Decommissioning of Wrecked Fukushima Nuclear Plant a Long Way Off

By Masahiro Amazawa / Yomiuri Shimbun Staff Writer

16:55 JST, February 5, 2021

OKUMA, Fukushima — Wreckage still litters parts of the Fukushima No. 1 nuclear power plant and reactor building girders remain exposed almost a decade after the March 2011 accident, serving as concrete illustrations that decommissioning the reactors still has a very long way to go.

The Yomiuri Shimbun was granted access to the plant Thursday, ahead of the 10th anniversary of the nuclear accident triggered by the Great East Japan Earthquake and tsunami. A hydrogen explosion damaged the plant’s No. 1 reactor building a day after the quake. From elevated ground about 100 meters west of the reactor building, the framework of the building’s uppermost floor, which was left exposed by the explosion, and piles of wreckage from the accident were clearly visible.

In the autumn of 2011, the plant’s operator, Tokyo Electric Power Company Holdings Inc. (TEPCO), constructed a temporary structure to enclose this damaged reactor building to prevent radioactive materials from being released into the air. The structure, dubbed a “cover,” was removed in the autumn of 2016 because it would hinder the work of removing 392 nuclear fuel rods from the spent fuel pool inside the building. TEPCO will install an even larger purpose-built replacement cover that can accommodate the work of extracting the nuclear fuel and a crane for lifting this fuel.

Fuel removal has been completed from reactor No. 4. TEPCO expects that removing fuel from pools inside the five other reactor buildings could take until 2031. Nearly a decade has passed since the nuclear accident occurred, but decommissioning the reactors remains an extremely complex operation.

About 1.2 million tons of water treated to remove most radioactive substances after being used for purposes such as cooling melted nuclear fuel is stored in about 1,000 huge tanks at the plant. The final disposal method for this treated water remains undecided, and there are concerns this could slow the decommissioning work.

After entering the plant premises by bus, we first got off at a spot about 35 meters above sea level that overlooks the Nos. 1 to 4 reactor buildings. Paving and other measures reduced radiation levels to such an extent that since 2018 it has not been necessary to wear protective clothing on 96% of the plant’s premises. We did not require such gear on this elevated area, which was no more than 100 meters from the reactor buildings.

But this year, the many workers involved in decommissioning the nuclear plant have been wearing masks and taking other measures to prevent the spread of coronavirus. The Yomiuri reporting team underwent PCR tests before going inside the nuclear plant.

Rows of water storage tanks fill much of the southern half of the plant site. Last autumn, the government strongly indicated a desire to resolve this problem with consideration being given to releasing treated water into the Pacific Ocean. However, fisheries groups and others opposed this option, so the plan remains undecided. “We must make sure this huge volume of treated water does not interfere with the smooth decommissioning of the nuclear plant,” was the only comment a company spokesperson would provide.

For the final stop of our visit, we put on protective gear and climbed up to a work area beside the top floor of the No. 3 reactor building. Looking south, we could see broken pipes, wall materials and other wreckage from the accident still on the ground between the Nos. 3 and 4 reactor buildings. My dosimeter showed a reading here of about 235 microsieverts per hour — the highest level of the trip. Spending a little more than four hours here would reach the legal annual radiation exposure limit for ordinary citizens of 1 millisievert.