NUCLEAIRES !JAPON, le 16 juillet 2007
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NUCLEAIRES !| http://www.asahi.com/english/Herald-asahi/TKY200707300083.html
--The Asahi Shimbun, July 22(IHT/Asahi: July 30,2007) We can't avoid quakes; we can avoid ignorance 07/30/2007 Torahiko Terada (1878-1935), a physicist and essayist, was also a social critic who constantly preached the importance of disaster-preparedness. Shortly before his death, he published an essay titled "Sainan Zakko" (Random thoughts on disasters), which consisted of his observations based on his seismological research over many years. Noting that the Japanese archipelago stretches precariously along a boundary between tectonic plates, he wrote, "It is as if the entire Japanese land is sitting atop a suspension bridge." And he warned: "The suspender cables could snap tomorrow, and the chances are actually quite high." Today, all sorts of artificial structures that did not exist in Terada's time are crowding this unstable "suspension bridge." Among them are the nation's 55 nuclear power reactors. On July 16, a powerful temblor off the coast of the Chuetsu region in Niigata Prefecture jolted the Kashiwazaki-Kariwa Nuclear Power Plant operated by Tokyo Electric Power Co. The quake revealed the facility's many weaknesses. An active fault lies directly under this plant, but this fact was reportedly overlooked at the time of construction. The quake caused radioactivity to escape into the atmosphere and the Sea of Japan, albeit in a negligible dose. A transformer on the plant premises caught fire and blazed unchecked for nearly two hours, spewing black smoke. Investigations by the flustered government have since revealed that other nuclear power reactors are just as ill-prepared for earthquakes. It is as if 55 swords are hanging precariously above the heads of the Japanese people. I understand that there are unfounded safety myths about nuclear power stations. The collapse of each such myth is accompanied by a tragedy. There was a time when everyone was taken in by the seemingly plausible argument that jumbo jets just could not crash. But this "myth" collapsed in Japan 22 years ago when a Japan Airlines jumbo jet smashed into a mountain in Gunma Prefecture, and I can still recall the disaster vividly. Earthquakes themselves are unpreventable, but humans can at least control earthquake damage, and that was actually the gist of Terada's argument. We don't need any empty myths. We need "true stories" based on lessons learned from the latest quake. http://search.japantimes.co.jp/print/nb20070801a2.html Tepco slashes profit estimate due to quake Kyodo News Tokyo Electric Power Co. on Tuesday sharply lowered its group profit estimates for fiscal 2007 in the wake of the quake-induced shutdown of the world's largest nuclear power plant, which it expects to reduce profit by up to ¥400 billion. Tepco, Japan's largest utility, now projects a group net profit of ¥65 billion for the year through next March, down from ¥310 billion estimated in April. The company also revised downward its consolidated pretax profit projection to ¥130 billion from ¥400 billion. It revised its group sales forecast slightly upward to ¥5.45 trillion from ¥5.40 trillion. The July 16 quake forced Tepco to shut down the Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture, the world's largest in terms of power generation capacity. The plant will remain halted indefinitely until the safety of its seven reactors can be fully ensured. The downward revisions of profits are based on the assumption that the plant will remain closed through the end of the current fiscal year. Of the envisaged loss of ¥400 billion, ¥282 billion represents fuel and other costs to generate 40 billion kilowatt-hours worth of electricity — the level of output of the Kashiwazaki-Kariwa plant — using the company's thermal power plants. The remainder reflects higher fuel procurement costs as a result of rising crude oil prices and the weak yen. "We are faced with a severe business outlook," Tepco President Tsunehisa Katsumata told a news conference. "Our first priority is to ensure a stable electricity supply to our customers and we will strive for greater efficiency in our businesses." Despite the electricity supply disruption caused by the suspension of the Kashiwazaki-Kariwa plant, Katsumata said Tepco does not plan to raise its rates. The company also is not considering cutting dividend payments for fiscal 2007, he said. For the first quarter of the fiscal year, the company said its group net profit was down 35.4 percent from a year earlier to ¥31.07 billion, or ¥23.03 per share. The Japan Times: Wednesday, Aug. 1, 2007 http://www.asahi.com/english/Herald-asahi/TKY200708010079.html UTILITIES: Plant damage to lower TEPCO earnings 08/01/2007 THE ASAHI SHIMBUN Tokyo Electric Power Co. said Tuesday the suspension of the Kashiwazaki-Kariwa Nuclear Power Plant will cause more than 400 billion yen in additional costs by March. The estimate does not take into account repair costs for the plant, damaged by the July 16 temblor, or reinforcements to improve its earthquake resistance, officials