alt Hacker NewsI wish this subduction zone idea would just die. It's dumb. Things move so slowly it wouldn't help, and subduction zones have large amounts of volatiles coming back up via mud volcanoes and, later, actual molten rock volcanoes.
If you want to dispose of waste deep in the sea floor do it far away from subduction zones. Or just store it cheaply in dry casks and minimize the net present value of the cost of dealing with the waste.
Short-term, subduction zones are deep, maximizing the difficulty for malicious actors trying to get their hands on the waste. The subduction itself is more a marketing feature, for folks who oppose putting the waste anywhere on the surface of the Earth.
Longer-term - it's mid-ocean ridges, not subduction zones, where you find all the volatiles and volcanoes. Yes, millions of years in the future, some micro-percentage of the subducted material will re-emerge, hundreds of miles away, via volcanoes. So will vastly more natural radioactivity, whether or not we dispose of nuclear waste in the subduction zone.