It's not new, it's that PWRs have to be built and operated with that capability (load following), which most nations didn't bother with until pretty recently because it does have a cost in complexity & efficiency. But France has done it that way pretty much the entire time.

> Gas peaker plants currently fill this gap.

Nukes with load following aren't peakers: PWRs can modulate output by 2~5%/minute (depending on their exact design and operating mode) between 30 and 100%. They're not reactive enough to compensate for wind, although they can work with the daily and seasonal patterns of solar pretty well.

The replacement for peakers are mostly batteries (hydro and pumped hydro where that's available but usually where available it's already done)

The EU has north of €1 trillion into new gas infrastructure. That's €1 trillion of commercial interests with a vested interest in negotiating the non-negotiable.

Using fossil fuels for transition is fine, particularly if it's replacing coal with natural gas. But building LNG terminals and installing gas turbines because ding dongs in Dusseldorf got scared of nukes a quarter of a continent away is a great way to raise the continent's energy prices, volatility and carbon continent.