What is the Zaporizhzhia nuclear power plant like and why its fire could have produced a catastrophe worse than Chernobyl

View of the nuclear plant before the Russian invasion (EnergoAtom)

The Zaporizhzhia nuclear plant, located in the homonymous region of the Ukrainian city of Energodar, burned for several hours this Friday after being attacked by the invading Russian forces, sparking concern throughout Europe due to the danger of a potential atomic catastrophe.

In fact, when the fire had not yet been controlled, the mayor of this districtDmitry Orlov, warned in his Telegram account that this fact constituted a “threat to world security”.

The Zaporizhzhia NPP (Nuclear Power Plant) began to be built by the Soviet Union in 1979 and the first of its six power units began operating in 1984, less than two years before the Chernobyl tragedy.

It is located in the steppe zone of Ukraine, on the shore of a water reservoir in the city of Kakhovka, located about 71 kilometers northeast of Kherson. It is the largest nuclear power plant in Europe and one of the largest in the world.

It has a total of six VVER-1000 type reactors, which work with pressurized water and can produce between 40,000 and 42,000 million kWh. of power, which represents a fifth of the average annual supply of electricity in the country. These reactors have a duration of between 40 and 60 years, or even more thanks to technological advances.

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It is operated by the national company NNEGC Energoatom and in its cooling pools there are hundreds of tons of highly radioactive nuclear fuelwhich is why three of them have been closed when the armed conflict with Russia began.

According to what is known so far, the main fire broke out in one of those six VVER-1000 reactors found at the plantwhich is under renovation and does not operate, but inside it has nuclear fuel.

The conception of these pressurized water reactors, considered among the safest, comes from those used in nuclear submarines and differs from those of Chernobyl, controlled with graphite and initially conceived to produce plutonium instead of electricity.

The VVER-1000 are powered by fuel enriched in the fissile isotope Uranium-235. They work thanks to the steam heated in the core, but unlike other reactors, the steam contaminated by radiation is not used to turn the turbines, but to heat another circuit of non-contaminated steam that is responsible for generating this movement. This technique makes it possible to maintain a relatively low level of radioactivity for the plant’s employees.

The nuclear power plant is on fire (Zaporizhzhya NPP via YouTube/via REUTERS)
The nuclear power plant is on fire (Zaporizhzhya NPP via YouTube / via REUTERS) (Zaporizhzhya NPP /)

Ukrainian authorities said on Friday that Russian shell fire caused a fire in a building dedicated to training and in a laboratory. After hours of uncertainty, the site was secured and the reactors “stopped safely,” according to US officials.

A tragedy potentially worse than Chernobyl

Unlike the Chernobyl plant, the one at Zaporizhzhia has all modern security measures and it was even the first facility of this type that has passed all the design review and approval stages required by national nuclear legislation, as detailed on its official website.

It was also one of the first Ukrainian nuclear power plants to have a dry storage system for spent fuel: 380 containers are treated to store the waste that will be generated during the general useful life of the establishment.

“The Russian army is firing from all sides on the Zaporizhzhia nuclear power plant, the largest in Europe. The fire has already broken out. If it explodes, it will be 10 times bigger than Chornobyl,” said the Ukrainian Foreign Minister, Dimitri Kulebawhen the fire was still burning.

Unlike Zaporizhzhia, the Chernobyl nuclear power plant had only four units equipped with RBMK-1000 type reactorswhich operate with boiling water using slightly enriched uranium and are moderated with graphite, while a mixture of nitrogen and helium circulates between the blocks to prevent oxidation.

Each of these reactors was capable of producing 3,200 MW of electricity, while the used fuel was stored in the SNF-1 and SNF-2 buildings, located within the same complex, which did not meet the main safety standards.

The Chernobyl catastrophe

At 01:23 a.m. on April 26, 1986, during a planned test at Unit 4 of the plant, an electrical outage occurred which, added to a series of operator errors, led to the meltdown of the unit’s graphite-moderated RBMK reactor core.

Chernobyl stopped working permanently in the year 2000 (REUTERS / Gleb Garanich)
Chernobyl definitely stopped working in the year 2000 (REUTERS / Gleb Garanich) (GLEB GARANICH /)

Since the reactor was not protected by a containment chamber, the resulting steam explosion tore through the roof of the unit and rained down pieces of fuel rods and highly radioactive graphite onto the surroundings. The resulting fires generated radioactive smoke that carried contaminated particles over Ukraine, Belarus and Russia, as well as parts of Scandinavia and Europe in general.

A plan was immediately created to control and decontaminate the area, under the implementation of a series of mechanized robots for the most dangerous tasks. However, the radiation levels were so high that the plates melted and the robots stopped working, so the task had to be done by hand. A radiation dose of 100 roentgens per hour is enough to kill a man, but Chernobyl levels exceeded 20,000 per hour.

According to a report by the World Health Organization entitled “Chernobyl, the true scale of the accident”, carried out in mid-2005, the direct fatal victims of this accident were 50, almost all members of the emergency service, but more than 4,000 people suffered from thyroid cancer as a result of radiation. Most of them were children or teenagers.

The high levels of contamination in the surroundings caused the region to be declared an “exclusion zone” and Chernobyl quickly became a ghost town, although the plant continued to function until the year 2000, when the now independent Ukrainian government decided to stop all activity in the place.

Effects of radiation on people

High levels of radiation in the exclusion zone remain even today (REUTERS/Yaroslav Yemelianenko)
High levels of radiation in the exclusion zone remain even today (REUTERS / Yaroslav Yemelianenko) (STRINGER /)

Radioactive material, particularly what can be found in Chernobyl, is considered unstable because it constantly spews high-energy particles and waves that can destroy cellular structures or produce reactive chemicals that attack the cell system of living things.

Although many cells in the human body can be replaced with some ease, this is not the case of DNA, which, just by being exposed to low levels of radiation, generates mutations that can also lead to, for example, different types of cancer.

This was well demonstrated after the aforementioned nuclear accident: before the plant exploded, in the neighboring country of Belarus, whose border is close to the current exclusion zone, around 82 oncological diseases were recorded for every 100,000 people, while ten years later that figure increased to 6,000 per 100,000 inhabitants.

According to some studies, the accident was so serious that the city of Chernobyl may not be inhabited for another 20,000 years.

During the 1986 catastrophe, the level of radioactivity reached 300 sieverts per hour, million times more than what is currently recorded in Zaporizhzhia, which according to the operator of the plant, was 0.1 microsieverts per hour, a level below the world average and much lower than that of a plane flight or an X-ray .


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