I don't think “nuclear theory” explicitly “rules it out”. There's certainly no result that leaps off the page and states that it most certainly is or is not pos

I don't think “nuclear theory” explicitly “rules it out”. There's certainly no result that leaps off the page and states that it most certainly is or is not possible. But there's a very clear threshold of Coulomb repulsion that would need to be overcome in order for this to work, and absolutely no trace of any phenomenon so-far calculated or measured that might allow it to be overcome at room temperature. So it is... shall we say “inherently incompatible with theory and what we know impinges upon those theories”?