Nuclear fission is actually by definition the least renewable energy source. Even coal and oil are renewable on long enough time scales. But there will never be more uranium than there is right now.
We actually don't have that much of it if we consider the long term future, only a thousand years or so. So nuclear is intended to be a bridge to eventual full renewable power generation and storage, an essential component in the present day but it's still a bridge.
Another thing to consider is that nuclear is the only power source that works in deep space away from the Sun. So if we're serious about exploring the solar system or further, we'd be best not to burn up all of our fissionable material right away.
Coal exist in the earth because back then the bacteria who could break down lignin and cellulose hadn’t evolved, so dead trees had the time they needed to compress.
There are such bacteria around now, though, and that means there will never be any new natural coal.
The process to produce coal is known for 100 years now. Its just not feasible, because no one needs coal. But its reversible. No one knows how to fuse uranium.
I wouldn't necessarily say never, it could potentially happen that a dead tree ends up in an environment that isn't conducive to lignin-eating bacteria getting to it, and I would not be at all surprised if it has happened and may continue to happen somewhere in the world since those bacteria evolved, though they would certainly be exceptional cases and almost definitely not happening at any significant scale.
It's also possible for those bacteria to go extinct one way or another. Again, not very likely. And if it did happen it would probably be due to some absolutely catastrophic disaster absolutely wrecking the Earth's ecosystem completely in which case we're probably not going to make it either, but hey, new coal!
A bit of a stretch maybe, but I'm considering us to be discussing whether an energy source is renewable on Earth. The Sun is not renewable, but by the time that it's no longer viable the Earth will be long gone as well! So as long as the Earth exists, I would say that solar PV and other solar driven processes like wind and hydro are renewable.
By these standards yes, deep geothermal and tidal are "not renewable" either.
I think we both agree on fertile material as discussed in another comment, the longevity issue is mostly with conventional LWRs burning up our fuel rapidly.
mostly with conventional LWRs burning up our fuel rapidly
Well, yes, the obvious counter argument being that, you will never build more advanced reactors on scale (some are already available), or develop new fuel cycle if you stunt the evolution process and block the technology we already have.
Imagine saying to be favourable to installing solar panels but only when they will be 100% recyclable and with efficiency close to the theorical maximum
"It wouldn't have bankrupted every program that tried if you'd just let us fill every body of water with lethal levels of Pu240, Cs137 and Tc99" isn't a great counter argument.
A thousand years is a massive over-estimate. Providing the 6TW or so of final energy with the stuff assumed to exist that's vaguely accessible for costs that don't exceed renewables' total cost is well under a decade.
No breeding program has ever done a full closed cycle and even if it were to happen, the currently proposed technologies only yield about 50 years.
No it's not. That's just delusional. All the ideas of a sustainable uranium fuel cycle are based on non-existent technology. Uranium is a finite resource and we have nowhere near enough of it to power the world, even if you ignore all the other problems.