said. The costs will increase because the company will switch to expensive thermal power generation during the suspension. The utility on Tuesday revised its net profit forecast for the current fiscal year from 310 billion yen to 65 billion yen. (IHT/Asahi: August 1,2007) http://www.asahi.com/english/Herald-asahi/TKY200708010089.html Nuke plant shaking was 6.8 times more intense than TEPCO limit 08/01/2007 THE ASAHI SHIMBUN Quake-induced shaking at a nuclear power plant in Niigata Prefecture was much more intense than initially reported, underscoring how ill-prepared the facility was for a major temblor. The July 16 earthquake caused the Kashiwazaki-Kariwa Nuclear Power Plant to sway a maximum 2,058 gals, according to Tokyo Electric Power Co. (TEPCO), operator of the plant. A gal is a unit of acceleration equal to 1 centimeter per 1 second squared. The utility said the shaking was not only the strongest recorded at a nuclear power plant in Japan, but might be the most powerful at any nuclear plant in the world. In at least one area of the Kashiwazaki-Kariwa plant, the shaking was 6.8 times larger than the maximum level taken into account when the plant was designed. "It cannot be helped if we are criticized for being too easy in our estimates of earthquakes," said Hideki Morishita, who is in charge of management of nuclear facilities at TEPCO. After the earthquake, the company announced that the maximum shaking recorded at the plant was 680 gals on the lowest basement floor of the No. 1 reactor. But on Monday, TEPCO revealed much higher readings from data recorded by 96 seismographs at various locations of the plant. Some of the seismographs failed to function for some data, the company said. TEPCO also said seismic wave patterns were recorded in 33 areas. They showed the plant was not prepared for such a jolt. The maximum 2,058-gal figure was recorded on the first floor of the No. 3 reactor's turbine building, according to the power company. This area was designed to withstand a maximum 834 gals. (suite)
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On the first floor of the turbine building of the No. 1 reactor, shaking of 1,862 gals was recorded, 6.8 times the cap of 274 gals. Because the seismographs were placed near turbines on higher floors, the level of shaking was likely larger than those underground, TEPCO said. The data on different seismic wave cycles showed that TEPCO also underestimated the maximum jolts in different frequencies when it designed equipment and facilities connected to all seven reactors at the plant. At reactors No. 2 through 5, for example, the jolts exceeded a frequency level of 0.1-0.5-second. Waves at this frequency can damage fuel rods, pressurized reactor vessels and major pipes, resulting in radioactive leaks. A seismograph close to a damaged ceiling crane at the No. 6 reactor recorded 1,541 gals. The crane could have dislodged, but it did not fall because of a safety catch device.(IHT/Asahi: August 1,2007) http://www.yomiuri.co.jp/dy/national/20070801TDY02005.htm Kashiwazaki firefighters stretched too thin / Lack of contingency plan left fire dept ignoring requests for help, doubling up on calls The Yomiuri Shimbun Kashiwazaki's fire department was unable to respond to calls for help in the wake of last month's Niigata Prefecture Chuetsu Offshore Earthquake as a number of fire trucks had been sent to the nuclear power station there to extinguish a transformer fire, according to sources. Fire trucks were dispatched to Tokyo Electric Power Co.'s Kashiwazaki-Kariwa nuclear power station even after firefighters had the fire under control, the sources said. The confusion at the fire department's control center at the time stemmed from its never having had to deal with multiple emergencies. Taking a lesson from the quake and its aftermath, the city's fire department headquarters plans to review its services and operation, manuals, the sources said. According to the Fire and Disaster Management Agency, under the Internal Affairs and Communications Ministry, multiple-disaster contingency plans are not in place in other local governments that are home to nuclear power stations, either. The Kashiwazaki case has served to highlight the problem as nuclear power plant operators have been under pressure to improve their own fire management systems. The fire took place immediately after the earthquake struck at 10:13 a.m. on July 16. As the fire service hotline was out of order, TEPCO made an emergency 119 call 14 minutes later. The headquarters decided it would dispatch nine vehicles from the city's main fire station and two substations in accordance with the manual on fighting fires at a nuclear power plant, but there were no vehicles or firefighters available as they had been dispatched following calls for help from local residents. The fire service then told the operator of the nuclear power plant to handle the disaster with its own firefighting team. At 11 a.m., the fire service finally was able to dispatch a chemical fire engine with five firefighters. The vehicle arrived at the site in 30 minutes and got the fire under control in 10 minutes. But the