It seems to me that, if they were able to sucessfully cage the dragon (see fig #3), there shouldn't be any airborne radionuclides. There's certainly plenty of info available on the good 'ol electric internet about testing containment, sucessful and otherwise.

Well, China has been supplying NK just as we do our allies. As long as it was profitable, they went on. Now, there is an issue. There might be a nuke next door from them. Guess they are now worried.

At least China is acting worried now. This is probably the best thing that could have happened for them. It takes the attention of the trade deficit and their currency peg until the mid terms are over at the soonest, and they are probably betting the results of the election will lock up one or both houses to keep them in the clear over both issues for the next two years. I think they are just acting upset to keep up their appearance.