IN 1964, the explosion of a nuclear-powered U.S. navy satellite increased the total world-wide atmospheric burden of plutonium by four per cent. Plutonium is a man-made element so carcinogenic that a dot-size particle can kill. Mexico`s first nuclear power plant is built on a geologic fault near an active volcano, only 30 kilometres from the epicentre of a recent major earthquake. The United States has dumped thousands of barrels of nuclear waste into the Atlantic and Pacific oceans. Radiation levels around one dump site are 260,000 times the background level. U.S. authorities may have collaborated in the cover-up of a huge Soviet nuclear disaster in 1949, to shelter their own industry from informed debate about nuclear safety. The Greenpeace Book of the Nuclear Age (McClelland & Stewart, 378 pages, $14.95 paper) is an international catalogue of such events, the fruit of formidable research. Disasters and nearmisses have been so abundant that some get only three lines. John May, the author, keeps his voice down and lets the accumulating horror of bare facts do the job.