This anon read this article a few years ago and has had a good long think about it.
All this proves is that it is not possible to create an atomic bomb using nuclear fusion. i.e. an atom bomb. It is still possible to create a nuclear bomb. Fine-milled thermate for the core, with very fine-milled plutonium on the outside. It would be the bomb version of a DU shell. It would leave a nuclear signature, so it looks like a nuke went off but it was actually a conventional explosion.
This also solves the argument about thermite vs tactical nuke in the trade centers. Both were used.