Tag Archive: Fukushima plant


Japan utility delays decision on halting reactors

A police officer walks in rubble at recovery operation in the area destroyed by the March 11 earthquake and tsunami in Kesennuma,  Miyagi Prefecture,http://news.yahoo.com/s/ap/20110507/ap_on_bi_ge/as_japan_earthquake

By MARI YAMAGUCHI, Associated Press Mari Yamaguchi, Associated Press 1 hr 48 mins ago

TOKYO – A Japanese power company postponed its decision Saturday on a government request that it halt three reactors at a coastal nuclear plant until safety measures can be improved to guard against future earthquakes and tsunamis.

Shutting down the reactors would likely worsen power shortages expected this summer.

On Friday, Prime Minister Naoto Kan said he had asked Chubu Electric Power Co. to suspend operation of the reactors at the Hamaoka Nuclear Power Station in Shizuoka prefecture until a seawall is built and backup systems are improved. Though not legally binding, the request is a virtual order.

The government is reviewing the safety of the country’s 54 atomic reactors since a March 11 earthquake and tsunami crippled the Fukushima Dai-ichi nuclear plant in the north. The disaster left more than 25,000 people dead or missing on the northeast coast.

The Hamaoka plant, which is about 125 miles (200 kilometers) west of Tokyo in an area where a major quake is expected within decades, has been a major concern for years.

Chubu Electric executives failed to reach a decision after discussing the request Saturday afternoon and decided to meet again after the weekend, company official Mikio Inomata said.

At issue is how to make up for the power shortages that would result from the shutdown of the three reactors. Inomata said they account for more than 10 percent of the company’s power supply.

Chubu Electric has estimated maximum output of about 30 million kilowatts this summer with the three Hamaoka reactors running, with estimated demand of about 26 million kilowatts.

“It would be tight,” Inomata said, adding that officials are discussing the possibility of boosting output from gas, oil and coal-fueled power plants and purchasing power from other utility companies.

Kan said the shutdown request was for the “people’s safety.”

“If an accident occurs at Hamaoka, it could create serious consequences,” he said Friday.

He noted that experts estimate there is a 90 percent chance that a quake with a magnitude of 8.0 or higher will strike the region within 30 years.

Since the March 11 disasters, Chubu Electric has drawn up safety measures that include building a 40-foot-high (12-meter-high) seawall nearly a mile (1.5 kilometers) long over the next two to three years, company officials said. The company also promised to install additional emergency backup generators and other equipment and improve the water tightness of the reactor buildings.

The plant does not have a concrete sea barrier now. Sand hills between the ocean and the plant are about 32 to 50 feet (10 to 15 meters) high, deemed enough to defend against a tsunami around 26 feet (8 meters) high, officials said.

Shizuoka Gov. Heita Kawakatsu called Friday’s government request “a wise decision” and vowed to secure alternative sources of energy.

Residents of Shizuoka have long demanded a shutdown of the Hamaoka reactors. About 79,800 people live within a 6-mile (10-kilometer) radius of the plant.

The Hamaoka plant provides power to around 16 million people in central Japan including nearby Aichi, home of Toyota Motor Corp.

Automakers and other industries have had troubles with interrupted supply lines, parts shortages and damage to manufacturing plants because of the March 11 disasters.

The nationwide newspaper Yomiuri welcomed the government request to shut down the reactors despite concerns about a power crunch.

“The idea is to use the lesson we learned (from Fukushima),” the Yomiuri said, urging other utilities to also improve safety. “An accident and subsequent release of radiation could paralyze the entire country.”

Thousands of people joined an anti-nuclear march Saturday in Tokyo’s crowded Shibuya shopping and entertainment district, chanting “No nuke plants!”

The Fukushima Dai-ichi plant lost its power and cooling systems in the magnitude-9.0 earthquake and ensuing tsunami, triggering the world’s worst nuclear accident since Chernobyl.

Radiation leaks have forced 80,000 people living within a 12-mile (20-kilometer) radius of the plant to leave their homes.

Since the Fukushima crisis unfolded, officials have acknowledged that tsunami safety measures at Japanese nuclear power plants are insufficient.

Tokyo Electric Power Co., operator of the Fukushima plant, has said the tsunami that wrecked critical power and cooling systems there was at least 46 feet (14 meters) high.

It said radioactivity inside the No. 1 reactor building has fallen to levels deemed safe for people wearing protective suits to enter after workers rapidly installed air filtering equipment Thursday — their first entry since shortly after the tsunami. Workers are to begin preparations as early as Sunday to install a cooling system.

___

Associated Press writer Shino Yuasa contributed to this report.

