Actually the article has a section devoted to environmental reasons why nukes aren't sustainable.

USA will have to go balls out on Nuclear and Wind to prudently use what fossil fuels are left; transportation will bear the blunt. This along will be enough to sink the economy; probably around 2010, we'll go into a recession and when it starts to rebound likes it has for the last 1/2 century, this time it will not be unable to. Thus, the stair stepping to a depression will commence.

eric_b:

Why? We functioned for centuries with far lower energy intensive economies, and the costs for building nuclear reactors are well defined and affordible. Supposing we somehow went on a deflationary spiral into a depression, sure we'd build less of them at first but eventually economic cycles swing up after the infrastructure adjusts. Certainly we aren't at the apex of civilization barring real cataclysm (major asteroid impact is the only thing I can think of that would absolutely end it.)

If you are talking about the intermediate time frame when oil shortages have the potential to shock the economy in potentially destructive ways, we can argue about how destructive such shocks will be, but they definately dont spell 'powerdown' of civilization or any other such nonsense.

shakespear1:
Yes. They are interesting because they have higher burnup than most LWR's and high operating temperatures, meaning higher carnot efficencies. Also their modular designs imply good economics.

But they do have some worrying features: containment buildings are just avoided in most designs, so if there is a serious accident it isn't contained. Also the pebbles are carbon coated for neutron moderation, which means that if there was some loss of coolant accident that pulled oxigen into the coolant loop, you have graphite fires that burn a la Chernobyl. The pebbles have a knack for getting stuckin the feeders/hoppers, they are difficult to reprocess, and the waste stream is volumentrically larger than LWR's.

They aren't really better or worse than LWR's, you just tradeoff some risks/costs and benifits. But you can make pebble bed reactors without neutron moderators for fast reactors for doing actinide burning if you like.