Australia Not Buying Astutes as AUKUS Sub: Safety

October 29, 2021 photo of HMS Astute (above) docked at Australia's Fleet Base West, Western Australia. The British High Commissioner to Australia, Vicki Treadell (light blue mask) is standing in the centre. (Photo: Commonwealth of Australia via Overt Defense)

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The Australian government has conjured up photo opportunities (one above) which could be considered to imply Australia will be acquiring an Astute-class SSN as its "AUKUS submarine" quite soon. 

But, due to nuclear training of Australians requirements, such an acquisition could only be fully Australian crewed in 15+ years. If you throw in a "must be built in Adelaide" requirement, then 20+ years from now. A delay of 15+ or even 20+ years would be too late for a UK-designed Astute-with-PRW2-reactor production line in the UK and/or Australia.  

You'll note that the UK designing most of "Australia's" AUKUS SSN (especially the hull) is taken as a given by sub watchers. In that regard see the photo of a UK design (yes an Astute, with no US Virginia in sight) on Australia's (AUKUS) Nuclear-Powered Submarine Task Force website. 

Meanwhile the Combat System (30-40% of the build) will be very likely integrated by Lockheed Martin. Lockheed Martin had been the designated Combat System integrator for the Attack-class, up until September 2021.

Other reasons Australia is not buying the UK's Astute-class SSNs.

-  The Astutes' general obsolescence by the late 2030s. 

-  Also see the UK shipyard built Astute-class's "cost overruns and delays". 

The major specific reason Australia is NOT buying the Astute is the Astute's PWR2 reactor and in connection with that, safety. The PWR2 (on UK Vanguard SSBNs as well as the Astutes) will not only be obsolete by the 2030s, but there are safety concerns that now cannot be fully reversed. 

A submarine reactor is the most expensive and safety sensitive component of a nuclear sub. You basically build a submarine around the reactor. Even fitting a new, safer reactor to an Astute class sub would change so many things (eg. the whole submarine's  dimensions, displacement, reactor management electronics, buoyancy and "quieting") that it would fundamentally be a new submarine - with a new name. 

The authors of Wiki report that, by 1997, the UK realised: 

“the size of the Rolls-Royce PWR2 required a much larger [SSN, in terms of] (width and length) and significantly improved acoustic quieting. A new understanding was reached between the [UK Ministry of Defence] and GEC-Marconi that this would be an entirely new class [called Astutes], and far more complex than originally envisioned.^[8]"

PWR2 Safety

The authors of Wiki further report:

"A safety assessment of the PWR2 design by the [UK] Defence Nuclear Safety Regulator in November 2009, was released under a [UK Freedom of Information] request in March 2011.^[8][9] The regulator identified two major areas where UK practice fell significantly short of comparable good practice, loss-of-coolant accident and control of submarine depth following emergency reactor shutdown.^[10][9] 

The regulator concluded that PWR2 was "potentially vulnerable to a structural failure of the primary circuit", which was a failure mode with significant safety hazards to crew and the public.^[9][11]

In January 2012 radiation was detected in the PWR2 test reactor's coolant water, caused by a microscopic breach in fuel cladding. This discovery led to HMS Vanguard being scheduled to be refueled early and contingency measures being applied to other Vanguard and Astute-class submarines, at a cost of £270 million. This was not revealed to the public until 2014.^[12][13]"