What are the risks facing Zaporizhzhya, the nuclear power plant in a war zone?

Nuclear power plants (NPPs) are complex and sophisticated facilities with several layers of safety measures, but no NPP in the world is built to withstand military conflict – yet this is just the risk that has befallen the Zaporizhzhya NPP in Ukraine. It was taken over by Russian forces in May 2022 and has since often had to operate in conditions that threaten safety at the facility.

In June, a Lithuania-based NGO named the Bellona Foundation published a report, authored by its nuclear advisor, Dmitry Gorchakov, analysing the risks associated with the hostilities around, near, or at the Zaporizhzhya NPP based on the facility’s design, safety measures, and the local geography.

Is Zaporizhzhya comparable to Chernobyl?

Whenever the Zaporizhzhya NPP has been threatened, various media reports have repeatedly drawn comparisons to the Chernobyl NPP and the infamous accident there in 1986. The Bellona report’s headline finding, however, is that any damage to the Zaporizhzhya NPP is unlikely to play out in the same fashion or at the same scale.

The principal difference between Chernobyl and Zaporizhzhya is that the former had RBMK reactors and the latter has VVER-1000 reactors. (This is the same reactor design installed at the Kudankulam NPP in India.) As the Bellona report also noted, Zaporizhzhya also takes advantage of safety measures installed in the aftermath of the Chernobyl and Fukushima disasters.

What is the reactor design at Zaporizhzhya?

Zaporizhzhya NPP is located southwest of Zaporizhzhia city, along the Dnieper river. It has six VVER-1000 reactors for a total power generation capacity of 6 GW.

The reactor complex consists of the reactor vessel, in which fuel rods are surrounded in water. Control rods are inserted at the top. The water acts as both coolant and moderator. A pressuriser holds the water at a high but constant pressure – around 150 atm – to prevent it from boiling. This is the primary cooling circuit.

As the water heats up, the heat is moved to a secondary cooling circuit, where it converts a separate resource of water into steam. This steam is fed to turbines that generate electricity.

In this design, the primary coolant and the moderator are the same substance (water), and it doesn’t leave the reactor vessel at any time.

In RBMK reactors like at Chernobyl, on the other hand, the coolant and the moderator are different (light water and nuclear graphite, respectively) and the coolant – which is radioactive for having been exposed to the nuclear fuel – flows out of the reactor vessel. One reason Chernobyl was so bad was that when the reactor was breached, the superhot graphite caught fire when it came in contact with air.

Unlike Chernobyl, the VVER-1000 reactor and its power-generation units at Zaporizhzhya are also placed inside a large airtight chamber called a containment. Its walls are 120 cm thick and made of prestressed concrete.

What is the risk at Zaporizhzhya today?

The Bellona report evaluated the risk of different types of accidents at the facility based on different types of damage sustained. In the worst case scenario, the containment is completely damaged and a projectile strikes a reactor while it is generating power.

The principal danger here is that the primary circuit water could depressurise as steam and escape into the air, along with radioactive material and other volatile substances. This mixture will contain the isotope iodine-131, which is easily dispersed by winds and accumulates in and damages the thyroid gland in humans. It has a half-life of around eight days and so, per the report, “would only pose a threat for several weeks”.

A breach and depressurisation would also release caesium-137, which has a half-life of 30 years and was responsible for contaminating much of Chernobyl’s surroundings after the accident.

How either isotope is dispersed depends on the immediate weather, especially the strength and direction of the wind. This said, due to design differences, what was released in sustained fashion at Chernobyl for around a week is likely to be released in a single, short burst at Zaporizhzhya. This in turn could keep the fallout to within around a few hundred kilometres, according to one estimate cited in the report.

What are other threats to Zaporizhzhya?

The worse scenarios are separated from the better ones depending on the reactors’ operational statuses. If the reactors have been shut for a few months, the iodine-131 will have almost completely decayed, removing an important threat. If a reactor has been in cold-shutdown – i.e. shutdown and the primary circuit is almost at atmospheric pressure – then the chances of an explosive leak also drop.

Since September 10, 2022, the six reactors at Zaporizhzhya have been shut. In late 2022, two were placed in a state of semi-hot shutdown, meaning the primary circuit was held at 200 degrees Celsius with heat from the decaying nuclear fuel. This was required to provide heat at the facility and for the nearby town of Energodar.

As of May 2023, all reactors but the sixth were in cold-shutdown.

