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Located in southeastern Ukraine, Zaporizhzhia Nuclear Power Station (ZNPP) is Europe’s largest power plant that produced 23% of all Ukrainian electricity before Russia's invasion.  This critical energy source is amidst the chaos and destruction of the ongoing Russia-Ukraine conflict, a harrowing struggle that has wrought immeasurable suffering and upheaval upon the region. Following its capture by the Russian forces on March 4th 2022, there have been drastic disruptions to safe energy production and a heightened global concern for nuclear safety in the region. 

Introduction and background

Zaporizhzhia Nuclear Power Plant (ZNPP), located in the Ukrainian city of Enerhodar, was built by Soviet design in the 1980s, with its last reactor being connected to the grid in 1995.  Amongst the ten largest nuclear facilities in the world, the Zaporizhzhia power plant consists of six water-cooling and water-moderating pressurized reactors.

A global nuclear scare started on February 24, 2022, when Ukraine informed the International Atomic Energy Agency (IAEA) that “unidentified armed forces” have taken control of all facilities of Chornobyl Nuclear Power Plant located in the Exclusion zone. The IAEA appealed for maximum restraint to avoid any action that may put the country’s nuclear facilities at risk and stressed the IAEA’s 2009 General Conference decision that “any armed attack on and threat against nuclear facilities devoted to peaceful purposes constitutes a violation of the principles of the United Nations Charter, international law and the Statute of the Agency”. Later that week, on March 2nd, Russia stated that its military forces have taken control of the territory around Ukraine’s Zaporizhzhya Nuclear Power Plant. The next day, a large number of Russian tanks and infantry broke through the block-post into the town of Enerhodar, just a few kilometers from the ZNPP. Director General Grossi, appealed for “an immediate halt to the use of force at Enerhodar and called on the military forces operating there to refrain from violence near the nuclear power plant.”

By March 4th, Ukraine informed the IAEA that the ZNPP had been shelled overnight, and a fire broke out on site. Although no essential equipment was affected, the first military action      resulted in the activation of the IAEA’s Incident and Emergency Centre in full response. At the end of the day, Ukraine announced that Russian forces had taken control of the ZNPP, but the power plant continued to be operated by its regular staff.  At the time, out of the plant’s six reactor units, two had undergone controlled shut down, two were being held in low power mode, one was shut down for maintenance and one was operating at 60 percent power. 

ZNPP’s dire situation since March 4, 2022

Before the conflict, the ZNPP had access to the grid through four high-voltage power lines, but they have now all fallen victim to the fighting. The back-up power lines connecting the ZNPP to a nearby thermal power station are also down. The plant had also previously temporarily lost direct access to the electricity grid but could then still receive power through available back-up lines, or from one of its reactors that was still operating at the time.

The Russian conquest was soon followed by disruptions in the electricity supply to the nuclear power plant, one of the seven indispensable pillars of nuclear safety. Less than two weeks after Russian forces seized the plant, Zaporizhzhia lost one of its three power lines. Since then, mainly as a result of shelling or other military action nearby, the nuclear plant has suffered numerous power cuts, mainly as a result of shelling. Although it has emergency diesel generators that are available to provide backup power, a secure off-site power supply from the grid is integral to ensuring nuclear safety. 

Thus, following its first complete external power outage in August, Director General Rafael Mariano Grossi set off from the Agency’s headquarters on an IAEA Support and Assistance Mission to Zaporizhzhia (ISAMZ) to undertake vital safeguards activities at the plant.  That October, Zaporizhzhia lost its last remaining external power source due to renewed shelling, and had to rely on diesel generators again to cool the reactor and support other nuclear safety and security functions. In the next week, Zaporizhzhia lost all external power two more times, receiving electricity from a backup system for the third time in a span of ten days. Similar incidents unfolded in November as well, as the IAEA Director General continued to urge for the critical need to demilitarize the zone. 

Based on historical data and industry experience, the nuclear industry aims for an average unplanned outage rate of less than 0.1 per reactor per year which statistically would mean less than one unplanned outage every 10 years. Zaporizhzhia Nuclear Power Plant experienced six in the past year alone. 

Cold shutdown of the ZNPP reactors doesn’t remove the risk – Spent fuel pools need constant cooling

The fission reaction that generates heat in a nuclear power plant is produced by positioning a number of uranium fuel rods in close proximity. Shutting down a nuclear reactor involves inserting control rods between the fuel rods to stop the fission reaction.

The reactor is then in cooldown mode as the temperature decreases. According to the U.S. Nuclear Regulatory Commission, once the temperature is below 200 degrees Fahrenheit (93 Celsius) and the reactor coolant system is at atmospheric pressure, the reactor is in cold shutdown.

When the reactor is operating, it requires cooling to absorb the heat and keep the fuel rods from melting together, which would set off a catastrophic chain reaction. When a reactor is in cold shutdown, it no longer needs the same level of circulation.

It was announced on September 11, 2022 by Energoatom, operator of the ZNPP that it was shutting down the last operating reactor of the plant’s six reactors, reactor No. 6. The operators have put the reactor in cold shutdown and this shutdown has mitigated a risk.

