How would an attack on the Zaporizhia nuclear plant affect?
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(CNN Spanish) --
The alarm over the security situation at the Zaporizhia nuclear power plant, the largest not only in Ukraine but in all of Europe, brings to mind many Chernobyl and the worst nuclear disaster in history.
The Zaporizhia NPP, located in the south, is one of four operating in Ukraine.
This count does not include Chernobyl, located in the north of the country near Pripyat, which was closed after the 1986 explosion.
The Chernobyl plant had, at the time of the accident, four reactors, according to the World Nuclear Association.
Zaporizhia, meanwhile, currently has six of the 15 reactors in the country, according to the International Atomic Energy Agency (IAEA), and accounts for a fifth of Ukraine's average annual electricity production, according to Energoatom. , the country's nuclear power operator.
According to the information available at the OECD, as of August 7, only two of the six were operational.
After Russian troops occupied the Zaporizhia plant in March, fears of a possible nuclear accident were sparked and experts in the field were quick to downplay concerns, warning that comparisons with Chernobyl were inappropriate and clarifying that modern plants are significantly more safer than the older ones.
Now the experts are once again cautious about it.
The construction of the Chernobyl plant kicked off the development of nuclear energy in Ukraine, explains the World Nuclear Association.
The first unit was commissioned in 1977 and unit number four in 1983. At the time of the 1986 accident, which took place as part of a failed safety test, two more units were still under construction, according to the information. of the OECD Nuclear Energy Agency.
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In the case of Zaporizhia, the first unit to function began in 1984, according to official information, and the remaining five that make up the complex continued to be inaugurated successively, the last in 1995.
The reactors, the key difference between Zaporizhia and Chernobyl
This photograph taken from a helicopter in April 1986 shows a general view of the destroyed reactor four of the Chernobyl nuclear power plant a few days after the catastrophe.
(Credit: VLADIMIR REPIK/AFP via Getty Images)
Chernobyl used known Soviet-era reactors known as RBMKs that were moderated by graphite.
The Zaporizhia plant, on the other hand, has pressurized water-cooled reactors known as the VVER model.
"The design of the VVER is inherently safer and more secure than the Chernobyl RBMK systems," Jon Wolfsthal, senior adviser to Global Zero and former director of arms control and nonproliferation at the National Security Council, explained in March on Twitter.
A VVER reactor can't "'get away' like the RBMK could," Malcolm Grimston, an honorary research fellow at the Imperial Center for Energy Policy and Technology in London, told the Science Media Center (CMC).
Russia takes control of the largest nuclear plant in Ukraine: what does it imply?
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For this reason, in March, experts ruled out that there could be a Chernobyl-like explosion that caused radioactive fallout across Europe and exposed millions of people to dangerous levels of radiation in the 1980s.
The pressure vessel of a modern reactor "is very robust and can withstand considerable damage from phenomena such as earthquakes and, to some extent, kinetic impacts," Robin Grimes, Professor of Materials Physics at Imperial College London, told SMC. , although it is "not designed to withstand" attacks with explosive weaponry.
Inside Ukraine's Power Plant, Concerns of a Nuclear Disaster Grow
retaining structures
Unlike what happened in Chernobyl, each Zaporizhia reactor is "enclosed in a pressurized steel vessel, which in turn is housed within a huge reinforced concrete containment structure," explains an article in the journal
Nature
.
Koji Okamoto, a nuclear security researcher at the University of Tokyo, said there that "the containment structure may have resistance to normal weapons."
What Fukushima Taught
Even if a reactor explosion were highly unlikely, other incidents could occur as a result of bombings or fires at the site, specialists warned in March.
"It's really the electrical and plumbing that is of concern," Joseph Cirincione, a fellow at the Quincy Institute for Responsible Statecraft, told CNN at the time.
Electricity at the Fukushima plant in Japan was cut off during the nuclear disaster there in 2011, while the reactors remained intact.
"That meant you couldn't pump cooling water through the reactors or the cooling ponds anymore," Cirincione said.
In the very unlikely event of a catastrophe in Zaporizhia, what difference would it make to Chernobyl?
Leon Cizelj, president of the European Nuclear Society, believes that "it is not very likely that this plant will suffer damage."
He told CNN that "in the very unlikely event that it is, the radioactive problem would mostly affect the Ukrainians who live nearby," instead of spreading throughout eastern Europe, as happened with Chernobyl.
"If we use past experience, Fukushima could be a worst case scenario comparison," Cizelj added, referring to the severe but more localized meltdown at the Japanese plant in 2011.
Nuclear power plants use a number of auxiliary safety systems, such as diesel generators and off-grid connections, to keep the reactors cool.
Zaporizhia also uses a sprinkler pond, a reservoir in which hot water from inside the plant is cooled.
If these systems failed, the nuclear reactor would heat up rapidly, causing a nuclear meltdown.
That would be the worst case scenario, according to experts.
But, although it would be disastrous locally, they explained that it would not have much of an impact on Europe as a whole.
Security concerns reach a tipping point
Fears about the safety of the Zaporizhia nuclear power plant have been growing, however, reaching a turning point days ago when bombardments damaged a high-voltage power line and forced one of the plant's reactors to stop operating. station, despite the fact that no radioactive leak was detected.
Following the attack, Energoatom said Russian shell fire had damaged a nitrogen-oxygen station and auxiliary building.
Russia, for its part, accuses Ukraine of attacking the area.
IAEA Director General Rafael Mariano Grossi was alarmed, saying the bombing underscored "the very real risk of a nuclear disaster that could threaten public health and the environment in Ukraine and beyond."
"Sadly, instead of de-escalation, there have been reports in recent days of other deeply worrying incidents which, if they continue, could lead to disaster," UN Secretary-General Antonio Guterres said in a statement.
"I urge the removal of any military personnel and equipment from the plant and to prevent any further deployment of forces or equipment to the site."
Who is in control of Zaporizhia and Chernobyl now?
Zaporizhia is under the control of the Russian forces that took over the site, although Energoatom personnel continue to operate the facility.
It is under "extremely stressful conditions", according to the OECD, while the nuclear safety regulator has said it is no longer in a position to monitor conditions.
The situation in Chernobyl is different.
In late February, during the first week of the war, the plant and the surrounding territory fell to Russian troops.
In late March, Ukraine reported that the Russians had left the area.
Putin's interest in that operation, according to experts who spoke at the time, was mainly linked to its location: the Chernobyl Exclusion Zone is in the middle of the most direct route from the Belarusian border, where one had been launched. of Russia's main attacks, to Kyiv.
This geographical location had already led the Ukrainian government to deploy troops to the site in early February, expecting an attack.
An IAEA delegation could visit the Zaporizhia nuclear power plant in early September, according to Mikhail Ulyanov, the Russian representative in Vienna, where the organization is based.
"We are discussing and will continue to discuss the modalities of the mission, the route, the number of people who will take part in it, how long they will stay at the plant, what tasks they are sent there for," Ulyanov said during an online briefing on Friday.
With information from Rob Picheta, Yulia Kesaieva, Olga Voitovych, Sana Noor Haq, Joseph Ataman, Germán Padinger, CNN's Nathan Hodge.
Chernobyl War in Ukraine
