UPDATE 1-IAEA reports fire at electrical substation due to military activity

The U.N.'s nuclear watchdog said ​on Friday that Ukrainian authorities advised that ​a fire had broken out at ‌an electrical ​substation due to military activity, causing a nuclear power station to be partially disconnected from off-site power.

The International Atomic Energy Agency said ‌firefighters were tackling the fire at the Dniprovska 750-kilovolt electrical substation. "As a result, an operating nuclear power plant - South Ukraine - was partially disconnected from its off site power supplies at the request of the grid ‌operator," the IAEA said on the X social media platform.

"Firefighters are currently deployed at the substation ‌to suppress the fire." The statement gave no details of the nature of the military activity.

The statement quoted IAEA Director General Rafael Grossi as expressing "deep concern", adding that "such substations that are critical for nuclear safety must never be targeted." The Dniprovska ⁠substation provides ​external power for the South ⁠Ukraine plant as well as the Zaporizhzhia nuclear power plant, seized by Russia in the weeks after the Kremlin's February ⁠2022 invasion of Ukraine.

Each side regularly accuses the other of military actions that undermine nuclear safety at ​Zaporizhzhia. The head of Russia's state nuclear corporation Rosatom this week said the situation around the ⁠Zaporizhzhia plant was reaching the "point of no return" due to increased Ukrainian attacks. The Zaporizhzhia plant, Europe's largest with six ⁠reactors, generates ​no electricity, but needs power to keep nuclear fuel at the facility remains cool.

One of the external lines to the Zaporizhzhia plant, also called Dniprovska, has been down since March 24 ⁠and the IAEA has been trying to arrange a ceasefire to carry out repairs. Ukraine has three ⁠working nuclear power ⁠stations and since the Russian invasion, its reliance on nuclear power has risen to up to 80% of its power needs, according to an industry ‌source.