Nuclear Power Plants Under Attack: The Legacy of Zaporizhzhia

April 2023
By Scott Roecker

Almost six months after Russia began its military assault on the Zaporizhzhia Nuclear Power Plant in March 2022, experts from the International Atomic Energy Agency (IAEA) finally set off on their first visit to assess the situation at the site.

Ukraine’s beleaguered Zaporizhzhia Nuclear Power Plant, under control of Russian forces for more than a year, is pictured in October from Prydniprovske in Dnipropetrovsk oblast. (Photo by Carl Court/Getty Images) The trip had been painstakingly negotiated over the summer months, with approvals needed from Ukrainian and Russian government officials. Finally, with an agreement in place, IAEA Director-General Rafael Mariano Grossi and his team of 14 safety, security, and safeguards experts were on the way to the beleaguered plant. By September 1, they had made it to the final checkpoint, just a few hundred meters from their destination, but were blocked from entering the facility. With bombings in the vicinity, the team refused to back down and eventually was allowed to enter. It was an inauspicious start to one of the most important missions in recent IAEA history.

Russia’s attempt to take control of the Zaporizhzhia plant, located in the small city of Enerhodar, began on the night of March 3. Widely broadcast videos clearly show explosions all around the nuclear facility. The jarring footage immediately raised questions about what might happen if a missile were to hit a nuclear reactor, spent fuel pools, nearby dry spent-fuel storage areas, or backup generators that have been needed frequently because of the unreliable power grid. Nuclear power plant security quickly became a hot topic in the news media, even as the very concept of how best to protect nuclear plants was turned upside down.

Until that harrowing night, nuclear security experts and practitioners focused mainly on the threat to nuclear facilities posed by insiders or terrorist organizations, not state actors with invading armies. Given what the world has witnessed at Zaporizhzhia, a new approach is needed that focuses on increasing resiliency to keep plants operating safely while reducing the risk of catastrophic radiation release. That had not been a big priority in the past. Equally important is the need to strengthen international laws and norms to head off any similar attacks in the future.

Surprise Attacks

In the lead-up to the war, few anticipated that Russia would go so far as to target Ukraine’s nuclear facilities, but it did not take long for Russia to make its intentions clear. On the first full day of fighting, Russian troops massed in neighboring Belarus poured over the Ukrainian border into the Chernobyl Exclusion Zone. The site was overtaken quickly as Russian forces set up a defense around the four nuclear reactors located at the site, including infamous Unit No. 4, which exploded during a routine test on April 26, 1986, with devastating consequences.

In the hours and days after that catastrophic accident, contamination spread over a large swath of territory, including what is now called the “Red Forest,” where a particularly large amount of radioactive dust had fallen a few kilometers east of the reactor. Fast forward to 2022 when occupying Russian troops dug trenches in this same area to protect against a Ukrainian counterattack that never came. After 36 days of occupation, Russian war goals shifted, and the troops left abruptly but not before looting the facility. No one knows how the radiation exposure will impact these forces.

Over the course of the war, Russia also has targeted nuclear research centers in Kharkiv and most recently in Kyiv. These centers include research reactors and related laboratories that support efforts to use nuclear materials for peaceful purposes, such as medicine and science. Both of these facilities, as well as a third one in Crimea, previously had housed highly enriched uranium, which can be used to build nuclear weapons. This material was repatriated to Russia in 2012 as part of the effort to minimize weapons-useable nuclear material under the nuclear security summit process launched by U.S. President Barack Obama. It is unclear why Russia chose to target these facilities.

The Zaporizhzhia Difference

Russia’s actions have generated a great deal of discussion regarding the risks associated with nuclear facilities in a time of conflict, but in recent decades, there are numerous examples of nuclear installations that have been attacked or destroyed. The earliest example of this was when Israel bombed a French-made research reactor in Iraq on June 7, 1981.1 A similar action took place in the Syrian desert on September 5, 2007, when two jets launched from Israel with a mission to destroy a facility that likely included what was intended to be a nuclear reactor.2 In both examples, the reactors were under construction and had not started operations, meaning they did not have any nuclear material at the site and there were no IAEA safeguards in place.

