Japan's government said last week that the release is likely to begin sometime in the spring or summer and continue for decades.
Japanese regulators are responsible for examining whether preparations for the release by the plant operator, Tokyo Electric Power Company Holdings, are consistent with its approved implementation plan.
At the request of Japan, IAEA is reviewing whether the reparations for the discharge comply with international standards.
A massive earthquake and tsunami in 2011 destroyed the Fukushima Daiichi plant’s cooling systems, causing three reactors to melt and release large amounts of radiation. Water used to cool the three damaged reactor cores, which remain highly radioactive, has leaked into the basements of the reactor buildings and has been collected, treated and stored in about 1,000 tanks that now cover much of the plant.
The government and TEPCO say the tanks must be removed so that facilities can be built for the plant's decommissioning. The tanks are expected to reach their capacity of 1.37 million tons later this year.
Most of the radioactivity is removed from the water during treatment, but tritium cannot be removed and low levels of some other radionuclides also remain. The government and TEPCO say the environmental and health impacts will be negligible because the water will be released gradually after further treatment and dilution by large amounts of seawater.
Some scientists say the impact of long-term, low-dose exposure to tritium and other radionuclides on the environment and humans is still unknown and the release should be delayed. They say tritium affects humans more when it is consumed in fish.
Local fishing communities have fiercely rejected the plan, saying their already badly hurt business will suffer again due to the negative image from the water release. Neighboring countries including China and South Korea have also raised concerns about potential health risks.
Caruso, who heads the IAEA’s Department of Nuclear Safety and Security, said the task force will release a report on this week’s mission within three months and make another visit to Japan in the second quarter of the year to meet with Japan’s industry ministry, the safety authority and TEPCO “to finalize any outstanding questions” before compiling a comprehensive report.