New Mexico recently had one explode due to improper materials used for absorption of liquid waste. To be frank I don't think it's worse than the chemical spills that happen routinely like the train in Ohio, but it isn't a small deal either.

https://www.latimes.com/nation/la-na-new-mexico-nuclear-dump...

That must have been a lot of pressure! There are videos floating around I have seen of running a train engine into them at full speed.

Yeah, the testing is bonkers. But really nothing can withstand enough heat and pressure. Eventually your container just turns into a liquid. I love this video of the testing:

https://www.youtube.com/watch?v=Rmp3_CLx4VY