NUCLEAIRES !JAPON, le 16 juillet 2007
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· · NUCLEAR POWER ON SHAKY GROUND / No price too high to pay for safe nuclear plants The Yomiuri Shimbun This is the second installment of a three-part series examining how earthquake-prone Japan can coexist with nuclear power plants, a concern that has surfaced in the wake of the July 16 earthquake in the Chuetsu region of Niigata Prefecture--the first temblor anywhere in which a fault line ran beneath a nuclear power plant. Following last Monday's earthquake, the asphalt-paved grounds of Tokyo Electric Power Co.'s Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture bulge and sag, blocking people's path. Immediately after the Niigata Prefecture Chuetsu Offshore Earthquake occurred, Shizuo Suda, deputy manager of the fire prevention division at Kashiwazaki Fire Department, entered the plant to inspect an electric transformer that had caught fire. After observing the scene, Suda became very concerned about the possibility of a secondary disaster occurring. He had never imagined that an earthquake would bring about such terrible destruction, and he thought to himself that if oil leaked from an underground pipe and ignited, there would be no remedying the situation. Suda's report to the Kashiwazaki municipal government indicating the seriousness of the situation at the plant prompted the municipal government to issue an emergency order to TEPCO instructing it to shut down the plant. Yumio Ishii, president of the Japan Society of Civil Engineers, said Friday: "I strongly feel we were lucky the disaster wasn't worse than it was. The quake-resistance standards for nuclear power plants definitely need to be reviewed." The late Nobu Kitamura, a prominent geologist and professor emeritus at Tohoku University, conducted research into faults across the country in the 1960s and '70s. He once described the Japanese archipelago, which is situated in a seismogenic zone, as follows: "If I throw a stone from here to there, countless faults lie underground in the space between. That's where Japan is located." Last Monday's quake, in which fault lines directly underneath the nuclear power plant shifted, showed Kitamura's description was no exaggeration. Japan is the only country located on four plates edging toward each other and many fault zones. Among 31 nations and regions that have nuclear power plants, Japan is the most at risk of being hit by earthquakes. Japan introduced nuclear power technology from Europe and the United States 50 years ago. The history of Japan's nuclear power industry has been a struggle against earthquakes. Inside a nuclear reactor, control rods designed to serve as brakes move between nuclear fuel rods that are assembled precisely spaced apart. If the spacing changes even slightly due to an earthquake, the control rods will cease to function as brakes. Japan Atomic Power Co.'s Tokai nuclear power station in Tokaimura, Ibaraki Prefecture, is the nation's first commercial nuclear power plant. A graphite reactor, imported from Britain, a nation that not face the threat of serious earthquakes, was used for the power plant. At the time of introducing the reactor, questions regarding its quake-resistance capabilities were voiced by many experts, forcing the company to make changes in the construction plan, including improvements to the graphite layers surrounding the fuel rods. The technology for light water reactors, which was used in many plants later, was imported from the United States, which has seismogenic zones on its Pacific Coast. Although those reactors were designed for optimum quake resistance, the United States is blessed with many choices for locating its nuclear plants, so it does not have to worry so much about making its nuclear plants capable of withstanding very strong quakes. Japan, however, had to develop the strictest quake-resistant standards for its nuclear power plants. But the tremors of the Niigata Prefecture Chuetsu Offshore Earthquake exceeded those standards. Seismic research has advanced significantly in the past half century. But it was only after the Great Hanshin Earthquake in 1995 that active faults in various regions earned serious attention. Also, it was not until the 1980s that understanding of the process of liquefaction began to deepen. Seismology is still developing, and quake-resistance standards for nuclear power plants always need to be reviewed. It is said that the cost of building one nuclear power plant in Japan is 300 billion yen--the highest in the world--as expenses for quake-resistance measures are high. In the electric power industry, many are reluctant to adopt strict antiseismic measures, saying costs will skyrocket if standards are made rigorous. Mitsumasa Hirano, chief secretary of the Japan Nuclear Energy Safety Organization said, "People have become to understand the uncertainty of seismology, and the social perception toward risk has changed since the Great Hanshin Earthquake." Electric power companies have been making efforts to balance cost and safety in setting quake-resistance standards for nuclear power plants, but it is not acceptable to delay the implementation of antiseismic measures simply because doing so will be expensive. (Jul. 