Japan nuclear power plant, damaged in earthquake, plans to release ‘slightly radioactive’ vapor

Japan’s nuclear safety agency plans to release what it described as “slightly radioactive” vapor from a nuclear power plant damaged by Friday’s record 8.9 earthquake, authorities said.

The temperature in one reactor’s nuclear fuel rods has built up to 50% above normal levels since the six-reactor facility was shut down following the most powerful earthquake on record in the island nation, the Nuclear and Industrial Safety Agency reported.

No radiation leakage had been detected, Cabinet Secretary Yukio Edano told reporters, but evacuation of about 3,000 residents in the surrounding area was underway as a precaution.

Photos: Scenes from the earthquake

Japanese media quoted the nuclear safety agency as saying it planned to release the vapor that has accumulated in the overheated reactor and that the release posed no danger to human health or the environment.

Plant operators have been unable to adequately cool the reactor since shutting down the plant after authorities declared a state of emergency in the country’s atomic power system, the Kyodo news agency reported. The U.S. Air Force delivered an emergency supply of reactor coolant to Japan to help deal with the problem, the U.S. State Department said.

The International Atomic Energy Agency in Vienna said it had asked Japanese authorities for more information about the problem at the plant in Onagaway, in Fukushima prefecture. In a report on its website, the U.N. nuclear agency said it had been informed by the Japanese industry overseers that no radiation release had been detected.

“Japanese authorities have also reported a fire at the Onagawa nuclear power plant, which has been extinguished,” IAEA added.

Photos: Scenes from the earthquake

The agency also said it had information from its International Seismic Safety Center that a 6.5-magnitude aftershock or second earthquake early Saturday local time struck near the coast of Honshu in the area of the Tokai nuclear plant. There were no immediate reports of damage or leakage concerns.