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  • Varun Rao

Australia severs the French Connection

by Varun Rao and Rahul Rao

The already murky world of geopolitical intrigue received a startling jolt last month when the leaders of Australia, the USA and the UK announced the AUKUS partnership. In a dramatic announcement, Australia’s Prime Minister Scott Morrison (“that fella Down Under”) cancelled a massive $90b contract with the French company DCNS to build 12 conventional diesel powered submarines in favour of nuclear submarines supplied by our new partners. The fallout has been immediate - our diplomacy with France appears to be severely damaged, and the Australia-China relationship has been strained further. Politics aside, what’s all the hoo-ha about, and why are nuclear submarines such a big deal?


First, the deal. While concrete details are scarce, broadly, the USA and UK will supply Australia at least 8 nuclear submarines over the next two decades or so. Thus equipped, Australia will join an elite club of only 6 other countries that operate these deadly machines of war - the USA, Russia, China, the UK, France and India - and will be the only one to do so without a domestic nuclear industry.

Second, the technology. All aspiring and actual maritime powers rely heavily on aircraft carriers and submarines. Conventional submarines are diesel-electric, an architecture broadly similar to some hybrid cars sold today. They run massive diesel engines that charge batteries, but these behemoths need to resurface for “snorkelling” - ingesting air to recharge their batteries.

Australia’s current Collins class fleet of six submarines were the largest diesel-electric subs in the world when they were first commissioned in the late 1990s. Power is obtained from three massive 18-cylinder turbodiesel engines and three 1400 kW generators. They were originally scheduled for retirement in 2026, but have been granted a $6.4 billion life-of-type extension (more on this later). Typical speeds are a paltry 10 knots (19 kph) when snorkelling, and about twice that when submerged. These subs are generally sufficient for short-range operations, but projections of power far from home generally require the long range capabilities of their nuclear counterparts.

Nuclear submarines, on the other hand, derive their energy from splitting atoms of nuclear fuel, such as highly enriched uranium (HEU), in on-board nuclear reactors (see our detailed description here) to generate heat, which is used to convert sea water into steam. The steam is made to rotate a set of turbines, resulting in the generation of electricity.

The main advantage of nuclear submarines is their ability to stay submerged for long periods of time, limited by the requirements of their human operators rather than fuel supplies. In theory, no refuelling is required over the life of the submarine. In Australia’s case, it is estimated that this capability would allow the Royal Australian Navy to deploy its subs for roughly seven times longer than its existing fleet.

They are also whisper quiet, relatively speaking, so quiet in fact that in 2009 French and British submarines collided into each other; bizarrely, the French navy did not even know what its sub had made contact with. Nuclear subs are fast, achieving around 25 knots when submerged or on the surface. Unlike their diesel-electric counterparts, which must trade-off speed and fuel consumption, they are not constrained by energy consumption considerations.

This infographic compares the days on station for a nuclear-powered submarine versus a conventional one [source].

It’s not all wine and roses though. Nuclear submarines tend to be larger than their diesel counterparts, which presents problems in shallow waters. There are also legitimate concerns around maintenance and repair, both requiring highly specialised skills that are scarce in Australia. Significant repairs will involve dry docking, shutting down the nuclear reactor, and then restarting it, all of which requires a local industry that we do not currently possess.

Then there is the issue of timing. The new nuclear subs are not likely to hit the water until the late 2030s, or even 2040 (marginally later than the abandoned French deal). Our current Collins class boats will be well into their fourth decade of service by then, a full 50% longer than their design life. This leaves a gaping capability hole in Australia’s strategic defense capabilities, one that will be only too obvious to our adversaries. The table below, prepared by Marcus Hellyer of ASPI, shows just how tight the timelines are. There is little-to-no overlap between the two fleets, suggesting an uneasy, protracted transition lasting a decade or so.

An uneasy transition between the Collins class boats and their nuclear replacements [source].

Some of this deficit could be filled by leasing a nuclear sub from the UK or USA as a stop-gap measure. Convivial relationships notwithstanding, it is unlikely either country would part with their crown jewels - the Virginia and Astute classes respectively. Realistically, our options are limited to the aging Trafalgar and Los Angeles fleets. Even so, the operational difficulties of maintaining an orphan fleet of superseded boats is not an appealing prospect, particularly given our lack of a local nuclear industry.

An even more unappealing prospect is that of a second life-of-type extension for our existing Collins fleet, hinted at by Vice Admiral Mike Noonan to a Senate hearing on October 15, 2021. Technical limitations of the second overhaul aside, if Australia goes down this route we will be fielding a fleet of 50 year old boats against the vastly superior arsenals of our maritime rivals.

Concluding remarks

Our shiny new submarines with (nominally) set-and-forget nuclear reactors will be significantly faster and more capable than our increasingly less credible Collins class boats. When this fleet is operational, Australia will be punching well above its weight in the region. Nonetheless, it is difficult to brush over the questions around timing - caught between a rock and a hard place, a capability gap seems inevitable for the first half of the 40s.

The AUKUS partnership is a watershed moment in Australia’s history, a rapid volte-face for a nation that has so vehemently opposed any local nuclear activity despite containing the world’s largest uranium reserves. It is also likely to eventually reignite the debate on nuclear power, sometimes touted as the quickest, cleanest way to reduce carbon emissions (while reserves last).

We've previously described some deadly creatures of the deep sea. It looks like Australia is about to add a few more.


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Disclaimer: This article is based on our personal opinions and does not reflect or represent the views of any organisations that we might be associated with.


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