Yes, the reactor cores would have to be replaced every 12-15 years. But if the reactors are mass produced and designed to swap out the cores, it doesn't have to be too expensive.
And not really cheap either.
The US navy swaps out reactor cores for 100-200 million dollars, and those are in submarines and ships. There is basically no maintenance outside of those.
For comparison, a GW of wind capacity is 1.6 billion every 20 years. For solar panels for 1GW of average generation you'll be paying 10 billion dollars or so every 25-30 years.
Where do you live that panels cost you $1.5+/Wp?
Furthermore, where do you live that panels will cost you $1.5+/Wp even thirty years from now?
You could literally throw it in the deep ocean and it'd still do less damage than a single day of Brazilian deforestation for biofuel production or a month of operation of a coal plant (partially because water is actually quite good at blocking radiation and not becoming radioactive, you can safely swim in a spent fuel rod storage pool).
Nuclear waste remains dangerous and harmful on a timescale that can almost be described as tectonic. The earths crust isn’t static or stationary, if you throw waste into the bottom of the ocean its not clear what will happen to that waste in 10 millions years time, or even 300 years time.
I agree that our current climate situation demands drastic actions, and theres a strong argument that solving the real harms today of climate change are worth taking the risk on the theoretical harms of nuclear power. But I don’t agree that nuclear power is currently “sustainable”, it’s almost certainly the best energy source we have today, but that doesn’t necessarily mean it will stay that way for long.
The tldr is that waste that decays slowly is doing so because its releasing less radiation. There's no radioactive stuff that we'd need to worry about on the million year timescale. The 10000 year timescale is the most where human health due to radioactivity might be a concern. And on those timescales your waste at the bottom of the ocean or 100ft below ground is almost certainly going to be still there and unaffected unless we or our successors decide otherwise.
Heck I'd say worrying about anything more than the 500 year timescale is absurd as I'd be very surprised if humans were still around in human form by then. We'll either have been genetically engineered, wiped out by those who have, wiped out by rogue AI or something else or been "uploaded" in some fashion.
Yes it is waste, but I don't see anyone making the argument with wind turbines or solar panels, which will create more waste in total.
You burry it deep in a geologically stable ground [1]. Was that not counted in the price?
[1] https://en.m.wikipedia.org/wiki/Deep_geological_repository
Yes, there's a 1 in 10000000 chance that 2000 years from now industrial age humans recovering from the apocalypse might dig a well in exactly that location and thousands will get sick with hundreds of deaths. You could multiply that by a hundred thousand cores and it would still be negligible compared to the hundreds of millions likely to die due to climate change in the next century
But what about if we had a Reactor Dump storing 100's of these reactors, and then something happened to that dump, either it was hit by a meter or it was intentionally attacked in some way. Could that result in an apocalyptical type event?
It would basically be a few Chernobyls in the worst case (a 1 in 1000 year asteroid impact winning the 1 in 100 million lottery and hitting the dump) and that mostly means extra birth defects and cancer (you wouldn't want to live somewhere that gave you a 10% chance if dying due to cancer age 40, but you could still have a civilization in such a location). It doesn't end life in the impacted area.
For intentional attacks there are much much easier ways of killing a lot of people.
You cannot do that. There is no place on Earth that we can be sure is geologically stable over that time period.
What a selfish thing to do: Make future generations pay for our current consumption for millennia.
Makes no sense to me, but my physics education was decades ago
The half life of most of the waste product from a gen-3 uranium reactor is measured in millions of years (235U's half life is ~700 million years, for example).
In some gen-4 molten salt reactor designs, most of the waste product would have a half life measured in hours, so they wouldn't need to be put into long-term containment at all. And the rest of the waste products would only require a few hundred years before they are emitting only background level radiation.
Hopefully someone with actual education on this can give a more complete answer, but that's my Reader's Digest understanding.
The metal containing the molten salts might become somewhat radioactive too.
All in all, this is still comparable in amount of waste to water cooled reactors.
And this was for modules manufactured in a period with 5-10 year warranties for the product. Today you get 25 year warranties. So you're basically claiming that QA massively worsened in the meantime.