Well apparently peak electricity in the early morning and early evenings isn't a thing and all electricity is used during the day? I mean yes this is what some people believe. When a lot of the places using renewables have had to look at Peaking power plants to cater for those exact reasons. I mean we've got ours as the OCTGs but ours is because our infrastructure is dying.
So what natural gas, oil or coal? We already know that natural gas and oil prices skyrocket because there is a literal cartel making sure its price stays high. Which leaves coal. Not to mention that none of those "peaking" plants are anywhere near renewable.
With nuclear there is so much fuel on earth (not to mention that we can bread more fuel) that it is effectively moot if it is renewable or not.
As for the lifetime of a reactor, there is a lot fallacies. If you are a non-engineer you can easily fall into the trap of believing that building's design life means it'll collapse the day after. It has absolutely nothing to do with that. It is simply what the engineer predicted the lifetime to be without a next assessment and likely maintenance work that will need to be carried out.
When a building is built (any building), it is built with a life expectation. After that time an engineer will assess the state of the building and recommend upgrades or alterations to provide an additional X years of service. In the building industry you see that often, sometimes they even consider tearing down the building.
People don't do this for their homes so they don't think it counts for their homes but actually it does. Your homes are typically built with a 50 year design life. After that the pipes will corrode through, the foundation will shift, the insulation around the wires have degraded to the point that it is brittle and just falls apart, your circuit breakers are likely worn out, etc.
The same is true of nuclear power plants. It doesn't suddenly mean you need to shut it down, game over. Even the reactor core which is peppered with neutrons which weakens steel is often still fine after the "design" life. It is at that point that x-rays are taken and an assessment is done to determine what if any work is required. FYI Koeberg is going through that very process right now.
The design life of solar, wind, etc. will be significantly lower than a nuclear power plant. Those renewables are not somehow exempted from engineering principles and the limits of the our physical universe. As quickly as you are installing renewables you'll need to be maintaining and replacing existing renewables. Sure it'll take a few years before that cycle begins but when it does, it'll never end. You will forever be replacing panels, replacing turbines, etc.