Russians and Ukrainians pass the buck to find out who is responsible for the partial destruction of the large Kakhovka hydroelectric dam, located in southern Ukraine and fed by the Dnieper. The Ukrainian authorities announced the disaster on Tuesday and, among other concerns, is that of the safety of the Zaporijja nuclear power plant. However, the situation seems reassuring on this side. “There is no risk of flooding of the plant by the dam which is located 150 kilometers to the south,” says Karine Herviou, Deputy Director General of IRSN (Institute for Radiation Protection and Nuclear Safety). The French expert confirms the information given on the ground by inspectors from the International Atomic Energy Agency, who monitor the largest nuclear power site in Europe.
Even if this risk of flooding is ruled out, what about the cooling of the plant? There will probably be a decrease in the flow of the Dnieper, due to the removal of the water reservoir. However, “there is no immediate risk for the cooling of the six nuclear reactors which are all shut down”, continues the Deputy Director General. No risk is therefore “envisaged for several weeks”, adds the French expert. This analysis thus corroborates that of the IAEA experts who assured on Twitter that there is no “immediate nuclear danger”.
“The level of the cooling basin has not changed,” said Yuri Tchernichuk, director of the Zaporizhia nuclear power plant, under the control of the Russian authorities, on Telegram. In addition to the large water retention basin, on the site of the plant there is a second water reserve, called in the jargon “Ultimate Heat Sink”, which allows it to be replenished to continue to permanently cool the six reactors. These facilities were bolstered following the Fukushima accident when extreme scenarios were imagined to reinforce plant safety. “One of them foresaw the destruction of the Kakhovka dam following an earthquake,” says Ludovic Dupin, of the French Nuclear Energy Company (SFEN).
The water capacity on the site therefore makes it possible to hold out for several weeks, even with a decrease in the level of the Dnieper. And in case these reserves on the site are too threatened, there could be “alternative resources”, indicated the director of the plant. We can imagine “a supply with tank trucks if necessary”, specifies Karine Herviou.
However, it indicates that another risk may arise, “the breakdown of the electricity supply”. Because even when stopped, the plant needs energy so that the pump systems bring water to permanently cool the nuclear fuel assemblies. But even in this case, “there are 20 small emergency generators, including 4 per reactor”, recalls the IRSN expert. While at the start of the crisis last year these generators could have provided energy for about ten days, now “they should be able to operate for at least two weeks, if there is no shortage of fuel on the site »
In this context, the reassuring analysis of the IRSN, in phase with that of the IAEA, must temper the alarmist declarations of the adviser to the presidency, Mykhaïlo Podoliak. “The world is once again on the brink of nuclear catastrophe, as the Zaporizhia nuclear power plant has lost its cooling source. And this danger is increasing rapidly, ”said adviser to Ukrainian President Volodymyr Zelensky, in a written message sent to journalists and relayed by AFP. Alarm calls are part of war.