Because there is zero market for it especially after Fukushima. It was tried by the recently privatised French military shipyards as a way to diversify (that's the Flexblue project mentioned in the article) and just couldn't be sold.
Its a shame IMO. There are lots of problems with nuclear power, but at least the problems are ones that make sense to humans. It seems like nuclear waste would be easier to handle than a ruined atmosphere.
