We came close to a nuclear disaster in Ukraine. During the night from Thursday to Friday, Russian tank fire once morest the Zaporozhye nuclear power plant, the largest in Europe, set fire to a building dedicated to training and a laboratory. The fire was quickly brought under control.
“We are lucky that there is no radioactive leak,” said Rafael Grossi, director general of the International Atomic Energy Agency (IAEA), at a press conference on Friday. Two people were, however, injured. Radiation monitoring systems around the site are functional, the agency said, specifying however that the Ukrainian operator might not access the entire site to verify it.
Ensuring the cooling function of nuclear reactors
But this unprecedented attack raises immense concerns. Because the proper functioning of a nuclear power plant requires constant vigilance. That the staff is not under pressure and can rest is vital to avoid mistakes. “It’s not just a humanitarian issue, it’s a technical issue,” warned Rafael Grossi earlier this week. A serenity that is far from guaranteed when, since this Friday, the Russian army has occupied the plant.
In a nuclear power plant, the most important thing is to ensure the cooling function of the nuclear reactors. “For this, you need competent personnel, capable of carrying out their mission, you need access to electricity via the external network or via emergency diesel engines, and therefore to fuel to run them, details Bruno. Chareyron, director of the laboratory of the Commission for Independent Research and Information on Radioactivity (Criirad). Cold water and working water supply pumps are also needed. »
“Major radiological risks”
The largest power plant in Europe, Zaporozhe has six reactors, ie as many nuclear cores to be cooled and pools in which the fuels are unloaded and put into deactivation under cold water. Therefore, fighting should not damage the water pumping systems in the Dnieper either.
If the safety of the nuclear installation is not ensured, “it is a loss of cooling capacity – this is what happened at Fukushima –, overheating of the fuel, explosive reaction by production of hydrogen, risk explosion and massive dissemination of radioactive substances, warns Bruno Chareyron. That is why attacking a nuclear power plant poses absolutely major radiological risks to Ukraine and to Europe. »
A containment enclosure “which offers a certain resistance”
The other risk is direct aggression. The containment enclosure – the large sealed concrete enclosure around the reactor – is designed to withstand the accidental fall of an aircraft. “They offer a certain resistance, but it all depends on what we are talking regarding, notes, with AFP, Karine Herviou deputy director general of the French Institute for Radiation Protection and Nuclear Safety (IRSN). An attack can also affect a part other than the containment enclosure and create an accident if it falls on safety systems. »
Faced with the seriousness of the situation, Rafael Grossi, Director General of the IAEA, offered to conduct negotiations by going to Chernobyl soon. Indicating that he is in discussions on this point, he wants to establish a framework between Ukrainians and Russians to ensure the safety of nuclear installations, in a country which has, beyond the Chernobyl site, a fleet of 15 reactors. “It is time to do something and not just tweet or comment from Vienna”, IAEA headquarters, he said, repeating that he was “extremely worried” regarding an unstable and fragile situation.
