The Russian invasion, coupled with an extended conventional war throughout Ukraine, could generate multiple International Atomic Energy Agency 'Level 7' accidents in a matter of days.
The invasion of Ukraine by Russia poses several nuclear threats, including the possibility of deliberate or inadvertent military strikes or cyber-strikes on nuclear facilities.
There is also the obvious difficulty of safely operating nuclear reactors in a time of war, including the impossibility of carrying out safeguards inspections. Last but not least, there remains the possibility that the conflict will escalate into nuclear warfare.
We are about to learn what happens when nuclear-powered nations go to war, putting nuclear power plants at risk of deliberate or accidental military strikes and thus risking a Chernobyl scale catastrophe.
Retaliation
It seems highly unlikely that either nation - or any sub-national groups - would deliberately target nuclear reactors or spent fuel stores in the current conflict. But assuming there is a 'gentleman's agreement' not to target nuclear power plants, how long would that agreement hold in a war that dragged on for years?
Either nation might choose to shut down its reactors in order to minimise risks. That would be a manageable and wise decision for a country with limited reliance on nuclear power – but it would be impractical for countries with a heavy reliance.
In any case, the radioactive reactor cores – whether kept in situ or removed from the reactors – would remain vulnerable, as would nuclear waste stores. Spent fuel cooling ponds and dry stores often contain more radioactivity than the reactors themselves, but without the multiple engineered layers of containment that reactors typically have.
And if there is an attack on a reactor or spent fuel store resulting in a Chernobyl or Fukushima scale catastrophe – whether deliberate or accidental, whether instigated by a nation-state or extra-state group – disaster response measures would likely be chaotic and woefully inadequate.
A strike on one warring nation's nuclear reactors or waste stores could result in like-for-like retaliation. Rinse and repeat until multiple Chernobyl or Fukushima scale catastrophes are unfolding simultaneously.
Conflict
Even if catastrophe was averted, the wisdom of operating nuclear power reactors would be reconsidered in the aftermath of war. The warring nations – and many others besides – would likely reduce their reliance on nuclear power or abandon it altogether.
Nuclear power plants are pre-deployed radiological weapons. Put bluntly, humanity might have the wisdom to phase out the use of pre-deployed radiological weapons for electricity generation before nuclear-powered nations go to war and deliberately or inadvertently cause nuclear catastrophes.
The Russian invasion, coupled with an extended conventional war throughout Ukraine, could generate multiple International Atomic Energy Agency 'Level 7' accidents in a matter of days.
Or we might have to learn the hard way that using pre-deployed radiological weapons to boil water wasn't such a great idea after all. All the more so given the manifold connections between the 'peaceful atom' and nuclear weapons programs.
The current conflict between Russia and Ukraine provides a test-case of the above war-gaming. The worst-case scenario of nuclear-powered nations at war would involve evenly matched adversaries fighting a long war. The current conflict isn't so much a war as an invasion of a weaker nation-state by a powerful adversary.
Most likely it will not drag on for years as some wars do. That said, simmering conflict stretching on for years is likely, so nuclear plants will remain at risk.
Disaster
Russia has several thousand nuclear weapons. Ukraine ceded ownership and control of nuclear weapons located in Ukraine to Russia in the aftermath of the Cold War - although that hasn't stopped Putin invoking the spectre of a non-existent Ukrainian nuclear weapons program in recent days.
Russia's 38 reactors supply 20.6 percent of the country's electricity. Ukraine's 15 power reactors across at four sites generate 51.2 percent of the country's electricity.
The risk of an inadvertent attack on reactors or nuclear waste stores is somewhat higher than a deliberate attack. Russia has just taken control of the Chernobyl nuclear site. The reactors were all closed long ago, but high-level nuclear waste remains on site.
James Acton from the Carnegie Endowment for International Peace notes that Ukraine has constructed a nuclear waste storage facility at Chernobyl for spent fuel from other nuclear plants, but the introduction of spent fuel has probably not yet occurred. Nevertheless, spent fuel from the Chernobyl reactors is still located there.
It's conceivable that waste stored at Chernobyl could be hit if and when Ukraine attempts to take back control of the site. The next Chernobyl-scale nuclear disaster could happen in Chernobyl. The containment dome over the infamous Chernobyl #4 reactor protects a huge inventory of radioactive material. The next Chernobyl-scale nuclear disaster could involve the same reactor.
Dystopian
Incursions and fighting around the Chernobyl plant could also disperse existing contamination. Russian military analyst Pavel Felgenhauer recently noted in the Washington Post: "The delivery of air-to-surface munitions, artillery, mortar and multiple rocket-launcher fire in the Belarus-Ukraine border area could also disperse radioactive debris in the soil."
Craig Hooper, a senior contributor at Forbes writes: "The world has little experience with reactors in a war zone. Since humanity first harnessed the atom, the world has only experienced two 'major' accidents ‒ Chernobyl and Japan's Fukushima disaster.
"A Russian invasion, coupled with an extended conventional war throughout Ukraine, could generate multiple International Atomic Energy Agency 'Level 7' accidents in a matter of days. Such a contingency would induce a massive refugee exodus and could render much of Ukraine uninhabitable for decades.
