Event sequence of the fukushima daiichi accident

Abstract

On March 11, 2011, the Great East Japan Earthquake and subsequent tsunami hit Fukushima Daiichi Nuclear Power Station. Flooding by the tsunami induced loss of AC and/or DC power for reactor cooling, hence the reactor water level decreased and fuel was exposed. Water reacting with high temperature fuel metal covering resulted in hydrogen generation and hydrogen explosion of reactor buildings. This accident caused radioactive release to the environment. In this chapter, an attempt has been made to understand in detail the mechanism of the accident progression for Units 1–3 that were in operation by utilizing results of computer simulations. It should be noted that, due to limited information and capability of the state-of-the-art severe-accident simulation tools, there are still unanswered questions, which should be tackled by academic research for improving and enhancing safety for the nuclear industry now and in the future.