Spent fuel pools also need constant circulation of water to keep them cool. And they need cooling for several years before being put in dry casks. One of the problems in the 2011 Fukushima disaster in Japan was the emergency generators, which replaced lost off-site power, got inundated with water and failed. In situations like that you get “station blackout” – and that is one of the worst things that could happen. It means no electricity to run the cooling system.

In that circumstance, the spent fuel overheats and its zirconium cladding can cause hydrogen bubbles. If you can’t vent these bubbles they will explode, spreading radiation. If there is a loss of outside power, operators will have to rely on emergency generators. But emergency generators are huge machines – finicky, unreliable gas guzzlers. And you still need cooling waters for the generators themselves.

The biggest worry is that Ukraine suffers from a sustained power grid failure. The likelihood of this increases during a conflict, because pylons may come down under shelling or gas power plants might get damaged and cease to operate. 

According to one of the IAEA’s latest updates (#154, April 21, 2023): 

“As a result of the warmer weather, the operator has started to put reactor Unit 6 in cold shutdown which is expected to be reached by the weekend, leaving only Unit 5 in hot shutdown to produce hot water and steam for the site. The two reactors were in hot shutdown during the winter to provide steam and heating to the ZNPP as well as heating to the nearby city of Enerhodar, where many plant personnel live.”

The cooling pumps for the spent fuel pools need much less electricity than the cooling pumps on the reactor’s primary and secondary loops, and the spent fuel cooling system could tolerate a brief electricity outage. Now, at least if the plant loses offsite power, the operators won’t have to worry about cooling an operating reactor with cranky diesel generators. However, the plant still needs a reliable source of electricity to cool the six huge spent fuel pools that are inside the containment structures and to remove residual heat from the shutdown reactors. 

The serious risk of military actions for spent fuel storage racks

One more important factor is that the spent fuel storage racks in the spent fuel pools at the Zaporizhzhia Nuclear Power Plant were compacted to increase capacity, according to a 2017 Ukrainian government report to the IAEA. The greater number and more compacted the stored spent fuel rods, the more heat they generate and so more power is needed to cool them.

There is also a dry spent fuel storage facility at the plant. Dry spent fuel storage involves packing spent fuel rods into massive cylinders, or casks, which require no water or other coolants. The casks are designed to keep the fuel rods contained for at least 50 years. However, the casks are not under the containment structures at the plant, and, though they were designed to withstand being crashed into by an airliner, it’s not clear whether artillery shelling and aerial bombardment, particularly repeated attacks, could crack open the casks and release radiation into the grounds of the plant.

The closest analogy to this scenario could be a terrorist attack that, according to a seminal study by the National Research Council, could breach a dry cask and potentially result in the release of radioactive material from the spent fuel. This could happen through the dispersion of fuel particles or fragments or the dispersion of radioactive aerosols.  This would be similar to the detonation of a “dirty bomb,” which, depending on wind direction and dispersion radius, could result in radioactive contamination. This in turn could cause serious problems for access to and work in the plant.

According to the IAEA’s latest update at the time of writing this analysis (#155, April 28, 2023):

“IAEA experts present at Ukraine’s Zaporizhzhya Nuclear Power Plant (ZNPP) were again forced to shelter this week after missile attack warnings, with the sound of continued shelling in the distance as military activity continues in the region. In addition, one landmine exploded near the site, Director General Rafael Mariano Grossi said today…The increased military presence and activity in the region again underlines the importance and urgency of agreeing on the protection of the plant, Director General Grossi added.”

What is going on and what can be done

We need to begin to realize and emphasize that the need for compromise extends beyond Russia alone. There has been a certain reticence around the acknowledgement that Ukraine, despite being the “aggrieved” country, must also be willing to make concessions.  To designate Russia as the sole provoker of hostilities at the Zaporizhzhia plant is an objective falsity. It would be illogical for Russia to shell the plant once it has already seized control, unless there were provocations from the Ukrainian side. Interestingly, in spite of countless calls to pacify the region from Ukrainian and international diplomatic leaders, The Times of London on April 7, 2023 published a report detailing a failed Ukrainian attack on the Russian-controlled Zaporizhzhia Nuclear Power Plant (ZNPP) that took place in October 2022. Ukrainian special forces launched an attack on the ZNPP, deploying US-provided HIMARS rockets at the site — an attempt that ultimately failed because of a stronger Russian counteroffensive. Any sort of projectiles nearing the site of a nuclear power plant is an inherently hazardous and potentially catastrophic assault, regardless of the origin of the launch.  

Given the high stakes involved and the potential for irreparable harm, it is imperative for even Ukrainian forces to exercise restraint and refrain from any military action that could escalate the conflict, including airstrikes on Zaporizhzhia, even if it is under Russian control. Taking into account the tumultuous events that have transpired at Zaporizhzhia this past year, for the sake of preventing a global nuclear disaster, it is pertinent to prioritize nuclear safety. Counterintuitive as it may seem, it may be more prudent for Ukraine to strategically withdraw from the ZNPP site and attempt to repatriate it later in the war, when more comprehensive diplomatic negotiations can happen and Russia potentially depletes its resources. 

