I thought that the FN had decided that CDG was too small, hence interest in CVF. That said, I am not sure why using several submarine reactors is a bad thing - I think (can't be bothered to check!) that the early US CVNs (eg Enterprise) were powered by up to 8 submarine sized reactors. Might not be a bad idea as at least we could share development costs with the submarine programme (Vanguard and Astute replacements) and they would provide steam for the cats.