The Bellona report discussed several possibilities based on combinations of conditions. One was the ‘Fukushima scenario’ – when the NPP becomes disconnected from the external power grid. This is dangerous because, when nuclear reactions aren’t happening in the reactor, the nuclear fuel has to be cooled, which means the coolant pumps need to operate. If they don’t, the fuel could become hot enough to melt through the reactor’s bottom, where it will contaminate soil, air, and water.

The report’s ultimate concern? The working conditions of the 3,000 or so people at the plant, most of whom have refused to sign new employment contracts with their new Russian employers, amidst — among other things — uncertainties over the management, violation of protocol, and “suspicions of disloyalty”.

What does the report recommend?

On June 6, 2023, the Kakhovka dam, which is downstream of the Zaporizhzhya NPP and in whose reservoir the plant is located, was breached. While the water level in the reservoir subsequently dropped, the Zaporizhzhya NPP wasn’t affected because the cooling pond from which it draws water is isolated from the water in the reservoir. The only way water can enter or exit the pond is through controlled sluice gates. The Bellona report suggested that the walls of the pond were built to withstand a water-level differential of 6 metres.

After considering the possibility of this breach as well, the report made the following recommendations (reworded):

* All reactors should be in shutdown or cold-shutdown states

* There should be no effort to move fuel at the same time as hostilities around the plant

* Hostilities should be kept out of the territory of the plant itself

* If/when Russian troops withdraw from the plant, plant staff should be rehabilitated

  • Zaporizhzhya NPP is located southwest of Zaporizhzhia city, along the Dnieper river. It has six VVER-1000 reactors for a total power generation capacity of 6 GW.
  • The Bellona report evaluated the risk of different types of accidents at the facility based on different types of damage sustained. In the worst case scenario, the containment is completely damaged and a projectile strikes a reactor while it is generating power.
  • If the reactors have been shut for a few months, the iodine-131 will have almost completely decayed, removing an important threat. If a reactor has been in cold-shutdown – i.e. shutdown and the primary circuit is almost at atmospheric pressure – then the chances of an explosive leak also drop.

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Ukraine accuses Russia of destroying major dam near Kherson, warns of widespread flooding

The wall of a major dam in a part of southern Ukraine that Moscow controls collapsed on June 6 after a reported explosion, sending water gushing downriver and prompting dire warnings of ecological damage as officials from both sides in the war ordered residents to evacuate.

Ukraine accused Russian forces of blowing up the dam and hydroelectric power station, while Russian officials blamed Ukrainian military strikes in the contested area.

The fallout could have far-reaching consequences: flooding homes, streets and businesses downstream; depleting water levels upstream that help cool Europe’s largest nuclear power plant; and draining supplies of drinking water to the south in Crimea, which Russia illegally annexed.

The dam break added a stunning new dimension to Russia’s ongoing war in Ukraine, now in its 16th month. Ukrainian forces were widely seen to be moving forward with a long-anticipated counteroffensive in patches along more than 1,000 kilometers (621 miles) of frontline in the east and south of Ukraine.

It was not immediately clear whether either side benefits from the damage to the dam, since both Russian-controlled and Ukrainian-held lands are at risk of flooding. The damage could also potentially hinder Ukraine’s counteroffensive in the south, while at the same time Russia depends on the dam to supply water to the Crimea region it annexed illegally in 2014.

A general view of the Nova Kakhovka dam that was breached in Kherson region, on Ukraine June 6, 2023 in this screen grab taken from a video obtained by Reuters.
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Amid official outrage, Ukrainian President Volodymyr Zelensky said he convened an urgent meeting of the National Security Council. He alleged that Russian forces set off a blast inside the dam structure at 2.50 a.m. (2350 GMT) and said some 80 settlements were in danger.

Ukraine’s nuclear operator Energoatom said in a Telegram statement that the damage to the dam “could have negative consequences” for the Zaporizhzhia Nuclear Power Plant, which is Europe’s biggest, but wrote that for now the situation is “controllable.”

The U.N.’s International Atomic Energy Agency said in a statement there was “no immediate risk to the safety of the plant,” which requires water for its cooling system.

It said that IAEA staff on site have been told the dam level is falling by 5 centimeters (2 inches) an hour. At that rate, the supply from the reservoir should last a few days, it said.

The plant also has alternative sources of water, including a large cooling pond than can provide water “for some months,” the statement said.

Ukrainian authorities have previously warned that the dam’s failure could unleash 18 million cubic meters (4.8 billion gallons) of water and flood Kherson and dozens of other areas where hundreds of thousands of people live.

