Fusion and fission are a big part in nuclear engery. Fission is a nuclear reaction or a radio active decay process in which the nucleus of an atom splits Fusion is nuclear reaction in which two or mor atomic nuclei collide at a very high speed and join to form a new type of atomic nucleus
Fukushima was a nuclear meltdown that happen due to a tsunami hitting the power plant and things continued into a earthquake. The dangers still associated with it is about the waste being radioactive.