[luckman212]

Would you mind sharing a link to "the xkcd thing" if you have it?

edit: sorry for being lazy, I scrolled a bit more and found it.

[johnisgood]

https://what-if.xkcd.com/29/

[ethbr1]

Relevant: "For the kinds of radiation coming off spent nuclear fuel, every 7 centimeters of water cuts the amount of radiation in half."

[wiz21c]

On the picture, the fuel rods are indeed protected by a huge quantity of water above them. But what happens below them ? They seem to be in direct contact with the ground...

[jjk166]

People tend to avoid casually tunneling under nuclear pools.

[afiori]

I would guess that in reality they are either suspended and/or there is enough concrete at the bottom