UN atomic agency says it is investigating 'extremely serious' claim that a missile flew directly over a Ukrainian power plant

• Ukraine says a missile flew straight over a nuclear power plant in Zaporizhzhia.
• The missile could have caused a nuclear accident if it strayed, the IAEA said.

The United Nations' atomic agency said it is investigating a report from Ukraine that a missile flew directly over one of its nuclear power plants.

Ukraine said the missile was spotted on April 16 on a surveillance camera at Southern Power NPP, a nuclear power plant in the Zaporizhzhia region, the International Atomic Energy Agency said in a Thursday statement. Insider has not seen the video, and the IAEA statement did not attribute responsibility for the missile launch.

If it is confirmed that a missile flew close to the power plant, it would be an "extremely serious" issue, IAEA director general Rafael Mariano Grossi said at a press conference.

"Had such a missile gone astray, it could have had a severe impact on the physical integrity of the NPP potentially leading to a nuclear accident."

As of Friday, Southern Power NPP was operating normally, and remote monitoring indicated no deviation from normal working conditions at the plant, according to Ukraine's nuclear energy operator Energoatom.

Earlier this week Ukrainian President Volodymyr Zelenskyy said that the way Russia has acted around Ukraine's nuclear power plants should be incentive for the world to take control of Russia's nuclear arsenal.

Since the start of the invasion, Russia has forcibly taken control of two nuclear sites in Ukraine: The decommissioned power plant in Chernobyl on February 24, and Southern Power NPP in Zaporizhzhia on March 4. While troops have stepped back from Chernobyl, they are still controlling Southern Power NPP.

"After all that the Russian military has done in the Chernobyl zone and at the Zaporizhzhia nuclear power plant, no one in the world can feel safe knowing how many nuclear facilities, nuclear weapons and related technologies the Russian state has," Zelenskyy said in the Tuesday night video address.

The IAEA has been sounding alarm bells about the risks posed to the nuclear safety of the Zaporizhzhia plant since Russian troops seized it.

The fighting has put pressure on the safeguards ensuring nuclear safety and security of the plant, the IAEA said in a report published Thursday.

On March 4, a projectile caused fire at a training center on the plant's grounds, the IAEA said. Russian troops later detonated the unexploded munitions left on the site from the day of the fire, Ukraine told the IAEA on March 15.

The plant has been operated by Ukrainian staff under the control of Russian troops since it was seized, the IAEA said. This raises the risk of human error, experts previously told Insider.

The fighting also disrupted three or four power lines that had been keeping the plant connected. Only one has been reconnected so far, the IAEA said.

Risk of nuclear accident is low, but still dangerous

Experts previously told Insider that the risk of a nuclear accident at the Southern Power NPP is extremely low, but has nevertheless been heightened due to the fighting.

The ongoing war could the first time in history that this level of active military conflict has happened in the immediate vicinity of a power plant, they said.

This makes it difficult to predict the risk of artillery hitting sensitive areas of the plant, such as the building containing the reactor, the spent fuel cooling ponds, or storage vats for cooled spent fuel, they said.

Southern Power NPP was not built to withstand conflict, they said.

Using any type of explosive near a nuclear reactor is "absolutely shocking. Really quite an astounding display of recklessness. That is a really stupid thing to do," Lewis Blackburn, an expert in nuclear waste materials from the University of Sheffield, previously told Insider.