Why was a French nuclear plant shut down?

A French nuclear plant was shut down due to a massive jellyfish swarm, which is a sometimes unexpected but significant issue for maritime operations, including nuclear power plants. When jellyfish swarm near intake systems, they can clog the cooling systems essential for the plant's operation. This can impair the facility's ability to cool its reactors adequately, leading to safety risks. As a result, shutting down the plant temporarily becomes necessary to clear the blockage and prevent any potential hazards related to overheating or equipment damage.

Other possible causes, such as equipment failure or environmental concerns, while relevant in different contexts, do not directly apply in this specific instance. A worker strike could also impact operations, but it is less likely to compel an immediate shutdown compared to a direct physical threat to the plant's functioning, such as a jellyfish swarm.