An announcement from Tokyo Electric Power Co. (TEPCO) said that the radiation was measured at 2,200 millisieverts per hour, which is a record high and enough to kill an unprotected person within hours.
It was unclear if the spike was caused by yet another spill of contaminated water at the plant, which has been a growing problem in recent weeks.
Japan’s Nuclear Regulation Authority said TEPCO cannot store the radioactive water forever, and it will eventually need to be dumped into the Pacific.
The country’s national fishermen’s organization recently criticized TEPCO’s management for their bungling of the disaster since a March 2011 earthquake and tsunami caused meltdowns at the plant.
Fleets have been waiting to resume fishing off Fukushima for more than two years, and the latest contamination scare and predictions don’t offer much hope that it will happen anytime soon.