The operator of the crippled Fukushima Daiichi nuclear power plant says the tanks for storing water that contains radioactive substances are expected to reach their capacity limit in three years' time.
Tokyo Electric Power Company, or TEPCO, revealed on Thursday that the tanks will become full around the summer of 2022.
Contaminated water generated at the plant is being treated to get rid of radioactive substances, but tritium is difficult to remove.
About 1.15 million tons of water containing tritium is being stored in nearly 1,000 tanks at the plant, and the volume continues to grow.
TEPCO plans to add more tanks before the end of next year, but it has no plans on what to do after that. The company says it will need to build facilities for storing spent fuel units at the plant as part of the decommissioning process. It says this will make it difficult to reserve land for more tanks.
Possible options under consideration to dispose of the tritium-laced water include creating large storage tanks, and diluting and releasing the water into the sea, underground, or into the air.
Local residents strongly oppose the release of the water into the environment, even if the contamination level is reduced below the government-set limits. They say this would only aggravate the harmful rumors about the prefecture.
Government officials have been discussing the issue with experts, but no decision has been made yet.