The Maze of Decommissioning: Searching for the Endpoints of Fukushima Daiichi Nuclear Power Plant, 2018-2019."

The Maze of Decommissioning: Searching for the Endpoints of Fukushima Daiichi Nuclear Power Plant, 2018-2019."

Between 2018 and 2019, less than a decade after the Fukushima Daiichi Nuclear Power Plant accident, the term "decommissioning" was used symbolically in the government's and TEPCO's explanations. The chaotic period immediately after the disaster had passed, and the site appeared outwardly tidy, with debris removed and radiation levels reduced. However, behind this orderly landscape, the exact location of the fuel debris could not even be determined, and the phrase "steady progress" was repeated without concrete measures for removing the debris being decided upon. Behind this was a complex intertwining of technical and political issues at the Fukushima Daiichi Nuclear Power Plant at the time.

After the accident at the Fukushima Daiichi Nuclear Power Plant, the decommissioning of the plant was not merely a physical removal operation, but one that required advanced technology and deep expertise. Several years after the accident, although progress had been made in reducing radiation levels and removing debris, technical progress in accurately identifying the location and condition of fuel debris in the accident reactor had been slow. At this time, the Fukushima Daiichi Nuclear Power Plant urgently needed to develop robotics and tele-operation technologies, and in particular, unmanned aircraft and robots were introduced to work safely in the high-radiation zone. However, it was difficult to completely locate the exact position of the fuel debris, and no concrete measures had been decided on how to remove it.

At the time, TEPCO and the government had a roadmap of "up to 40 years to complete decommissioning," but this figure was only a "rough estimate," and in reality the specific process to complete decommissioning and the definition of termination remained unclear. This ambiguity drew criticism from experts and Diet members. A major problem in the progress of decommissioning was the removal of fuel debris and the associated technical challenges. Fuel debris is the high-temperature material that solidified in the reactor after the meltdown, and special equipment and techniques were needed to remove it.

Furthermore, the advancement of decommissioning technology at nuclear power plants had become an important factor in international competition, and comparisons were being made with the decommissioning technologies of other countries. In particular, the decommissioning support technology developed by Siemens of the U.S. and the expertise of Areva of France in decommissioning high-temperature gas-cooled reactors were attracting attention, but the application of these technologies was limited for decommissioning accident reactors such as those at the Fukushima Daiichi Nuclear Power Plant, and original technological development was required.