Yes, a modern nuclear plant requires tons & tons of concrete. Yes, it costs tons & tons of money. It also gives you gigantic amounts of energy, and you can adjust its output. Windmill and solar panels only produce energy when there's wind or sun, so their actual energy output is much lower than their peak power output, and you can't decide to turn them on or off at will like you can with a nuke plant to adjust it to the energy needs of the country.

You want to be renewable only? Then you need to install several times the power output you need, and enough energy storage to have your energy at will: dams, batteries… This is going to cost a lot.

Also, shutting down a nuke plant takes about a minute, then you need very little water to keep it cool. Completely dismantling it takes much longer of course, but it takes so little surface compared to its energy output that you might as well just leave it there to rot.