The site of the worst nuclear disaster in history might be turning into an accidental wildlife sanctuary.  More than 100,000 people had to leave the 1,600 square miles surrounding the Chernobyl nuclear plant, after an explosion in one of the nuclear reactors spewed tons of radioactive material into the air in 1986.  The number of deaths, particularly those from radiation exposure and cancers, has been disputed over the years, with some figures being as low as 43 and others closer to 4,000, or higher.