Nuclear isn't a guarantee at all. Typically, only half of the French reactors are operating. There are a lot of problems:

* a plethora of safety problems, often created due to a lack of maintenance and lax oversight - most famously more than a dozen reactors are offline for years because of corrosion in neglected backup cooling systems

* large reactors require huge amount of cooling water. They usually take water from rivers and release the warmed water right back to it, but rivers often run low in the summer, or are already so warm that rising the temperature any more would kill the river.

* nuclear reactors are hard to regulate below a threshold of about 40% of their peak, which requires base load demand to be reserved just for them if they are to be run.

The last one is almost funny, because the base load problem of nuclear reactors is often somehow portrayed as a benefit. Power production must match power consumption though, so an inflexible power source is a burden. Without the ability to export power to its neighbours, France's reactors would have even less uptime than they have now.

Does a nuclear reactor not run day and night, wind or no wind, in the same way as any other 'traditional' power plant? yes it does. If you build a nuclear plant you know how much you'll get out. You don't with wind farms hence massive margins compared to what turbines are rated for.

With wind you are totally reliant on the weather, which is also why offshore wind tends to work better as apparently wind patterns are more constant and predictable.

Your three bullet points are all strawman arguments.

> Typically, only half of the French reactors are operating.

You're going to need some serious citation for that.

It's not typical though it is the case at the moment [1] (in French)

The argument is a little disingenuous in any case because temporarily stopping reactors for maintenance, especially planned maintenance (in this case delayed because of Covid), is not at all the same as the inherent uncertainty that sources dependent on the weather (e.g. wind) suffer from.

As said, with nuclear/gas/coal/etc you know what you'll get pretty much day in day out. With wind it's never guaranteed.

[1] https://www.radiofrance.fr/franceculture/podcasts/la-questio...