Grim anniversary: Zaporizhzhia nuclear plant must not become the next Chornobyl

Shaun Burnie, Jan Vande Putte, Daryna Rogachuk

Greenpeace Green Reconstruction Ukraine Project

26 APRIL 2024

Chornobyl is one of the most recognised synonyms for disaster in the world. Its legacy is to serve as a universal reminder of the terrible consequences of nuclear power when it goes wrong: on this day in 1986, a test procedure produced an explosion at the power plant in Pripyat, Ukraine, causing a chain reaction that blew a colossal release of radioactive contamination across Europe and eventually the whole Northern hemisphere.  

For people of Ukraine, the Chornobyl disaster is a personal tragedy. Millions have been affected by the destruction of reactor unit 4 and the radiation it released into the environment, either directly or through their families, friends and colleagues. The disaster may have been nearly 40 years ago but its impact is still felt across generations. 

Today, 38 years later, the spectre of nuclear catastrophe looms large, not only at the abandoned region around Pripyat. The ongoing illegal Russian military occupation of the south-east Ukrainian Zaporizhzhia nuclear power plant creates a direct threat of another nuclear catastrophe. Aggressively capturing the largest nuclear plant in Europe, one of the 10 biggest in the world, places not only Ukraine and neighbouring countries in danger, but also most of Europe.

By deliberately firing missiles at Ukraine’s wider energy infrastructure, the Russian military places Ukraine’s four nuclear power plants – South Ukraine, Rivne, Khemelnitsky and Zaporizhzhia - at risk of an emergency power loss and station black-out. All are vulnerable,  but it is the Zaporizhzhia plant most at risk: the amount of radioactivity on the site and conditions of the plant as a result of direct military occupation, along with  the behaviour of Russian armed forces and Rosatom, the Russian state nuclear corporation, risk a disaster that would, like Chornobyl, be a result of decisions made in Moscow.

The Chornobyl RBMK reactor design had evolved out of the Soviet Union’s military reactors in the 1950’s which were used for producing plutonium for nuclear weapons. Even before the construction began on the first large RBMK reactor at Leningrad in 1970 it was known by designers at the Kurchatov Institute that the design had major flaws that would make it unstable to operate. As early as 1965 scientists warned that the instability included a ‘positive steam coefficient’ which could lead to an explosion. They were ignored. Twenty years later that design flaw and others led to two massive explosions that destroyed the Chornobyl unit 4 reactor. The high temperatures in the reactor contributed to the burning of hundreds of tons of graphite, melting of nuclear fuel and the release of an estimated 450PBq of radioactive iodine, cesium, strontium and plutonium and many others. The radioactivity rose to between 7km and 9 km into the atmosphere and at these high altitudes were carried great distances and deposited across Europe and eventually the whole northern hemisphere. For the hundreds of thousands of inhabitants of Chornobyl, Pripyat and hundreds of villages and towns across northern Ukraine it was the end of a way of life as evacuations were implemented. The battle of Chornobyl that was fought in the hours, days, weeks, months and the years between 1986-1990, eventually engulfed over 600,000 firefighters, soldiers, janitors, and miners – collectively called ‘liquidators’ who were sent to the Chornobyl site after the explosion. Many tens of thousands have suffered long term health consequences and mortality. 

For the decades that followed, hundreds of Ukrainian scientists, engineers and technicians worked every day to monitor, investigate and and seek to recover control of the nuclear plant site and the vast radioactive exclusion zone - until 24 February 2022, when Russian armed forces invaded and installed Rosatom. Although the Russian occupation of Chornobyl ended in March 2022, the impact and consequences continue today. The nuclear plant and the exclusion zone now sit on the front of Ukraine’s defensive line with Belarus and Russian forces.

Pripyat, Chornobyl, 3 November 2023. S Burnie/Greenpeace - photos from Media Library

The Russian threat at the Zaporizhzhia nuclear plant today

Only days after the start of the full-scale invasion on 24th of February, Russian armed forces attacked and then occupied the Zaporizhzhia nuclear power plant in the South of Ukraine. The citizens of Energodar and workers at the power plant heroïcally put barricades of cars, trucks, tires and sandbanks on the main road leading to the nuclear plant to block the advancing Russian troops, but they were overwhelmed.

The attack damaged the plant, including its electricity infrastructure, which is vital for maintaining the cooling function of the hot nuclear fuel in the reactor buildings. 

At that moment, the power plant was still producing electricity, which means an enormous amount of heat is produced by the nuclear fuel. One reactor core that is producing heat for the electricity generation has the power of 2 million water cookers. In a crisis, that reactor would be shut down, but the radioactive fuel remains extremely hot even after that. If the cooling would be stopped after shutdown, it would take only hours for the cooling water to boil off, expose the hot nuclear fuel to the air and melt down, leading to a new major nuclear disaster. 

Luckily, the power supply was not interrupted during the occupation, but it could have happened. In a peaceful situation, the workers at the power plant still have several options to restore cooling in an emergency, but under the threat of war, this is severely compromised. For instance, the Russian attack set off a fire at the training centre of the nuclear plant and the Ukrainian fire brigade that wanted to extinguish the fire was stopped by the Russian troops. 