fire department dispatched three more vehicles and 12 firefighters as it was unable to get a full picture of the situation as firefighters were experiencing difficulty with radio communications. The three vehicles arrived at the site at about 12:10 p.m., after the fire was extinguished. The fire department headquarters, meanwhile, received about 130 calls for assistance over the two hours until the fire was under control. "We had to tell a number of citizens that we wouldn't be able to help them because we were short of manpower and equipment," a fire service official said. The city's firefighting manuals do not stipulate how to act during complex disaster situations. Therefore, drills have never been conducted under the scenario that there is a shortage of both firefighters and vehicles. The fire service also had been unable to dispatch a command vehicle to the nuclear power plant to assist in communications, as the vehicle had been seat to a different location. A fire service official said: "If we had been informed that the fire already was extinguished, there's no way we would have sent more trucks. We were preoccupied amid the confusion and unable to put much thought into communications. After we finish examining the case, we'll review our operation systems and manuals." === Tremor bigger than predicted A tremor measured at the nuclear power plant was 2.5 times greater than the estimated maximum, it was learned Tuesday. Although no damage to major machinery, such as the reactor pressure vessel, was found, TEPCO will have to rewrite its safety blueprint before it can consider reopening the plant. According to a survey conducted by TEPCO, almost every seismometer placed in the power plant's buildings recorded tremors far exceeding the design estimate. The biggest east-west tremor recorded at the first floor of No. 3 reactor's turbine building was 2,058 gal, about 250 percent greater than the estimated maximum of 834 gal. A gal is a unit of gravitational acceleration equal to one centimeter per second squared. It is the first time such a large tremor has been recorded at a nuclear power plant in Japan, and it is also believed to be the largest recorded by any nuclear plant in the world, TEPCO said. Ninety-seven seismometers are positioned in the buildings and grounds of the power plant. Almost all those placed in buildings recorded tremors stronger than the maximum estimate, including one measuring 680 gal at a nuclear reactor building. A wavy pattern of seismic activity was recorded by 33 new-model seismometers. TEPCO closely studied the tremors that hit the nuclear reactor buildings and found that almost every object and piece of equipment in the buildings shook more violently than had been predicted in the design estimate. Primary-importance machinery, such as the reactor pressure vessel and emergency reactor core cooling equipment, are designed to be able to withstand earthquakes much more severe than those projected in the design estimate. Meanwhile, the time cycle of seismic waves that caused the strongest tremors in the quake fell between 0.5 second and one second at each reactor in the plant. The reactors likely avoided damage because the time cycle at which sympathetic vibration would have been triggered in them is much shorter, according to TEPCO. Prof. Kazuki Koketsu of Tokyo University's Earthquake Research Institute said TEPCO "underestimated tremors that might be caused by an unknown active fault because its research into active faults around the power plant was insufficient." (Aug. 1, 2007) http://search.japantimes.co.jp/print/nn20070801a9.html Fault near nuke plant seen causing March quake A recent seabed study has confirmed that an active seismic fault more than 18 km long and running near a nuclear power plant was the cause of the magnitude-6.9 earthquake that jolted the Noto Peninsula and its vicinity in March, according to the National Institute of Advanced Industrial Science and Technology. About 15 km of the fault, located near Hokuriku Electric Power Co.'s Shika nuclear plant, and some 5 km that extends onshore from it, are believed to have caused the quake, the institute said, countering the utility's view that three different faults were responsible for the temblor. Prior to the Noto quake, the fault had been active once or twice in the last 20,000 years, the institute said. In the seafloor tectonic survey conducted July 3 to 10 jointly with the Japan Coast Guard off the city of Wajima and the town of Shika in Ishikawa Prefecture, the institute found the fault near the quake's focus, using a high-resolution sonic profiling device it has developed. Near the fault, an erosion surface formed about 20,000 years ago and sediment layers covering it were distorted about 3 meters up and down, indicating quakes had occurred once or twice before the March 25 temblor. As a result of the quake, the seabed south of the fault was elevated about 50 cm, the institute said. The institute plans to conduct a similar study on the magnitude-6.8 earthquake that hit Niigata Prefecture on July 16, research team leader Yukinobu Okamura said. The Japan Times: Wednesday, Aug. 1, 2007 |