Advertisements

Workers enter Japan nuclear reactor building

http://news.yahoo.com/s/ap/20110505/ap_on_re_as/as_japan_earthquake

By TOMOKO A. HOSAKA, Associated Press Tomoko A. Hosaka, Associated Press 2 hrs 10 mins ago

TOKYO – Workers entered one of the damaged reactor buildings at Japan’s stricken nuclear power plant Thursday for the first time since it was rocked by an explosion in the days after a devastating earthquake, the plant’s operator said.

Tokyo Electric Power Co. said workers connected ventilation and air filtration equipment in Unit 1 in an attempt to reduce radiation levels in the air inside the building.

The utility must lower radiation levels before it can proceed with the key step of replacing the cooling system that was knocked out by the March 11 quake and subsequent tsunami that left more than 25,000 people dead or missing along Japan’s northeastern coast.

Workers have not been able to enter the reactor buildings at the Fukushima Dai-ichi nuclear power plant, about 140 miles (230 kilometers) northeast of Tokyo, since the first days after the tsunami. Hydrogen explosions at four of the buildings at the six-reactor complex in the first few days destroyed some of their roofs and walls and scattered radioactive debris.

TEPCO spokesman Junichi Matsumoto called Thursday’s development “a first step toward a cool and stable shutdown,” which the utility hopes to achieve in six to nine months.

In mid-April, a robot recorded radioactivity of about 50 millisieverts per hour inside Unit 1’s reactor building — a level too high for workers to realistically enter. Readings taken later in April in another part of the building were as high as 1,200 millisieverts.

The decision to send the workers in was made after robots last Friday collected fresh data that showed radiation levels in some areas inside the building were safe enough for workers to enter, said Taisuke Tomikawa, another TEPCO spokesman.

Two utility workers, wearing a mask and air tank similar to those used by scuba divers, entered the reactor building for about 25 minutes to check radiation levels. They were exposed to 2 millisieverts during that time, Tomikawa said. Outside the building, the utility erected a temporary tent designed to prevent radioactive air from escaping.

Later, 11 other workers — two from TEPCO and nine from its subcontractors — wearing similar gear went into the reactor building to install ducts for the air filtering equipment. Twenty other workers provided help from outside.

The utility hopes to start allowing workers into the building to set up a cooling system around mid-May. In addition to reducing radioactivity with the new air filtering system, it hopes to reduce it further by removing or covering up contaminated debris inside the building, Matsumoto said.

TEPCO is proceeding with a plan to fill the Unit 1 containment vessel with water to soak the core and cool it, and also plans to install big fans as an external cooling system, he said. TEPCO hopes to take similar steps at Units 2 and 3 but is struggling with tougher obstacles such as contaminated water leaks and debris.

Radiation leaking from the Fukushima plant has forced 80,000 people living within a 12-mile (20-kilometer) radius to leave their homes. Many are staying in gymnasiums and community centers.

___

Associated Press writer Mari Yamaguchi contributed to this report.

http://news.yahoo.com/s/ap/20110412/ap_on_bi_ge/as_japan_earthquake

By YURI KAGEYAMA and RYAN NAKASHIMA, Associated Press Yuri Kageyama And Ryan Nakashima, Associated Press 53 mins ago

TOKYO – Japan raised the crisis level at its crippled nuclear plant Tuesday to a severity on par with the 1986 Chernobyl disaster, citing high overall radiation leaks that have contaminated the air, tap water, vegetables and seawater.

Japanese nuclear regulators said they raised the rating from 5 to 7 — the highest level on an international scale of nuclear accidents overseen by the International Atomic Energy Agency — after new assessments of radiation leaks from the Fukushima Dai-ichi plant since it was disabled by the March 11 tsunami.

The new ranking signifies a “major accident” that includes widespread effects on the environment and health, according to the Vienna-based IAEA. But Japanese officials played down any health effects and stressed that the harm caused by Chernobyl still far outweighs that caused by the Fukushima plant.

The revision came a day after the government added five communities to a list of places people should leave to avoid long-term radiation exposure. A 12-mile (20-kilometer) radius already had been cleared around the plant.

The news was received with chagrin by residents in Iitate, one of the five communities, where high levels of radiation have been detected in the soil. The village of 6,200 people is about 40 kilometers from the Fukushima plant.

“It’s very shocking to me,” said Miyuki Ichisawa, 52, who runs a coffee shop in Iitate. “Now the government is officially telling us this accident is at the same level of Chernobyl.”

Iitate’s town government decided Tuesday to ban planting of all farm products, including rice and vegetables, said local official Shinichi Momma. The national government earlier banned rice growing there but not necessarily vegetables.

