War in Ukraine: after the capture of Chernobyl, is there a risk of a nuclear incident?

Since the announcement on Thursday of the takeover of the Chernobyl zone by Russian forces, the International Atomic Energy Agency is on the alert. “Any armed attack and threat against nuclear installations devoted to peaceful purposes constitutes a violation of the principles of the Charter of the United Nations and of international law”, has already warned its director general Rafael Mariano Grossi.

What would be the risks for populations in the event of a frontal attack or collateral damage? It is of course difficult to answer: the trajectory and extent of a possible radioactive cloud would depend on the force of the impact, the area affected, and the weather conditions… “We also don’t know if the famous dome financed by Western countries to protect the exterior from the radioactive elements present in the reactor of the power plant would resist a missile strike or other types of explosions.If ever studies have been made on the subject, their results are kept secret”, notes a researcher.

“However, the greatest risks are not necessarily where you think,” says David Boilley, president of the Association for the control of radioactivity in the West (ACRO). Admittedly, the molten fuel present in the reactor is the most contaminated part. However, the short-lived radionuclides disappeared from the site over time. This is the case, for example, of iodine 131″. Graphite – one of the substances used at the time in the heart to create the nuclear reaction – is no longer present either. However, by burning, this product was largely responsible for the massive releases high up in the sky in 1986.

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“Even in the event of an attack, we would probably not have Chernobyl bis”, concludes David Boilley. Which wouldn’t prevent other dark scenarios from happening. The most obvious is probably the attack or damage to one of the 15 nuclear reactors still in operation in Ukraine. “It would be much more worrying from my point of view than an incident on the Chernobyl dome. The water cooling system could be put out of service, like in Fukushima. short, which makes them potentially more dangerous for the population in the event of an accident”.

Another problem could possibly arise at the level of the lake located at the foot of the Chernobyl power plant. “Initially, it was used to cool it. It then received a lot of radioactive waste. The water there is ultra-contaminated, as are the sediments. It is one of the hot spots in the area and it is just separated from the Pripyat river by a dyke built after the 1986 disaster. And this river flows into the Dnieper which, for its part, crosses the city of Kiev”, explains the researcher.

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The worst is never certain, but this barrier could undoubtedly break more easily than the sarcophagus, leading to cascading contamination. “Every four or five years, we have heavy floods in this region. Sometimes they overwhelm the contaminated areas and this increases the level of radioactivity in the drinking water in Kiev, which is located 130 km to the south. hour, the thresholds recorded remain below the standards. But a rise in the concentration of radioelements in the Dnieper would undoubtedly cause panic among part of the population”, indicates David Boilley. An additional destabilizing factor.