Nuclear being "problematic" is vastly overblown. That's why I think the answer to the title is a resounding no: we still have a lenthy nuclear buffer before a proper energetic collapse, so at the very least it is not imminent.
https://www.reddit.com/r/dredmorbius/comments/2awjj2/thought...
The issues are multiple, many are not technical in nature (which means that the solutions are also not technical in nature).
Among them: risk, particularly systemic risk (not strictly limited to fallout or acute plant operational scenarios -- think Japan stressing its grid and industrial capacity following Fukushima), scale (Derek Abbott, "Is Nuclear Power Globally Scalable", IEEE), Proliferation, the 10,000 year perspective (language, cultures, institutions...), credibility.
The near-term prospects are also not great. For once-through conventional plants, there's about an 80 year fuel reserve, 6 if we go all-out nuclear. Advanced thorium designs aren't proven and are likely 20-25+ years from deployment (those are ambitious Chinese estimates). Controlled energy-positive fusion strikes me as a "never going to happen" option, and quite likely with even greater systemic risks than fission (fission reactions aren't that hard to make happen, fusion is very hard). I'm aware of claims that uranium can be extracted from seawater -- that strikes me as possibly but not hugely credible.
And nuclear fails (of and by itself) to address numerous other concerns, notably a liquid fuels replacement, or scarce minerals availability -- humans are running short of numerous resources, not just energy.
It's also worth noting that one of nuclear's harshest critics was one of its most effective engineers: US Navy Admiral Hyman G. Rickover, father of the nuclear navy.
http://www-pub.iaea.org/iaeameetings/cn216pn/Thursday/Sessio...
Pro: Cost data are provided (but without comparison to existing uranium mining costs). Quick check suggests that recent prices are on the order of $83/kg, vs, > $1,000/kg given in the study.
http://www.indexmundi.com/commodities/?commodity=uranium
If I'm reading that correctly they're delivering 1 kg of natural (non-enriched) uranium for about $1,000. The energy value delivered by that (at $0.09/kWh) is around 1,000x greater, which is a good thing.
Con:
This appears to be largely theoretical, there are no large-scale deployments, and questions of viability, durability, maintenance, recovery (of both filtration material and uranium from it), etc., isn't given. This is very immature technology (See: http://redd.it/24sdvf).
For building out infrastructures we'll be needing likely within a few decades, if not earlier, that's not much lead time.
I'd really like to see some field-trial data and comprehensive cost and durablility discussion. Marine environments are harsh.
I haven't tried to figure it out very carefully, but I imagine the cost estimates include production, deployment and collection of the harvester material, and that the degradation of the material is factored in (it wouldn't be all that surprising if the estimates treated it as disposable after 1 or few uses, because that is an easy way to make a conservative estimate).
Assume good faith.
As with risks, there are issues in how costs are computed in that for much of the present economy they're predicated on underpriced fossil fuels. Another longer discussion I don't have time for here, but it's something Charles A.F. Hall discusses in his analysis of the Cobb-Douglas production function.
I am MUCH more scared of a nuclear war breaking out over diminishing oil resources than I am about peaceful nuclear energy. That would be mankind's biggest and worst irony.
IMHO, it is bordering on insane to not consider peaceful nuclear energy as someone who is keen on saving the planet.
Sure, conserving, saving, making everything more efficient is fine and laudable. But one still has to support the energy needs of some 7e9 people.