Later.

Reactors in the US, on which the German designs are based, have already received their extensions to 80 years.

Experts see no particular problems in extending that to 100 years or even further.

https://www.scientificamerican.com/article/nuclear-power-pla...

https://www.utilitydive.com/news/how-long-can-a-nuclear-plan...

https://www.energy.gov/ne/articles/whats-lifespan-nuclear-re...

Fission reactors are not very useful targets in war. In Ukraine, their fleet of nuclear reactors are what's keeping the electricity grid running. And they are building new ones. In war time.