Cyberattacks against nuclear facilities also are a growing concern, with countries using such tactics for a variety of objectives, from gathering data to causing physical damage to the facilities. In the case of the largest nuclear reactor in India, hackers associated with North Korea infiltrated its system to uncover information on how that particular reactor design operates.3

More famously, the Stuxnet computer virus was uploaded to computers operating centrifuges at Iran’s Natanz uranium-enrichment plant in the mid-2000s, causing the centrifuges to fail at a much higher rate than would be expected, much to the bafflement of the scientists at that facility. The Stuxnet attack, which was widely attributed to the United States and Israel, was even more implausible because the computers in question were not connected to the internet. It was an important reminder that so-called air-gapped digital systems that are disconnected from networks are still vulnerable to sophisticated attacks.

The situation unfolding in Ukraine, however, is quite different from the types of one-off attacks in Iraq, Syria, and Iran, none of which could have ended with a catastrophic radiation release. The Zaporizhzhia plant has been subjected to prolonged shelling near and, at times, directly at the facility, risking the possibility of a deadly release at any moment. The motives of the earlier attacks, whether aimed at stealing nuclear secrets or preventing weapons proliferation to new countries, were also different. At Zaporizhzhia, the attacks forced specialists from warring countries to work alongside each other to maintain operations throughout the conflict. To operate a reactor this way is less than ideal, to say the least.

Furthermore, the war in Ukraine is the first time military attacks have been launched on multiple nuclear facilities in a country that has a robust and mature nuclear power infrastructure. Although there are obvious strategic gains to be had by taking control of commercial power-producing facilities such as Zaporizhzhia, Russia also has taken aim at nuclear research facilities that hold little to no strategic importance. These brazen barrages increase the possibility of a significant nuclear incident that could change the course of nuclear power expansion around the world, similar to what was seen in the aftermath of previous nuclear accidents at Chernobyl and in 2011 at Fukushima Daiichi in Japan. Those accidents dampened interest in nuclear power because countries were concerned about the safety of nuclear reactors.

Nuclear Security Implications

Today, the concept of nuclear security has been fundamentally upended. Before Zaporizhzhia, responsible states doing their best to protect their nuclear facilities would develop a threat assessment, known as a design basis threat, to identify the full range of realistic threat scenarios. These would include situations in which adversaries seeking to gain access to facilities might commit an act of sabotage or steal special nuclear material that could be used in a nuclear weapon. Based on the scenario, nuclear operators would create and evaluate the security systems against the threat. The possibility of a state actor, with an invading army, taking control of a nuclear facility would be considered a scenario beyond the threat assessment and not something against which the nuclear operator should prepare to defend.

Despite the limitations inherent in trying to protect a plant from being bombed or attacked by an army, nuclear operators still can take important steps to reduce the risk of radiological release in times of conflict or in other situations that might impede normal operations. Over the last several years, there has been an increase in crises impacting nuclear facilities, whether due to staffing issues related to the COVID-19 pandemic or disruptions and threats related to climate change, including an increase in forest fires. There are lessons to be learned from all these events on how to reduce risk in times of crisis.

One lesson centers on the concept of resiliency.4 In the case of Zaporizhzhia, having adequate backup power options onsite and offsite has helped maintain essential cooling functions at the reactors and spent fuel ponds during times when the main power to the site was cut off. Without proper cooling, a reactor could melt down, as it did in the wake of the 2011 tsunami at Fukushima. The risk of radiation release is also a serious concern with the spent fuel ponds. Having sufficient options for backup power, as well as other key supplies, should be a mandatory requirement at all nuclear power plants worldwide.

Reducing the amount of spent fuel stored at nuclear facilities is another way to reduce risk. Once the fuel is removed from the reactor core, it must cool for a period of time before it can be shipped to an off-site location for long-term storage and disposition. Given the relatively limited options available for long-term storage, however, radioactive spent fuel too often is stored at reactor sites beyond the time required to cool it before transport to a more safe and secure location. Countries must prioritize the development of long-term repositories for nuclear materials to reduce the associated risks of radiation release. Until then, fuel should be transferred from pools to hardened, on-site facilities.

The IAEA Seven Pillars

In addition to and building from the two priorities outlined above, the IAEA has outlined what it calls seven “indispensable” pillars of nuclear safety and security for nuclear installations in response to the situation at Zaporizhzhia.5 The agency believes these pillars are essential for the safe operation of that facility and applicable to reactor operators facing other crises. They were issued the day after Zaporizhzhia came under attack and almost six months before the IAEA team of experts visited the site.

