8 Avril 2015
March 31, 2015
The people in charge of decommissioning the Fukushima Daiichi Nuclear Plant have been hit with one setback after another.
They've had to battle leaks of radioactive water, and face accusations of misconduct. It's lost them a lot of public trust, and they're trying to win it back. They still face some major challenges with the decommissioning process.
Tokyo Electric Power Company has created a subsidiary dedicated to tackling those challenges. The company will oversee every step of the decommissioning work.
NHK WORLD's Yoichiro Tateiwa sat down with Naohiro Masuda, the man who leads that company.
Naohiro Masuda is in charge of the entire decommissioning process at Fukushima Daiichi. And he brings valuable experience to the job. He's worked as a nuclear engineer for decades. He's faced criticism for a long delay in letting people know about radioactive water reaching the ocean. TEPCO announced the leak almost a year after workers discovered it. And Masuda didn't shy away from accepting the blame.
"I focused on finding out where the radioactive water was coming from and why, instead of sharing the information with the public. I greatly regret my decision and I want to apologize for how I handled it."
Naohiro Masuda / President, Fukushima Daiichi Decommissioning Company
Fukushima Daiichi still generates more than 300 tons of radioactive water every day. But Masuda says workers at the plant know how to handle it. He discussed his plan to build a massive ice wall around the plant... to stop any more groundwater getting in... and getting contaminated. Some experts have questioned whether that will work. Masuda says he's confident it will.
"We've done some experiments at the plant on a smaller scale. We built a 40-meter ice wall. And that proved successful. We managed to stop water entering the site. Now we are going to do it on a bigger scale, a 1,500 meter wall. I'm confident this will be just as effective as it was on a smaller scale."
Masuda's engineers have finished removing spent fuel from the No.4 reactor building. He says the next step is to remove spent fuel from the No.3 reactor building.
"A hydrogen explosion left the number 3 reactor building full of radioactive rubble. We've finished removing it. But radiation levels are still extremely high. That's why we have to work remotely. We've built cranes to do that work. We're just waiting for the workers to finish cleaning up around the building so we can bring the cranes in."
Masuda says radiation in some areas of the crippled reactor buildings is still so high that workers can only stay there for a few minutes. The hardest part of decommissioning the plant will be removing the fuel that's cooled and turned into highly radioactive debris.
"We have no idea about the debris, we don't know its shape or strength. We have to remove it remotely from 30 meters above. But we don't have that kind of technology yet. It simply doesn't exist."
Experts say workers will have to keep the debris submerged in water to prevent radiation from being released. But Masuda says that's not as easy as it sounds.
"We still don't know whether it's possible to fill the reactor containers with water. We've found some cracks and holes in the three damaged container vessels. But we don't know if we've found them all. If it turns out there are other holes, we might have to look for some other way to remove the debris."
The government wants that work to begin in 2020. I asked Masuda how confident he is that he can hit that target and his answer was surprisingly candid.
"It's a very big challenge. Honestly speaking, I cannot say it's possible but I also do not wish to say it's impossible."
I also asked Masuda what he needs most for the operation to succeed.
"That's hard to say, but probably experience. How much radiation exposure can people tolerate? What kind of information do residents in the area need? There is no text book to teach us what to do. I have to make decisions every step of the way. And I must be honest with you... I cannot promise that I will always make the right decision."