Workers face high radiation levels and stress during challenging Fukushima plant cleanup

The radiation levels at the Fukushima Daiichi nuclear power plant have significantly decreased since the devastating meltdown 14 years ago. In many areas, workers now only wear surgical masks and regular clothing, reflecting the improved safety conditions.

However, the situation is different for those who venture into the reactor buildings, especially the three that were damaged during the 2011 earthquake and tsunami. These workers must adhere to strict safety measures, including wearing full facemasks with filters, multi-layered gloves and socks, shoe covers, hooded hazmat coveralls, a waterproof jacket, and a helmet.

Undertaking the challenging task of removing melted fuel debris from the reactors as part of a massive nuclear cleanup operation that may span over a century, workers are not only dealing with immense psychological strain but also facing hazardous radiation levels.

The Associated Press, which recently visited the plant for a tour and interviews, takes a closer look.

Cleaning 880 tons of melted fuel debris

A remote-controlled extendable robot with a tong had several mishaps including equipment failures before returning in November with a tiny piece of melted fuel from inside the damaged No. 2 reactor.

That first successful test run is a crucial step in what will be a daunting, decades-long decommissioning that must deal with at least 880 tons of melted nuclear fuel that has mixed with broken parts of internal structures and other debris inside the three ruined reactors.

Akira Ono, chief decommissioning officer at the Tokyo Electric Power Company Holdings, which manages the plant, says even the tiny sample gives officials a lot of information about the melted fuel. More samples are needed, however, to make the work smoother when bigger efforts to remove the debris begin in the 2030s.

A second sample-retrieval mission at the No. 2 reactor is expected in coming weeks.

Operators hope to send the extendable robot farther into the reactor to take samples closer to the center, where overheated nuclear fuel fell from the core, utility spokesperson Masakatsu Takata said. He pointed out the target area as he stood inside the inner structure of the No. 5 reactor, which is one of two reactors that survived the tsunami. It has an identical design as No. 2.

Hard to see, breathe or move

Radiation levels are still dangerously high inside the No. 2 reactor building, where the melted fuel debris is behind a thick concrete containment wall. Earlier decontamination work reduced those radiation levels to a fraction of what they used to be.

In late August, small groups took turns doing their work helping the robot in 15- to 30-minute shifts to minimize radiation exposure. They have a remotely controlled robot, but it has to be manually pushed in and out.

“Working under high levels of radiation (during a short) time limit made us feel nervous and rushed,” said Yasunobu Yokokawa, a team leader for the mission. “It was a difficult assignment.”

Full-face masks reduced visibility and made breathing difficult, an extra waterproof jacket made it sweaty and hard to move, and triple-layered gloves made their fingers clumsy, Yokokawa said.

To eliminate unnecessary exposure, they taped around gloves and socks and carried a personal dosimeter to measure radiation. Workers also rehearsed the tasks they’d perform to minimize exposure.

The mission stalled early on when workers noticed that a set of five 1.5-meter (5-foot) pipes meant to push the robot into the reactor’s primary containment vessel had been arranged in the wrong order.

A camera on the robot also failed because of high radioactivity and had to be replaced.

The workers’ highest individual radiation dose was more than the overall average but still far below anything approaching a 100-millisievert five-year dose limit.

Even so, a growing number of workers are concerned about safety and radiation at the plant, said Ono, the decommissioning chief, citing an annual survey of about 5,5,00 workers.

In 2023, two workers splashed with contaminated sludge at a water treatment facility suffered burns and were hospitalized, though they had no other health problems.

Making sure it’s safe

Yokokawa and a plant colleague, Hiroshi Ide, helped in the 2011 emergency and work as team leaders today. They say they want to make the job safer as workers face high radiation in parts of the plant.

On the top floor of the No. 2 reactor, workers are setting up equipment to remove spent fuel units from the cooling pool. That’s set to begin within two to three years.

At the No. 1 reactor, workers are putting up a giant roof to contain radioactive dust from decontamination work on the top floor ahead of the removal of spent fuel.

To minimize exposure and increase efficiency, workers use a remote-controlled crane to attach pre-assembled parts, according to TEPCO. The No. 1 reactor and its surroundings are among the most contaminated parts of the plant.

What’s next?

Workers are also removing treated radioactive wastewater. They recently started dismantling the emptied water tanks to make room to build facilities needed for the research and storage of melted fuel debris.

After a series of small missions by robots to gather samples, experts will determine a larger-scale method for removing melted fuel, first at the No. 3 reactor.

Experts say the hard work and huge challenges of decommissioning the plant are just beginning. There are estimations that the work could take more than a century. The government and TEPCO have an initial completion target of 2051, but the retrieval of melted fuel debris is already three years behind, and many big issues remain undecided.

Ide, whose home in Namie town, northwest of the plant, is in a no-go zone because of nuclear contamination, still has to put on a hazmat suit, even for brief visits home.

“As a Fukushima citizen, I would like to make sure the decommissioning work is done properly so that people can return home without worries,” he said.