300 years is still far too long. You simply cannot expect most organizations to survive that long and remain trustworthy. Apart from that the real costs would still be very high.
The point is, we have a lot of nuclear waste right now that needs containment for 10,000 years. Put it through liquid thorium reactors (or integral fast reactors) and you reduce the amount of waste by a couple orders of magnitude, while reducing the timeframe to 300 years. Do you have a better plan for it?
300 years is feasible from an engineering perspective while 300,000 years is not. We know how to build a storage facility that won't let materials leach into the water table for 300 years.
> You simply cannot expect most organizations to survive that long and remain trustworthy.
Not needed.
> Apart from that the real costs would still be very high.
We've already built buildings with the required longevity. You'll have to be more specific/give better support to your assertion.
> 300 years is feasible from an engineering perspective while 300,000 years is not.
Besides engineering, communication of that facility's purpose is also important. You don't want a fancy storage facility becoming a tourist destination in 100k years either. Barring a massive collapse - loss of global knowledge and societal progress scenario (asteroid impact, super volcano, whatever), there's a great chance of some version of our modern languages surviving and being mostly readable to somebody on Earth born in 2312.
Conveying the waste storage site's inherent danger to that person 300 years from now is fairly easy task for our current society; just as we have lots of things from 1712 that still exist and are still mostly comprehensible.
We simply can't fathom how we'll communicate danger to someone ~15x further into the future than the entirety that our current civilization has even existed. Look at how much trouble we had deciphering hieroglyphics and that was only 6,000 years ago. It may not even be humans that come across it 300,000 years from now.
300 years is still a lot better than 10,000+ [1]years we are currently looking at for spent uranium fuel. If we can use current supplies in the thorium reactor then we will benefit greatly because our power production will serve as waste management for current uranium waste reserves.
