Russia-Ukraine war: Chernobyl power cut sparks fears of potential for radiation leaks

Vital cooling systems for controlling nuclear waste at the decommissioned Chernobyl nuclear power plant are offline, leading to concerns that radioactive waste might escape

By Matthew Sparkes

Fears of a potential radiation leak at the Chernobyl nuclear power plant are growing after a power cut at the site. Without electricity it will be difficult to cool ponds that contain hazardous nuclear waste and to filter the air inside the vast containment building that houses the remains of the reactor that was destroyed during an infamous disaster at the site in 1986.

Ukraine’s foreign minister, Dmytro Kuleba, warned in a tweet that reserve diesel generators will operate for only 48 hours. “After that, cooling systems of the storage facility for spent nuclear fuel will stop, making radiation leaks imminent,” he wrote.

Spent nuclear fuel from Chernobyl’s former reactors is stored in a large cooling pond that is constantly replenished with fresh, cold water to keep its temperature down. Without an electricity supply – which the Ukrainian government says the site now lacks – this cooling has stopped, which will allow the water temperature to rise and increase the rate of evaporation.

If the ponds are allowed to run dry then there is a chance that radioactive material could be released into the environment. There are also concerns that electrical air filters in the containment building around the reactor will stop, causing condensation that may harm the building.

An update from the State Nuclear Regulatory Inspectorate of Ukraine on 9 March said that there were no immediate concerns: “There are no violations of Nuclear Power Plant (NPP) safe operation limits and conditions. Radioactive situation meets established norms. Systems of NPP physical protection work in normal mode.”

Mark Wenman at Imperial College London said in a statement to the UK Science Media Centre that although the power cut was a “concerning development” there was no immediate risk of a radiation leak.

“The last reactor unit at Chernobyl was shut down over 20 years ago and units 1 and 2 were shut down between 1991 and 1996. This means the heat produced by the fuel in the storage ponds will have substantially reduced over the 20 to 30 year period,” he said. “The fuel storage ponds are also very deep and [it] would likely take weeks for the water to boil down even without cooling pumps active. This should hopefully allow enough time for the power to cooling systems to be restored.”

The situation at Chernobyl has been tense since the first day of the invasion when Russian troops seized the site. Scientists monitoring radiation levels at Chernobyl are unable to access their laboratories and instruments because Russian troops now control the plant. Other staff still working on the site on safety monitoring and decommissioning efforts are being held in poor conditions without the chance to take breaks away from the facility to rest, according to the International Atomic Energy Agency’s (IAEA).

Radiation levels spiked at the site on the day it was captured by Russian forces, which was put down to Russian tanks disturbing dust that contained radioactive material. But many of the radiation sensors around the plant have been offline since.

The IAEA director general, Rafael Mariano Grossi, has warned that a series of incidents at sensitive facilities across Ukraine have taken place in recent days. The IAEA says this presents a risk to safety, although there are no signs or evidence of radiation leaks.

“We cannot go on like this. There has to be clear understandings, clear commitments, not to go anywhere near a nuclear facility when it comes to military operations,” said Grossi at a press conference on 7 March.

Ukraine’s state-controlled energy company, the National Nuclear Energy Generating Company of Ukraine, said in a statement on 9 March that its staff are still present at all six of the country’s nuclear power plants but are “forced to coordinate all technical issues with the occupiers”.

“The workers of the station are under strong psychological pressure from the occupiers,” said the statement.

The company reports that the Zaporizhzhia power plant is currently occupied by 50 units of heavy equipment and 400 soldiers. Details of the force at Chernobyl weren’t given.