The World Data Center for Geoinformatics and Sustainable Development, a Ukrainian nongovernmental organization, estimated that nearly 100 villages and towns would be flooded. It also reckoned that the water level would start dropping only after five-seven days.

A total collapse in the dam would wash away much of the broad river’s left bank, according to the Ukraine War Environmental Consequences Working Group, an organization of environmental activists and experts documenting the war’s environmental effects.

Mykhailo Podolyak, a senior adviser to President Volodymyr Zelensky, said that “a global ecological disaster is playing out now, online, and thousands of animals and ecosystems will be destroyed in the next few hours.”

Villages ordered to evacuate

Videos posted online began testifying to the spillover. One showed floodwaters inundating a long roadway; another showed a beaver scurrying for high ground from rising waters.

The Ukrainian Interior Ministry called for residents of 10 villages on the Dnipro’s right bank and parts of the city of Kherson downriver to gather essential documents and pets, turn off appliances, and leave, while cautioning against possible disinformation.

The Russian-installed mayor of occupied Nova Kakhovka, Vladimir Leontyev, said it was being evacuated as water poured into the city.

Damaged buildings are seen as the Nova Kakhovka dam was breached in Kherson region, Ukraine on June 6, 2023 in this screen grab taken from a video obtained by Reuters

Damaged buildings are seen as the Nova Kakhovka dam was breached in Kherson region, Ukraine on June 6, 2023 in this screen grab taken from a video obtained by Reuters
| Photo Credit:

Ukraine controls five of the six dams along the Dnipro, which runs from its northern border with Belarus down to the Black Sea and is crucial for the entire country’s drinking water and power supply.

Oleksandr Prokudin, the head of the Kherson Regional Military Administration, said in a video posted to Telegram shortly before 7 a.m. that “the Russian army has committed yet another act of terror,” and warned that water will reach “critical levels” within five hours.

Ukraine’s state hydro power generating company wrote in a statement that “The station cannot be restored.” Ukrhydroenergo also claimed that Russia blew up the station from inside the engine room.

Leontyev, the Russian-appointed mayor, said Tuesday that numerous Ukrainian strikes on the Kakhovka hydroelectric plant destroyed its valves, and “water from the Kakhovka reservoir began to uncontrollably flow downstream.” Leontyev added that damage to the station was beyond repair, and it would have to be rebuilt.

Ukraine and Russia have previously accused each other of targeting the dam with attacks, and last October Mr. Zelensky predicted that Russia would destroy the dam in order to cause a flood.

Authorities, experts and residents have for months expressed concerns about water flows through — and over — the Kakhovka dam.

In February, water levels were so low that many feared a meltdown at the Zaporizhzhia nuclear plant, whose cooling systems are supplied with water from the Kakhovka reservoir held up by the dam.

By mid-May, after heavy rains and snow melt, water levels rose beyond normal levels, flooding nearby villages. Satellite images showed water washing over damaged sluice gates.

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All the latest from the Ukraine war this Monday

These are the latest developments from the Ukraine war today.

Russia Batters Ukraine ahead of Victory Day celebrations

Moscow launched dozens of missiles and drones towards Kyiv and other Ukrainian cities on Sunday night, injuring at least five people.

Russian missiles caused a huge fire at a foodstuff warehouse in the Black Sea city of Odesa, with blasts reported in several other Ukrainian regions early on Monday morning.

Ukraine’s top military brass said it shot down all 35 Iranian-made Shahed drones that were launched during the night.

Five people were hurt in Kyiv, according to the city’s major Vitali Klitschko. Two of these injuries were caused by drone wreckage falling in the west of the capital.

The strikes came as Russia prepares for its annual Victory Day celebrations, which mark the Soviet Union’s victory over Nazi Germany.

Russian President Vladimir Putin has played on Russia’s victory in the Second World War in his narrative around the Ukraine invasion, calling leaders in Kyiv Nazis.

“Unfortunately, there are dead and wounded civilians, high-rise buildings, private homes and other civilian infrastructure were damaged,” the General Staff of Ukraine’s Armed Forces said in its daily update.

Air raid alerts blared for hours over roughly two-thirds of Ukraine on Sunday.

Anxiety grows about Ukraine nuclear plant

Worries over Europe’s largest nuclear power plant grew on Sunday after local authorities ordered civilians living nearby to evacuate.

