For renewables (solar, wind) to work reliably you have to provide on-demand backup, invest in energy storage systems and increase investments in electric as renewables are often far away from consumers. (German offshore wind in north, major industrial consumers in south). So direct comparison of isolated costs of renewables and nuclear is misleading. You have compare the whole system.

Well no it isn't, this problem is so small that it's not even worth installing any additional cooling method. It's also the lowest consumption period of the year, making the problem even more irrelevant as some plants are already offline for maintainance anyways.

And since the poster didn't knew that, I'm not sure the cost analysis holds up.