A Step Away from a New Chernobyl? What is Happening at the Zaporizhzhya NPP and is there a Risk of a New Nuclear Disaster?

There has been talk of explosions at Ukrainian nuclear plants since late February, when Russian troops entered the territory of the Chernobyl nuclear power plant and then the Zaporizhzhya nuclear power plant (ZNPP), which the Russian army occupied in early March. Ballistic missiles are now flying over the ZNPP, and the site in front of the plant is being shelled. We shall explain how great the threat of radiation leakages is and why it is difficult to connect the plant to the Russian electricity grid

The Russian army pays special attention to ZNPP. First of all, the nuclear plant is a military base for Russian soldiers. Head of Ukrainian Energoatom Petro Kotin says that the Zaporizhzhya NPP has been under occupation since 4 March. At the same time, up to 50 units of heavy military equipment and about half a thousand soldiers are stationed directly on the territory of the plant.

In this way, the Russians are using the territory of the nuclear power plant as a military base. For example, on 9 August, Russian troops fired missiles at the Nikopol district of Dnipropetrovsk region from the territory of ZNPP site, according to Head of the presidential office Andrii Yermak. The Russians also arrange provocations of the plant itself, for example, on August 5 they fired at it from occupied Energodar. Then three “arrivals” were recorded near the Zaporizhzhya NPP industrial site.

Petro Kotin explains that there is a lot of nuclear materials at the nuclear plant, so the Russians think that no one will attack them directly at the plant. At the moment, the plant is operating for the Ukrainian power grid, but not at full capacity, as many of the lines around the plant have been damaged. The staff are also Ukrainian, although Rosatom employees are present, whose task it is to monitor the military. The Russian occupants fully control security at the plant: personnel access to workplaces and to the plant.

The head of Energoatom explains that the danger of a radioactive fuel leak will remain until the end of the war. However, the extent of the plant’s damage depends on where the missile or shell hits. ZNPP has a lot of nuclear materials, as it consists of six power units loaded with nuclear fuel, which makes it the biggest nuclear power plant not only in Ukraine, but also in Europe. In addition, there are six near-reactor pools, almost filled with spent nuclear fuel. They stand near the reactors, directly next to the units themselves. In addition, ZNPP has another nuclear facility, the spent nuclear fuel storage facility, which stands directly on the site in the open air. It is 174 concrete containers for dry storage of already spent nuclear fuel.

The fuel cycle is as follows: fresh fuel enters the plant, then runs in the reactor for about 4 years. After that, the fuel is moved to near-reactor pools for 3-5 years, until it cools down enough to be lifted out of the water and put into the air, where it stands in concrete containers at the spent nuclear fuel storage site. In other words, this repository is also a separate nuclear facility.

Petro Kotin says that the nuclear fuel is spent but is still very dangerous. He says that when fresh fuel is brought to the plant, it is not active at all. The process begins when the nuclear material enters the reactor, and a nuclear reaction occurs. Then the fuel heats up and constantly produces nitrones, alpha particles, gamma particles and radiation – the nuclear fuel becomes a very active material. This is why it is stored in special containers for hundreds of years until it decays.

“The situation is the same at the Chernobyl nuclear power plant. When there was an explosion, the active material fell out on the roof. There was a situation where soldiers were working there, but one could stay on the roof for no longer than 30 seconds, because one gets radiation. A soldier would run up, use pliers to take this material, throw it down from the roof and run away. It just depended on how much of this material was released,” says Petro Kotin.

A slightly different situation could arise if a missile hits the reactor compartment, penetrates the barriers (concrete, metal cladding) and enters the reactor or the nuclear fuel pool – the integrity is broken and the nuclear material escapes and spreads. However, one missile will not penetrate the cladding, but 2-3 can damage the cladding and release the nuclear fuel.

“If the reactor lid is breached and the nuclear material in the centre is hit, it will also be scattered, just like in Chernobyl. If the missile hits one or two fuel assemblies (FAs) that arrived at the plant from the manufacturer, then it will have much less consequences. But if it hits the storage location – containers, concrete, and a metal basket where the spent fuel elements are, and the missile manages to get to the fuel itself, it will leak across the territory – we would have a radiation accident”, – explains the Chief Nuclear Engineer of Ukraine.

Director General of the IAEA Rafael Mariano Grossi also says there is a risk of emissions. Thus, the aforementioned Russian shelling on 5 August near the dry spent nuclear fuel storage facility at Zaporizhzhia NPP damaged the plant’s external power supply system, walls, roof and windows in the spent nuclear fuel storage area and communication cables. These cables on particular that are part of the radiation monitoring system, which could affect the operation of the three sensors that detect radiation leaks. In other words, you could say the plant could have been “blinded” and workers might not have noticed the spread of radioactive material.

In addition, a Ukrainian ZNPP guard was injured. By the way, the same Petro Kotin says that the Russian occupiers bully Ukrainian personnel. For example, a diver working at the plant Andrii Goncharuk was tortured to death and died after being held in custody. He was taken to hospital and two hours later the man died of beating. A ZNPP maintenance technician Sergei Shvets was burst in his flat and shot with an automatic round there: five bullets entered his body, but he survived afterwards. According to Petro Kotin, around 100 plant employees have been captured, tortured and abused.

“Some people come out after 2-3 days, but they come out already with a broken psyche. They are actually required to acknowledge the “Russian world” and say something on camera for Russian propaganda,” the Head of Energoatom said.

We have to understand that at the same time Russia started implementing a plan to connect the ZNPP to the Russian energy system and disconnect it from the Ukrainian one. But technically it is not so easy to do. The thing is that the power lines of the Kakhovska substation and of the Melitopol substation damaged in 2014-2015, which connected Crimea with the territorial Ukraine, have to be restored.

However, the main issue is the mismatch between the technical characteristics of the Ukrainian and Russian electricity grids. Thus, the Ukrainian power grid is connected to the European power system (ENTSO-E), which operates at a frequency of 50 Hz. This system is not synchronised with Russia, which also operates on this frequency.

“Let me explain: two 50Hz sinusoids that do not match in peaks. When we have a peak, they have a minimum and vice versa. The process when they coincide is called synchronisation. We (Ukraine) synchronised it with Europe and disconnected from Russia at the beginning of the war,” Petro Kotin says.

At the moment, however, the Russians are actively trying to circumvent this problem. For example, employees of Rosatom have handed over a special programme to the plant in order to reconnect the ZNPP to Crimea. To do this, first the Russian specialists need to completely disconnect the entire south of Ukraine – occupied parts of Kherson and Zaporozhye regions – from electricity. Then they need to power the occupied regions from the substation in Dzhankoy, gradually reach the Kakhovka substation, and then directly to the ZNPP. Petro Kotin says that after the above procedures it will no longer be possible to connect this NPP to the Ukrainian energy system, it will remain on the Russian frequency.

At the same time, it is believed that the Ukrainian military could cut the transmission lines at the Zaporizhzhya NPP if the Russian occupiers “cut off” ZNPP from the Ukrainian power grid, thus thwarting the Kremlin’s plans to appropriate the nuclear plant.

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Autorius: Voras.online