Ukraine’s embattled Zaporizhzhia nuclear power plant, the largest in Europe, has entered its fifth consecutive day operating solely on emergency diesel generators, as of Saturday, September 27, 2025. The ongoing crisis, triggered by a complete loss of external power supply, has reignited fears of a nuclear disaster and drawn sharp warnings from international watchdogs and environmental groups alike. Meanwhile, President Volodymyr Zelenskyy announced a sweeping $90 billion arms agreement with the United States and criticized Hungary for what he described as “dangerous” drone surveillance activities over Ukrainian territory.
The Zaporizhzhia plant, situated on the front line of the Russia-Ukraine conflict, has been held by Russian forces since March 2022. The six-reactor facility, though currently in cold shutdown, remains heavily dependent on external electricity to maintain its cooling and safety systems. According to Greenpeace Ukraine, the plant’s external power was severed on Tuesday, September 23, following shelling that damaged the only remaining transmission line linking the plant to Ukraine’s energy grid. This marks the tenth such blackout since the Russian invasion began in February 2022, Ukrainian Minister of Energy Svitlana Hrynchuk told the Associated Press.
“The plant remains in blackout mode, which is a significant violation of the conditions for its normal operation,” Hrynchuk stated, underscoring the gravity of the situation. The International Atomic Energy Agency (IAEA) director general Rafael Grossi met with Russian President Vladimir Putin on Thursday, September 25, in an attempt to broker a restoration of power. However, the external supply remains cut, leaving the facility reliant on its last line of defense: diesel generators.
Jan Vande Putte, a radiation and nuclear energy specialist at Greenpeace Ukraine, emphasized the precariousness of the current situation. “Emergency diesel generators are considered the last line of defense, used only in extreme circumstances,” he warned. “These are undoubtedly the most serious and important events since the beginning of the occupation of the ZNPP by Russia in March 2022.”
The reactor core and spent nuclear fuel must be continuously cooled to prevent overheating, which could lead to catastrophic meltdowns—echoing the disasters at Fukushima in 2011 and Chernobyl in 1986. The latter, located about 480 kilometers northwest of Zaporizhzhia, remains a somber warning of the consequences of nuclear mishaps. The IAEA continues to rotate staff through the facility to monitor safety and provide expertise, but the proximity of the front line and repeated attacks have complicated oversight and risk mitigation efforts.
The Russian-controlled Telegram channel for the plant sought to assuage public fears, stating that “sufficient diesel fuel reserves are available on-site to ensure long-term autonomous operation of the generators.” However, experts caution that diesel reserves are finite, and resupplying them during ongoing hostilities is fraught with danger and uncertainty.
Adding another layer of complexity, satellite analysis by Greenpeace Ukraine suggests that Russia may be preparing to restart at least one reactor despite the perilous wartime conditions. The environmental group reports that Russian engineers have begun constructing 201 kilometers of power lines to connect substations in the occupied cities of Melitopol and Mariupol, with work starting in December 2024. According to Greenpeace’s analysis, Russia has also finished building a new water supply system for the plant’s cooling pond and has deliberately damaged a key 750-kilovolt power line that previously linked the plant to Ukraine’s grid. The Associated Press noted it could not independently verify these findings.
Putte argued that these developments align with Russia’s state-owned nuclear energy company Rosatom’s “long-standing goal” to “connect to the illegally occupied power grid in Zaporizhia and Donetsk regions and restart the nuclear reactor.” He contended that it was Russia’s “deliberate actions” that led to the facility’s disconnection from Ukraine’s external power grid.
For residents of Zaporizhzhia city, located about 440 kilometers southeast of Kyiv, the plant’s troubles are more than an abstract concern. The city remains under Ukrainian control, but its proximity to the front line has made it a frequent target for attacks, further complicating the already precarious situation at the nuclear facility.
While the nuclear crisis unfolds, President Zelenskyy used a press briefing in Kyiv on Saturday to announce what he described as a “mega deal” for weapons purchases from the United States. The $90 billion package, which includes a separate “drone deal” for Ukrainian-made drones to be bought directly by the U.S., marks a significant escalation in military support for Ukraine. “We discussed and agreed on the main points with the President (Trump). Now we are moving on to practical implementation,” Zelenskyy said. He explained that Ukraine had provided detailed specifications of its military needs, including requests for long-range weapons systems, to the U.S. government.
Amid the arms deal announcement, Zelenskyy sharply criticized Hungary for its drone activities over Ukrainian territory. “I believe they are doing very dangerous things — very dangerous things, first and foremost for themselves,” he said, claiming that Ukrainian intelligence had tracked at least one Hungarian drone using photos and electronic monitoring. He did not elaborate on what Hungarian intelligence was seeking within Ukraine. In response, Hungarian Foreign Minister Peter Szijjarto fired back on Facebook, accusing Zelenskyy of having “lost his mind” and “seeing things.” Hungary, under Prime Minister Viktor Orbán, has maintained close ties with Russia and has repeatedly expressed skepticism about military aid to Ukraine.
In a further revelation, Zelenskyy disclosed that an Israeli Patriot air defense system has been operational in Ukraine for the past month, with two additional systems expected to arrive in the fall. “The Israeli (Patriot) system is operating in Ukraine. Already a month, it’s been working for one month,” he said, but declined to provide further details, citing security concerns. Israel’s Defense Ministry refused to comment on the deployment.
As the Zaporizhzhia crisis drags on and regional tensions deepen, the situation remains fluid and fraught with risk. The world watches closely, hoping that disaster can be averted and that diplomatic efforts—however halting—might yet restore a measure of stability to Ukraine’s nuclear heartland.