There is also something about "fast-neutron"/"slow-neutron" (I don't recall which one) capture based fission reactors which could give a purpose to a significant part of nuclear waste.
If I understood not too badly (but I expect to be very wrong), only China and Russia have such nuclear reactors. In my country, the public research project was cancelled without being able to do the same than China and Russia. I heard that with such reactors, it extends by hundreds of years, if not thousands, the ability of fission reactors to produce "enough" energy, that based on current fuel reserve estimation.
ofc, reducing energy consumption (= reduce worldwide population, reduce heating/AC, stop commuting ...) and switching as much as possible to "stored" "renewable" energy should always be a primary focus (even if nuclear fusion becomes real).
The most successful was Russia's BN-800 but "problems ((...)) indicated a redesign was needed", and construction of it's successor (the BN-1200) was put on indefinite hold. Problems related to cost and process/security seem quite difficult(?)
https://en.wikipedia.org/wiki/BN-1200_reactor
Russians are back to the drawing board. The sole officially actively pursued (since 2021) pertinent design, BREST-OD-300 ( https://en.wikipedia.org/wiki/BREST_(reactor) ) will only (when completed, if ever) be a demonstrator (low power).
It seems there is a difference between "fast-neutron" reactors and breeder reactors: the article states that russian BN-600 and BN-800 are "fast-neutron" reactors but not in "breeder" mode.
Since I am garbage in nuclear physics, I am wondering if those "fast-neutron" reactors "but not breeders" can reuse a significant part of current nuclear waste?
I'm not a specialist. If I understand correctly "breeder mode" depends upon fuel composition (which actinide/isotope, in which proportion...). Non 'fast-neutron' mode is dubbed 'thermal' and seems less interesting as it obtains less energy (however some fuel, such as thorium, may enhance its performance), however it has benefits (less difficult to design/build/exploit(?)).
ofc, reducing energy consumption (= reduce worldwide population, reduce heating/AC, stop commuting ...) and switching as much as possible to "stored" "renewable" energy should always be a primary focus (even if nuclear fusion becomes real).
wow, so many "if" and "I don't really know". :(