The practical arguments in favor of nuclear seem to assume that new nuclear technology only needs to compete with old nuclear technology.

Let's set aside the safety argument. They're claiming $0.46 per kilowatt-hour for a technology they haven't developed yet. I believe that's about an order of magnitude more expensive than what wind can do right now. Heck, right now my local utility's website is reporting a retail spot price of seven cents per kilowatt-hour. Maybe paying six times as much is worthwhile for the reduced carbon footprint relative to fossil fuels, but if that's the argument then just say that rather than weakening your position by calling it "cheap" when it's easy to see that it isn't.