DECOMMISSIONING WITH OVERHEAD CRANES OVERHANGING THE REACTOR BUILDING FROM THE FORMER TURBINE BUILDING

抄録

It is necessary to accurately grasp the circumstances for the decommissioning plan of Tokyo Electric Power Co. Inc.'s Fukushima Daiichi Power Station. The decommissioning of Unit 1 will be carried out first. Since March of 2022, TEPCO has been investigating the inside of Unit 1's containment vessel using underwater robots. At the entrance of the pedestal that supports the reactor, it was confirmed that the reinforcing bars and the concrete around the inner skirt had become exposed. These are extremely important for earthquake resistance. If a seismic event occurs, the seismic force on the reactor will not be transferred to the bedrock supporting the power plant. According to our trial calculation, if an earthquake of 440 gal or more occurs, it is predicted that the pedestal base would fail and the reactor would collapse. First of all, it is necessary to urgently take countermeasures against the reactor falling over. This document proposes an emergency countermeasure plan. After that, we propose a decommissioning plan for the entire power plant that can be implemented with current technology.