The International Atomic Energy Agency (IAEA) has spent months trying to persuade Russian and Ukrainian officials to avert disaster at Zaporizhzhia nuclear plant, located in southeastern Ukraine.

The facility was captured by Moscow early in the war but has been caught in the crossfire ever since.

Evacuations were ordered by Yegeny Balitsky the Russia-backed governor of Ukraine’s Zaporizhzhia province, raising fears that fighting in the area would intensify.

Balitsky on Friday ordered civilians to leave 18 Russian-occupied communities, including Enerhodar, home to most of the staff at the plant.

More than 1,500 people had been evacuated from two unspecified cities in the region as of Sunday, Balitsky said.

Moscow’s troops seized the plant soon after invading Ukraine last year, but Ukrainian employees have continued to run it during the occupation, at times under extreme duress.

Ukraine has regularly fired at the Russian side of the lines, while Russia has repeatedly shelled Ukrainian-held communities across the Dnieper River.

The fighting has intensified as Ukraine prepares to launch a long-promised counteroffensive to reclaim ground taken by Russia.

“The general situation in the area near the Zaporizhzhia Nuclear Power Plant is becoming increasingly unpredictable and potentially dangerous,” IAEA Director General Rafael Grossi warned on Saturday.

“We must act now to prevent the threat of a severe nuclear accident and its associated consequences for the population and the environment. This major nuclear facility must be protected,” he said.

Analysts have for months pointed to the southern Zaporizhzhia region as one of the possible targets of Ukraine’s expected spring counteroffensive, speculating that Kyiv’s forces might try to choke off Russia’s “land corridor” to the Crimean Peninsula.

Moscow thwarts Ukrainian drone attack in Crimea

Russia says it has shot down Ukrainian drones attacking the Crimea peninsula on Sunday.

The Russian administration in Crimea said it had repelled a night attack by a dozen Ukrainian drones, though Ukraine has not confined this.

The unmanned ariel vehicles were launched on the port city of Sevastopol, capital of the peninsula and home to Russia’s Black Sea fleet.

According to Moscow, the drones were neutralised by anti-aircraft defences and electronic jamming.

“No infrastructure in the city was damaged,” said Mikhail Razvojayev, the city governor.

Since the summer of 2022, the peninsula – annexed by Moscow in 2014 – has been regularly hit by drone attacks and alleged Ukrainian sabotage.

At the end of April, one drone strike caused a huge fire in an oil depot in Sevastopol.

Wagner stays put in Bakhmut

The boss of the Wagner mercenary group said on Sunday that Moscow had “promised” more support, allowing it to continue fighting in Bakhmut.

On Friday, Yevgeny Prigozhin released an inflammatory video attacking the Russian military. In it, he vowed to withdraw his mercenary force from Bakhmut, the epicentre of fighting in the east, if they were not given more ammo.

“Last night, we received a combat order. They promise to give us all the ammunition and armaments we need to continue operations,” he said on Sunday in an audio message.

Fighting over Bakhmut has raged since summer, with the small salt mining city town gaining a huge symbolic value.

Russia is eager for a clear battlefield victory, especially on the eve of the Victory Day celebrations.

Wagner’s troops have played a key part in Russia’s deadly assault on Bakhmut, which had ground the city to a ruin.

Their forces are in control of 95% of the city, according to Prigozhin.

But the Ukrainian army says it is clinging on, defending itself fiercely. It is hoping to exhaust Russian forces in Bakhmut, which has been likened to a meat grinder.

“The enemy is not going to change its objectives and is doing everything to control Bakhmut,” said General Oleksandr Syrsky of the Ukrainian land forces.

Russia accused of using phosphorus in Ukraine

Ukraine accused Russia of using phosphorus on Saturday, releasing a video that purported to show the telltale white fire of the destructive munitions.

International law prohibits the use of white phosphorus or other incendiary weapons in areas where there could be concentrations of civilians, though it can also be used for illumination or to create smoke screens.

Phosphorus munitions are designed to set fire to objects and cause horrific burn injuries.

Euronews could not independently verify where the video was shot or when, but chemical weapons expert Hamish de Bretton-Gordon, a former British army colonel, said it was clearly white phosphorus.

“This is being fired directly at Ukraine positions and this would be a war crime,” he said.

“I expect because the Russians have failed to take Bakmut conventionally, they are now using unconventional tactics to burn the Ukrainian soldiers to death or to get them to flee.”

Russian forces haven’t commented on the claim.

They have rejected previous accusations from Ukraine they had used phosphorus munitions.

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