The figure of 2024 came from a DoE document and was for...

The figure of 2024 came from a DoE document and was for deliveries of tails to Paducah. As you say completion could be later; government red tape for nuclear projects in the US is legendary although I would hope that the Wilmington approval in 2013 could expedite approval of Paducah but will still have differences, one I understand is seismic activity (little earthquakes) in the Paducah area (evidently the reason centrifuges would not be viable in the area). It's not only construction that's subject to delay it's also unforeseen difficulties on issues which worked on a prototype (i.e phase II) but no so well on upscaling for production that are a risk.