It seems that the 2011 nightmare isn't over yet as latest developments on the containment of radioactive materials (including the water that's used to cool the reactor) have failed and some of the irradiated water may already have leaked into the Pacific Ocean. Japanese fishermen are dismayed at what they call "incompetence" of the government agency responsible for the disaster management. God forbid, if the irradiated water flows out into the sea because it will cause a major disaster on not only the Japanese fishing industry but also on the rest of South East Asia.
The problem with nuclear meltdowns or leaks is that the radiation stays for a very long time, try 10,000 years. Yeah, that's scary enough and if you don't want to accept it there is an ancient city or probably cities between the borders of India and Pakistan that have a strange level of radiation that only a nuclear explosion could have caused. Now those cities are believed to be at least 5,000 years old; unfortunately, the Indian government has closed off the site for any further studies so archeologists can't confirm how old the cities are. But most of the experts suggest that it may be as old as 12,000 years. The point is radiation is a very nasty stuff and we wouldn't want it especially in the pacific Ocean.