The nuclear safety and security situation at Ukraine’s Zaporizhzhya Nuclear Power Plant (ZNPP) has deteriorated further, with the facility losing all access to external power due to renewed shelling overnight, Director General Rafael Mariano Grossi of the International Atomic Energy Agency (IAEA) said today.
The shelling damaged the ZNPP’s last remaining operating 750 kilovolt (kV) power line shortly after midnight, forcing Europe’s largest nuclear power plant to rely on its emergency diesel generators for the electricity it needs for reactor cooling and other essential nuclear safety and security functions, Director General Grossi said, citing information from the IAEA team of experts present at the site.
While those generators have fuel for ten days the lack of off-site electricity is a deeply worrying development that underlines the urgent need to establish a nuclear safety and security protection zone around the ZNPP, the Director General said.
“The resumption of shelling, hitting the plant’s sole source of external power, is tremendously irresponsible. The Zaporizhzhya Nuclear Power Plant must be protected,” he said.
As part of efforts to agree and implement such a zone as soon as possible, the Director General held talks with Ukrainian President Volodymyr Zelensky in Kyiv on Thursday and he will also discuss the issue in the Russian Federation early next week, before returning to Ukraine.
The protection zone “is an absolute and urgent imperative” in order to prevent a nuclear accident, he said.
A secure off-site power supply from the grid is essential for ensuring nuclear safety. This requirement is among the seven indispensable nuclear safety and security pillars that the Director General outlined at the beginning of the conflict.
Before the conflict, the ZNPP had access to the grid through four high-voltage power lines, but they have now all fallen victim to the fighting. The back-up power lines connecting the ZNPP to a nearby thermal power station are also down. The plant had also previously temporarily lost direct access to the electricity grid but could then still receive power through available back-up lines, or from one of its reactors that was still operating at the time.
The loss of external power comes a day after the IAEA experts at the ZNPP reported that shelling had damaged a power line providing electricity to the plant’s reactor unit 6, which temporarily received power from its emergency diesel generators instead. Yesterday, the nearby city of Enerhodar – where the ZNPP’s staff and their families live – lost electricity after shelling damaged an electrical transformer at the thermal power station, and shelling continued today at the industrial site outside the nuclear power plant site.
After the connection to the 750 kV line was lost early today, all sixteen of the plant’s available diesel generators started operating automatically, providing its six reactors with power. When the situation stabilised, ten of the generators were switched off, leaving six to provide the reactors with electricity. Efforts are under way to increase the available fuel stocks for the diesel generators.
All the plant’s safety systems continue to receive power and are operating normally, the IAEA experts were informed by senior Ukrainian operating staff at the site. Although the six reactors are in cold shutdown, they still require electricity for vital nuclear safety and security functions.
The location of the damage to the 750 kV power line has been identified outside the ZNPP site and it will be repaired by the grid operator, the IAEA expert team reported. A damaged electrical transformer at the switchyard of the thermal power station will also be repaired, but the timing depends on the shelling in the area. The IAEA team was also informed that the electricity connection between the ZNPP’s own switchyard and reactor unit 6 had been fixed.
Senior operating staff at the ZNPP had informed the IAEA team on Wednesday about plans to re-start reactor unit 5 at reduced power to produce steam and heat for the needs of the plant, but those preparations were halted after the plant lost all external power.