Some years ago I was at a seminar where Ziggy Switowski (then head of the ANSTO) was one of the speakers. From memory he thought that it would take Australia 20(?) years to develop self-sufficiency in the expertise required to support a nuclear industry i.e. be able to design, build, operate, then decommission, a nuclear power station. Presumably a slightly simpler set of problems than nuclear power plants in a maritime environment.
I assume the RAN will be using existing nuclear technology but, even if sailors are despatched tomorrow (or 'yesterday'?), I would imagine there will need to be a few British and / or US accents on the Australian submarines for some time. It may even be an ongoing requirement for Australia to get access to the technology.