The Russian-occupied Zaporizhzhia nuclear plant has lost external power for over 72 hours, forcing the facility to rely entirely on emergency diesel generators, The Guardian reports.

The 72-hour threshold represents a critical safety benchmark established after Japan’s Fukushima disaster, with the extended outage now pushing Europe’s largest nuclear facility into uncharted risk territory.

International Atomic Energy Agency (IAEA) Director General Rafael Grossi called the unprecedented outage “deeply concerning” before meeting Vladimir Putin in Moscow on Thursday, though no resolution emerged.

What three days without power means for nuclear safety

The power cut began on Tuesday when the last external transmission line failed on Russian-controlled territory. Seven of 18 backup diesel generators now power critical cooling systems, with fuel reserves to last approximately 20 days, according to IAEA assessments.

European stress tests conducted after Japan’s 2011 Fukushima meltdown established 72 hours as the maximum safe period for nuclear plants operating without external electricity. The Zaporizhzhia facility – capable of powering 4 million homes – crossed that red line days ago.

The continuing loss of external power “increases the likelihood of a nuclear accident,” Grossi warned. All six reactors remain in cold shutdown since 2022, but cooling systems require constant power to prevent overheating of nuclear fuel.

Moscow building infrastructure for permanent control

Satellite imagery analyzed by Greenpeace reveals Russia has constructed extensive new infrastructure around the occupied facility, including a dammed water inlet and 125 miles of power lines connecting to occupied Mariupol and the Russian electrical grid.

The construction suggests Moscow intends permanent control despite international demands for withdrawal. In September, Putin proposed “joint control” over the plant involving Russia, the US, and Ukraine – a proposal Kyiv rejected as nuclear blackmail.

Ukrainian President Volodymyr Zelenskyy has repeatedly stated the facility “will not operate for Russia” and requires Ukrainian management to function safely.

Russian occupation triggers systematic safety violations

Since capturing the plant, Russian forces have violated nearly all international nuclear safety principles, according to IAEA reports. Moscow uses the facility as a military base, storing armored vehicles and equipment inside reactor buildings while establishing firing positions on rooftops.

Since the occupation began, Russia has caused what Ukraine’s Energy Ministry calls ‘systemic, critically dangerous deformations’ at the site. This includes the destruction of the Kakhovka dam, which eliminated the primary water source for cooling reactors, and nine full disconnections from Ukraine’s power grid – creating what the ministry describes as ‘an extraordinary threat scenario, unanticipated by design standards or international safety frameworks.’

Russian operators blamed Tuesday’s power loss on Ukrainian shelling – claims Kyiv denies. Ukraine maintains it does not target the facility or surrounding areas, since it would be incredibly risky.

Europe watches as nuclear risks escalate

The extended blackout compounds fears across Europe about potential radiation releases from the continent’s largest nuclear installation. The facility’s 6,000-megawatt capacity could generate enough electricity annually to power countries like Ireland or Slovakia.

Greenpeace describes the current situation as “a new critical and potentially catastrophic phase” of the occupation. Ukrainian officials suspect Russia may be engineering the crisis to justify connecting the plant permanently to its electrical grid, severing ties with Ukraine’s power system.

The IAEA maintains a monitoring mission at the site. Grossi has visited five times since the occupation began, with Ukraine planning to prioritize the plant’s liberation in any future diplomatic talks with Russia.