What do we know about the radioactive collapse after the Chernobyl site was hijacked by Russia?

The ghost of the Chernobyl accident has recently reappeared in the news. On February 24, the first day of the invasion of Ukraine, Russian troops actually ruled the place and expressed concern.

At an emergency meeting on Wednesday, March 2, the International Atomic Energy Agency (IAEA) stated that “no casualties or destruction were observed” at the scene. I also recalled that it is “most important” for the person in charge of safety and security at the site to be able to carry out work with peace of mind. 20 minutes Evaluate the development of the situation in this highly polluted area, located about 100 km north of Kyiv.

“There is no danger to the masses”?

The worst nuclear accident in history on April 26, 1986 left a mark for hundreds of years. A large amount of highly radioactive substances are stored on the premises. “Most of it is stored in the water to limit the level of radiation emitted and to cool it permanently,” said director Bruno Chareilon. In the laboratory of the Commission for Independent Research and Information on Radioactivity (Criirad). The site also stores over 20,000 m3 of solid and liquid waste.

This is why Ukraine’s announcement of increased radiation levels on Friday, February 25, worried all nuclear safety authorities. These data are provided specifically by automated control systems, with beasons located throughout the exclusion zone, approximately 30km around Chernobyl. This monitoring device is operated by DAZV, the Ukrainian state agency responsible for managing the region.

With the first press release on February 25, the International Atomic Energy Agency (IAEA) was quite relieved. “The levels reported by regulatory agencies – up to 9.46 microsieverts per hour (μS / h) – are low and have been measured since the creation of exclusion zones. Therefore, they do not pose a danger to the public. »» »

But such a statement shocks Bruno Charleyron. “Staying in a place with a radiation dose of 9.46 μS / h for a little over an hour already induces a non-negligible dose due to external irradiation. It means that the evolutionary phenomenon is happening from the moment of heightening, and unless you understand it, you cannot understand the risk. It is a reality for the people there. »»

Differences in reading that raise questions

Nuclear physics engineers are also wondering about the radiation levels reported in the IAEA press release. This does not correspond to the values ​​observed by Criirad at the DAZV site, which updates the radiation dose several times a day. Gamma rays. Therefore, sensors near the plant showed a value of 65.5 μS / h on the evening of February 24, and then a value of 92.7 μS / h on the morning of February 25.

“The natural level of radiation is usually 0.1 μs / h, which is a very important result,” commented Bruno Chareyron. In this zone, the previous day, the value of this sensor was about 3 μS / h. 9.46, this does not match the measurements we accessed: why does the IAEA show this? I asked an international organization that did not answer this question.

Screenshots of the DAZV website that update the gamma ray levels of Chernobyl several times a day. Here, the SRTV sensor showed a value of 92.7 μS / h at 10:40 am on February 25.
Screenshots of the DAZV website that update the gamma ray levels of Chernobyl several times a day. Here, the SRTV sensor showed a value of 92.7 μS / h at 10:40 am on February 25. -Screenshot / DAZV

Asked by 20 minutesThe French Institute for Radiation Protection and Nuclear Safety (IRSN) cannot explain this difference in measurements. “We tried to figure out what could justify this increase in beacon dose rates, but we couldn’t really find a consistent explanation,” admits Karine Herviou, Deputy Director of Nuclear Safety at IRSN. ..

Sensor system that does not work for 3 days

In addition, this automated control system was inactive from the morning of February 25th to February 28th. Following a press release from Ukrainian safety authorities, the IRSN indicates that power outages may be involved. Therefore, the DAZV website does not have any information about ambient radioactivity during this period. Most of the beacons started working again on Monday.

“The most significant increase in sensors has returned to levels similar to those before February 24,” said Bruno Chareyron, director of the Criirad Institute. First of all, this is very good news. And this rather supports the idea of ​​measurement malfunction. “To one Commission for Independent Research and Communications, communicated on February 25, revealed these possibilities. Sensors may have been damaged in combat, electromagnetic waves may interfere with certain sensors, computer systems may malfunction, or they may be hacked.

What do you think of the tank passage hypothesis?

On Friday, Ukrainian authorities raised a hypothesis of the movement of military vehicles that could disturb the soil still contaminated in the 1986 accident. For Bruno Chareilon, “it’s hard to imagine that this could explain all the measurements.” “In any case, the fact that we fall to the same level after a few days is unlikely to hypothesize the mass dispersion of radioactive material,” emphasizes the director of the Commission for Independent Research and Development.

The Deputy Director of IRSN calls for the utmost attention. “There is no hypothesis to take over. I don’t know if the Beacon had a malfunction. However, if there was a resuspension of contamination due to the passage of the tank, she said,” Because the Beacon has a deposit of particle radiation, the Beacon Make sure you are logically saying, “Usually measure slightly higher background noise.”

“There is no event that could have caused the radioactive release.”

For the Criirad director, the situation needs to be clarified on a sensor-by-sensor basis. “We need to keep very large amounts of highly radioactive material as safe as possible, and that’s why it’s worth understanding whether Russians guarantee the situation. »»

As shown in the February 25 press release, IRSN has confirmed that there is no “evidence of an event that may have caused the radioactive release” based on current information. “The situation is still a concern because the country is in a state of war,” adds Karine Herviou, but currently no increase in radioactivity has been detected in neighboring European countries.