> Is this Nuclear option just F.U.D. over renewables and storage so that investment dries up and fossil fuels remain to be used?
Pretty much.
The "plan" put forward by Dutton is pure vaporware - there are no costings, there is no agreement on using the peoposed sites, there is nothing planned about repealing an existing nuclear ban .. it's 100% kick the can of climate action down the road to some magical time when nuclear will be "off the shelf" and affordable in Australia.
The Australian scientific advisory have recently done a full report on realistic energy options, their costings for nuclear rely on things happening in the world that haven't happened yet and nuclear still comes in as the most expensive per unit energy - and that's being optimistic about the kinds of delays actually seen in the US and the UK.
Now, nuclear is working in South Korea, in parts of Europe, China has a 100 reactor plan and they're all in on construction of new reactors now.
Australia is different, smaller population, no existing nuclear power generation experience or skills - it's cold start.
The reality is that Dutton and many of the Liberal|National Coalition don't take climate change seriously and they simply want to build new coal fired power stations and extend current gas usage "until nuclear is cheap".
> So if Australia does not have something like a large base load of power (coming from Nuclear) it will get left behind in having large scale data centres onshore
Hardly - Australia mines minerals in the billions of tonnes per annum, easily dwarfing anything attempted in the US - these operations run 24/7/365 non stop and consume large amounts of energy.
Already the large miners, Rio Tinto, Fortescue, et al. are buying up cattle stations to convert to solar farms to generate power 24|7 - excess solar during daylight for direct power plus hydrogen and by product production, and gas turbines at night using daytime generation - the largest trains with the heaviest loads in the world are going electric, 100 tonne dump trucks are already electric (with onboard fossil fuel generators) and being converted to use batteries | burn gas, etc.
The same kind solar at massive scale that is planned to export power to Indonesia and elsewhere can power data centres if needs be - Adelaide is already powering smelters with renewables.