23, 2007) · · N-plant shows scars of quake Kiyohiko Yoneyama Yomiuri Shimbun Staff Writer Ground at Tokyo Electric Power Co.'s Kashiwazaki-Kariwa nuclear power plant damaged by the Niigata Prefecture Chuetsu Offshore Earthquake, is shown in a picture taken Saturday. The inside of the complex of the Kashiwazaki-Kariwa nuclear power plant shows the damage inflicted by the Niigata Prefecture Chuetsu Offshore Earthquake, with the ground caved in places and the walls scorched around an electric transformer at one of the reactors. Even officials at the plant are having difficulty coming to terms with the damage. On Saturday, Tokyo Electric Power Co. opened the plant to the media for the first time since the quake hit last Monday. An oily smell filled the air near the transformer for the No. 3 reactor. Oil that is supposed to be sealed inside the transformer has been draining out of it since its insulation came off with the quake. Walls were charred from the fire. Fire hoses that employees at the plant apparently used to put out the fire were left scattered near a fire hydrant dozens of meters from the walls. Roads and gravel paths were rippled, undulating like the sea. Unlike the buildings housing the reactors, which stand on firm ground, the transformer is on relatively soft ground, which sank in the temblor. The depression, which a TEPCO employee measured in front of reporters, was 50 centimeters long. Other places in the complex also showed damage. Soil beside a diesel tank near the plant's No. 1 reactor sank as much as 1.6 meters, damaging pipes that distribute water for firefighting. Work to replace the pipes was under way. "One problem was that electric transformers and other facilities weren't made as quake-resistant as the reactor buildings, which are designed to withstand strong quakes," the plant's senior official said. "We need to discuss how best we can learn lessons from this quake when designing future facilities." However, further unexpected scenes were witnessed inside the reactor buildings, which were built on top of solid bedrock and supposedly more able to withstand tremors. Water containing a small amount of a radioactive substance was discovered at the plant's No. 6 reactor building. The building's third floor and the deck floor between the third and fourth floors, which houses equipment to control the reactor and other devices, was designated as a noncontrolled area, meaning radioactive substances are not supposed to be handled there. After the quake, however, about 1.5 liters of the tainted water was sprinkled on the floors of the noncontrolled area. The plant official said the water probably dripped from ducts and electric cables hanging from the ceiling, after first spilling over from a spent fuel pool to the fourth floor. As this was an unexpected leak, a TEPCO official conducted a reinspection. A bucket and paper towels were placed on a pink sheet spread on the floor in case radioactive water drips from the ceiling again--an oddly low-tech image compared with such a state-of-the-art facility. (Jul. 23, 2007) · · Govt OK's IAEA check of quake-hit nuclear plant The Yomiuri Shimbun The government formally decided Sunday that it would accept the International Atomic Energy Agency's offer to send an inspection team to the Kashiwazaki-Kariwa nuclear power station, hit by a powerful earthquake on July 16 in Niigata Prefecture, a government source said the same day. The Nuclear and Industrial Safety Agency of the Economy, Trade and Industry Ministry will convey the government decision to the Vienna-based U.N. agency Monday. Tetsuya Terasawa, director of the public relations department at the Tokyo Electric Power Co.'s Kashiwazaki-Kariwa plant, said during a press conference Sunday, "If there is an offer to conduct an inspection of our plant [from the IAEA], we'll respond [to it], with the hope the team can grasp the present state of affairs," making clear the plant's willingness to accept such an offer. It will be the first time the government has accepted an IAEA offer to inspect a nuclear facility in connection with a nuclear-related incident since a criticality incident that occurred at a JCO Co. nuclear fuel-processing plant in Tokaimura, Ibaraki Prefecture, in September 1999. The government has decided to accept the IAEA offer, as a senior official of the NISA put it, "Because there have apparently been false news reports overseas, which describe the problems at the [Kashiwazaki-Kariwa] plant as being as serious as the Chernobyl disaster [that occurred in 1986 in Ukraine]." On Wednesday, IAEA Director General Mohamed ElBaradei urged the government to conduct a full and transparent assessment of damage to the plant and added that his agency "would be ready to join Japan through an international team in reviewing the accident and learning the necessary lessons." NISA will ask the IAEA to conduct the inspection at the facility in question at the earliest possible time. NISA also plans to make public the result of the government's inspection on damage to nuclear facilities wrought by the latest earthquake at a meeting of officials representing nuclear-related organizations of the IAEA-member countries and territories, to be held in September in Vienna. In addition, NISA is coordinating