Authorities say ‘no practical alternative’
Japan’s Nuclear Regulation Authority has formally approved Tokyo Electric Power Company’s (Tepco) plans for the release of treated water from its Fukushima-Daichi nuclear power station into the ocean.
The plan, given initial approval last year, includes standards for the levels of radioactive materials contained in the water when it is released from the station, which has been permanently shut down since a March 2011 earthquake and tsunami.
Construction of an undersea tunnel to be used for the water release is expected to be completed by the end of June.
The government and Tepco aim to start discharging the water around spring or summer this year. The process is being monitored by the International Atomic Energy Agency.
In February this year, the NRA approved Tepco’s draft operation plan, which included the types of radioactive materials whose levels will be measured when the water is released and standard levels for them.
The water is being stored in tanks at the Fukushima-Daiichi site and is treated through a process known as advanced liquid processing system (Alps) to remove most of the radioactivity. Tritium, which cannot be removed by Alps, and some very low levels of other radionuclides, remain in the water after processing.
The water was largely used to cool the three damaged reactor cores, which remain highly radioactive. Some of it has since leaked into basements of the reactor buildings but was collected and stored in tanks.
Space for the tanks is running out and the long-term management of the treated water is necessary to allow for the further decommissioning of Fukushima-Daiichi.
Last month, Tepco said the tanks are set to reach their full capacity around February to June 2024.
Japanese authorities have said there is no practical alternative to releasing the water as storage space ran out. They said there is no risk to human health and that operating nuclear plants around the world release similar water every day.
Five disposal methods for the water were being considered by the government: controlled discharge into the sea, ground injection, discharge as steam, discharge as hydrogen, and solidification for underground burial.
