No need for fusion which will take decades to breakeven if ever. Man has already mastered the atom. Fission can power humanity for hundreds of thousands of years. Even without fast fission breed reactors, fuel reprocessing, and or particle accelerator driven breed/burn reactors. The amounts of uranium in the oceans is so best we can use the once through and bury the wastes for as long as humanity exists. Even without waste partitioning or MOX fuel reprocessing the volumes of wastes are so dense for $150 a kg you can put as much as you will ever make in shale, granite or basalts below 1000 meters. At typical burnups of 45 gigawatt days per metric ton of fuel even $500kg uranium costs under 4 tenths of a US cent per kilowatt hour in fuel costs. Disposal is already payed for with a tenth of a cent charge to the US government. $150 kg is 150,000 a ton in waste costs, at 45GWd/mtU that’s 1.08E9 kilowatt hours worth over 20 million dollars per ton of fuel in power sales at the basebar cheap rate of $20 per megawatt hour. Typical power sales rate for wholesale via ERCOT are $50_80 megawatt hour peak rates into the $150s lately. Wastes is a political problem not costs nor technical both favor direct geologic disposal. When you can make 20+ million in revenue off a 150,000 cost it makes deep sense to reprocess at $1000 kg in heavy metals to partition wastes and recover MOX fuels.
https://newatlas.com/nuclear-uranium-seawater-fibers/55033/
“So as the cost of extracting U from seawater falls to below $100/lb, it will become a commercially viable alternative to mining new uranium ore. But even at $200/lb of U3O8, it doesn’t add more than a small fraction of a cent per kWh to the cost of nuclear power”
Thear are the kind of wells I still 5 rigs at a time off megapads. Shale is perfect to lock up wastes in. It’s impermeable, geologically stable and chemically inert.
Fusion looks to be an expensive dead end, and fission has a terrible accident record. The total cost of ownership for running a nuclear plant is ridiculous. What's really needed is technology to bring down the cost of antimatter, or technology to use smaller amounts of it to disassemble atoms. Using antimatter is much more efficient and doesn't require blasting high energy neutrons everywhere.