It has been more than 32 years since one of the world’s worst nuclear accidents destroyed a reactor at the Chernobyl complex in Ukraine.  Harvard University historian Serhii Plokhy new book, entitled Chernobyl, sorts out the many consequences of the accident, for the health of people in Northern and Eastern Europe and for the politics of the Soviet Union and its successor states. 30-plus years and we’re still learning new things about the persistence of radiation and its human impacts.