The pillars provide specific guidance on a range of topics, beginning with the foundational components for safe operation. These include the physical integrity of reactor facilities such as the reactor and spent fuel ponds and the safety and security systems. They expand from there to focus on the importance of the human element in the safe operation of a nuclear power plant, addressing the working conditions and the ability to maintain communications with regulators and relevant organizations.

The pillars clearly reflect concerns with the situation at the two nuclear sites when occupied by Russia. In the case of the employees at Chernobyl, one shift of nearly 300 employees was forced to remain at the site for more than three weeks.6 The conditions at Zaporizhzhia, where employees reportedly have been forced to operate under duress and intimidation, also do not meet this IAEA guidance.

The remaining pillars address resiliency and the importance of effective radiation monitoring systems and adequate emergency response measures. On the latter point, establishing a robust emergency response plan for nuclear facilities can prevent a bad incident from turning into something truly disastrous. The international community has stepped up here and sent supplies to Ukraine, which have been helpful in preventing a serious incident at nuclear power plants across the country.7

Rafael Mariano Grossi, director-general of the International Atomic Energy Agency (IAEA), briefs journalists in Kyiv in January after his agency finalized the stationing of permanent IAEA missions at three Ukrainian nuclear power plants: Rivne, Chernobyl, and South Ukraine. (Photo by Sergii Kharchenko/NurPhoto via Getty Images)To monitor the situation at nuclear sites in Ukraine with regard to these pillars, the IAEA has stationed a permanent presence at Zaporizhzhia since the initial site visit in September. This monitoring team initially included two experts focused on nuclear safety and security and has been expanded to four experts in recent months to cover additional topics, such as safeguards. This group provides much needed, unbiased information about what is taking place at the site. The experts also provide regular updates via the IAEA website. In early 2023, the IAEA deployed permanent missions to the other nuclear facilities in Ukraine: Khmelnytsky nuclear power plant, Rivne nuclear power plant, South Ukraine nuclear power plant, and Chernobyl. With these additional teams in place, the IAEA will have at least 11 nuclear safety and security experts in Ukraine at any given time.8

The international community should incorporate the concepts outlined in the seven pillars for nuclear facilities worldwide. As crises around nuclear sites have become a more frequent occurrence, the IAEA pillars are as applicable in those situations as they are in Ukraine today. Although the IAEA guidance is somewhat tailored for the situation in Ukraine, the pillars nevertheless provide a baseline on which countries could expand and strengthen a best practices regime for operating nuclear facilities in challenging conditions.

International Laws and Norms

Following Russia’s invasion, it is clear that the international legal and normative foundation also should be strengthened to head off potential future attacks on nuclear facilities. Existing international laws and norms regarding the protection of nuclear installations in times of conflict are outdated and incomplete. The 1949 Geneva Conventions state that “nuclear electrical generating stations…shall not be made the object of attack” unless they are providing electrical power in “regular, significant and direct support of military operations.” One lesson from Ukraine is that the legal framework for protecting nuclear facilities needs bolstering, as do international norms pertaining to such behavior.

There have been several initiatives over the years to do so. India and Pakistan signed a bilateral agreement in 1989 to recommit every year to forgo targeting nuclear installations in each other’s country and to provide an annual list of facilities that qualify for that agreement. The Pelindaba Treaty that created an African nuclear-weapon-free zone includes an explicit “prohibition of armed attack on nuclear installations.” These bilateral and regional approaches could be the starting point for a discussion on language for a stronger international norm.

The United States could lead on strengthening this norm by pledging not to attack other countries’ civilian nuclear facilities and encouraging other countries to do the same. Another possibility could be to establish a consensus that an attack on a civil nuclear facility is in no one’s interest and does not achieve any legitimate military goal.

There is an excellent opportunity for such an announcement at the upcoming Group of Seven (G7) summit in Hiroshima in May. Each member country (Canada, France, Germany, Italy, Japan, the United Kingdom, and the United States) has operating nuclear power reactors and a vested interest in the continued safe operation of nuclear reactors worldwide. As is now well established, the negative consequences of nuclear accidents are felt around the world. The G7 nations can take the first step toward reinforcing these improved norms and then encourage other countries to join this pledge.