Japanese officials said the leaks from the Fukushima plant so far amount to a tenth of the radiation emitted in the Chernobyl disaster, but said they eventually could exceed Chernobyl’s emissions if the crisis continues.

“This reconfirms that this is an extremely major disaster. We are very sorry to the public, people living near the nuclear complex and the international community for causing such a serious accident,” said Chief Cabinet Secretary Yukio Edano.

But Edano told reporters there was no “direct health damage” so far from the crisis. “The accident itself is really serious, but we have set our priority so as not to cause health damage.”

Click image to see photos of quake, tsunami damage

Hironobu Unesaki, a nuclear physicist at Kyoto University Research Reactor Institute, said the revision was not a cause for worry, that it had to do with the overall release of radiation and was not directly linked to health dangers. He said most of the radiation was released early in the crisis and that the reactors still have mostly intact containment vessels surrounding their nuclear cores.

The change was “not directly connected to the environmental and health effects,” Unesaki said. “Judging from all the measurement data, it is quite under control. It doesn’t mean that a significant amount of release is now continuing.”

Prime Minister Naoto Kan, in a national television address, urged the public not to panic and to focus on recovering from the disaster.

“Right now, the situation of the nuclear reactors at the Fukushima plant has been stabilizing step by step. The amount of radiation leaks is on the decline,” he said. “But we are not at the stage yet where we can let our guards down.”

Continued aftershocks following the 9.0-magnitude megaquake on March 11 are impeding work on stabilizing the Fukushima plant — the latest a 6.3-magnitude one Tuesday that prompted plant operator Tokyo Electric Power Co., or TEPCO, to temporarily pull back workers.

Officials from Japan’s Nuclear and Industrial Safety Agency said that the cumulative amount of radioactive particles released into the atmosphere since the incident had reached levels that apply to a Level 7 incident. Other factors included damage to the plant’s buildings and accumulated radiation levels for its workers.

“We have refrained from making announcements until we have reliable data,” said NISA spokesman Hidehiko Nishiyama said. “The announcement is being made now because it became possible to look at and check the accumulated data assessed in two different ways,” he said, referring to measurements from NISA and Japan’s Nuclear Security Council.

NISA and the NSC have been measuring emissions of radioactive iodine-131 and cesium-137, a heavier element with a much longer half-life. Based on an average of their estimates and a formula that converts elements into a common radioactive measure, the equivalent of about 500,000 terabecquerels of radiation from iodine-131 has been released into the atmosphere since the crisis began.

That well exceeds the Level 7 threshold of the International Nuclear and Radiological Event Scale of “several tens of thousands of terabecquerels” of iodine-131. A terabecquerel equals a trillion becquerels, a measure for radiation emissions.

The government says the Chernobyl incident released 5.2 million terabecquerels into the air — about 10 times that of the Fukushima plant.

If the leaks continue, the amount of radioactivity released in Fukushima could eventually exceed the amount emitted by Chernobyl, a possibility that Naoki Tsunoda, a TEPCO spokesman, said the company considers “extremely low.”

In Chernobyl, in the Ukraine, a reactor exploded on April 26, 1986, spewing a cloud of radiation over much of the Northern Hemisphere. A zone about 19 miles (30 kilometers) around the plant was declared uninhabitable, although some plant workers still live there for short periods and a few hundred other people have returned despite government encouragement to stay away.

In 2005, the Chernobyl Forum — a group comprising the International Atomic Energy Agency and several other U.N. groups — said fewer than 50 deaths could be confirmed as being connected to Chernobyl. It also said the number of radiation-related deaths among the 600,000 people who helped deal with the aftermath of the accident would ultimately be around 4,000.

The U.N. health agency, however, has said about 9,300 people are likely to die of cancers caused by radiation. Some groups, including Greenpeace, have put the numbers 10 times higher.

The Fukushima plant was damaged in a massive tsunami that knocked out cooling systems and backup diesel generators, leading to explosions at three reactors and a fire at a fourth that was undergoing regular maintenance and was empty of fuel.

The magnitude-9.0 earthquake that caused the tsunami immediately stopped the three reactors, but overheated cores and a lack of cooling functions led to further damage.

Engineers have pumped water into the damaged reactors to cool them down, but leaks have resulted in the pooling of tons of contaminated, radioactive water that has prevented workers from conducting further repairs.

A month after the disaster, more than 145,000 people are still living in shelters. The quake and tsunami are believed to have killed more than 25,000 people, but many of those bodies were swept out to sea and more than half of those feared dead are still listed as missing.

___

Associated Press writers Shino Yuasa and Noriko Kitano in Tokyo and Eric Talmadge in Soma contributed to this report.

%d bloggers like this: