Worker handling plutonium in a glove box at a processing plant at Los Alamos National Laboratory,New Mexico,USA. Plutonium (atomic number 94,symbol Pu) is almost exlusively a man- made substance,although a minute quantity of its major isotope,Pu-239,is formed by the decay of uranium,the heaviest naturally-occurring element. Pu-239 is capable of undergoing nuclear fission (splitting) into smaller nuclei,a process that is accompanied by a vast release of energy. Hence its use as an explosive in atomic bombs and as a fuel in nuclear reactors. Plutonium is highly toxic and a potent carcinogen (cancer-forming agent),even in minute quantities |