cumbria, north-west England, occupies a privileged position. The company is already building a version of its Type 26 frigates for Australians at a new shipyard in Adelaide. Rolls-Royce, which supplies the propulsion systems for British submarines, could build reactors for the Australian fleet.

Taylor de Rusi points out that despite Britain’s problems with the Astute program, which was hampered by delays and increasing costs at the start, the submarines are cheaper than their American counterparts.

How long will it take?

Australian Morrison said this week he expects the first nuclear submarines to be built in Adelaide by 2040. Much can still go wrong; building submarines is a huge undertaking and most programs are known to be behind schedule and over budget.

Britain’s new Astute submarines may be state-of-the-art, but their acquisition is a sobering reminder that things will take longer – and cost more – than originally anticipated.



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