The operator of the Fukushima Daiichi nuclear power plant says it aims to install facilities to release treated water into the sea around mid-April of 2023.
Tokyo Electric Power Company announced on Tuesday that it has filed a plan for handling the water with Japan's nuclear regulators.
The facilities will be used to deal with water that has been treated after being used to cool molten nuclear fuel at the damaged plant. It is currently being pooled in tanks within the premises. While most radioactive substances have been filtered out from the stored water, a substance called tritium is difficult to remove.
In line with government policy, TEPCO plans to discharge treated water into the sea after diluting it with seawater so that tritium and other radioactive materials are below levels mandated by national regulations.
The submitted documents detail dilution procedures as well as the design of an undersea tunnel to release the treated water about one kilometer off the coast.
TEPCO says it wants to start construction work around June next year after getting Nuclear Regulation Authority approval and gaining local understanding.
Matsumoto Junichi, a TEPCO official in charge of the plan, said the firm will explain the plan to local residents and related parties in parallel with regulatory screening.
He also said the company wants to ensure safety in the design and operation of the facilities.
TEPCO faces the challenge of figuring out how to ease persistent worries among local residents and others over the release of treated water.