"Turning the Ukraine into a dystopian landscape, pockmarked by radioactive exclusion zones, would be an extreme method to obtain the defensive zone Russian President Vladimir Putin seems to want. Managing a massive Western-focused migratory crisis and environmental cleanup would absorb Europe for years."
He adds: "Put bluntly, the integrity of Ukrainian nuclear reactors is a strategic matter, critical for both NATO and non-NATO countries alike.
Toxic
"It seems unlikely that Russia has mobilized trained reactor operators and prepared reactor crisis-management teams to take over any 'liberated' power plants. The heroic measures that kept the Chernobyl nuclear accident and Japan's Fukushima nuclear disaster from becoming far more damaging events just will not happen in a war zone."
Bennett Ramberg, a former foreign affairs officer in the US State Department's Bureau of Political-Military Affairs, and author of the 1985 book Nuclear Power Plants as Weapons for the Enemy, discussed the nuclear risks associated with the Russia‒Ukraine conflict in a February 14 piece for Project Syndicate.
Ramberg writes: "Power plants are common targets in modern conflict, because destroying them inhibits a country's ability to carry on fighting. But nuclear reactors are not like other energy sources. They contain enormous amounts of radioactive material, which can be released in any number of ways.
"Aerial bombing or artillery fire, for example, could break a reactor's containment building or sever vital coolant lines that keep its core stable. So, too, could a cyberattack that interrupts plant operations, as would a disruption of offsite power that nuclear plants rely on to keep functioning.
"Were a reactor core to melt, explosive gases or belching radioactive debris would exit the containment structure. Once in the atmosphere, the effluents would settle over thousands of miles, dumping light to very toxic radioactive elements on urban and rural landscapes"
Detonate
Ramberg discusses the chaos that would ensue: "[R]eactor operators who might mitigate the fallout would be more prone to flee for fear of being shot or bombed. If a reactor is in the middle of a chaotic battlefield, there may not even be any first responders, and ill-informed populations hearing rumors would be on their own wandering ‒ and panicking ‒ in contaminated zones.
"After the guns went silent, Ukraine would be saddled with the long-lingering effects that follow from any nuclear accident. And, as Chernobyl demonstrated, it would not be alone. Radiation releases do not observe national borders, and Russia's proximity would make it a sink for radioactive aerosol deposits. …
"Ukrainian anxieties about its nuclear vulnerability bubbled up in 2014 when Russia invaded and annexed Crimea. Concerned that further conflict could result in a reactor attack, it appealed to the International Atomic Energy Agency and the Nuclear Security Summit to help boost its defenses. Unfortunately, there is no defense that can withstand a Russian bombardment."
A deliberate attack on a nuclear plant would almost certainly be counter-productive, but that doesn't mean it won't happen. Ramberg draws this comparison: "A case in point was the March 26, 2017, bombing of the Islamic State-held Tabqa Dam in Syria.
"Standing 18 stories high and holding back a 25-mile-long reservoir on the Euphrates River, the dam's destruction would have drowned tens of thousands of innocent people downstream. Yet, violating strict 'no-strike' orders and bypassing safeguards, US airmen struck it anyway. Dumb luck saved the day again: the bunker-busting bomb failed to detonate."
Triggers
There were reports in 2015 that a sabotage attack on power transmission towers forced emergency shutdowns of a number of reactors in Ukraine. However the source of the reports was rt.com, a Russian government mouthpiece which lacks credibility.
More generally, Russia seems to have wanted to highlight security and safety threats at nuclear plants in Ukraine since the 2014 invasion, while Ukraine has seemed keen to downplay any incidents - and highlight future risks in the event of an escalation of Russia's attacks. Where the truth lies, nobody knows: it is lost in the fog of the low-level warfare that has played out since 2014.
Cyber-warfare is another risk which could jeopardise the safe operation of nuclear plants. Russia is one of the growing number of states actively engaged in cyber-warfare. James Action notes that a Russian cyber-attack disrupted power supply in Ukraine in 2015.
Nuclear facilities have repeatedly been targets of cyber-attack, including the Stuxnet computer virus targeted by Israel and the US to disrupt Iran's uranium enrichment centrifuges in 2009. Reports from the UK-based Chatham House and the US-based Nuclear Threat Initiative have identified multiple computer security concerns specific to nuclear power plants.
Putin reportedly has greater ambitions than invading and controlling Ukraine, so who knows where the escalation will lead, what risks will emerge, how long it will drag on, and whether it triggers a response from NATO countries and the US/NATO alliance more generally.
Posture
The risk of nuclear warfare is very low, but it is not zero. Perhaps the greatest risk is that one or another nuclear-armed nation will mistakenly believe itself to be under nuclear attack and respond in kind.
Near-misses have happened before. For example, in 1979, a US training tape showing a massive attack was accidentally played. In 1983, a Soviet satellite mistakenly signalled the launch of a US missile. In 1995, Russia almost launched its missiles because of a Norwegian rocket studying the northern lights.
