OKUMA, Fukushima — The site of the Fukushima Daiichi nuclear power plant continues to see new construction projects some 11 years after the disaster triggered by the 2011 Great East Japan earthquake and tsunamis.
This Mainichi Shimbun reporter had the opportunity to tour the plant for the first time in seven and a half years and reflect on why new facilities keep popping up even as the plant heads towards dismantling.
When I last visited the Fukushima nuclear power plant, high radiation levels relegated me to observing the site from inside a bus, but when I visited on February 26, I was able to enter the outdoor area near the reactor buildings of Units 1-4, where the incidents occurred. Progress has been made in decontaminating radioactive materials scattered during the meltdown, and 96% of the premises can now be walked around in normal work clothes.
While dismantling seems to be progressing, various facilities have been newly built and the water problem remains. A growing number of reservoirs are storing contaminated treated water after it has been pumped out to cool fuel debris that melted in the crash, as well as groundwater and rainwater that spilled into buildings. Inside the tanks, the contaminated water is caused to reach a radioactive concentration below the regulatory levels.
On the seventh floor of a building near the entrance to the site, a representative from Tokyo Electric Power Co. Holdings Inc. (TEPCO) gave me an overview of the entire facility. I could see two large cranes on the ocean side around Units 1-4, and another large crane and frame structure on the mountain side. When I asked about it, the representative told me that the frame was assembled in a remote location to reduce worker exposure to radiation. But this was not a facility being dismantled; it is a blanket 66 meters long, 56 meters wide and 68 meters high that will wrap around Unit 1.
The hydrogen explosion in Unit 1 blew off the roof of the building and 392 pieces of nuclear fuel remain in its spent fuel pool near the ceiling. Their removal should begin during the 2027 to 2028 financial year. To do this, the surrounding debris must be removed and the installation of the cover will prevent the work from dispersing radioactive dust.
Ground improvement work was progressing on the south side of neighboring Unit 2. There, a work platform to remove 615 pieces of nuclear fuel from Unit 2 will be constructed, with start-up scheduled for fiscal year 2024 to 2026.
Buildings in Units 1 through 4 were damaged and contaminated, so various structures, such as platforms and covers, had to be built to remove nuclear fuel from the pools. Particularly visible was the thick steel frame of the Unit 4 facility, which was completely defuelled in 2014. Although 53 meters tall, it surprisingly uses about the same amount of steel as the 333 meter tall Tokyo Tower. As the nuclear fuel has been removed in order, new construction work is continuing around the reactor buildings.
The Japanese government decided in April 2021 to release treated water stored in at least 1,000 tanks into the ocean. The decision is no stranger to the construction boom.
At the Nuclear Regulatory Authority’s March 1 review meeting on treated water discharge, TEPCO explained that offshore discharge was necessary “to safely and regularly dispose of fuel debris and fuel spent nuclear”. The company has listed at least 10 facilities for future construction. In other words, the tanks must be removed to provide land for these facilities.
Related construction work had already begun at the seaside, where workers dug vertical holes to contain the treated water before it was discharged. After the approval of the implementation plan, the construction of the underwater tunnel and other works necessary to release the water 1 km offshore will also begin.
Meanwhile, some broken cranes and damaged buildings were left behind without being dismantled. The representative told the Mainichi Shimbun that this was partly because they were trying to keep the volume of solid waste processing low.
Construction of facilities is also underway to process ever-increasing amounts of solid waste. The rep said a white building I spotted on the northwest side of the site was the Volume Reduction Facility and that construction is underway for a solid waste storage facility opposite.
The volume reduction facility scheduled for completion in March 2023 will use crushing and other methods to reduce volumes of concrete and scrap metal. Although nine storage buildings already exist, a 10th will soon be built. Nearby was also a new incineration facility to burn downed trees. TEPCO estimates that the solid waste generated will reach a volume of 794,000 cubic meters by March 2033 and there will continue to be more related facilities.
Removal of fuel debris will begin in late 2022. In the future, facilities to retain fuel debris and to store and reduce the volumes of high radiation dose solid waste generated by the work will also be required.
Each year creates new tasks that generate more waste, and the facilities to accommodate them. These buildings are also destined to eventually become solid waste. While this cycle continues, a final waste disposal method is not determined. The government and TEPCO timetable indicates that there are 20 to 30 years left for the dismantling of the plant. But on the site, where new construction projects continue to appear, a clear picture of the end of dismantling has yet to emerge.
(Japanese original by Takuya Yoshida, Department of Science and Environmental News)