There is a long list of dangerous incidents caused by the reckless attitude of the Russian occupiers. Most dramatic was the destruction by Russia of the Nova Kakhovka dam on 6 June 2023, which not only led to an enormous damage and suffering below the dam, but also emptied the Kakhovka reservoir which is the ultimate cooling water reservoir for the Zaporizhzhia nuclear plant. Because all reactors have been shut down since September 2022, lowering cooling needs, that water supply is rather stable for the moment, but it’s tight.

The electricity supply needed to run the cooling pumps is even more critical. To date, external electricity supply has been interrupted eight times completely, making the cooling dependent on the 20 diesel generators on the site. But on top of that, there is a lack of maintenance of such critical equipment since the occupation, and a lack of qualified personnel. Ukrainian workers have been tortured and killed, many have left. Some Russian workers have been brought in by the Russian nuclear company Rosatom, but they lack experience. We should thus doubt the reliability of such emergency diesels, especially if they have to work for a longer period of time.

The ultimate blow to nuclear safety however is the plan of Rosatom and Moscow to attempt to restart one or more reactors at the Zaporizhzhia nuclear plant. The existing cooling water resources are far from sufficient to cool an operational reactor. Rosatom would have to build a new pump system, which would not be as reliable, and they do not have the workforce and expertise to control an operational reactor. Such a plan is thus a direct nuclear threat to Ukraine and its neighbouring countries in Europe.

What worries us today, is that Russia might have launched a disinformation campaign to pave the way for blaming Ukraine in case something goes very wrong. Hiding behind false flag attacks might make it easier for them to take higher risks. That is why it is so important to remember Chornobyl today, the way it happened, through irresponsible deliberate decisions and acts by the Soviet system. 

The international community needs to act to lower the risks. In the first place to avoid a restart of a reactor in Zaporizhzhia. The IAEA so far has not made an unambiguous statement calling Russia not to restart. They even hinted at engaging into a process to define the safety requirements for a restart. Such signals are dangerous, as they can and will be used by Moscow to justify the restart process. Also the UN Security Council needs to act, by debunking the disinformation by Russia and calling for a no restart.  Finally, as many ambassadors at the Security Council stated last week on 15 April, the only solution is for Russian troops to stop the war, leave the Zaporizhzhia nuclear plant and return back to Russia, respecting the territorial integrity of Ukraine.


Greenpeace has written to Rafael Mariano Grossi, the International Atomic Energy Agency (IAEA) Director General calling on him to make clear to Rosatom and the Russian government that restart of Zaporizhzhia under Russian control is not possible. The IAEA must do all it can to prevent restart and not cooperate with Rosatom. IAEA must not seek to accommodate the interests of the nuclear industry, while disregarding who they are or what they have done. Three years before the Chornobyl disaster, the IAEA Deputy Director General, B. A. Semenov, wrote assuredly that, “The safety of nuclear power plants in the Soviet Union is assured by a very wide spectrum of measures…The regulation of safety by official documents is one of the main tools for ensuring the safety of nuclear power plants in the USSR.”1 In 1986 this led the IAEA to accept without serious scrutiny the Soviet government's evidence on the causes of the Chornobyl disaster – blaming it on plant workers, and ignoring the fundamental reactor design flaws.2 After the hosting of the Post-Accident Review Meeting on the Chernobyl Accident, Vienna, in August 1986, IAEA Director General Dr Han Blix, concluded that, “There is no reason to think that the Soviet Government is more willing than others to take conscious risks with the populations of great cities.”3 As we now know, the Kremlin was indeed more than prepared to put lives at risk across Ukraine and beyond by operating the unsafe Chornobyl nuclear reactors as it is today at Zaporizhzhia. Nearly forty years later the people of Ukraine and the wider world are in danger of history repeating itself with the Russian government's disregard for nuclear safety and security amidst its illegal war against Ukraine. The IAEA must not repeat the mistakes of the past and blindly accept Moscow and Rosatom assurances that restart will meet Russian regulatory standards. Rosatom and the Russian nuclear regulator Rostekhnadzor have no legitimacy in Ukraine and no right to make any decisions on the Zaporizhzhia nuclear plant - that responsibility lies only with Ukrain’s nuclear regulator SNRIU and government.

1. IAEA Bulletin, Nuclear safety in the USSR, B. A. Semenov, IAEA Deputy Director General, Head of the Agency's Department of Nuclear Energy and Safety., IAEA BULLETIN, VOL.25, No. 2, June 1983, see

2. State Commiittee for Using the Atomic Energy of USSR, The Accident At The Chernobyl Aes And Its Consequences, Prepared for the International Atomic Energy Agency Expert Conference (25-29 August 1986, Vienna), Working Document For Chernobyl Post Accident Review Meeting Not For Publication, see; INSAG-1 International Nuclear Safety Advisory Group, 1986. Summary Report on the Post-accident Review Meeting on the Chernobyl Accident A Report by the International Nuclear Safety Group INSAG Series No. 1 Subject Classification: 0603-Nuclear power plants STI/PUB/740, Vienna: IAEA

3. IAEA, The post-Chernobyl outlook for nuclear power A view on responses to the accident from an international perspective, IAEA Bulletin, Autumn 1986, see


Lucia Sumegova - partnership coordinator - 

Polina Kolodiazhna - partnership coordinator - 

Daryna Rogachuk- communication officer -
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