[TeMPOraL]

Trying to toss radioactive waste into the Sun would be a ridiculous waste of fuel. To do that, you have to cancel out Earth's orbital velocty; that's 30 km/s of ∆v (or execute some very clever gravity assists).

What you'd want to do is to shoot it out into an orbit around the Sun that's slightly lower or higher than Earth's. The chance of it somehow returning to Earth is so low that the Sun will go out before it happens.

Still, the whole concept is wasteful and dangerous anyway. For one, as others mentioned, a launch failure would mean large-scale contamination on the planet. Two, you can safely store this waste on Earth for many orders of magnitude less money and work.

> People still seem to make the same mistake our ancestors did regarding tossing stuff into the ocean.

“Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.” Throwing something out into orbit around the Sun isn't going to be a problem, like, ever.