Dont nuclear reactors need a lot of water?
If they are driving turbines.
That’s not to say that weapons aren’t being developed in land based electric plants.
I would think so, but I’m not up on that.
Yes. There are components - spent rods? something that is awaiting proper disposal - are stored sometimes in pools that look like olympic swimming pools. Was visiting at a facility once and was given the tour and shown such pools. That is at least one large water application wrt nuclear materials that I am aware of.
Fuel rods require cooling. Water is a perfect medium to keep them cool. That, at least, is my understanding. Environmentalists justifiably have concerns with this.