Comment The UN nuclear chief has warned of a possible “nuclear catastrophe” after the bombing of Europe’s biggest nuclear power plant, once again urging Russia and Ukraine to allow a mission of experts access to the facility to help secure it . The bombing of the Zaporizhzhia nuclear power plant in southeastern Ukraine highlights the potential for “catastrophic consequences” from attacks on and near the facility, Rafael Grossi, director general of the International Atomic Energy Agency (IAEA), said in a statement on Saturday. “Military action that jeopardizes the safety and security of the Zaporizhzya nuclear power plant is completely unacceptable and must be avoided at all costs,” Grossi’s statement said. After Friday’s bombing, Russia and Ukraine blamed each other for the attack. The facility, near the front lines of the fighting, has been under Russian control since March, but is still staffed by Ukrainians. In his late-night speech on Friday, Ukrainian President Volodymyr Zelensky noted the bombings in Zaporizhia as another reason why Russia should be recognized as a “state sponsor of terrorism,” something he has repeatedly called for. Zelensky also argued for sanctions against Russia’s nuclear industry. “This is purely a safety issue,” he said. “He who poses nuclear threats to other nations is certainly not capable of using nuclear technologies safely.” In turn, the Russian Defense Ministry blamed Ukraine for the attack, saying protection from Russian-backed forces was the reason the plant was not more extensively damaged. The shelling destroyed two power lines and a water pipeline, leaving more than 10,000 residents without water and electricity, the defense ministry said in a statement. Russia initially seized the facility after one of its missiles sparked a fire at the plant complex, sparking concerns about the safety of Ukraine’s four nuclear facilities that have continued in the months since. “Ukrainian personnel operating the Russian-held plant must be able to perform their important duties without threats or pressures that undermine not only their own security but that of the facility itself,” Grossi said in his statement. The American Nuclear Society (ANS) backed Grossi’s calls to stop attacks on the facility and send a mission there, condemning the bombings in a statement on Saturday. “It is unjustifiable for a civilian nuclear facility to be used as a military base or targeted in a military operation,” said the agency’s president, Steven Ard, and chief executive, Craig Piercy. Friday’s bombing did not damage any of Zaporizhzhia’s six reactors and did not release radioactive material into the environment, Grossi said, but the plant was damaged elsewhere. He added that an IAEA mission to the nuclear plant would allow inspectors to assess it and gather information independent of reports from Ukraine and Russia. However, the situation around Zaporizhia is likely to become more, not less, dangerous, according to the British Ministry of Defence, because the fiercest fighting is shifting in the direction of the power plant. The IAEA has been working for months to ensure the safety of Ukraine’s nuclear facilities. In April, Gross led an expedition to the country’s Chernobyl plant – the site of one of the world’s worst nuclear disasters in 1986 – after Russian-backed forces withdrew from it in March. He led a monitoring mission to the site in early June, with experts assessing its condition and providing training in radiation monitoring equipment. A similar mission to Zaporizhzhia, Grossi said, is “critical” to its security. “But this will need cooperation, understanding and facilitation from both Ukraine and Russia,” he said, adding that UN Secretary-General Antonio Guterres supported the agency’s plan. Grossi was in New York on Monday for the tenth review conference of the Treaty on the Non-Proliferation of Nuclear Weapons. In his keynote address, he discussed the IAEA’s “seven pillars” of nuclear safety and security, which include the physical integrity of facilities, reliable communication with regulators and the ability of personnel to work safely. Those pillars, Grossi said in his statement, had been breached in Zaporizhia — during Friday’s bombing and in the months since the Russian invasion. “We cannot afford to waste any more time,” he said. “For the sake of protecting people in Ukraine and elsewhere from a possible nuclear accident, we must all put aside our differences and act now.”