Also, a recent rethink of the safety of the German AVR has also taken some luster off of the PBR concept.

Will there be a web site to track progress on the plant? This may seem like a crazy question, but the first two European "new build" plants, Olkiluoto 3 and Flamanville 3, both have web sites.

I don't have time to search for the exact reference or the numbers, but there was a European study of the total life cycle environmental costs, including CO2 and other pollutants, of various energy technologies. In terms of CO2, hydro was lowest. Nuclear, solar, and wind were roughly the same. (I believe nuclear was computed two ways, once with gaseous diffusion--still used, but being phased out--for enrichment and once with gas centrifuge. Gas centrifuge produced lower CO2 emissions, but neither figure was astoundingly high.) I believe nuclear (and wind and solar) come in at around 6% of coal. The concrete and steel use in a nuclear plant was taken into account in the study, as were emissions from mining. There is also a Swedish environmental report with similar conclusions.

As for what percentage CO2 reduction in US power plant emissions could be expected, that would depend on how much of the new capacity replaced gas, and how much replaced coal. Any (expensive) gas used for base load would be the first candidate for replacement. That would reduce the impact on CO2 because baseload gas fired plants, expecially the combined cycle plants most useful for base load generation produce less (half?) the CO2 per unit of electricity generated of coal plants, though still far more than nuclear plants. Once you cut into coal, which produces about 50% of US electric power, you see some serious CO2 savings.

Two other comments:
The statement was that there would be a 30% reduction in emissions from POWER plants. I think electric power plants only account for about half on US CO2 emissions, so you would only get a 15% or so reduction in overall CO2 emissions.
From your question, I suspect you are being misled by a discredited Dutch study which claims ridiculously high CO2 emissions for both nuclear plant construction and uranium mining.

...just as the current cold winter in North America canNOT be considered as casting douby...

More fundamentally, no one drought can be directly attributed to global warming, just as the current cold winter in NA can be considered as casting doubt on global warming.

Over time, global warming may make droughts such as the one that exacerbated the current AU fire situation more common. During the change, the vegetation left over from the wetter period before global warming will result in some spectacular fires, but it will only be in hindsight that we can say fires were a result of the change.