Regarding the threats and possible consequences of the nuclear blackmail from the Russian Federation

1. General

Zaporizhzhia NPP (ZAEP) is the largest nuclear power plant in Europe, with six VVER-1000 power units. The station does not supply electricity to the Ukrainian power network since September 11, 2022. Five reactors are in "cold mode", one, the 5th, is in "hot shutdown" mode to meet the station's own needs.

The facilities of the station were seized by the armed forces of the Russian Federation and merged into the FDUP Zaporizhzhia NPP (so-called “state property” of the Russian Federation). The operator is JSC “Operating Organization of Zaporizhzhia NPP”, founded by Rosenergoatom JSC (part of the Rosatom government company).

From September 1, 2022, several IAEA specialists have been on duty at the ZNPP and periodically shift.

It has been established:

“The Armed Forces of the Russian Federation have already prepared everything necessary for a terrorist act. In the event of a disaster, the zone of radioactive damage will be determined by the direction of the wind.} (President of Ukraine Volodymyr Zelenskyi, June 22, 2023).

“The Russian occupiers planted explosives in the cooling pond of the Zaporizhzhia nuclear power plant. If they disable it by detonation, there is a high probability of significant problems.” (Chief of the Defense Intelligence of Ukraine, Major General Kyrylo Budanov, June 20, 2023).

“The situation with nuclear safety and security at Zaporizhzhia NPP is extremely unstable. The loss of the Kakhovsky Reservoir was a disaster for the region as a whole and increased serious difficulties for this large nuclear power plant” (Director of the IAEA, Rafael Grossi, June16, 2023)

2. Potential hazards that could lead to disaster

Both the reactor and the nuclear power plant are quite complex objects. There are quite a few accident scenarios. It is known that the Zaporizhzhia NPP, according to technical safety requirements, is designed for certain protection from external influences, but it was not foreseen that the reactors of the ZNPP would end up in the zone of intense hostilities.

Let’s consider the main security threats at the ZNPP.

2.1 Shallowing of the Kakhovsky Reservoir as a result of the destruction of the Kakhovska Hydro Power plant (HPP) dam

After the detonation of the Kakhovska HPP, the cooling of the ZNPP takes place through several sources (Fig. 1):

During the past two weeks, the ZNPP received the water it needed for cooling from the discharge channel of the nearby Zaporizhzhia Thermal Power Plant (ZTPS), which is separated from the reservoir. In this regard, the water level in the canal decreases by ten centimeters per day and is currently about 17 meters. It is assumed that the volume of water in this channel will provide cooling of the ZNPP reactors for 2 months.

All water reserves combined for cooling will be sufficient approximately until September 1, 2023.

The ZNPP plans to start pumping in additional water (primarily from additional wells), but these reserves have not been assessed.

Nuclear reactors will not be able to operate normally and safely if the cooling pond is blown up.

If small pools are damaged, for example, a hole is formed as a result of a missile strike, and the water from the pool leaves, then the heat released by radionuclides can lead to a fairly strong heating and even to the ignition of discharged fuel. This kind of fire can eventually lead to a rather serious release of radiation.

The following circumstances should be considered:

Fig. 1 Location diagram of the ZNPP objects

2.2 The lack of backup power

A real danger will cause stopping the power supply of the reactors in the ZNPP. If it is impossible to maintain the operational efficiency of the infrastructure, a chain of probabilities will be triggered that can lead to the power loss of the plant and the impossibility of starting the reserve capacities to support the removal of the residual energy release of the active zones, which is what happened at Fukushima. Emergency catastrophic shutdown of reactors and de-energization of the station.

The safety of the Zaporizhzhzhia nuclear power plant depends on a single working transmission line of external power supply of 750 kilowatts, necessary for cooling the reactor and other important nuclear safety functions, compared to 4 lines before the beginning of the Russian invasion of Ukraine( the last one with a capacity of 330 kilowatts was disconnected 4 months ago). The Zaporizhzhia nuclear power plant lacks the power of its own backup power system in case of repeated disconnection of this line.

In order to start up a new, still cold power unit, there are special boiler rooms at nuclear power plants. They generate heat to warm up the equipment before starting work.

The peculiarity of the Zaporizhia nuclear power plant is that it does not have its own boiler house and heat without the nearby Zaporizhzhia thermal power plant, the most powerful thermal power plant in Ukraine. If the reactor turns out to be de-energized, it may not be able to support the pumps that cool the reactor core.

