[wazoox]

Actually nuclear plant have been designed for a minimal lifespan of 40 years. Most can be run safely 60, 80 or even maybe 100 years.

Renewables don't provide the energy density to power our industrial world. Simple as that.

Fossils emit much more pollution than nuclear in volume, and that will last arguably as long (CO2 we're dumping in the atmosphere will stay up there for millennia; coal ashes will remain toxic forever and we make megatons of them, not mere kilos).