The Wall.
Remember, Power Plants are walled by a far denser form of concrete than standard building material, since they are a defence against accidents and leakages.
The video is something special, since it shows just how tough that material is, though, I'd be interested to see how it would cope against a much heavier, fuel-loaded civilian jet in a simlar test.
It was like the crashing a train into a Nuclear Waste Storage tank in the UK, all nice and impressive, but the concern wasn't about the tanks when they are brand new, it was the fact they would be expected to hold the waste for hundreds of years until it was safer, and that the containers may fatigue in that time.