War, in our opinion, is the worst enemy of nuclear safety. This is an unprecedented and volatile situation. Only through active, pragmatic engineering and nuclear diplomacy can an amenable and lasting solution to this vexing problem be found.

In the foreword of President John F. Kennedy’s book, Profiles of Courage, his brother, Robert Kennedy said, President Kennedy was fond of quoting Dante that “the hottest places in Hell are reserved for those who, in a time of great moral crisis, maintain their neutrality” (December 18, 1963).  The potential catastrophic consequences of the Zaporizhzhia nuclear power plant conflict demand action and a willingness to take a stance.  For Ukraine, taking a stance can mean stepping back and protecting the world from a nuclear calamity. The failure to do so risks being condemned to the “hottest places in Hell,” not in a figurative sense, but in a literal one. As the memory of the Chornobyl Disaster of 1986 still lingers, the potential danger posed by Zaporizhzhia's six reactors far surpasses that of the single reactor that caused the Chornobyl disaster. In the unfortunate event of an explosion, the repercussions would be hexfold that of Chernobyl's catastrophic aftermath, marking a somber moment in the history of nuclear power.

Despite the uncertainty surrounding the outcome of the  Russia-Ukraine conflict, the end of this protracted war is imminent. Even if we are facing problems that, as Robert Kennedy put it, people “fifty, even ten years ago, would not have dreamed would have to be faced,” it is of utmost importance to prioritize humanity above political objectives. 

Following Dr. Henry Kissinger’s advice, Ukraine may like to exercise diplomacy, which “is the art of restraining power”, rather than brute force to repatriate its own Zaporizhzhia Nuclear Power Plant, considering the high risks associated with military action on site. Ukrainians should not shame their military officers if they retreat from Zaporizhzhia, but rather, commend them for their strategic investment into the future prosperity of their country, their continent and possibly, their planet. A true measure of a hero lies not in their victories, but in their willingness to fight for what is right, even in the face of overwhelming odds. Right now, possibly accepting status quo at Zaporizhzhia is, at least in our opinion, what is the most right, but most certainly what is imperative. With Russia’s adamant military politics, Ukraine would be bravely resisting aggression on behalf of the world, on behalf of a future. 

We realize that the IAEA has called on Russia and Ukraine to set up a “safety and security protection zone” around the plant. However, the IAEA is a science and engineering inspectorate and technical assistance agency. Negotiating and establishing a protection zone at a nuclear power plant in a war zone is entirely unprecedented and totally different from all past IAEA efforts. Establishing a protection zone requires negotiations and approvals at the highest political and military levels in Kyiv and Moscow. 

It could be accomplished through backchannel, Track II-type diplomacy, specifically nuclear safety-focused engineering diplomacy. In the meantime, the IAEA needs strong support from the United Nations Security Council in the form of a resolution, mandate or the creation of a special commission.

Admittedly, this is only a stopgap measure. In parallel with the International Atomic Energy Agency’s effort under the leadership of its Director, General Rafael Mariano Grossi, we believe that the U.N. Security Council should immediately empower a special commission to mediate between the warring parties. It could be modeled after the United Nations Monitoring, Verification and Inspection Commission in 2000, and appoint a prominent, senior international statesman as its head.

We believe the person should be of the caliber and in the mold of the legendary former director general of the International Atomic Energy Agency, Dr. Hans Blix of Sweden. Blix led the agency at the time of the Chernobyl accident in 1986 and commands respect in today’s Russia and Ukraine.

The great Prussian military theorist Carl Philipp Gottfried von Clausewitz once said:

“War is a mere continuation of policy by other means.” 

These words still resonate today, reminding us that the quest for peace is not just about putting an end to violence, but about forging a path towards progress and prosperity. It is incumbent upon us to recognize that bringing an end to this conflict is not merely a cessation of violence, but a catalyst for the advancement of policy. As we strive towards resolving conflicts and achieving a lasting peace, it is our duty to recognize that this effort is not merely a tactical move, but a transformative one. By embracing a policy-driven approach, we can internalize the true nature of conflict, and use it as a means to move forward and effect real change.

So let us be bold, but at the same time be pragmatic, and let us remember the words of Clausewitz as we work towards a brighter future for all. Let us see war not as an end in itself, but as a means to an end – a means to build a world where conflict is a thing of the past, and policy is the key to progress.

President John F. Kennedy’s bold vision for political courage and making compromises in his aforementioned book, Profiles of Courage, also beautifully applies to this very context of Ukraine preserving its principles of sovereignty and territorial integrity while tactfully compromising with Russia over safeguarding Zaporizhzhia:

“We shall need compromises in the days ahead, to be sure. But these will be, or should be, compromises of issues, not of principles. We can compromise our political positions, but not ourselves. We can resolve the clash of interests without conceding our ideas... Compromise does not mean cowardice. Indeed it is frequently the compromisers and conciliators who are faced with the severest tests of political courage as they oppose the extremist views of their constituents.”