ideas to hold a symposium, jointly with IAEA, concerning damage caused to the Kashiwazaki-Kariwa nuclear power station by the Niigata Prefecture Chuetsu Offshore Earthquake. With regards to the IAEA inspection of the Kashiwazaki-Kariwa nuclear plant, Niigata Gov. Hirohiko Izumida on Sunday sent a petition to the central government to accept the inspection offer. (Jul. 23, 2007) · · Niigata quake injured total rises to 1,812 07/23/2007 THE ASAHI SHIMBUN KASHIWAZAKI, Niigata Prefecture--The number of people injured in last week's earthquake here stands at 1,812, or 500 more than counted earlier, city administrators said over the weekend. Ten people, mostly senior citizens in Kashiwazaki, died amid collapsed buildings. City hall officials investigating damage from the 6.8 magnitude temblor said 953 homes had totally collapsed and 735 were partially destroyed. As of Sunday night, about 2,700 people remained in temporary shelters at 70 schools, gymnasiums and other public facilities in Kashiwazaki, Kariwa, Izumozaki and Tsubame. Many residents have been told to evacuate their homes because of the continued risk of landslides. On Sunday, 12 people in three households in Nishiyama in Kashiwazaki and elsewhere were told to evacuate, bringing the total to 334 people in 146 households. The Niigata prefectural government is expected to begin constructing temporary housing for evacuees today. A total of 833 units are to be erected by Aug. 15 at 23 locations, such as the park in front of JR Kashiwazaki Station. About 22,000 homes were still without water in Kashiwazaki and Kariwa on Sunday, while about 32,000 in the two areas were also without gas supply. Meanwhile, a section of Route 8 in Nagaoka in the prefecture that had collapsed was expected to reopen to traffic today.(IHT/Asahi: July 23,2007) · · Izumida calls for IAEA tests 07/23/2007 THE ASAHI SHIMBUN Niigata Governor Hirohiko Izumida on Sunday asked the government to allow the International Atomic Energy Agency (IAEA) to inspect the leakage of radioactive material from the Kashiwazaki-Kariwa Nuclear Power Plant caused by the July 16 earthquake. The government had rejected a request by the IAEA to inspect the plant, saying the damage was so serious that the people concerned are too busy repairing it.(IHT/Asahi: July 23,2007) · · More damage found at TEPCO plant 07/23/2007 THE ASAHI SHIMBUN Last week's earthquake caused more damage to the Kashiwazaki-Kariwa Nuclear Power Plant in Niigata Prefecture than officials first realized, according to operator Tokyo Electric Power Co. (TEPCO). It said oil leaks and structural damage were found at five more transformers, not just the one at the No. 3 reactor that triggered a fire. The fire apparently started when the transformer's copper conductor came into contact with other metal, igniting oil used as electric insulation. Meanwhile, the transformer at the No. 1 reactor shifted from its base during the temblor and some of its wiring to became disconnected. In transformers at reactors No. 1, 2, 4 and 7, barriers set up for preventing oil spills tilted or sank because of the temblor. Transformers at six of the plant's seven reactors were damaged in the quake, according to TEPCO. The transformers at the No. 5 reactor were not damaged. Reactors 2, 3, 4 and 7 were running when the main temblor hit at 10:13 a.m. on July 16. Operations were suspended at the No. 1, 5 and 6 reactors because they were undergoing inspections at the time. While government guidelines require that reactors are secured to bedrock, requirements are less strict for peripheral facilities such as transformers. Experts said this explained the many problems with transformers during the quake. Niigata prefectural government officials who inspected the plant the following day said it was "simply by chance" that a fire broke out only at the transformer of the No. 3 reactor.(IHT/Asahi: July 23,2007) · · Radioactive water likely flowed via electric cables after earthquake 07/23/2007 THE ASAHI SHIMBUN Radioactive water that leaked into the sea from a quake-hit nuclear power plant likely flowed along electric cables protruding from a damaged floor before reaching drainage ditches, the plant's operator said Monday. The July 16 earthquake rocked a storage pool containing about 2,300 kiloliters of water and spent nuclear fuel on the fourth floor of the No. 6 reactor building of the Kashiwazaki-Kariwa Nuclear Power Plant in Niigata Prefecture, according to Tokyo Electric Power Co. (TEPCO). The radioactive water reached a hole about 8 centimeters in diameter where the electric cables run through for equipment used to transport spent fuel, TEPCO said. Under normal circumstances, packing material fills the spaces between the sides of the hole and cables. But the packing material apparently came loose in the magnitude 6.8 earthquake, allowing the water to flow along the cables and then into an air-conditioning duct before pouring into drainage ditches that leads to the Sea of Japan, TEPCO said. The water traveled down three floors of the building. The floor where the storage pool is located is in a radiation-controlled area. But the floors where the water flowed are outside the restricted zone, the utility said. Water drops were found on the surface of the cables, inside the air-conditioning duct and elsewhere, TEPCO said. (suite)
