If you want 99.9999% uptime with no backup then the nuclear fleet will need months or years of storage due to the prevalence of correlated unplamned outages.
Back in reality, a good enough renewable system with >95-99% uptime has less than 10% of the storage that will be found in the accompanying country’s EV fleet. Even if you are too allergic to nuance to understand the real solution for the remainder, simply planning a renewable rollout and assuming existing fossil fuel peakers for down periods over 12 hours will take 20-100 years to release as much carbon as delaying one of the years waiting for late, over budget nuclear reactors.