Zaporizhzhia attacked again: the nuclear risks from reckless military action

A DRONE strike at the Zaporizhzhia nuclear power plant on Sunday triggered a new crisis at the facility that has been repeatedly brought to the brink of disaster by the war between Russia and Ukraine.

Russia, which has been in control of the facility, Europe’s largest, for almost two years now, accused Ukraine of launching the attacks. The International Atomic Energy Agency (IAEA), the global nuclear watchdog, confirmed there had been “at least three direct hits”, including on one of the six reactors at the plant, but did not say who was responsible.

While nuclear safety had not been compromised, “this is a serious incident with potential to undermine integrity of the reactor’s containment system”, the IAEA said. Director general Rafael Mariano Grossi said “such reckless attacks significantly increase the risk of a major nuclear accident and must cease immediately”.

Zaporizhzhia is one of five nuclear power stations in Ukraine, which meets almost half of its electricity demand through nuclear energy. the six reactor sat zap orizhzh ia have the capacity to produce 5,700 MW of electricity.

The drone attacks came three days after the power station suffered its most recent loss of external power supply. Nuclear power plants are connected to more than one external power source to run essential safety and security operations, including the crucial task of cooling the reactors. The Zaporizhzhia plant has six external power lines, but outages or disconnections during the war have on several occasions left it dependent either on a single external source or on generators. The facility has suffered complete blackouts on eight occasions since August 2022, and managed only on generators.

The power station has also faced frequent shelling and mortar attacks from both sides, making it the most dangerous nuclear site in the world currently — even though other nuclear power stations in Ukraine have also suffered shelling and lost external power at some point during the war.

Strong but vulnerable

Most nuclear reactors are made of several layers of steel and concrete, and are designed to absorb shocks from earthquakes of magnitude 8 or even higher. Ordinary shelling or gunfire can't impact them seriously, and it is not surprising that the drone attack did not cause much physical damage to the Zaporizhzhia station.

It is, however, not clear how a nuclear power plant would fare against a powerful bomb or missile attack. Such an incident has never happened, and no country is expected to be so reckless as to bomb a nuclear reactor. However, the war around Zaporizhzhia seems to be testing that assumption.

Risk from power outage

A power outage poses the biggest risk, and is the major concern. The insides of nuclear reactors get heated to thousands of degrees Celsius, and have to be constantly cooled. This is usually done by a circulation of water, which is maintained through an external power source. Multiple power lines are usually available at nuclear stations, which are also equipped with generators to maintain additional layers of redundancies.

The failure to adequately cool the reactors can result in meltdowns or explosions. In the Fukushima disaster of 2011, the nuclear plant itself survived the magnitude 9 earthquake, and shut down its operations in response. But the resultant tsunami flooded the entire area, including the power station, which disabled all power lines and backup systems. As a result, three reactors at the facility suffered partial meltdowns and allowed the leakage of nuclear radiation.

As part of the lessons from the Fukushima disaster, several nuclear reactors installed ‘passive’ cooling systems as an additional layer of safety. ‘Passive’ systems do not require electricity and can, therefore, continue to operate even after a power outage. One example would be of a system that relies on gravity— water circulation is maintained by ensuring that the supply comes from a higher-altitude location.

Courting avoidable disaster

All these measures, however, are meant to deal with eventualities that are beyond the control of humans. The magnitude 9 earthquake in Fukushima in 2011 was an unexpected, once-in-a-century event, against which the best of preparations might not have been adequate.

The situation in zap orizhzh ia, on the other hand, is entirely avoid able. russia and ukraine have been courting disaster, and the rest of the world has been unable to do anything apart from warning them of the dangers, of which they are already fully cognizant.

The IAEA has a team stationed at the Zaporizhzhia station, but its main job has been to offer technical advice to keep the facility safe, and to intervene in regular maintenance activities. It cannot stop the war, or convince the two sides to keep a safe distance from the nuclear reactors.

The drone attack has made a mockery of the five principles that Director General Grossi put before the UN Security Council last year for the two warring sides to follow. There has been no damage this time, but there is no guarantee that another attack will not take place.

Grossi issued another appeal on Sunday: “I firmly appeal to the military decision makers to abstain from any action violating the basic principles that protect nuclear facilities. No one can conceivably benefit or get any military or political advantage from attacks against nuclear facilities. This is a no go.”