This is exactly what happened at “Fukushima 1”. There were systems that were supposed to provide cooling of the reactor's active zone, but due to a powerful tsunami, they were destroyed, and the reactor was left without cooling. Despite the fact that it was formally stopped and still enough remained, the heat release of decay products and as a result the active zone melted. Due to high temperature hydrogen began to generate, which eventually exploded. As a result, the protective shell was depressurized and a significant amount of radioactive substances came out.

In case of loss of electricity at nuclear plants there are spare generators. At “Fukushima-1” these generators also were disabled by the tsunami.

At the Zaporizhzhia nuclear power plant, there are 3 diesel plants, they all are located on the industrial site. One spare diesel generator is able to work for about a day, with a strong economy 3 spare diesel stations will be able to work for a maximum of 4 days.

If they stop working and the station, as before, will not receive electricity from the outside, then cooling the active zone of the reactor will become possible.

In this case, a serious accident is possible up to the melting of the active zone, how it happened at Fukushima.

2.3 Detonation of storage of radioactive materials

A feature of the Zaporizhzhia nuclear power plant is the presence of a dry storage facility for spent nuclear fuel. Spent fuel is placed there after five years in the aging pool, when it has already cooled down and its activity has decreased. Dry storage is a large container that stands in rows on an open area on the territory of the station. They can stand like this for dozens of years.

Dry storage is another potential source of radioactivity. Containers do not have any hermetic protection, so they can be vulnerable to combat operations, although they have a certain safety margin.

Rockets were not fired at them, but they were fired from a grenade launcher during the tests.

They are designed with the expectation that they will be used during transportation. And here the question arises, how to secure them? And the calculations were made based on the grenade launcher and this kind of effect, fire effect, etc. That is, these are quite stable buildings.

If a dry nuclear fuel storage facility is hit by a missile, radiation will be released because the spent fuel still contains long-lived nuclides, but it will be localized within 10-30 meters.

Due to the fact that the dry spent nuclear fuel storage facility stores spent fuel that has already cooled after the impact, it will not ignite. The fire would generate a stream of air, which then would go into the atmosphere, where it would spread. Here everything will be local, this is another level of danger.

The containers themselves are unlikely to hurt, but losing control over them (and the control and monitoring systems for the dry storage of spent nuclear fuel has already been damaged) threatens with unforeseen consequences. It is not known what happens inside this container.

2.4 Mines around the Zaporizhzhia nuclear power plant and on its territory

The armed forces of the russian federation laid mines:

According to the combat instructions of the Armed forces of the Russian Federation, mines are installed for “defensive purposes”.

2.5 Intensification of hostilities in the area around the Zaporizhzhia nuclear power plant

The military situation is becoming more and more tense in connection with the counteroffensive of the defense forces of Ukraine in this direction (along the left bank of the Dnipro).

2.6 The simultaneous destruction of the shell in all power units of the Zaporizhzhia nuclear power plant with the destruction of the reactor (the worst-case scenario)

The difference between the nuclear reactors of the Chernobyl nuclear power plant and the Zaporizhzhia nuclear power plant lies in the level of safety. Unlike the Chernobyl nuclear power plant, the Zaporizhzhia nuclear power plant is protected much more reliably.

At the Chernobyl nuclear power plant, the reactor of the ZNPP was in the open air, protected by a hermetic shell, which was absent at the Chernobyl nuclear power plant. In 2011, during the accident at Japan's nuclear power plant “Fukushima-1” protective shell that equipped the plant's reactor was able to withstand approximately 98 percent of the radioactive content and released into the air approximately 2 percent of those radioactive substances that could go outside if there was no container.

The hermetic shell, which is equipped with a reactor at the ZNPP, must not only receive radiation inside the power unit, but also protect it from external influences. These can be both natural disasters and plane crashes, terrorist attacks and explosions. The container has a certain safety margin, but there is also a limit. If it is not the fall of a heavy aircraft or an explosion next to the power unit, this sealed shell is able to withstand, then the impact of a sufficiently powerful warhead, for example, a missile or a bomb, may well lead to its damage. However, damage to the container will not damage the reactor.

To damage the reactor, it is necessary to hit the same place several times with high-precision projectiles. First 1-2 projectiles pierce the hermetic shell, and subsequent ones, hitting the same hole inside, can damage the reactor. In the event that a jet emission occurs through a hole punched in the shell, it will in any case be smaller than in Chernobyl and the scale of the accident will be different.

The largest radioactive release will occur if the shell of all power units of the ZNPP is breached and the nuclear reactor is affected.

It cannot be ruled out that the consequences of such an accident will affect the territory with a length of 100-200 kilometers. Weaker increases in the radiation background can be felt much further away, because it depends on the direction and strength of the wind.

