

Not really enough information. I will assume that by “installed solar power” you mean peak generation when the sun is shining, and that instead of peak use, you mean 40% of average use, i.e. let’s suppose that at an average moment the country consumes 100GW and, if the sun is shining, generates 40GW from solar.
Assume further the sun is up for half the year and the sky is clear for half the year, meaning the total amount of your yearly electricity you can generate with solar is 10% assuming typical weather. Then you would be able to reliably power the country with a combination of nuclear totalling 90% of average use (90GW) and enough storage that you can ride out cloudy periods.
I mean the UK has 6% of its energy over the year come from solar, and 30% from wind, and installations are only accelerating, so this amount of installed solar is far from unrealistic.
Installing storage approximately doubles the LCOE of solar energy, so this is also feasible from a cost point of view as we get rid of dispatchable gas turbines.
I am not saying we should get rid of nuclear. I am saying we should keep some nuclear, also once we have got less gas and more storage. Does this resolve some things in this discussion for you?