In the first of a two-part series, Peter Briggs examines the technical and security risks of relying on highly enriched uranium and an unproven British reactor design for AUKUS submarines.

The political narrative surrounding the AUKUS submarine project anchors itself to a valid technical premise: that Australia will receive a sealed, life-of-type reactor, ensuring strict containment of its nuclear material throughout the operational lifecycle. However, this focus on the end product obscures two distinct, unexamined challenges on Australia’s waterfront: a demanding, early-stage industrial integration sequence, and Australia’s absolute dependence on an un-prototyped British reactor design.

Long before a domestic AUKUS submarine ever touches salt water, the construction line at Osborne, South Australia, must accommodate these complex realities. This brings forward the timeline for physical security, regulatory oversight and international safeguards frameworks well before the first hull modules are even joined, as forecast in the March 2023 AUKUS Nuclear-Powered Submarine Pathway.

Prior to initial criticality, a new naval reactor core generates no decay heat and produces no fission-product radiation, making it radiologically benign in an industrial environment. Consequently, the immediate industrial challenge at Osborne during assembly is not one of radiological containment, active shore-supported cooling loops or real-time telemetry. Instead, the burden is defined entirely by the stringent demands of physical security, strict chain of custody and international non-proliferation protocols.

Assuming SSN-AUKUS uses the standard manufacturing sequence followed in the US and UK, the reactor will arrive from Rolls-Royce UK, fully sealed as a self-contained unit encasing the fuel and control rods, shipped inside a robust transportation vessel. Shipyard personnel then weld the external pipework and slide the hull “tube” module over the reactor unit, creating a single, integrated hull section that is subsequently mated with other modules during final consolidation. The immense structural, safety and operational challenges of relying on these un-refuellable British architectures are highlighted by independent research submitted to the Parliament of Australia. Alternatively, the reactor could be imported within a completed hull section containing the reactor. The intended solution should be........

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