– “So the reactors will come from USA or UK as will the required nuclear fuel. How will Australia deal with the nuclear waste?”
Presumably, removing spent fuel and refuelling will be done together. Either the subs will go somewhere for a fuel change (Diego Garcia perhaps), or they will rendezvous with some kind of service vessel which brings new fuel and takes away the spent rods. Or, if done in an Australian port, the spent fuel could be stored until taken for reprocessing.
The UK used to do this with Magnox reactors in various countries; spent fuel elements from all over the world went to Sellafield, earning the UK the nickname “the world’s nuclear dustbin”. The idea was that by selling reactors but retaining control over the fuel cycle the UK could make money and gain power, and build up a stockpile of plutonium. But the reprocessing facility at Sellafield got trashed in 1974(?) when the Magnox stations were run flat out to try and break the miners’ strike, leading the spent fuel pond, Building B30, to become the most contaminated site in Europe, gaining the nickname “Dirty Thirty”.