Whole country? Not likely. These things following predictable patterns of disbursal and deposition. If there is a major effluent release, the plume will track a reatiely narrow line over land following wind direction. Particulates that end up in the ocean will become so diffuse as to be non-existent. Gamma would all be local and temporary. Too soon to write off Japan. This is not the movies, and no one in the industry can watch “China Syndrome” with a straight face. Don’t work that way.
For all the hysterics about Chernobyl, it has become one of the great wildlife preserves in the worlds. Many of the elderly never left and continue to live there.. and no, they didn’t sprout a second head or such other nonsense.