There was a young teenager who was building his own atomic bomb. The feds shut him down and confiscated all his equipment. He gathered americium from hundreds if not thousands of discarded smoke detectors. They found him because his neighborhood had unusually high radiation. Supposedly, he had gathered more than enough material to make a viable bomb. I don't think he suffered ill effects from radiation exposure.
It was an interesting book.
He was trying to build a breeder reactor using Thorium transmuting to U233 which is fissonable.
His mistake was not knowing this reaction also produces U232, a gamma ray emitter.
It could have killed everyone within 100 yards if they hadn’t turned it off.