A safe nuke is not more expensive than a dangerous nuke. Nukes are expensive, period.

For example, the Fukushima accident would never happened if the plants had been protected by a comparatively cheap 20 metre high seawall.

And even if such a thing was lacking and the plants had indeed suffered core meltdowns, 99.9% of the radioactive emissions would have been avoided if the plants had been equipped by protective filters, cheap and simple enough that all Swedish nukes had them installed in the 80's.

Peak oil is not an energy crisis. It is a liquid fuel crisis.