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An estimated 1.2 cubic meters of radioactive water flowed into the sea, but the company said it is still not certain about the total amount of water that flowed from the pool. A "considerably large amount of water" must have spilled out, a TEPCO official said. "We never assumed that water could flow out of the pool," an official said. "We'd like to come up with countermeasures." The distance between the surface of the water and the top of the pool is more than 1 meter. The temblor also caused the spent fuel pools at the plant's six other reactor buildings to overflow. But no radioactive water leaked into the uncontrolled areas in these cases, according to TEPCO. TEPCO said the radioactive water that reached the Sea of Japan posed no threat to humans or the environment. But the government's Nuclear and Industrial Safety Agency said it regards the incident as extremely serious.(IHT/Asahi: July 23,2007) · · PLANS REQUIRE PUBLIC TRUST Nuclear power expansion takes direct hit The Japan Times: Monday, July 23, 2007 By JOSEPH COLEMAN The Associated Press Japan's nuclear power industry is among the world's most ambitious. Spurred by fears of global warming, planners envision a rapid expansion of plants, capacity and cutting-edge technologies. But a series of radioactive leaks at the world's largest atomic plant following last week's killer earthquake in Niigata Prefecture has given the industry a public relations headache that will be difficult to cure. "You cannot have nuclear power without public trust," said Jan Beranek, nuclear energy project leader for the Greenpeace environmentalist group. "And you cannot trust people who don't tell you the truth or who build nuclear plants in earthquake zones." Problems at the sprawling, seven-reactor Kashiwazaki-Kariwa plant included a fire charring an electrical transformer, planks toppling into a pool of spent nuclear fuel and some 400 barrels of atomic waste tipping over. Disclosures of radioactive leaks seeped out over several days, exacerbated by operator Tokyo Electric Power Co.'s delays in notifying the public. First came word, 12 hours after the quake, that some 1,200 liters of radioactive water had sloshed out of a tank and was flushed out to sea. In the following days, Tepco released a list of 50 malfunctions, damages and mistakes, announced that radioactive materials had spewed from an exhaust vent and had to acknowledge the water leak contained 50 percent more radioactivity than initially reported. The list was later updated to 63 cases. RELATED STORIES Quakes rarely damage nuclear power plants Mayor orders Tepco atomic plant idled Government to let IAEA inspect quake-hit nuke plant The company was further embarrassed Thursday when yet another leak was discovered from an exhaust vent, indicating leaks continued as late as Wednesday night, nearly three days after the quake. Tepco, regulators and even environmentalists agreed the amounts of radioactivity involved were minuscule and posed no threat. But the most damaging result from the troubles was the realization that the world's largest nuclear power plant in terms of capacity was not structurally equipped to withstand such a powerful earthquake -- this despite Japan's long history as one of the most seismically active places on Earth. Until last year, the government required nuclear plants to be built to withstand a magnitude-6.5 quake. Last week's was magnitude 6.8. In September, it began implementing tougher guidelines, though they have not set a fresh magnitude level. Regulators acknowledge they need to take a fresh look at the rules. "Earthquake safety at nuclear facilities is an issue of utmost concern to the public, and it's imperative that we ensure safety as soon as possible," said Atsuyuki Suzuki, chairman of the Nuclear Safety Commission. For some scientists, however, there are no guidelines strong enough to protect a plant. Katsuhiko Ishibashi, an earthquake specialist at Kobe University's Research Center for Urban Safety and Security, said one problem is that scientists are unable to pinpoint fault lines with any accuracy. "This situation clearly showed the insufficiency of the old guidelines for examining the seismic design of nuclear power plants," he said, arguing no plant could survive a direct hit from a quake. The troubles facing Japan's nuclear industry come just as it is getting a shot of fresh energy from concern over climate change. Atomic power figured high in the government's proposal to cut world greenhouse gas emissions in half by 2050. Japan has 55 reactors producing about 30 percent of its electricity, with plans to build another 11 by 2017, eventually boosting nuclear power's share of electricity production to 40 percent. Down the road, the government is pushing for development of next-generation light water reactors around 2030, and so-called fast-breeder reactors that produce plutonium that can be reused as fuel, fulfilling a Japanese dream of energy self-sufficiency. The government, however, already faces difficulties in finding communities willing to host reactors, mostly because of a long list of past accidents and coverups of malfunctions -- including some at Tepco. The problems at Kashiwazaki could make that expansion even more difficult. While many Japanese understand the need for energy to power the world's second-largest economy, they are hesitant to trust operators. "It is impossible to guarantee 100 percent safety," conceded Yumi Shimoda, a 40-year-old marketing consultant in Tokyo. "But what scares me is the fact that they tried to cover up the truth in order to claim safety." · · NUCLEAR POWER ON SHAKY GROUND / Plant shutdowns mean more CO2 emissions The Yomiuri Shimbun This is the third and final installment of a three-part series examining how earthquake-prone Japan can coexist with nuclear power plants, a concern that has surfaced in the wake of the July 16 earthquake in the Chuetsu region of Niigata Prefecture--the first temblor anywhere in which the fault line ran beneath a nuclear power plant. Every summer, officials at the Electricity Infrastructure Division of the Natural Resources and Energy Agency in Kasumigaseki, Tokyo, hardly have time to sleep due to their heavy workload. They are in charge of coordinating with electric power companies on estimates each power plant can provide so that the Kanto area will be supplied with enough electricity during the year's peak energy consumption period. Damage from the Niigata Prefecture Chuetsu Offshore Earthquake on July 16 forced Tokyo Electric Power Co. to shut down all seven reactors at the Kashiwazaki-Kariwa nuclear power plant, which are capable of generating a combined 8.2 million kilowatts, making it one of the world's largest nuclear power plants. The shutdown comes just a few weeks before the busiest of summer days for these officials arrives. "I don't know if any of us are sleeping even an hour a day," said an exhausted Kyoji Yoshino, chief of the Electricity Infrastructure Division. There are 55 nuclear reactors in the nation. Over the past 30 years, the percentage of all electricity in the country that comes from nuclear energy has risen from 6.5 percent to 31 percent. However, only 35 nuclear power plants are in operation due to a series of reactors shutdowns. The No. 1 reactor of Hokuriku Electric Power Co.'s Shika nuclear power plant was shut down after it was revealed in March that the power company failed to report a criticality accident in 1999. There also are a number of reactors that are not in operation due to regular checkups. The Kashiwazaki-Kariwa nuclear plant is expected to be out of service for up to 18 months as earthquake-resistance reinforcements have to be made to meet stricter requirements, and a detailed geological survey around the plant must be conducted. Securing enough electricity for the summer, therefore, appears to be a tight rope act for the agency. The government has regarded nuclear power as crucial for stable electricity supplies, and power companies have long touted nuclear power as a trump card in tackling global warming. In April, TEPCO President Tsunehisa Katsumata, who also is chairman of the Federation of Electric Power Companies of Japan, announced a federation action plan that called for promoting further energy production through nuclear means. "We are in a crucial stage of deciding a future framework to combat global warming," Katsumata said at a press conference, adding that Japanese people as a whole should do more to reduce global-warming gas emissions. TEPCO, the industry leader, has been the standard bearer for promoting nuclear power. "[The shutdown of Kashiwazaki-Kariwa] will inevitably affect our efforts to meet the target of reducing carbon dioxide," a strained Katsumata said Friday while on what he calls a pilgrimage to make apologies after the reactors at the plant were ordered to shut down due to its insufficient fire-extinguishing system. It is certain the quake will force the government to rewrite its scenario for reducing greenhouse gases. Under the Kyoto Protocol, Japan aims to cut such emissions by 6 percent from its 1990 level in 2008-12. But this assumes 84.1 percent of the nation's nuclear reactors are in operation. Such emissions in fiscal 2005 totaled the equivalent of 1.36 billion tons of carbon dioxide. To meet that target, Japan needs to reduce greenhouse gas emissions by 14 percent from fiscal 2005. Of the 14 percent, the government had hoped to meet a reduction of 5.5 percent by boosting production at nuclear power plants. If the Kashiwazaki-Kariwa plant is shut down for a year and its shortfall in power generation is supplemented by coal-generated power, CO2 emissions will increase by about 40 million tons. Yoshio Tamura, administrative vice minister of the Environment Ministry, did not hide his disappointment over the plant's shutdown. "The shutdown of the plant was so painful for us, particularly when we had high hopes for increasing the rate of operation at nuclear plants," Tamura said. In addition, momentum has gathered to review earthquake-resistance levels at nuclear power plants across the country. "If more nuclear plants decide to shut down until they confirm their earthquake-resistant levels are sufficient, the damage [to efforts to reduce global warming gas emissions] will be incalculable," another high-ranking official at the ministry said. The Los Angeles Times described last week's