3. The possible consequences of the accident at the Zaporizhzhia nuclear power plant

The consequences of the accident will depend on the realized scenario of the disaster, the extent of destruction, the direction and strength of the wind, as well as more than 100 other factors.

The level of radiation spread as a result of a potential disaster at the Zaporizhzhia NPP will depend on whether the accident was technical, for example, a reaction to turning off the facility's power supply for several days. In such a situation, the severity of the consequences will be somewhere between what happened in Chernobyl and what happened in Fukushima.

Consequences led to such a large and wide dispersal of radioactive activity (in Chernobyl) is probably less likely at the reactors in Zaporozhzhia, which are light water reactors and more similar to European reactors.

The experts’ opinions of the possible accident’s scenario at the Zaporizhzhia NPP could vary in the range from “nothing terrible will happen” to “Chernobyl will seem like a small thing”.

The difference between other events at nuclear power plants that have occurred so far in history and the potential accident at the ZNPP is that earlier accidents occurred due to non-man-made causes. A disaster at the ZNPP can occur due to human activity.

3.1 The spread of radiation

First of all, the surrounding areas are affected by the radiation cloud, followed by the more distant ones (Fig. 2).

According to the data obtained during the simulation of the accident at the ZNPP based on the model under which an earthquake occurs (see "Geopolitics and Security", 2015), the radiation cloud picked up by the wind can spread over an area of 2 million square kilometers. The exclusion zone near the station can reach 30,000 square kilometers. Taking into account the location of the power plant, pollution will affect a large area of Ukraine, the Russian Federation, as well as Georgia, Turkey, and Bulgaria.

In case of prevailing winds from the west or south-west direction, the Dnipropetrovsk, Zaporizhzhia, Kharkiv, Kherson, Donetsk, and Luhansk regions of Ukraine will be affected. Border regions of the Russian Federation (Rostov, Voronezh, Belgorod Kursk Oblasts). Winds can carry radiation to Europe. The disaster could devastate most of Europe, the Russian Federation, and the Mediterranean.

If northerly or northeasterly winds prevail on the day of the accident, the adjacent regions of Ukraine (Dnipropetrovsk, Zaporizhzhia, Kherson and Mykolaiv regions, the Crimean Peninsula) will be in the path of radioactive clouds.

The level of this radioactive background will not immediately lead to the death of people. No one will die immediately, but there will be economic damage because there will be an exclusion zone. The consequences may not appear immediately, but in the long run they can be very serious.

Fig.2 Spread of radiation

(Description of the fig. 2)

In case of an accident with a radiation leak

2 million Ukrainians will need to be immediately resettled in Melitopol, Zaporizhzhia, Kryvyi Rih and the surrounding area. To eliminate the consequences of the accident, it will be necessary to involve more than a million people.

3.2 Aquatic resources

In contrast to the AES of Fukushima, which stands on the coast of the Pacific Ocean, the ZNPP is located on the bank of the Kakhov reservoir of the Dnipro River. During the accident in Japan, a significant part of the radioactive water was poured directly into the ocean. The ZNPP’s case looks far more dangerous – the volumes of water and the ability to level the consequences of dumping radioactive substances are incomparable.

The Kakhov reservoir will be polluted, followed by the Dnipro. Radioactive particles will end up in the Black Sea. Approximately for a period of up to 200 years, it will not be possible to use the Dnieper water either for drinking or for technical purposes.

3.3 ЗThe growth of cancer diseases of the thyroid gland and the risks of other cancer diseases

Radioactive isotopes of cesium iodine and, in smaller quantities, strontium are released into the environment. The same case was after the accident at the Chernobyl nuclear power plant.

During the accident at the Chernobyl nuclear power plant, fuel remained in the operating reactor. Many short-lived and long-lived radionuclides were accumulated in the fuel remaining in the working reactor. But on the 1st day after the accident, the radiation released was dominated by short-lived nuclides, which at that time had not yet had time to decay.

The short-lived nuclides in the non-working three power units at the ZNPP have long since decayed, so the level of radiation in them is lower. In the power unit that was shut down due to shelling in early August 2022, some of the short-lived nuclides, such as iodine 131, have decayed, but not all of them. For example, cesium 134 has a half-life of 2 years, for cesium - 137 -30 years.

Thus, it is likely that the Russian Federation is using the ZNPP to play on the West's fears about a nuclear disaster in Ukraine. It is also likely that the Russian Federation is trying to stop the desire to intervene, to provide Ukraine with military support for a counteroffensive. In addition, the Armed Forces of the Russian Federation can effectively use the ZNPP as a shield to prevent strikes by Ukrainian defense forces on Russian forces and equipment.