Earthquake in Japan
Japanese Nuclear Power Plant Withstands Earthquake;
No Environmental Impact From Radioactive Releases
July 19, 2007
The Kashiwazaki-Kariwa nuclear power plant successfully withstood a major earthquake that struck northwestern Japan on July 16. The operating reactors shut down as designed. Some radioactivity was released as result of the event, but no public or environmental harm has resulted from the releases. The Japanese regulatory agency and the company operating the plant have investigated and found no environmental or safety impact beyond the plant site.
Background
A strong earthquake that struck northwestern Japan on Monday affected operations at the seven-unit Kashiwazaki-Kariwa nuclear power plant. Four of the reactors shut down automatically, as designed (the other three were not operating at the time).
The earthquake caused approximately 300 gallons of water to be discharged into the Sea of Japan. The water contained a small amount of radioactivity—about two microcuries, according to officials with Tokyo Electric Power Co. (TEPCO).
According to official reports, no “significant change” to the seawater has been detected near the plant. Jun Oshima, an executive at TEPCO, told the Associated Press that “the radioactivity is one-billionth the legal limit” of the water from the plant.
The earthquake also tipped over barrels containing low-level radioactive waste.
The Japanese Nuclear and Industrial Safety Agency and TEPCO have identified no health or safety impacts from the plant resulting from the earthquake.
The earthquake, estimated at 6.6-6.8 on the Richter scale, also caused a transformer fire at the facility that was quickly extinguished. The fire and the releases were not related.
Despite the considerable damage to the surrounding area, the Kashiwazaki-Kariwa nuclear plant performed as designed and withstood the effects of the earthquake. No environmental damage has resulted from the quake’s impact on the plant.
U.S. and Japanese nuclear plants are built using multiple safety barriers and redundant, physically separated safety systems to ensure public health and safety even in severe circumstances like hurricanes and earthquakes.
Nuclear plants in Japan and the United States are built to withstand earthquakes of a magnitude equivalent to or greater than the largest known earthquake for the region where they are located.