earthquake as a disaster striking "the world's largest nuclear power plant," adding: "The latest troubles could have broad implications for plans to increase the percentage of electricity that comes from nuclear energy in an economic powerhouse that rests on highly volatile geological plates but has little coal, and no oil or natural gas." Satoru Tanaka, a member of the supply and demand division of the Advisory Committee on Energy and Natural Resources and a professor at Tokyo University, said: "First and foremost, it is essential to improve the reliability of this nation's technology for nuclear power generation as a key source of its electric power. This should be complemented by efforts to ensure the country can avail itself of multiple energy sources, including natural energy." Many observers electric power industry must thoroughly disclose information regarding the world's first earthquake to hit a nuclear power plant that sits on a fault and to establish reliable earthquake-resistance technology if the nation wants to restore its credibility in nuclear energy. This series of articles was written by four science news department staff writers--Nobuhiko Harada, Masae Honma, Tatsuo Nakajima and Kiyohiko Yoneyama. (Jul. 24, 2007) · · N-plant likely to stay shut for long time The Yomiuri Shimbun The revelations of the extent of the damage to the Kashiwazaki-Kariwa nuclear power plant have made it impossible for Tokyo Electric Power Co. to draw up a specific schedule for the resumption of operations at the plant. Sixty-three problems have been discovered so far at the plant, which was heavily damaged by the Niigata Prefecture Chuetsu Offshore Earthquake a week ago. The nuclear reactor cores, which are the most important part of a nuclear reactor, have not been inspected yet. However, the inspection can only be undertaken next month at the earliest. TEPCO is discussing whether it is possible to visually inspect the cranes using a remote-control camera. Revalidation of the facilities' antiseismic capacities poses bigger problems than any inspection and repair of facilities. After analyzing the seismic wave pattern in the latest earthquake, TEPCO will have to recreate the quake through a computer simulation to learn how the plant's buildings and other facilities were rocked by the quake. TEPCO must confirm whether the facilities can stand a bigger earthquake than the one that hit last week. By checking TEPCO's report and listening to the opinions of experts, the Nuclear and Industrial Safety Agency of the Economy, Trade and Industry Ministry will decide whether to allow TEPCO to resume operation of the power plant. Three reactors at the Onagawa nuclear power plant of Tohoku Electric Power Co. in Miyagi Prefecture, which was hit by a stronger than anticipated for earthquake in August 2005, were finally allowed to be restarted this month after operations were suspended for about two years. (Jul. 24, 2007) · · Quake cleanup delays reactor core checks Kyodo News Tokyo Electric Power Co. may not be able to begin reactor core checks of its quake-hit nuclear power plant in Niigata Prefecture until September because it needs to clean up contamination inside one of the seven reactors and remedy other safety woes, company officials said Monday. In addition to repairing the damage, the utility must also solve a host of problems that emerged after the magnitude-6.8 quake hit the Kashiwazaki-Kariwa nuclear plant July 16, including an inadequate fire-extinguishing system and uncertainty over the plant's ability to withstand earthquakes like the one that struck along the fault the complex apparently sits on. Restarting the world's largest atomic power complex before the August peak power demand period is not expected. A prolonged suspension may in turn cause other problems, including an increased release of carbon dioxide from thermal power plants Tepco will have to restart to make up for the shortfall. To check the core contained in the reactor pressure vessel, Tepco said it must remove radioactive water believed to have leaked from a pool for storing spent fuel rods. Some of the water flowed into the nearby sea. Since the quake, the water has been left on a floor located above the reactor pressure vessel at one of the seven reactors. The vessel is filled with cooling water and an underwater camera is needed to inspect control rods and other materials inside. The utility also has to check whether the crane set up to lift the vessel's lid is working properly. "We need at least several weeks for these preparations, and the start of checkups will be after mid-August at the earliest and may possibly not be before September," a Tepco official said. Tepco also needs to confirm how the water leaked into the sea, and repair buckled roads at the plant site as well as damaged fire equipment. Even after all these problems are fixed, Tepco has to gauge the plant's ability to withstand a strong temblor and gain approval from the central government and local authorities before it can go back online. "Since the earthquake, our hands are full in dealing with the issues that face us. We have not yet reached the point of deciding in detail about a future timetable," a company official said. The Japan Times: Tuesday, July 24, 2007 |
