CHERNOBYL, Ukraine — As the scene of an attack on Ukraine’s capital Kyiv, the Chernobyl Exclusion Zone, one of the most toxic places on earth, probably wasn’t the best choice. But that didn’t seem to bother the Russian generals who took over the site in the early stages of the war.
“We told them not to do it, that it was dangerous, but they ignored us,” Valeriy Simyonov, the chief safety engineer at the Chernobyl nuclear power plant, said in an interview.
Apparently unperturbed by security concerns, Russian forces stomped around the site with bulldozers and tanks, digging trenches and bunkers — and exposing themselves to potentially harmful doses of radiation that linger below the surface.
On a visit to the recently liberated nuclear power plant, scene of the world’s worst nuclear disaster in 1986, winds blew dust swirls across the streets and scenes of disregard for safety were evident everywhere, though Ukrainian nuclear officials say no major radiation leak has been sparked in Russia’s months military occupation.
In just one site of extensive trenches, a few hundred yards outside of the town of Chernobyl, the Russian army had dug an elaborate maze of sunken walkways and bunkers. An abandoned infantry fighting vehicle stood nearby.
The soldiers had apparently camped in the radioactive forest for weeks. While international nuclear safety experts say they have not confirmed any cases of radiation sickness among the soldiers, cancer and other potential health problems related to radiation exposure may not develop for decades.
Mr Simyonov said the Russian military deployed officers from a nuclear, biological and chemical unit, as well as experts from Rosatom, Russia’s state-owned atomic energy company, to consult with the Ukrainian scientists.
But Russian nuclear experts seemed to have little leverage over army commanders, he said. The military seemed more concerned with planning the attack on Kyiv and, after that failed, using Chernobyl as an escape route to Belarus for their battered troops.
“They came and did what they wanted” in the zone around the station, said Mr Simyonov. Despite the efforts of him and other Ukrainian nuclear engineers and technicians who remained on site during the occupation, working around the clock and unable to leave except for a shift change in late March, the entrenchment continued.
The earthworks weren’t the only case of recklessness in treating a site so toxic it still has the potential to spread radiation well beyond Ukraine’s borders.
In one particularly unwise action, a Russian chemical, biological and nuclear protection unit soldier picked up a source of cobalt-60 at a landfill site with his bare hands and in a matter of seconds exposed himself to so much radiation that it went off the scale of a Geiger counter, said Mr. Simyonov. What happened to the man is unclear, he said.
The most worrying moment, Mr Simyonov said, came in mid-March when power was cut off to a cooling pool storing spent nuclear fuel rods containing many times the amount of radioactive material released in the 1986 disaster. That raised fears of fire among Ukrainians if the water cooling the fuel rods boils away and exposes them to the air, although that prospect was quickly dismissed by experts. “They emphasize the worst-case scenarios that are possible but not necessarily plausible,” said Edwin Lyman, reactor expert at the Union of Concerned Scientists.
The greater risk of a prolonged blackout, according to experts, was that the hydrogen produced by the spent fuel could build up and explode. Bruno Chareyron, laboratory director at CRIIRAD, a French group that monitors radiation risks, cited a 2008 study on the Chernobyl site that suggested this could happen in about 15 days.
The march to Kyiv on the west bank of the Dnipro River began and ended in Chernobyl for the Russian military’s 31st and 36th combined-arms armies, traveling with a support squad of special forces and ethnic Chechen fighters.
The formation stormed into Ukraine on February 24, fought in the Kyiv suburbs for nearly a month, and then retreated, leaving behind burned armored vehicles, their own war casualties, widespread destruction, and evidence of human rights abuses, including hundreds of civilians on the streets of the city of Bucha.
Withdrawing from Chernobyl, Russian troops blew up a bridge in the exclusion zone and set up a dense maze of anti-personnel mines, tripwires and booby traps around the defunct station. According to the Ukrainian government agency that manages the site, two Ukrainian soldiers stepped on mines in the past week.
In a bizarre latest sign of the unit’s misadventures, Ukrainian soldiers found discarded equipment and electronic equipment on roads in the Chernobyl zone. These were apparently looted from towns deeper in Ukraine and jettisoned during the final retreat for unclear reasons. Reporters found a washing machine on a roadside just outside the city of Chernobyl.
Staff at the Chernobyl-based Exclusion Zone Administration suffered under the Russian occupation, but nothing approaching the barbarism with which Russian forces harassed civilians in Bucha and other towns around Kyiv.
