If the nuclear plant has a melt down how far away will there be major health concerns in Japan?

Question:

I know it is 50 miles to stay away. So if something worse were to happen how far would it effect people?

Answer:

The radiation can travel vast distances in the wind depending how much is leaked into the atmosphere and which way the wind is blowing. If the wind is hard and there is a lot leaked it could affect other Countries. Let's all hope not and no results may be known for a very long time