Some nuclear submarines for Australia exponents have suggested Australia consider leasing aging UK Trafalgar-class nuclear submarines.
Beware, submarine reactors and the complex pipes connected to them, wear out, sometimes needing urgent inspection.
Trafalgar-class Service Problems
"In 1998, [HMS] Trenchant experienced a steam leak, forcing the crew to shut down the nuclear reactor. [Trenchant had earlier had a seafloor accident off Australia's west coast in 1997].
In 2000 a leak in the PWR1 reactor primary cooling circuit was discovered on [HMS] Tireless, forcing her to proceed to Gibraltar on diesel power.[17] The fault was found to be due to thermal fatigue cracks, requiring the other Trafalgar-class boats, and some of the remaining Swiftsure-class boats, to be urgently inspected and if necessary modified.[17]
In 2013 the UK Defence Nuclear Safety Regulatorreported that the reactor systems were suffering increasing technical problems due to ageing, requiring effective management. An example was that [HMS] Tireless had had a small radioactive coolant leak for eight days in February 2013.[18]"
Thanks to UK Government Reporting via The Guardian and Wikipedia.