Just because it's safe doesn't mean it's the best we have right now.
It's massively expensive to set up
It's massively expensive to decommission at end of life
Almost half of the fuel you need to run them comes from a country dangerously close to Russia. (This one is slightly less of a thing now that Russia has bogged itself down in Ukraine)
It takes a long time to set up.
It has an image problem.
A combination of solar, wind, wave, tidal, more traditional hydro and geothermal (most of the cost with this is digging the holes. We've got a lot of deep old mines that can be repurposed) can easily be built to over capacity and or alongside adequate storage is the best solution in the here and now.