On the first day of the war in Ukraine, the Russian military seized the Chernobyl nuclear power plant. Shortly afterwards, the radiation level at the site of the plant jumped up to 20 times. We examined the information of Ukrainian specialized structures and asked nuclear physicist Andrei Ozharovsky what could be the reason for such an increase and what does such a level of radiation background mean for a person.

What happened at the Chernobyl nuclear power plant?

On the evening of February 24, Prime Minister of Ukraine Denis Shmygal announced the loss of control of the Chernobyl zone. “The Chernobyl zone, the so-called exclusion zone, and all facilities of the Chernobyl nuclear power plant have been taken under control by Russian armed groups,” he said.

On the same evening in the vicinity of the Chernobyl nuclear power plant, the radiation background increased up to 20 times at some points, monitoring by the Saveecobot project shows. As stated on the website, this monitoring reflects information of the Ukrainian company Ecocenter, which specializes in monitoring of all components of the environment in the exclusion zone.

One of the sensors located near the Chernobyl nuclear power plant, as of 20:00 this afternoon, showed a gamma radiation level of 3.09 microsieverts per hour, and as of 21.50 this read 65.5 microsieverts per hour. At several other nearby sites, there was a spike of 58.8 and 54.2 microsieverts per hour.

The information about the increased radiation level is confirmed by the State Inspectorate for Nuclear Regulation of Ukraine.

“Data from the automated radiation monitoring system of the exclusion zone, which are available online, show that gamma radiation dose control levels (red dots) were exceeded at a significant number of observation points. We are unable to establish the reasons for changes in the radiation background in the Exclusion Zone due to the occupation and military struggle on this territory,” the organization says.

What can be the reason for the sharp increase in radiation?

• The first thing to think about is that the sensor may malfunction. It happens often. But it happens, as a rule, with a single sensor. Here we see several points with a sharp increase in the dose rate [radiation],” explains nuclear physicist Andrei Ozharovsky.

He points out that, judging by the way monitoring is reflected on the site, the system replenishes data automatically, regardless of who controls the Chernobyl NPP facilities at that moment.

• I am inclined to assume that this is not a glitch, but really such readings. In this case, it most likely indicates a leak. How serious it is, we will see based on how long it lasts, how far it spreads. This will be seen from the sensor data. If there is a consistent increase in dose rates elsewhere over the next few days, then something is definitely leaking.

The expert gave two of the most likely reasons for the dramatic increase in rates. The first version of the expert is that parts of the plant system were destroyed during military operations.

• It is not only the fourth reactor (there was an accident there in 1986 – Editor’s note). There are units 1, 2 and 3, the spent fuel storage facility, as well as radioactive waste and various buildings. In units 1-3, by the way, the reactors are being decommissioned at the moment and they are without containment, unlike unit 4. There is radioactive graphite and other hazardous substances there,” says Andrei Ozharovsky.

The second theory, says the interlocutor, is that some systems, including those ensuring safety, could have stopped working as a result of the failure of the ChNPP employees to show up for work.

It is known that due to martial law in the country, only operational staff necessary to ensure the operation of the Chernobyl nuclear power plant site remained at the site. This was stated by Acting General Director of the plant Valery Seida.

In addition, the presence of Russian military on the territory of the plant may influence the increased figures.

• In this case, the radioactive mediums could start to flow up. What we see [on the monitoring map] is very similar to a point source, with a sensor next to it, which is catching it. By the way, that’s how sensors should stand – close to the place where it might “leak” in order to see whether it’s happening or not,” the nuclear physicist continues.

While we were preparing this material, the State Inspectorate for Nuclear Regulation of Ukraine reported that Ecocenter specialists attribute the jump to the disturbance of the topsoil from the movement of large amounts of heavy military equipment in the exclusion zone and an increase in air pollution. “The condition of Chernobyl nuclear facilities and other sites is unchanged,” the statement said.

How does this increase in radiation affect people?

The background value or safe level of radiation is considered to be about 0.2 microsieverts per hour. Often the equivalent wording of 20 micro-roentgen per hour is used. In this case, radiation does not cause any harm to the human body.

Andrey Ozharovsky notes that people will not suffer from the very fact of increasing radiation background at some points on the Chernobyl NPP sites. Consequences occur after the radionuclides enter the nature.

• It is important to understand that the sensor measures the dose rate of gamma radiation (this is an external exposure. -Note: Zerkalo.io). But for people and any living creatures it is not external radiation that is dangerous, but internal. We get the first one, for example, when we undergo a fluorography. Now we’re talking about the fact that radionuclides enter the environment – they fall out somewhere, are carried by the air, then they will be washed away by water. So the number of dangerous radionuclides of non-natural origin in the environment will grow. And people will suffer after some time, having received them inside,” the expert explains.