Nuclear power can cause an explosion like the Chernobyl disaster that occur in 1986 that release large quantities of radioactive contamination to the planet and was consider to be the worst accident in History. That disaster caused a lot danger to the human life because it got spread widely in USSR and Europe. Women where afraid to give birth to unhealthy baby's and older people stay at their home to die from the radioactive contamination.   In 2011 there was another accident with nuclear power that caused radiation in Japan caused by a tsunami and earthquake with a magnitude of 9.0 . The accident in Japan affected thousands of residents and some evacuated to another country because of the radiation.

http://upload.wikimedia.org/wikipedia/commons/thumb/2/2a/SH-60B_helicopter_flies_over_Sendai.jpg/800px-SH-60B_helicopter_flies_over_Sendai.jpg

http://www.huffingtonpost.com/2011/02/02/chernobyl-25-years-after-_n_816902.html