The Russians came in seemingly endless columns on the first day of the war, said Natasha Siloshenko, 45, a cook at a cafeteria that serves nuclear workers. She had watched cautiously from a side street.
“There was a sea of vehicles,” she said. “They came through the zone in waves and quickly headed towards Kyiv.”
As far as she could tell, there was little or no fighting in the Zone. The tank columns only went through.
During the occupation, Russian soldiers searched the homes of nuclear technicians and engineers, firefighters and relief workers in the city of Chernobyl. “They took valuable items” from apartments, she said, but there was little violence.
Workers tried unsuccessfully to warn the Russians about radiation hazards.
The background radiation in most of the 18-mile exclusion zone around the nuclear power plant poses little risk after 36 years and is about the same as flying at high altitude. But in invisible hot spots, some covering an acre or two, others just a few square feet, radiation can reach thousands of times normal ambient levels.
A soldier in such a place would be exposed every hour for a whole year to what experts say is safe, said Mr Chareyron, the nuclear expert. The most dangerous isotopes in soil are cesium-137, strontium-90 and various isotopes of plutonium. Days or weeks spent in these areas carry a high risk of causing cancer, he said.
Throughout the zone, radioactive particles have settled to depths of a few centimeters to a foot in the ground. They pose little threat when left underground, where their half-life usually elapses benignly for decades or hundreds of years.
Russia-Ukraine War: Key Developments
missile attack. At least 50 people were killed and nearly 100 injured in a rocket attack on a crowded train station in eastern Ukraine, according to Ukrainian officials.
Until the Russian invasion, the main threat from this contamination was uptake in mosses and trees that can burn in wildfires, spread of the toxins in smoke, or by birds eating radioactive, ground-dwelling insects.
“We told them: ‘This is the zone, you are not allowed to go to certain places,'” said Ms. Siloshenko, the workers had told the Russians. “They ignored us.”
At one dug-in position, Russian troops had dug a bunker from the sandy side of a road embankment, leaving behind piles of rubbish — food wrappers, discarded boots, a blackened cooking pot — suggesting they had been living underground for an extended period.
Nearby, a bulldozer had cleared away the topsoil to build berms for artillery positions and half a dozen foxholes.
The forest in the area had recently burned down, suggesting that a fire swept through the area during the Russian occupation, increasing Russian soldiers’ exposure to radioactive smoke and dust from agitated ground.
The Director-General of the International Atomic Energy Agency, Rafael Mariano Grossi, issued a statement Thursday saying the agency had not been able to confirm reports of irradiated Russian soldiers in the zone or make an independent assessment of radiation levels at the site . The agency’s automated radiation sensors at Chernobyl have been non-functional for more than a month, he said.
The Ukrainian government’s radiation monitors stopped working on the first day of the war, said Kateryna Pavlova, a spokeswoman for Ukraine’s Chernobyl Zone Administration Agency. Readings from satellites, she said, showed slightly increased radiation in some areas after the Russian occupation.
Armored vehicles, which run on treads rather than wheels, pose the main risk to radiation safety in a larger area, as they churn up the radioactive soil and spread it to areas of Belarus and Russia when retreating, Ms Pavlova said. “The next person who comes by may be contaminated,” she said.
The five-day power cut did not result in a catastrophe, but it still caused great concern among the operators of the plant, said Sergei Makluk, shift supervisor, at the nuclear power plant on Thursday evening.
The back-up generators that are on use about 18,000 gallons of diesel fuel per day. In the first few days, Russian officers assured workers at the plant that they would have enough fuel, which came from supplies carried for armored vehicles in the fighting in the Kyiv suburbs, Mr Makluk said. But by day five, given the military’s well-documented logistical problems, officers said they would no longer supply the diesel.
“They said, ‘There’s not enough fuel for the front line'” and that instead a power cable to Belarus should be used to draw electricity from the Belarusian grid to cool the waste pool.
Mr. Simyonov, the chief safety engineer, called the threat to cut diesel supplies for generators “blackmail” to force authorities in Belarus to solve the problem. Anyhow, power was restored in time and the nuclear fuel never came close to overheating.
All in all, the digging of trenches and other dubious activities posed far less risk than the dumping ground, and most of it for the Russian soldiers themselves, Mr Simyonov said, adding wryly: “We invite them to dig more trenches here.” if you want to.”
Reporting was contributed by William J. Broad from New York.