Absent these norms, the IAEA has been working tirelessly to establish a nuclear safety and security protection zone around Zaporizhzhia. What seems like a commonsense policy—in the words of the IAEA, “Don’t shoot at the facility, don’t shoot from the facility”—must be reinforced with verifiable legal mechanisms. Although many of the relevant governments and international organizations are focused on preventing the unthinkable from taking place at Zaporizhzhia, there is more work to be done now to stave off any other future conflict that could threaten nuclear reactors.

Nuclear Energy Implications

The jury is still out on what Russia’s actions in Ukraine will mean for nuclear energy in the future. Nuclear newcomers, as well as countries with more advanced nuclear energy capabilities, are taking note of Russia’s actions. The images of a military force using a nuclear reactor as a base of operations to launch attacks on nearby cities create another difficult complication for countries considering nuclear power.

A multi-layered confinement structure at Ukraine’s Chernobyl nuclear power plant seals off the debris of the plant’s fourth reactor that resulted from the disastrous 1986 nuclear accident. (Photo by Hennadii Minchenko/ Ukrinform/Future Publishing via Getty Images)As like-minded states seek to roll back climate change and reach zero carbon emissions in the next few decades, nuclear power could play an important role in the overall mix of energy sources to achieve that goal. If a significant nuclear incident occurs at Zaporizhzhia or elsewhere in Ukraine or during the next conflict, it could have a major chilling effect on global interest in expanding nuclear energy. That was the reaction in the wake of other serious nuclear incidents, including Chernobyl, Fukushima, and Three Mile Island, which all led to unintended release of radioactive particles. As a result, the world turned away from nuclear power for a time in favor of other, less climate-friendly sources. Given the enormous challenges of climate change, another such disaster could have significant long-term impacts that go well beyond the specific environmental impacts from the nuclear incident itself.

Ironically, Russia had positioned itself as a global leader in nuclear energy in the last several decades and is providing nuclear reactors to several countries, including Egypt, Iran, and Turkey. The scenes of Russian forces firing weapons at Zaporizhzhia certainly will give some nations pause about continuing cooperation with Russia on nuclear power. Indeed, last May, Finland terminated its contract with Rosatom, Russia’s semiprivate, semiofficial agency responsible for nuclear reactor designs and manufacturing, for the purchase of one nuclear power reactor.

Fortunately for Finland and other countries considering nuclear power, there are options from which to choose. Given the events in Ukraine, it is more important than ever to implement a nuclear energy program that is safe, secure, and consistent with the nonproliferation norms that have been established over the last few decades. New types of small modular reactors that are currently in the design phase in Canada, France, Japan, and the United States should give countries more options and flexibility when considering nuclear power if they are deployed responsibly.

There is much work to be done to strengthen security around nuclear power plants in times of crisis. Although Russia’s actions in Ukraine pose the most immediate challenge, the world cannot wait until a resolution of that war to begin tackling this broader issue. For now, one can only hope that a nuclear catastrophe in Ukraine is avoided and that Enerhodar (“energy’s gift” in Ukrainian) remains the vision for nuclear energy in the future.



1. Joyce Battle and William Burr, “Israeli Attack on Iraq’s Osirak 1981: Setback or Impetus for Nuclear Weapons?” National Security Archive, June 7, 2021,

2. “Israel Admits Striking Suspected Syrian Nuclear Reactor in 2007,” BBC, March 21, 2018,

3. Prabhjote Gill, “Here’s Why North Korean Hackers Attacked India’s Nuclear Power Plant,” Business Insider India, November 13, 2019,

4. Geoffrey Chapman et al., “Nuclear Security in Times of Crisis,” Centre for Science and Security Studies, King’s College London, 2021,

5. International Atomic Energy Agency (IAEA), “IAEA Director General Grossi’s Initiative to Travel to Ukraine,” March 23, 2022,

6. Reis Thebault, “After 600 Hours in Russian-Controlled Chernobyl Power Plant, Workers Get to Go Home,” The Washington Post, March 21, 2022.

7. “IAEA Delivers Radiation Monitoring Equipment to Ukraine,” Nuclear Engineering International, July 20, 2022,

8. IAEA, “Update 143 - IAEA Director General Statement on Situation in Ukraine,” January 26, 2023,

Scott Roecker is the vice president for nuclear materials security at the Nuclear Threat Initiative.