> I always had the impression that the storage requirements for nuclear waste are a lot bigger than what they needed to be

This is debatable and I don't like to -- especially in a public setting -- give an authoritative answer of "yes" or "no" because truth is that neither of these would be correct.

I'd rather state some of the factors involved and give you the idea that this is complicated and that there are very smart people working on these issues and we have good reason to trust them (rather than trying to reason through the problem entirely by ourselves[0]).

So the question about nuclear safety is not a binary one, and truthfully this is true for any question about safety (or most things!). Instead it is about level of acceptable risk. This can be VERY small and to the point where we just treat it as a binary case (but it isn't!) or certain bounds. This type of risk assessment is quite complex, especially with nuclear, and depends of the __type__ of failure. So this also includes a whole other topic of failure design/engineering (e.g. skyscrapers are __designed__ to collapse in on themselves. Not to make them weaker or to cause them to fail, but to control the way that they fail __if__ they fail. You don't want your building falling over and taking out another building (creating a cascading effect), so if it falls in on itself it is less likely to cause more damage. Bridges are another common example if you want to learn more).

Nuclear safety design is quite complex because of all the ways things can go wrong and our great concern for safety (making this a WELL studied topic and why the nuclear industry is one of the safest, and arguably the safest in terms of power generation. Even including the 3 main disasters). Disasters are complex and I'll bet you most of what you've heard about Chernobyl, Fukushima, and 3 Mile are quite limited in accuracy. This isn't because of dishonesty or malintent, but because of the complexity.

So the big questions about nuclear storage is how long we want to have a high confidence in our storage. Certainly we have a large and abnormal margin of safety in nuclear compared to other industries, but the question is if we want this or not (that's not a question that science answers, that's a public policy question and to answer appropriately we need to be aware of our answers to this question for other comparable industries (which means not assuming or "reasoning your way through it." It means spending time)) There are some people who want the high level waste to be safely stored for tens of thousands of years and under strong conditions such as not necessarily understanding English or our conventional warning signs (there's a whole rabbit hole to go down here![1]). But there are others who think it is fine to have a safety solution that is good for several hundred years and that we should use this as we invent better techniques. With this, we actually have the technology and even use it today. This route would allow us to store waste on site and there's discussion of ways to cheaply and effectively decommission plants ontop of themselves. (FWIW, this is the option I'm in favor of) Part of the reason some want this method is because it's extremely reasonable to believe that we actually want this material and as our technology has advanced in the last 70 years, we've learned how to extract much more energy from our fuel (which means much lower waste products, which means lower length of half-lives on material, which also means we can recycle old fuel and turn it into new fuel. To understand this properly we need to understand how the fuel actually works, but this is another long topic. I'll just say that we use a very small portion of it. And I'll also mention that France gets about 17% of its total electricity from recycled nuclear. Not 17% of nuclear energy, 17% of __total__ electricity[2]).

The last thing I want to say is we have to keep in mind how much material we're discussing here. I think people grossly overestimate this. Here's a picture of __all__ of France's high level waste[3]. All 60 years of it. It could fit in a Costco. This video[4] shows Russia's. Again, all 60 years worth. And it is worth noting that Russia isn't doing the same recycling as France, so all that material is technically still fairly valuable. You should compare this to other industries. This is important when we're considering our risk assessment because the footprint of waste storage is still an environmental concern. And if we're producing 240 metric tons of coal waste every year (many train cars worth), it can put this into perspective because all that needs to go somewhere. While numbers aren't quite that high for renewable sources it is non-zero.

And one more thing I need to stress to people. From the perspective of scientists, there is 0 people pushing for an all nuclear power solutions. That's considered idiotic. It is similarly considered idiotic to push an all solar or all wind solution. The consensus is we need a well diversified portfolio of energy generation and that the right choice depends on where the power is being generated and needed. Also in the opinion of scientists the argument is more often about "should nuclear be on the table or not." (I for one think it should be) But being on the table doesn't mean it has to be used. Given the context of this thread, I'm sure many of you can see that there is likely no reason to build nuclear plants in the American southwest where there is bountiful sunshine and wind[5]. The question is far less obvious if we are talking about the Pacific Northwest or New England. The question also matters when 50% of zero carbon energy in the US comes from nuclear and where in some regions it is the __only__ zero carbon producer of electricity[6] (but that's more complicated, because we can build renewables in those locations, but politics is also an issue. But that is why I keep stressing not pretending to be experts in complex topics because that's how people get deceived. And I'll say that both "nuclear bros" and "anti-nuclear-pro-renewable" crowd often get a lot of things wrong, though their hearts are in the right place. Both typically get the proliferation question wrong as well as the thorium and waste questions wrong. I mean both nuclear and climate are quite complicated subjects, so it's probably unsurprising).

So I don't know if this actually helps answer your question or not.

[0] "our" role on the public side is to decide policy, not science. We can litmus test and should definitely be skeptical of claims but at the end of the day there needs to be some trust somewhere and the question is who you're placing it in. The people that publish tons and tons of papers that aren't actually readable to the average person or the person who writes laws and doesn't know a positron from a neutrino. The world is specialized and we need to make sure we know what our individual limits are.

[1] https://en.wikipedia.org/wiki/Long-term_nuclear_waste_warnin...

[2] https://world-nuclear.org/information-library/country-profil...

[3] https://x.com/Orano_usa/status/1182662569619795968

[4] https://www.youtube.com/watch?v=_5uN0bZBOic&t=105s

[5.0] https://www.nrel.gov/gis/solar-resource-maps.html

[5.1] https://www.nrel.gov/gis/wind-resource-maps.html

[6] https://app.electricitymaps.com/zone/US-SE-SOCO