France nuclear capacity 20% offline amid heat, jellyfish

France had 20.4 percent of its nuclear generating capacity unavailable Wednesday as extreme heat, drought and a jellyfish invasion disrupted reactors, according to AFP calculations based on EDF data.

Between 9:45 a.m. and 10:00 a.m., EDF's nuclear fleet reached a new peak in outages attributed to “environmental constraints” or “external environmental causes,” both by number of reactors affected and lost generating capacity. Thirteen of EDF's 57 reactors were affected: eight were fully shut down and five were operating at reduced power.

Much of the lost capacity came from the Gravelines nuclear power plant in northern France, where five of six reactors were fully or partly shut down after jellyfish clogged pumps used to cool the units. EDF earlier said the situation at Gravelines had no impact on the safety of facilities, personnel or the environment.

Outside Gravelines, other shutdowns or production cuts were linked to extreme heat and drought, which reduced access to water needed for cooling. France uses nuclear power to generate around 70 percent of its electricity.