That could possibly done, but then, no one had created such a design yet. It is also not trivial to cool in the gigawatt range. Actually, many power plants even run into cooling issues in some time of the year, as they often rely on local rives to provide the cooling and the water supply as well as maximum water temperatures (animal and plant live) limit their cooling capacity in normal operations.

In Belgium there were even streetlights being installed along all highways to use up nuclear energy when the grid was not consuming it.