FUKUSHIMA--Thousands of kilometers from the war’s front lines in his home country, Ukrainian Mark Zheleznyak is waging his own private battle here to do his part. 

The scientist forecasts areas likely to be contaminated if radiation escapes from the embattled Zaporizhzhia nuclear power plant in southeastern Ukraine, one of Europe’s largest nuclear facilities.

The plant, occupied by Russian forces and operated by Ukrainian engineers, has been in a precarious state since last year as it has lost external power off and on, raising the specter of a nuclear catastrophe.

The estimates of the diffusion of radioactive materials that he and colleagues make are expected to be used by Ukrainian authorities as an evacuation guide for residents in the event of an emergency.

“I am fighting here as a scientist,” said Zheleznyak, who is with Fukushima University’s Institute of Environmental Radioactivity, in a recent interview. “The only weapon I have is my expertise in environmental science, and I am using it to help people in my homeland.”

Zheleznyak, 72, took up the challenge after he received a request for assistance from an official close to the Ukrainian government in late February 2022, shortly after the Russian invasion began.

Incessant artillery shelling made it impossible for Ukrainian scientists to access their research organizations in Kyiv. Power failures have become routine in Ukraine since the war started.

The researchers face difficulty in swiftly forecasting the diffusion of radioactive materials when an emergency arises. 

Zheleznyak and his colleagues in Japan and elsewhere formed a team, including members from the Japan Atomic Energy Agency, which has been involved in developing the forecast model, and a German university. 

The team sends a daily diffusion prediction online to the Ukrainian side after determining which regions of the country would likely be affected in the event that radiation is spewed. They use weather forecast data for Ukraine, including wind direction, available through the Japan Meteorological Agency and other organizations. 

Radioactive materials being blown by the wind in the atmosphere fall to the ground when it rains. The direction of the wind and the volume of rainfall will have significant implications for the spread and severity of radioactive contamination.

The team compares the results of the estimation made by scientists in Japan and Germany to enhance its accuracy.

“What we are doing is humanitarian assistance through science,” said Kenji Nanba, head of Fukushima University’s Institute of Environmental Radioactivity.

The Zaporizhzhia nuclear power plant is home to six reactors with an output capacity of 1 gigawatt each.

The reactors were all eventually shut down after the Russian army took control of the facility in March 2022.

But it is vital for operators to continue cooling the reactor cores, as well as spent fuel pools, through an external power supply to keep the facility safe.

Still, operators have had to resort to emergency diesel generators several times as plants have been cut off from the power grid during the war.

Zheleznyak said if a radiation leak occurs, residents could be forced to flee to a location up to 400-500 kilometers from the facility.

That would entail the evacuation of people in some regions of Russia and Moldova, he added.

After the 1986 catastrophe at the Chernobyl nuclear plant, also located in Ukraine, Zheleznyak undertook a study of the contamination of rivers and waterways around the site.

He also participated in the development of a method to forecast the diffusion of radioactive substances, a project launched by the European Commission in the 1990s. The Ukrainian government adopted the method.

Zheleznyak arrived in Japan in 2013 to take a research position at the institute, two years after the triple meltdown at the Fukushima No. 1 nuclear power plant.

He intended to make the best use of his prior experiences in forecasting changes in the contamination of rivers and dams affected by the accident at the Fukushima plant. 

While he spent the past year on the project preparing Ukrainians for a possible nuclear accident, the safety of his family and other Ukrainians is constantly on his mind.

He is in daily contact with his wife, Olga, and daughter Olena, who both live in the Ukrainian capital. But some of his acquaintances were killed in the war, he added.

He said he is devastated by the destruction the military conflict has wrought on Ukraine.

He and his family would often visit Bucha, where many civilians were slaughtered by Russian troops, and Irpin, which turned into a bloody battlefield for fierce fighting.

He said lush forests and vast, breathtaking gardens in the cities, which are located close to Kyiv, were unforgettable.

Zheleznyak added that he will continue to do his part in Japan to help Ukraine, but hopes that a cease-fire will be reached soon.

“I am deeply disappointed by the fact that the war is still raging despite the more than 100,000 deaths of Russian soldiers and with the apparent support of the Russian public,” he said.