In the fifth of a six-part series on AUKUS infrastructure, the choice of highly enriched uranium raises questions about proliferation, safety, waste, regulation and the civil burden placed on Australian shipyards.

While Parts 1 through 4 of this series evaluated the physical infrastructure logjams and severe workforce deficits facing Henderson and Osborne, the most foundational flaw of AUKUS Pillar 1 lies in the choice of reactor fuel.

Under the current trilateral agreement, Australia is slated to acquire US Virginia-class and UK-designed SSN-AUKUS submarines powered by Highly Enriched Uranium (HEU). These reactors use weapons-grade fuel enriched to approximately 93 per cent Uranium-235. Each reactor contains between 200 and 500 kilograms of weapons-grade material, enough fissile material for dozens of nuclear weapons locked inside a single hull.

Advocates argue that HEU cores provide a “life-of-type” reactor that never requires refuelling over a 33-year operational span. However, this convenience comes at a significant strategic and civil cost: unprecedented non-proliferation precedents, heightened radiological hazards, extreme post-criticality safety liabilities and severe regulatory barriers that compound Australia’s domestic infrastructure crisis.

The non-proliferation precedent and IAEA safeguards

Transferring multi-tonne quantities of weapons-grade HEU across Australia’s planned fleet to a non-nuclear-weapon state creates a dangerous precedent in global non-proliferation architecture. Under Article 14 of Australia’s Comprehensive Safeguards Agreement with the International Atomic Energy Agency (IAEA), routine safeguards inspections are suspended while nuclear material is locked inside a military non-proscribed activity.

While Australia remains deeply committed to non-proliferation, utilising the Article 14 exemption to remove hundreds of kilograms of weapons-grade material from routine IAEA oversight creates a legal blueprint for threshold states to exploit. If other non-nuclear nations follow this precedent to withdraw enriched material from international monitoring under the guise of naval propulsion programs, global non-proliferation checks will be severely eroded.

Conversely, adopting a Low-Enriched Uranium (LEU) propulsion architecture – enriched to under 6 per cent U-235, identical to the fuel used in civil nuclear power stations – completely eliminates this proliferation liability. The French Navy (Marine Nationale) has operated LEU reactors........

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