CHORNOBYL ZONE, Ukraine — American Yasuo Onishi poses for a photo against the giant white steel arch of the New Safe Confinement, smiling proudly.
Onishi has a good reason to be proud. Back in the early 2000s, the nuclear waste management consultant helped design the confinement that in November finally covered the Chornobyl nuclear power plant’s entombed fourth reactor. After the explosion and fire in 1986, the ruined reactor had been hastily covered with a steel and concrete shelter, which is crumbling and unstable.
“It’s so wonderful to see (the new confinement) finally being made,” Onishi told the Kyiv Post on May 17.
Onishi came to Chornobyl from Washington with a delegation of Japanese scientists from the Fukushima nuclear power plant and Japan’s Atomic Energy Agency to deepen cooperation on nuclear waste management.
A program funded by NATO’s Science for Peace and Security Program brings together scientists from Ukraine, the United States and Japan to figure out how to manage the radioactive fallout from the Chornobyl disaster. It is estimated that more than 100 tons of nuclear waste, in the form of dust and molten core materials, still remain in the fourth reactor.
The program is the next step in cleaning up after the biggest nuclear power plant disaster in history.
Experts will analyze the New Safe Confinement and decide whether it is safe for people to dismantle the highly radioactive steel constructions covering the ruined reactor, and remove the remains of nuclear fuel elements from the reactor.
One of the Japanese experts, Tadahiro Washiya, the head of the fuel debris and analysis division of Japan Atomic Energy Agency, said this program could be just the start.
“Our nations could learn a lot from each other, share their experiences in radioactive waste management, and even create a mechanism for disposing of nuclear waste in the future,” Washiya said.
Waste disposal
In 2018, the French construction consortium Novarka will finish the inside of the New Safe Confinement.
While the 36,000-ton arched structure covered the fourth power block in November, construction inside continues: Novarka is building an intricate system of hydraulic cranes that will help to dismantle the unstable metal constructions of the old shelter, as well as remove the remains of nuclear fuel elements.
The New Safe Confinement cost 1.5 billion euros and has taken more than 10 years to build. More than 40 countries contributed to a special Chornobyl Shelter Fund created in 1997. The European Bank for Reconstruction and Development provided more than 500 million euros of its own resources to support the construction.
Ukraine is responsible for the radioactive waste disposal process.
The Japanese are natural partners. They faced the same challenge after an earthquake and subsequent tsunami caused the Fukushima Daichi nuclear disaster in 2011, the worst incident since Chornobyl’s explosion in 1986.
The tsunami caused by the earthquake flooded the emergency generators that would have provided power to control and operate the pumps necessary to cool the Fukushima reactors. The lack of cooling led to three nuclear meltdowns, hydrogen-air chemical explosions, and the release of radioactive material from the plant.
Onishi, who was a consultant in both Chornobyl and Fukushima, said the disasters had been different in nature. The Japanese, unlike the Ukrainians, had to start the process of removing the nuclear material immediately after the disaster to prevent radioactive contaminants from getting into the sea.
Make it safe
Now that the New Safe Confinement has covered the reactor, the task is to dissemble by 2023 the temporary shelter that was built over the ruined reactor in the first seven months after the disaster. The parts of the shelter will be buried in nuclear waste depositories in the nearby village of Buryakivka.
That will help the Chornobyl workers reduce the possibility of the old constructions collapsing, and will clear space for the next stage of work — the recovery and disposal of the remaining nuclear fuel.
As explained by Sergiy Paskevych, a radioecologist from the Institute for Safety of Chornobyl Nuclear Power Plant, the cranes that are being constructed inside the New Safe Confinement structure “are basically a system of remotely operated cutting tools that will chop up the old steel constructions, while a special dust extractor will remove the radioactive dust.”
“So it is a sort of a gigantic robot that will dismantle the dangerous nuclear waste, while an operator manages and controls the work, sitting at a safe distance,” said Paskevych.
Ukrainian scientists have created a plan to dismantle only one metal construction so far.
“We will start cutting as soon as Novarka finishes the system,” Paskevych added.
Radiation levels are still high in the Chornobyl zone. They range from 500 to 1,000 micro-roentgens per hour — while as safe does is considered to be only 30 micro-roentgens per hour. So scientists will have to figure out how to ensure maximum safety for the workers that will be involved in the decommissioning process.
Onishi said nowadays nuclear reactor decommissioning procedures are going on in many countries of the world, including in Japan, the United States, and countries in Europe. The particular problems faced in each case is unique.
“But by cooperating, the scientists of these nations will help each other to achieve their own countries’ goals,” Onishi said.
