By the summer of 2022, storage tanks holding processed contaminated water at the Fukushima Daiichi NPP site will become completely full, according to Tokyo Electric Power Co (Tepco). This marks the first time Tepco has given a date for when full capacity will be reached in the tanks holding the water processed to remove most radioactive substances, Asahi Shimbun reported on 9 August. Tepco has presented their estimates to meeting of a subcommittee under the Ministry of Economy, Trade and Industry, which deal with the issue.
The melted fuel in the three destroyed reactors continues to be cooled using water, which then becomes contaminated with high levels of radioactive substances. Groundwater has also seeped into the reactor buildings, increasing the high volume of accumulated contaminated water. While most of the radioactive substances are being removed through processing equipment, tritium remains in the processed water. Some 960 large storage tanks, which have been constructed at the site currently hold about 1.15 million tons of the processed water, The Nikkei reported.
Tepco continues to install new storage tanks, but space limitations mean that by the end of 2020, a maximum storage capacity of about 1.37 million tons will be reached. Officials estimate that, even if the groundwater volume is reduced, the storage tanks will become full by mid-2022. An average 170 tons of contaminated water was produced each day during fiscal 2018, mostly as the result of groundwater flowing into the ruined plant. Tepco, which has a government-backed fund as its top shareholder following a 2012 bailout, aims to reduce the volume to 150 tons a day next year. But even at the reduced level, the tanks would reach full capacity in 2022.
One option being considered by the central government is to dilute the processed water and gradually release it into the ocean. But local fishermen are fiercely opposed to this solution. Sources cited by Asahi Shimbun said the industry ministry was planning to present another option of storing the processed water for a long period outside the Fukushima plant site, which was acceptable to the fishermen. However, Tepco is sceptical about the possibility of finding a community willing to host such a storage site and has also noted that problems would arise in transporting the processed water to a new location.
After the ministry subcommittee considers how to deal with the processed water, the central government will decide on a basic plan, which will be coordinated with other relevant parties, including the local governments involved.