Reactor accident, radioactive waste… what are the risks at the Ukrainian power plant in Zaporijjia?

Published on: 08/20/2022 – 15:08 The international community has its eyes on Zaporijjia, where Russians and Ukrainians have been clashing for weeks near Europe’s largest nuclear power plant. This tense situation poses several nuclear risks that all belligerents and their supporters wish to avoid. France 24 takes stock of the possible scenarios. The Zaporizhia nuclear power plant has been the focus of concern in recent weeks in Ukraine. Fighting around this site under Russian control is daily, and several international actors fear that the situation will degenerate. The latest, Vladimir Putin, said he feared on Friday August 19 that the bombings on the spot would end up causing a “large-scale (nuclear) disaster which could lead to the radioactive contamination of vast territories”. Russian President and Emmanuel Macron agreed on an inspection “as soon as possible” of the Zaporijjia power plant by the International Atomic Energy Agency (IAEA) in order to “assess the situation on site”. IAEA Director Rafael Grossi “welcomed” in a statement “recent statements indicating that Ukraine and Russia support the IAEA’s goal of sending a mission”. The main risk: a meltdown accident in the core of a nuclear reactor When it comes to a possible nuclear disaster, especially in Ukraine, one naturally thinks of Chernobyl in 1986, which remains to this day the most big accident in history – at least thirty dead, according to the UN scientific committee, but the toll could be much heavier if we count the indirect deaths. Traveling to Ukraine on August 18, Turkish President Recep Tayyip Erdogan was also alarmed at the danger of a “new Chernobyl”, believing that “any potential damage to Zaporijjia would be suicide”. According to Emmanuelle Galichet , teacher-researcher at the National Conservatory of Arts and Crafts (Cnam), “it is not possible to have an accident like that of Chernobyl on the Zaporijjia power plant. It will not be an accident with a radioactive cloud above of Europe as we have seen in the past”. And the doctor in nuclear physics to qualify: “This does not mean that there is no risk, zero risk does not exist.” The main risk at the center of concerns is well known to experts in atomic energy: a nuclear reactor core meltdown accident. A diplomat told AFP on Friday that Westerners were mainly concerned about the continued water cooling of the Zaporizhia nuclear reactors, more than the impact of a blast , because they are designed “to withstand” the “worst”. “Reactor cores need to be cooled, and for that they need water and electricity”, explains Bernard Laponche, former engineer nuclear power at the Atomic Energy Commission (CEA). The nuclear physicist is less worried by bombardments on the plant – “protected by a thick concrete dome” – than by missiles which would fall next to it, whether on the electricity grid which supplies the plant or on the water pipes .Without water and or electricity, “there can be a core meltdown accident like at Three Mile Island (in the United States in 1979) or in Fukushima (in Japan in 2011)”, specifies Bernard Laponche. Radioactive waste, another nuclear risk The other identified risk concerns nuclear waste on the Ukrainian site. “At the Zaporijjia power plant, you have two types of storage,” explains Emmanuelle Galichet. “There is the real spent fuel that comes out of the reactor core: it is stored in pools which are in the containment building, and which are therefore completely protected. And there are spent fuels in the open air. “It is these last fuels that also raise fears. According to Bernard Laponche, “if a missile falls on this waste, there is immediately either a fire or an explosion. And since a waste dump is a place where there is a considerable amount of radioactivity, this can produce a radioactive cloud which can go to Russia, Poland or Western Europe. nuance the threat that this waste can represent by explaining that they are in the open air, “which means that their radioactivity has decreased a lot”. She thus considers that in the event of a bombardment, “their risk of radioactivity in the environment is very unlikely.” “Complicated” to cut Zaporijjia from the Ukrainian electricity network Seeing Zaporijjia disappear from the Ukrainian electricity network is another risk that weighs on the nuclear power plant. The UN Secretary General, Antonio Guterres, visiting Ukraine on August 19, has also asked Russia not to cut the power plant from the Ukrainian network. “The Ukrainian electricity network was connected to the Soviet network , then Russian. And almost the day of the start of the war in Ukraine (end of February, editor’s note) – because it had been prepared for a long time – the Ukrainian network was connected to the European network (…), which is a very delicate operation to carry out”, explains Bernard Laponche. So switching the Zaporijjia power plant back to the Russian electricity network is technically possible, but it would not be easy, according to Emmanuelle Galichet: “Anything is possible when you want to cut a power supply, but these are industrial procedures which are all the same extremely complex. The engineers on site know how to do this kind of industrial procedure, but it always involves risks (including the risk of loss of electrical power if the current is not properly cut, editor’s note)”. Finally, preventing these nuclear and electrical risks from becoming a reality seems possible on condition of stopping the fighting in the Zaporijjia area. Antonio Guterres thus called for “demilitarizing the plant”. Nuclear physicist Bernard Laponche also wants this outcome, and he concludes: “It is very surprising that no one has ever considered the risk of war during the construction of these power plants at from the 1970s and 1980s. We were then in a period of perpetual peace, and we realize today that these are places of considerable risk.