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UPDATE: More Problems at Quake-hit Nuclear Plant

Critics say plant design regulations are too weak, predict future catastrophe

3 min read

25 July 2007—Ten days after a deadly earthquake damaged the world’s most powerful nuclear complex, the list of incidents and shut down has risen to 63 from the 50 known last week, and the Japanese government is receiving strong criticism. The Kashiwazaki-Kariwafacility—located about 200 kilometers northwest of Tokyo—is closed indefinitely following a magnitude-6.8 earthquake and the discovery that the plant may be sitting on an extension of a major fault line.

Critics say the government was lax in its inspection of the fault line in the seabed near to where the 7-reactor, 8.21-gigawatt plant was constructed. Bowing to the rising criticism, Akira Amari, minister of the Ministry of Economy, Trade and Industry (METI), told the Japanese press, Tuesday: ”Asked whether [we] took insufficient measures, I can’t help but say yes.” And in an about-face, the government announced it would now allow a team from the International Atomic Energy Agency (IAEA) to inspect the damage at the facilities.

Academic experts are increasingly calling for the government to take more responsibility for the design of nuclear plants. Though the guidelines were revised last year, ”they are still insufficient and have several loopholes,” according to Katsuhiko Ishibashi, a professor and earthquake specialist at Kobe University. ”They need to be reviewed again,” he told the foreign press in Tokyo last Friday. He added that unless ”fundamental improvements in nuclear plant earthquake countermeasures are made, Japan would suffer from a catastrophic [disaster] in the near future.”

The most recent problem found at the plant is damage to a ceiling crane above the No. 6 reactor. The crane is used to lift the lid of the pressure container off the reactor. Until the crane is fixed Tokyo Electric Power Co. (TEPCO) says it will not be able to check the reactor’s core.

Meanwhile TEPCO revealed that during the earthquake a surveillance camera at the No. 3 reactor recorded waves higher than 1 meter in the fuel storage pool. The water level, normally 40 centimeters below the top of the pool, eventually overflowed, some of the water finding its way to the sea. Both TEPCO and METI reiterated, however, that the impact of the spill and of a separate leak of radioactive iodine into the air were negligible.

Ichiro Takekuro, executive vice president and nuclear officer at TEPCO and a former director of the Kashiwazaki-Kariwa complex, told reporters Tuesday that the company was still ”carrying out detailed inspection of the facilities and equipment,” and would be conducting a ”detailed review of the facility’s design and TEPCO’s response to the quake.”

The facility is closed indefinitely, leaving a shortfall of 8.21 gigawatts just as the peak summer demand sets in. According to Takekuro, TEPCO estimates a maximum demand of 61.1 gigawatts, and it will be able to secure 62.14 gigawatts without the Kashiwazaki-Kariwa nuclear power station by starting up shuttered fossil fuel plants.

On a personal note, Takekuro told reporters that the last 10 days had been the busiest and most miserable of his career. Given that detailed inspections are still continuing and turning up further incidents on a daily basis, the situation will likely get worse for Takekuro and his colleagues before things improve.

See the 19 July IEEE Spectrum story on the plant closing: ”Quake-hit nuclear plant shut down indefinitely.”


When the next big earthquake hits Tokyo, engineers bet even a few seconds can save lives [see ”How to Master a Seismic Disaster,” IEEE Spectrum, June 2007].

The Japan Meteorological Agency is responsible for tracking earthquakes and other natural disasters in and around Japan. On its Web site, you can see a plot of earthquakes that have occurred there during the past week: https://www.seisvol.kishou.go.jp/eq/weekly_map/japan/weekly.shtml.

For a more global view, see the U.S. Geological Survey's weekly worldwide map of earthquakes. It shows disturbances with magnitudes of 4.0 or greater (or 2.5 or greater within the United States and adjacent areas): https://earthquake.usgs.gov/eqcenter/recenteqsww.

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