Zakhar Ivanov, a research fellow at the Department of Preparedness and Radiation Monitoring of the State Scientific and Technical Center for Nuclear and Radiation Safety, told ICTV Fakty what could happen in the event of a terrorist attack at the Zaporizhzhya Nuclear Power Plant in a commentary.
According to him, in reality only the terrorists who occupied the NPP can know this.
It is important for us that the containment shell (physical barrier and passive safety system) of the nuclear reactors remains intact. Then it will be easier and faster to stabilize the power unit. The station's personnel will also be able to reduce the leakage of radioactive aerosols into the environment.
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According to Zakhar Ivanov, a leakage of aerosols through the containment shell is still possible, but these are negligible doses compared to if this protective system did not work.
— As long as the containment shell is intact, although it also has its limits, it will perform its function as a physical and technological barrier to the maximum, — said Zakhar Ivanov.
The expert noted that the ZNPP power units were designed for peaceful use. At that time, design and non-design accidents were envisaged, as well as ways to eliminate or minimize them. But it was still assumed that the emergency would occur inside the power unit, and not an external terrorist attack.
The protection of the power units, even at the design stage, did not provide for protection against intentional detonation by explosives.
Zakhar Ivanov recalled that since September 2022, the nuclear reactors of the Zaporizhzhya NPP have been mainly in “cold shutdown” — this means that active nuclear fission does not occur.
— In particular, iodine-131, which everyone is so worried about. There have already been 35 half-lives of iodine-131. That is, its amount is negligible compared to if the reactor had been operating at full capacity, – said the radiation monitoring expert.
Even if there is some kind of accident with a leak of radioactive aerosols to the outside, there is no need to run to buy and take stable iodine preparations — potassium iodide. The Ministry of Health may recommend iodine prophylaxis in a very small area, or not recommend it at all.
Another potential hazard on the territory of the Zaporizhzhya NPP is the dry storage of spent nuclear fuel. Zakhar Ivanov notes that the fuel is spent and there are no fission reactions there. Therefore, in the event of an explosion of spent nuclear fuel, there should be no iodine in the radioactive cloud of aerosols.
The consequence of the explosion of the dry storage may be contamination of the site itself or tens to hundreds of meters of the territory of the Zaporizhzhya NPP. That is, there is no threat to large territories.
If Russian terrorists blow up (damage) the cooling pond, then the cooling of the reactor core will deteriorate.
There is such a phenomenon as residual energy release. Even when the reactor is shut down, the nuclear fuel produces heat that must be removed to prevent meltdown.
— If there is no cooling rate — there will be fewer ways to further cool the reactors. Of course, there are other systems for removing heat from the core, but the loss of any of them makes it impossible to further duplicate the protection systems, — stated expert Zakhar Ivanov.
Will there be an exclusion zone?
What can happen at the Zaporizhia NPP should not be compared with what happened at the Chernobyl nuclear power plant. At the Zaporozhye station there is a different type of power unit — more technologically advanced. Accordingly, another type of potential accident may occur.
According to the radiation monitoring expert, in the event of a terrorist attack at the Zaporizhia NPP there should not be such a powerful steam explosion, such a colossal spread of radioactive aerosols into the environment. Due to the fact that the reactors at the Zaporizhia NPP are not operating, an accident similar to the one that occurred at the Chernobyl NPP in 1986 is not expected.
Whether tens of thousands of square kilometers of territory may be contaminated — the State Scientific and Technical Center for Nuclear and Radiation Safety has not yet predicted. Everything may be limited to the territory of the industrial site or even less — all because power units are not working.
Wind rose of Energodar — where the cloud of radioactive aerosols may go?
Over the course of the year, the State Scientific and Technical Center for Nuclear and Radiation Safety conducted observations and calculations regarding the negative impact on the territory of Ukraine from a possible accident at the Zaporizhzhya NPP.
Weather conditions were taken as a basis. For example, the territory of the city of Kyiv, the Kyiv region, as well as Vinnitsa and the region rarely figured in the calculations. Some amount of radionuclides could be recorded (within the calculations), but it did not contribute to the formation of significant doses of radiation.
According to the wind rose (shown in the diagram for the city of Energodar), typical for the ZNPP location area, the most probable directions of spread of a potential cloud with radioactive aerosols are the western and southwestern territories.
The diagram below shows the probabilities of radiation spread in the event of an explosion under certain meteorological conditions.
That is, hypothetically, certain settlements in the territories of the Kherson, Zaporizhia and Dnipropetrovsk regions may be affected. However, the nature of the contamination can only be predicted after receiving information about the incident and the weather conditions that developed at the site at the time of its occurrence.
— We currently do not foresee the need to implement countermeasures at distances greater than 100 m from the power unit. However, everything depends on the event that may occur, — stated Zakhar Ivanov.
Should I take an iodine preparation?
There are currently no prerequisites that in the event of an emergency radioactive iodine-131 will get into the air.
As for stable iodine preparations, here you should listen only to the recommendations of the Ministry of Health of Ukraine, because this is its authority.
According to Zakhar Ivanov, the negative risks from taking the preparation may be worse than from how much a person inhales. Especially when the presence of radioactive iodine in the emission is not expected.
