TOKYO (Kyodo) -- Japan's industry ministry on Friday recommended releasing treated radioactive water from a crippled Fukushima nuclear plant into the ocean, saying it would be preferable to releasing it into the atmosphere.
The government has been exploring ways to dispose of more than 1 million tons of water used to cool the melted-down cores at, and groundwater near, the Fukushima Daiichi power plant, as the complex is running out of storage space.
The water is being treated using an advanced liquid processing system, or ALPS, before being stored in tanks at the plant. But this does not remove tritium and has been found to leave small amounts of other radioactive materials.
Local fishermen have voiced strong opposition to releasing the water into the ocean, saying consumers will be afraid to buy seafood caught in the area.
Still, the government is leaning toward either dumping the water into the Pacific Ocean, or boiling it and releasing the vapor into the atmosphere.
Both are "realistic options," the Ministry of Economy, Trade and Industry told a government subcommittee on Friday, adding that releasing the water into the ocean would make it easier to monitor radiation levels.
This method could be carried out "with more certainty," it said, because the plant's operator, Tokyo Electric Power Company Holdings Inc., had experience in it, albeit on a much smaller scale, before a powerful earthquake and tsunami triggered a triple meltdown at the plant in March 2011.
The ministry has said the health effect of either approach would be minimal, estimating it would result in between 0.052 and 0.62 microsievert annually for a discharge into the ocean, and 1.3 microsieverts if released into the atmosphere. That compares with the 2,100 microsieverts people are exposed to daily.
Other methods the subcommittee has considered include injecting the water deep into the ground, solidifying and burying it, and extracting only the hydrogen and releasing it into the atmosphere.
Meanwhile, the ministry stressed the importance of gaining the understanding of the local community before making a decision, and of preventing the spread of misinformation that would raise undue fears.
The amount of the water is increasing by about 150 tons per day and TEPCO is fast running out of tanks to store them in. The utility is looking to expand capacity to 1.37 million tons by the end of 2020, but has no plans beyond then.