There are plenty of dry areas like in the American Southwest which can be projected to not have meaningful water attempt ingress in that time frame.
Also, fission reactors make phenomenal sense on aircraft carriers, submarines, etc.
Every miner knows most holes fill with water sooner or later.
Corollary: Every sailor knows most vessels are sunk sooner or later.
Aircraft carriers and Submarines are not civilian infrastructure, and if they sink offshore where no can live... will usually pose less of a problem like buoyant waste barrels popping up later.
We are in the age of bargain conflicts, where throwing gold bricks at adversaries makes less sense strategically. =3
We've already leached too much uranium into the groundwater for many to drink just from the mining alone.