In the context of this article's thought experiment, fission's probably out of the question.

However, for other scenarios, it is indeed a viable option, considering that it's statistically the safest (last I checked), very clean, and packs a high energy density.

The problem, though, is that fissile material is subject to a lot of the same availability problems as fossil fuels (if not worse), plus quite a few safety concerns (particularly when it comes to radiation, though coal mining poses this sort of risk, too). The energy density is much better, so we could probably get by for a very long time (especially with things like breeder reactors, increased use of thorium instead of or alongside uranium or plutonium, etc.), but ultimately, we'll need to transition to something like fusion power at the very least.

Fissile material is easily available. Current prices just make exploiting most reserves uneconomical.

I am not sure what time spans you speak about. Thousands of years is possible on fission with current technology and at current levels of demand.

Easily available in what context, though? To us in the modern day, yeah, it's probably pretty trivial to mine such nuclear fuels, but the article discusses a lack of that technology.

There is less fissile material than fossil fuels. And the reactors are huge and heavy. Thousands of year maybe at current consumption levels, not if all energy consumption was replaced with nuclear.

The article's thought experiment is useless, it's not even internally consistent. He imagines a world where we could be able to collect old solar panels, but all knowledge is lost. Now what on earth is going to destroy every library in every town all over the earth, but leave solar panels on the rooftops intact? A single small-town library would contain huge amounts of useful knowledge. If we include the knowledge contained in the heads of the survivors, the only realistic way of losing all (or even most) useful knowledge is killing everyone.

"A single small-town library would contain huge amounts of useful knowledge"

I can envision a future where libraries have few books. Here's one at a school in Florida - http://www.reuters.com/article/2014/08/25/us-usa-florida-lib... . Here's a broader commentary about libraries which don't have physical collections, including a public library in San Antonio - http://www.mnn.com/lifestyle/arts-culture/stories/is-a-libra... .

I doubt that small-town libraries will get rid of all books. Libraries do have collections of local history which are unlikely to be part of a digital archive. (Eg, phone books from the 1950s, local high school yearbooks, photo collections and films about the annual downtown parade, publications from the local genealogical society, etc.)

But if in 100 years small-town libraries have mostly switched to digital collections, then yes, it's possible for the knowledge to disappear even if the infrastructure remains.

I don't think it's likely, but it's not completely inconsistent.

They won't do that everywhere. The world's a big place.

You won't find how to do such things in most libraries, you would get the geenral idea, but the details would be still too hard to figure out.

What do you mean?

I thought of that too, but I wonder how much energy it takes to do fusion research and get the first power-producing fission reactor built from the starting point of knowing nothing about nuclear physics.

I don't think it takes a lot of energy to get a reactor running - there are even natural ones around. Mining involves some chemicals but is fairly low-tech. Enrichment requires a lot of precision in the centrifuges, but not a lot of raw energy; you would need high quality tools and dedicated skilled labour, but you don't need grid power. Most of the high-tech engineering of modern reactors is around safety, but in this scenario presumably you'd just use slave labour.

Research is another question, but it's likely that a society that was more heavily based on electricity would discover relativity sooner than we did.

The centrifuge technique is a recent innovation. The original calutron method was horrendously energy intensive.

Also you don't have to enrich uranium at all if you can instead enrich water for a heavy water reactor or use a graphite moderated reactor.