TOKYO: Tokyo Electric Power Company Holdings Inc. said Tuesday it may spend up to 20-30 years releasing to the environment contaminated water from its disaster-crippled Fukushima No. 1 nuclear power plant.

The possible time span was mentioned in draft plans TEPCO drew up in line with a government panel's report in February calling the release of the water to the ocean or into the air in the form of vapor "realistic options."

The company currently stores roughly 119 tons of water that still contains tritium and other radioactive substances after going through the clarification process at the nuclear plant, which suffered the triple meltdown in March 2011 caused by a 9.0-magnitude earthquake and monster tsunami. The storage amount is ever increasing.

According to the draft plans, TEPCO will first conduct secondary treatment work to reduce radioactive substances in the water other than tritium, which cannot be removed by any existing systems, to levels below national standards.

Following the treatment, the water will be released to the ocean after being diluted with seawater to lower the radiation level to 1,500 becquerels per liter, or emitted into the air from a tall exhaust stack after being vaporized.

TEPCO also plans to enhance its use of social media to prevent surrounding communities from being hurt by ungrounded rumors about exposure to radiation from the released water.

JIJI Press