Question

give one reason how increasing dependence on nuclear power generation is a threat for future generation

Answer 1

Hope this answer will be useful for you;

More nuclear power plants means more dangerous things for the climate. These can even result in a severe death. The best example of this is Chernobyl, Russia. The nuclear plants are the threats because it released radioactive materials everywhere. The problem of global warming can be increased and the ultimate result is pollution.  

Answer 2

because it releases radioactive materials everywhere