(UPDATE: Somehow jellyfish was repelled, and the full operation started. To read about the response the senior vice minister in charge of securing safety of the plant to the jellyfish attack, go to my latest post.)
Even the jellyfish is anti-nuclear these days in Japan. A large number of jellyfish clogged up the water intake at Ooi Nuclear Power Plant, and KEPCO may be forced to delay the full operation of Reactor 3.
From Fukui Shinbun (7/8/2012):
Reactor 3 at Ooi Nuclear Power Plant power decline due to jellyfish, full operation may get delayed
Nuclear and Industrial Safety Agency and KEPCO announced on July 8 that due to a large outbreak of jellyfish at the water intake for Reactor 3 at Ooi Nuclear Power Plant (in Ooi-cho, Fukui Prefecture, 1.18 million kilowatt pressurized water reactor) the electrical output decreased slightly. The full operation is scheduled at about 1AM on July 9, but that may be delayed.
According to KEPCO, jellyfish swarmed the water intake, and the company reduced the amount of seawater intake for the heat exchanger for the steam that turns the turbine at 2:55PM on July 8, which lowered the power generation efficiency. The electrical output had reached 100% at 11:20PM on July 7, but it is currently about 2% lower.
KEPCO will delay the full operation if jellyfish don't go away by 9PM on July 8. The full operation may not start until 7AM on July 9.