It doesn't help that NATO and Russian military doctrines allow for the use of tactical nuclear weapons to fend off defeat in a major conventional war. It doesn't help that some missiles can carry either conventional weapons or nuclear weapons, increasing the risk of worst-case thinking and a precipitous over-reaction by the adversary.
And it doesn't help that Putin's recent statements could be construed as a veiled threat to use nuclear weapons, or that less than a week ago a referendum in Belarus revoked the nuclear-weapon-free pledge in its constitution, or that Belarusian president Aleksander Lukashenko recently joined Putin to watch the Russian military carry out a nuclear weapons exercise, or that Lukashenko has said Belarus would be open to hosting Russian nuclear weapons.
Beatrice Fihn, executive director of the International Campaign to Abolish Nuclear Weapons, points to other concerns. "Russia and Belarus are not alone in their aggressive and irresponsible posture either," she writes.
Explosions
"The United States continues to exploit a questionable reading of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) that prevents states from 'possessing' nuclear weapons but allows them to host those weapons. Five European states currently host approximately 100 US nuclear weapons: Belgium, the Netherlands, Germany, Italy and Turkey …"
In a worst-case scenario, the direct impacts of nuclear warfare would be followed by catastrophic climatic impacts.
Earth and paleoclimate scientist Andrew Glikson noted in a recent article: "When Turco et al. (1983) and Carl Sagan (1983) warned the world about the climatic effects of a nuclear war, they pointed out that the amount of carbon stored in a large city was sufficient to release enough aerosols, smoke, soot and dust to block sunlight over large regions, leading to a widespread failure of crops and extensive starvation.
"The current nuclear arsenals of the United States and Russia could potentially inject 150 teragrams of soot from fires ignited by nuclear explosions into the upper troposphere and lower stratosphere, lasting for a period of 10 years or longer, followed by a period of intense radioactive radiation over large areas."
He added: "Such an extreme event would arrest global warming for 10 years or longer, possibly in part analogous to the consequences of a less abrupt flow of polar ice melt into the oceans …"
Flimsiest
Richard Garwin poses these questions: "What happens with a failed state with a nuclear power system? Can the reactors be maintained safely? Will the world - under the IAEA and UN Security Council - move to guard nuclear installations against theft of weapon-usable material or sabotage, in the midst of chaos? Not likely."
There are examples of International Atomic Energy Agency (IAEA) safeguards being suspended in the event of war or domestic political turmoil, including in Iraq in 1991, some African states, Yugoslavia, and most recently in Ukraine itself.
In 2014, Ukraine's ambassador to the IAEA circulated a letter to the organisation's board of governors warning that an invasion could bring a "threat of radiation contamination on the territory of Ukraine and the territory of neighbouring states." Ukraine's parliament called for international monitors to help protect the plants.
No special measures were put in place to safeguards nuclear facilities in Ukraine. IAEA safeguards inspections have been compromised in Crimea since Russia's 2014 invasion - indeed there may not have been any inspections whatsoever. IAEA safeguards inspections in eastern Ukraine have also been compromised as a result of Russia's 2014 invasion.
Thus the IAEA has been unable to conclude that all civil nuclear materials and facilities in Ukraine have remained in peaceful use. Not that such conclusions carry much weight: the IAEA routinely reaches comforting conclusions based on the flimsiest of evidence.
Smuggled
Ukraine noted in its report to the 2016 Nuclear Security Summit that state nuclear inspectors were unable to safely perform their duties in Crimea and certain areas of the Donetsk and Luhansk regions in 2014.
Even before the Russian invasion, Ukraine's nuclear industry was corrupt, regulation was inadequate, and nuclear security measures left much room for improvement. For the time being, it is highly unlikely there will be any regulation whatsoever of the country's ageing reactors and other nuclear facilities.
Yet another problem is that the risk of nuclear smuggling could worsen. Former Soviet states have been at the heart of the global problem of nuclear smuggling since the collapse of the Soviet Union.
In May 2014, Ukrainian authorities announced the seizure of radioactive material that had been smuggled into the country from a separatist region, and speculated that the intention may have been to use the material as a radiological weapon.
Scrutiny
Russia's invasion of Ukraine will adversely affect its nuclear export business. For example the planned Hanhikivi reactor in Finland is unlikely to proceed and the plan for two Russian reactors in Hungary might also be abandoned. Russian-led reactor construction projects in numerous other countries could be jeopardised.
Swedish utility Vattenfall announced there would be no more deliveries of nuclear fuel from Russia until further notice and that no new orders will be placed for fuel from Russia. There will likely be many similar announcements from countries, companies and utilities currently involved in civil nuclear trade with Russia.
Australian uranium exports to Russia were suspended in 2014 as a result of Russia's invasion of Ukraine, its threat to invade Georgia, and the downing of flight MH176. "Australia has no intention of selling uranium to a country which is so obviously in breach of international law as Russia currently is," Australia's prime minister told parliament.
There is no prospect of a resumption of Australian uranium sales and other suppliers might also black-list Russia. Domestic mines currently supply about half of Russia's annual requirement of about 6,000 tonnes of uranium. Russia's involvement in overseas uranium projects might also come under scrutiny.
This Author
Dr Jim Green is the national nuclear campaigner with Friends of the Earth Australia.