Except when we dig out all the fuel necessary for this (I know, this plan wants to use existing material, so this has already happened - but still, contamination is contamination). That part is always conveniently glanced over. Or when we need to store the waste, a problem that is still unsolved (I did not see anything mentioning that this will produce non-radioactive waste).
Yeah, apart from that, clean as anything.
"In other words, all the highly enriched uranium and weapons-grade plutonium collecting dust since the Cold War could be put to use for peaceful purposes."
So take the stuff that we are struggling to deal with now and distribute it far and wide across the land, underground. Got it.
"...this could be the source of energy that provides carbon-free electricity."
Well thank god it doesn't produce carbon emissions, one of the easiest to manage climate problems we have.
"So I really think that in the, say, 20 years it's going to take us to get fusion and make fusion a reality..."
Oh wow, it's like the six degrees of pipe dreams.
Look - I'm really all for fusion. If it ends up working - great. Throw out billions to get there? Be my guest. But how about, in the meantime, we invest money in technology that only produces pollution that we know we can manage. Because then, if our pipe dream fails, we are left with stuff that actually works. Not thousands of waste nightmares buried deep across the soils of our childrens' future.