After the Zaporozhye nuclear power plant, it was Chernobyl’s turn to focus on Ukraine. The Ukrainian operator Ukrenergo announced on Wednesday, March 9, that the supply of electricity to the facility was “completely” cut off due to Russian military actions. However, according to experts, power outages do not pose a serious security threat.
What happened ?
The plant, which caused the worst civilian nuclear disaster in 1986, “was completely disconnected from the grid due to the military actions of the Russian occupiers,” the operator wrote without further ado on his Facebook page. In view of the fact that the offensive continues, “there is no possibility to restore the borders,” he specified.
It has been replaced by standby diesel generators that “will be able to support vital site activities for up to 48 hours,” the regulator said. “After that, the cooling systems for the stored fuel will stop,” Ukrainian Foreign Minister Dmytro Kuleba warned.
The Chernobyl nuclear power plant, site of the worst civilian nuclear disaster in history in 1986, includes decommissioned reactors, including a sarcophagus-covered Reactor No. 4, and storage facilities for radioactive waste.
Telephone communications have also been cut at the facility, where more than 200 technicians and security guards have been blocked since February 24. Now they operate under Russian command. The International Atomic Energy Agency (IAEA), the UN’s nuclear police force, has asked Moscow to allow them to alternate with other teams, as rest and fixed hours are necessary for the site’s safety.
What is the risk?
The damaged reactor itself is not a problem, Karine Herviou, deputy director general of the French Institute for Radiation Protection and Nuclear Safety (IRSN), told AFP. Because “a melted heart doesn’t need a cooling system.” And the fuel is still stored in the on-site pool?
Considering the time that has passed since the 1986 Chernobyl accident, “the heat load of the spent fuel pool and the volume of cooling water is sufficient to ensure efficient heat removal without electricity,” the International Atomic Energy Agency (IAEA) notes. Thus, this power outage “does not have a major safety impact”.
The 20,000 fuel assemblies stored in the pool are “relatively cold” and even if power is not restored in 48 hours, “according to what we know from the facilities, there is no danger of radioactive releases,” confirms Karin Erviu, deputy general manager. French Institute for Radiation Protection and Nuclear Safety (IRSN).
In this case, studies conducted after the Fukushima accident in Japan in March 2011 “show a slow temperature increase of about 60°C, but no dehydration of the assemblies.” “The water will gradually heat up, but will not be brought to a boil,” she says.
What about existing power plants?
Power outages “would create more problems” at the country’s four operating power plants, “where it is absolutely essential to cool the fuel in the core or in the pool,” the head of the IRSN estimates. “There is much more heat that needs to be evacuated there” than in Chernobyl.
The generators could “supply the cooling systems” for 7-10 days.” In addition, without electricity, “a Fukushima-type scenario would arise with the risk of a reactor core meltdown.”
From the very beginning of the Russian invasion, IAEA Director General Rafael Grossi called for maximum restraint. He repeatedly offered to visit Ukraine to lay the groundwork for securing the facility during a conflict that first occurred in a country with a major nuclear program.
“This time, if an accident occurs, the cause will not be a tsunami caused by mother nature, but the result of human failure to act when we knew we could and should have,” he said earlier in the week.