After a previous unsuccessful test there was some news about a spike in radioactivity. At the time there was some speculation about the source as the isotope found did not match previous tests or accidents. As for the reindeer being radioactive, yes there have been some fallout here from different Soviet nuclear test and accidents. Also leaks at the British Sellafield plant have been traced. I have not checked, but the Chernobyl accident probably was the one raining most radioactivity down on Norway.