Beginning paragraph: Nuclear energy has become a new form of power used in multiple areas e.g the use in medical treatment, preservation for goods, transmutation doping of semiconductors and nuclear energy as a way of generating electricity is currently developing in a fast speed. Moreover, nuclear energy is generally treated as an economic, safe, reliable, and clean resource. The nuclear power plant, as well has many advantages such as it cause less pollution to the environment; the uranium is abundant in earth; the process of generating electricity would not intensify greenhouse effect and so on. However, the safety of nuclear power has long been a issue that is needed to be solved. Fukushima Chernobyl and Three Miles Island accidents all showed that even the probability of having such an accident is low, but the aftermath is really disastrous. From these miserable experiences, what can we learn from and what can we do to evade such kind of problems?