The head of the International Atomic Energy Agency has visited the crippled Fukushima Daiichi nuclear power plant to assess progress in its decommissioning and preparations for releasing treated water from the plant.

Director General Rafael Mariano Grossi, along with four other IAEA officials, spent two hours inspecting the plant on Thursday morning. The visit was Grossi's first to the plant since February 2020.

According to officials of the plant's operator, Tokyo Electric Power Company, the IAEA delegation was shown ongoing work to install a cover over the No.1 reactor building in preparation for removing spent fuel from inside. The team was also briefed on how the huge volume of treated water from the plant is being stored, and how its radiation levels are being analyzed.
Grossi later told reporters that he's impressed that both the decommissioning process and the preparations for releasing treated water into the ocean have been progressing far beyond what he expected.

He said that as the planned date for starting the discharge of the treated water approaches, the IAEA will continue to analyze and verify information to be released by TEPCO and government officials on the matter.

On Wednesday, Japan's nuclear regulator approved TEPCO's plan to discharge treated water from the plant into the ocean after diluting it so that the level of tritium after filtration is within what national regulations allow.

The IAEA says it will publicize a report on the discharge plan by its planned start next spring, based on the findings of the director general's inspection and reports from a taskforce visit in February.
Water being used to cool molten fuel at the plant mixes with rain and groundwater. The water is treated to remove most radioactive materials, but still contains tritium -- the radioactive isotope of hydrogen.