From an unexpected AUKUS (Australia, UK, and USA) declaration in September 2021, the immediate benefit of Australia is getting US nuclear-powered propulsion technology for submarines.

It has raised huge controversy about nuclear proliferation, especially when Australia remains an ardent supporter and global leader of the nuclear non-proliferation treaty (NPT). If the deal is finalized, then a non-nuclear-weapon country, Australia would be the first country to operate a nuclear-powered submarine.

From the evolution of the submarine and subsequently, with the technological development, the submarine remained a hidden threat out at sea. It is also a strategic asset to a nation. Its highly technical and costly to procure, even more, expensive to maintain.

Presently Australia is operating six ‘Collins”-class diesel-electric powered submarines. These submarines have limited capabilities at sea compared to a nuclear-powered submarines.

They are much quieter, have longer endurance, and can carry much higher payloads that would pose a formidable deterrent threat at sea.

Under the AUKUS deal, Australia would be getting eight (unconfirmed source) nuclear-powered submarines or technology from the USA and UK.  Until now, the USA has shared its nuclear propulsion technology with the UK only.

This nuclear propulsion has given rise to huge controversies, China and some regional countries of the Indo-Pacific see the AUKUS deal as nuclear proliferation.

The deal has many implications, such as nuclear reactor is critical to running and maintaining, and disposing of nuclear waste.  Also, it incurs more money, defence budget needs to increase which will be taxpayers’ money, as such, Australian citizens should be well aware and convinced the money spent is justified.

This deal also suggests a great shift in the strategic power balance in the Indo-Pacific region.  Let’s discuss a few basic concepts of why nuclear propulsion has given rise to controversies.

The submarine reactor can be of two types of fuel – HEU (Highly Enriched Uranium) or LEU (Low Enriched Uranium).  The danger is that the nuclear bomb is made of HEU.

LEU is not used for making nuclear bombs. Nuclear submarines are designed and operated for more than 35 years, and they may carry nuclear fuel (HEUs) for a whole period lifetime without refueling.

For example, the US’s Virginia Class submarine’s propulsion system is operated and designed to run by HEU fuel for the whole lifetime.  In general, a submarine needs about half a ton of HEUs.

So, Australia’s eight submarines require roughly 4 tons of HEUs. With this much of HEUs, 160 nuclear bombs can be made, most known nuclear nine countries don’t have such stockpiles.

The good news is that, unlike nuclear bombs, the submarine’s reactor does not require HEUs. Instead, it can be run by LEUs. Out of six countries operating nuclear-powered submarines, France and China are using LEUs for their submarine reactors and these LEUs are not suitable for making nuclear weapons.

Of course, they need refueling in the dockyard every 6 to 7 years, and, for France, it is ten years without hampering the submarine’s operation.


The USA is carrying out an experiment to use LEU for the lifetime of submarines instead of HEUs for the reactor intending to decelerate the proliferation of weapon-grade uranium.

Recently US Congress has approved $20 million to develop LEU as an alternative to HEUs to propel submarines and aircraft carriers. Of course, it needs to compromise the space to accommodate a larger reactor as compared to HEUs.

For a US Virginia Class submarine, the size of a reactor is roughly about 5 feet by 8 feet, and in the case of LEU, it would not be more than one and half times larger than the HEU reactor which can be well accommodated in 400  feet plus submarine.

Australia assures that nuclear non-proliferation remains a cornerstone. Australia is one of the first countries that used HEUs at HIFAR (High Flux Australian Reactor)  since the 1960s to produce radioisotopes for 50 years.

Intending to stop proliferation and considering it to be too dangerous, Australia, through a landmark decision,  decided to shift to LEU reactor OPAL (Open Pool Australian Lightwater) in 2007.  So, Australia is very much aware of the danger of HEU and pledged to remain a non-nuclear-weapon country.

Although a country like Australia is late to adopt nuclear propulsion in Submarine, getting nuclear propulsion technology through the AUKUS deal would be a quantum lift in naval technology.

Since the start of the COVID-19 pandemic, Australia felt the heat of external threats. Yet, Australia desires to remain a non-nuclear-weapon country and is likely to pursue other advanced technology like AI (Artificial Intelligence), hypersonic missiles, quantum, etc under the AUKUS deal.

Given the track record, Australia would choose the best option of no risk AUKUS proliferation for the submarines. The AUKUS working groups are now endeavoring to find out the best options suited for the Australian submarine.

The above discussion suggests best option for propulsion reactors is LEUs, not HEUs which can significantly reduce the risk of nuclear proliferation.