Construction projects surge at Fukushima nuclear plant despite decommissioning progress

OKUMA, Fukushima -- The site of the Fukushima Daiichi Nuclear Power Station continues to host 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 visit the plant for the first time in seven and a half years, and reflect on why new facilities continue to appear even as the plant moves toward decommissioning.

The last time I visited the Fukushima Nuclear Power Station, high radiation levels relegated me to observing the site from inside a bus, but on my Feb. 26 visit I was able to enter the outdoor area near the reactor buildings of Units 1 to 4, where the incidents occurred. Progress has been made toward decontaminating radioactive materials scattered in the meltdown, and 96% of the premises can reportedly now be walked around in normal work clothes.

While decommissioning seems to be advancing, various facilities have been newly constructed, and the issue of water remains. A rising number of tanks store treated water contaminated after it was pumped to cool fuel debris that melted down in the accident, as well as groundwater and rainwater that flowed into the buildings. Inside the tanks, the contaminated water is made to reach a radioactive concentration below regulation levels.

On the seventh floor of a building located near the site's entrance, a Tokyo Electric Power Co. Holdings Inc. (TEPCO) representative gave me an outline of the entire facility. I could see two large cranes on the ocean side around Units 1 to 4, and another large crane and framework structure on the mountain side. When I asked about it, the representative told me the frame was being assembled in a remote location to reduce worker radiation exposure. But it wasn't a facility being dismantled; it's a cover measuring 66 meters long, 56 meters wide, and 68 meters high that will wrap around Unit 1.

The hydrogen explosion in Unit 1 blew the building's roof off, and 392 pieces of nuclear fuel remain in its spent fuel pool near the ceiling. Their removal is scheduled to start in fiscal 2027 to 2028. For this to happen, the surrounding debris must be removed, and the cover's installation will help prevent the work dispersing radioactive dust.

Ground improvements works were progressing on the neighboring Unit 2's south side. There, a working platform to remove 615 pieces of nuclear fuel from Unit 2 will be built, with its start slated for fiscal 2024 to 2026.

The buildings for Units 1 through 4 were damaged and contaminated, so different structures, such as platforms and covers, had to be built to remove nuclear fuel from the pools. Particularly conspicuous was the thick steel frame of the Unit 4 facility, from which fuel was completely removed in 2014. Although 53 meters high, it surprisingly uses about the same amount of steel as the 333-meter-high Tokyo Tower. Since the nuclear fuel is being removed in order, new construction work continues in reactor buildings' vicinities.

The Japanese government decided in April 2021 to release into the ocean treated water stored in at least 1,000 tanks. The decision is not unrelated to the boom in construction.

At the Nuclear Regulation Authority's March 1 review meeting on treated water discharge, TEPCO explained the offshore release was needed "to safely and steadily remove fuel debris and spent nuclear fuel." The company listed at least 10 facilities earmarked for future construction. Put another way, the tanks need to be removed to provide land for these facilities.

Related construction work had already started at the seashore, where workers dug vertical holes to contain treated water before its release. After the implementation plan's approval, undersea tunnel construction and other necessary work to release the water 1 km offshore will also begin.

Meanwhile, some broken cranes and damaged buildings have been left on site without being dismantled. The representative told the Mainichi Shimbun this was partly due to them trying to keep the solid waste processing volume low.

Also underway is construction of facilities to handle ever-increasing solid waste amounts. The representative said a white building I spotted in the site's northwest side was the volume reduction facility, and that building work is going ahead for a solid waste storage facility in front of it.

The volume reduction facility scheduled for completion in March 2023 will use crushing and other methods to reduce concrete and metal debris volumes. Although nine storage buildings already exist, a 10th will soon be constructed. Nearby was also a new incineration facility for burning logged trees. TEPCO estimates solid waste generated will reach a volume of 794,000 cubic meters by March 2033, and that there will continue to be more related facilities.

Fuel debris removal will begin at the end of 2022. In the future, facilities to hold fuel debris and to store and reduce volumes of solid waste with high doses of radiation generated by the work will also be needed.

Each year creates new tasks that generate more waste, and the facilities to accommodate it. These buildings are also destined to eventually become solid waste. While this cycle continues, a final disposal method for the waste is undetermined. The government's and TEPCO's timetable says 20 to 30 years of plant decommissioning remain. But on site, where new construction projects continue to appear, a clear picture of when decommissioning will finish has yet to emerge.

(Japanese original by Takuya Yoshida, Science & Environment News Department)