Besides the fact that America is America where its sidekicks are concerned, as far as naval reactors go, America has the greater experience with HEU even though France (Orano, previously Areva) runs the most advanced LEU light water power gen reactors in Europe. Its 1.6GWe PWR is the largest output reactor in the world but naval reactors are a different animal, GE reactor on the Seawolf is 165MWth driving 2x26MW steam turbines...