nuclear-news

Swarm of jellyfish shuts nuclear power plant in France.

‘Massive and unpredictable’ swarm entered filter drums that pull in water, Gravelines operator EDF says.

​Jillian Ambrose Energy correspondent, 11 Aug 25

‘Massive and unpredictable’ swarm entered filter drums that pull in water, Gravelines
operator EDF says.

A swarm of jellyfish has forced the shutdown of one of
the largest nuclear power plants in France after entering the water intake
systems used to cool the coastal reactors. Three reactors at the Gravelines
nuclear power plant in northern France shut down automatically late on
Sunday, according to the French nuclear company EDF, after the filter drums
of the pumping stations became packed with a “massive and
unpredictable” swarm of the marine creatures.

The entire nuclear plant,
capable of powering about 5m homes, was brought offline when a fourth
reactor shut down shortly after the free-swimming invertebrates jammed the
power plant, which had already lost its two other reactors for planned
summer maintenance work. Jellyfish have a long history of derailing the
normal operations of coastal power plants, which tap the ocean for the vast
amounts of cool water needed to keep temperatures in check.

The repeated
problems caused by unexpected jellyfish numbers prompted scientists at the
University of Bristol to develop an “early warning tool” to predict the
sudden, en masse appearance of jellyfish swarms that might disrupt coastal
power plants. The Torness nuclear plant in Scotland, which is also owned by
EDF, was forced to shut for a week in 2021 after jellyfish clogged the
seaweed filters on its water intake pipes, a decade after jellyfish shut
the plant for a week in 2011.

Jellyfish swarms have also closed nuclear and
coal power plants in Sweden, the US, Japan, and even caused a major
blackout in the Phillipines in 1999 that some mistakenly feared was linked
to the Y2K bug or a government coup.

 Guardian 11th Aug 2025, https://www.theguardian.com/world/2025/aug/11/swarm-of-jellyfish-shuts-nuclear-power-plant-in-france

August 13, 2025 - Posted by Christina Macpherson | environment, France