CRITICALITY SAFETY CONTROL OF FUEL DEBRIS PRODUCED BY THE ACCIDENT OF FUKUSHIMA DAIICHI NUCLEAR POWER PLANTS - TECHNICAL DEVELOPMENT IN JAPAN FROM 2012 AND THE FUTURE

摘要

On 11th March 2011, Japan was attacked by the "2011 off the Pacific coast of Tohoku Earthquake." It was the greatest earthquake ever recorded around Japan. It caused big tsunami and it also attacked Tohoku sea coast area severely and violently. Approximately 16,000 people passed away and still about 2,600 people are lost by the earthquake and the tsunami. This extraordinary natural disaster affected the society of Japan deeply. But more serious problem is the severe accident occurred in Fukushima Daiichi Nuclear Power Plants (1 FNPP) after the earthquake and tsunami attack. By the tsunami after the earthquake, because of loss of ultimate heat sink (LUHS), three reactors of 1 FNPP were damaged and the intact fuel became fuel debris.