You wouldn't expect significant radiological contamination from bombing an HEU facility deep underground? This isn't like exposed reactor core material.
They do have reactors though, do they not? Hitting the spent fuel pools and/or the reactors would produce detectable radioactive contamination. The HEU? Not so much as its half-life is 700 million years, and the stuff is dense and will quickly settle down.
With a half-life between 700 million years (for U-235) and 4 billion years (for U-238). And it's dense stuff that will immediately settle on the ground. You're not going to detect it from afar.
