An International Atomic Energy Agency team of experts said in a review published on April 2 that the two options for the controlled disposal of treated water stored at the Fukushima Daiichi nuclear power plant are “technically feasible.” A Japanese advisory subcommittee outlined the two options—vapor release and discharge to the sea—for the water that is being stored at the plant following the 2011 accident.
The details:The team also said that the two options are routinely used by operating nuclear power plants worldwide under specific regulatory authorizations based on safety and environmental impact assessments. The IAEA experts said that the subcommittee’s recommendations to the Japanese government were based on a comprehensive and scientifically sound analysis addressing the necessary technical, nontechnical, and safety aspects. The government had requested the IAEA’s review of the management of the water treated through the advanced liquid processing system (ALPS). The review included the Subcommittee on Handling ALPS Treated Water Report, issued on February 10.
The IAEA and Japan have been cooperating over the past decade to deal with the aftermath of the Fukushima accident, in areas such as radiation monitoring, remediation, waste management, and decommissioning. During an official visit to Japan in February, IAEA Director General Rafael Mariano Grossi discussed progress made so far toward decommissioning the plant with Prime Minister Shinzo Abe and other senior government officials, as well as future challenges related to the stored water (NN, Mar. 2020, p. 84). Grossi said that the IAEA would continue to offer its technical assistance to Japan in addressing those challenges.
Background: Contaminated water from Daiichi is treated through the ALPS process to remove radionuclides, other than tritium, and then stored at the site. The total tank storage capacity will amount to approximately 1.37 million cubic meters by the end of 2020, and all the tanks are expected to be full around the summer of 2022.
The IAEA team said that water management, including the treated water disposal, was critical to the sustainability of the Daiichi plant decommissioning activities. Reiterating advice from an IAEA decommissioning review mission to the plant in 2018, the experts said that a decision on the disposition path for the stored treated water—after further treatment as needed—should be made urgently, considering safety aspects and engaging all stakeholders. Once Japan has decided on its preferred disposition option, the IAEA said, it will be ready to work with the country to provide radiation safety assistance before, during, and after the disposition.
What they're saying: "The safe and effective implementation of the disposition of ALPS-treated water is a unique and complex case,” said team leader Christophe Xerri, director of the IAEA’s Division of Nuclear Fuel Cycle and Waste Technology. “Solutions are available. They will require sustained attention, safety reviews, regulatory supervision, a comprehensive monitoring program supported by a robust communication plan, and proper engagement with all stakeholders.”
The American Nuclear Society has also come out in favor of the subcommittee's recommendations. On March 3, ANS President Marilyn Kray sent a letter to Hiroshi Kajiyama, head of Japan’s Ministry of Economy, Trade, and Industry. “Several senior members of the ANS technical leadership reviewed the ALPS subcommittee report and determined that it provided balanced and highly credible recommendations that are consistent with current regulatory standards in Japan and around the world,” Kray noted.