Image: This handout picture, released from Toky
Tepco  /  AFP - Getty Images
This picture, released from Tokyo Electric Power Co. on Wednesday, shows damaged No.3 and No. 4 reactors at the Dai-ichi nuclear plant in Fukushima. staff and news service reports
updated 3/16/2011 2:29:46 AM ET 2011-03-16T06:29:46

Workers at a quake-damaged atomic power plant briefly suspended operations and evacuated Wednesday after a surge in radiation made it too dangerous to remain there, dealing a setback to Japan’s frantic efforts to stem a nuclear crisis.

Chief Cabinet Secretary Yukio Edano said work on dousing the overheated reactors with water was temporarily disrupted by the need to withdraw.

"The workers cannot carry out even minimal work at the plant now," Edano said. "Because of the radiation risk we are on standby."

The workers were allowed back into the plant less than an hour later after the radiation levels receded, Reuters reported.

The radiation spike was apparently the result of a release of pressure that had built up in one of the reactors, officials said, though it was not immediately clear which one. Steam and pressure build up in the reactors as workers try to cool the fuel rods, leading to controlled pressure releases through vents — as well as uncontrolled explosions.

The nuclear crisis has triggered international alarm and partly overshadowed the human tragedy caused by Friday's magnitude 9 earthquake and tsunami, which pulverized Japan's northeastern coastline, killing an estimated 10,000 people.

How much radiation is dangerous?

Frantic effort
Authorities have tried frantically to avert an environmental catastrophe at the Fukushima Dai-ichi complex in northeastern Japan, 170 miles north Tokyo.

Story: What you need to know about the twin disasters in Japan

Edano said the government expects to ask the U.S. military for help. He did not elaborate. He said the government is still considering whether and how to take up the various offers of help from other countries.

Officials had originally planned to use helicopters and fire trucks to spray water in a desperate effort to prevent further radiation leaks and to cool down the reactors.

"It's not so simple that everything will be resolved by pouring in water. We are trying to avoid creating other problems," Edano said.

"We are actually supplying water from the ground, but supplying water from above involves pumping lots of water and that involves risk. We also have to consider the safety of the helicopters above," he said.

Some academics and U.S. nuclear experts said they feared the worst.

"It's more of a surrender," said David Lochbaum, a nuclear engineer who now heads the nuclear safety program for the Union of Concerned Scientists, an activist group that opposes the expansion of nuclear power. "It's not like you wait 10 days and the radiation goes away. In that 10 days things are going to get worse."

"It's basically a sign that there's nothing left to do but throw in the towel," Lochbaum said.

"This is a slow-moving nightmare," said Dr. Thomas Neff, a research affiliate at the Center for International Studies, which is part of the Massachusetts Institute of Technology.

The government has ordered some 140,000 people in the vicinity to stay indoors. A little radiation was also detected in Tokyo, 150 miles to the south, triggering panic buying of food and water.

France urged French nationals in Tokyo to leave the country or head to southern Japan. It said it had asked Air France to provide planes for their evacuation.

Damaged fuel rods
There are six reactors at the plant. Units 1, 2 and 3, which were operating last week, shut down automatically when the quake hit. Since then, all three have been rocked by explosions. Compounding the problems, on Tuesday a fire broke out in Unit 4's fuel storage pond, an area where used nuclear fuel is kept cool, causing radioactivity to be released into the atmosphere.

Units 4, 5 and 6 were shut at the time of the quake, but even offline reactors have nuclear fuel — either inside the reactors or in storage ponds — that need to be kept cool.

Meanwhile, the Nuclear and Industrial Safety Agency estimated that 70 percent of the rods have been damaged at the No. 1 reactor.

Japan's national news agency, Kyodo, said that 33 percent of the fuel rods at the No. 2 reactor were damaged and that the cores of both reactors were believed to have partially melted.

"We don't know the nature of the damage," said Minoru Ohgoda, spokesman for the country's nuclear safety agency. "It could be either melting, or there might be some holes in them."

Meanwhile, the outer housing of the containment vessel at the No. 4 unit erupted in flames early Wednesday, said Hajimi Motujuku, a spokesman for the plant's operator, Tokyo Electric Power Co.

Japan's nuclear safety agency said later fire could no longer be seen at Unit 4, but that it was unable to confirm that the blaze had been put out. Tokyo Electric Power was also considering spraying boric acid by helicopter to prevent spent nuclear fuel rods at No. 4 from restarting a chain reaction.

Several experts said that Japanese authorities were underplaying the severity of the incident, particularly on a scale called INES used to rank nuclear incidents. The Japanese have so far rated the accident a four on a one-to-seven scale, but that rating was issued on Saturday and since then the situation has worsened dramatically.

France's nuclear safety authority ASN said Tuesday it should be classed as a level-six incident.
The Fukushima Dai-ichi complex was due to be decommissioned in February but was given a new 10-year lease on life.

Its reactors were designed by General Electric. ( is a joint venture between NBC Universal and Microsoft. GE is a part owner of NBC Universal.)

Japan has a total of 55 reactors spread across 17 complexes nationwide.

The Associated Press and Reuters contributed to this report.

Video: Workers withdrawn from damaged nuclear plant

  1. Closed captioning of: Workers withdrawn from damaged nuclear plant

    >>> inside the nuclear power plant have been pulled. extremely high levels of radiation have been measured. a lot of nuclear experts believe they were the last, best line of defense against a full-scale nuclear meltdown and nuclear catastrophe. just hours ago, a watchdog group in washington had predicted this had moved past a level six catastrophe and was heading toward something like chernobyl , a number seven. let's go to the fast-moving developments in addition to pulling those 50 workers who had been risking little lead their lives to try to stave off a nuclear meltdown . there have been major problems at reactor number four. earlier it was spitting out very high levels of radiation. to give you an idea of the levels we are talking about, take the amount which in a year can cause cancer. it has been putting up four times that amount in just a single hour. the problem at number four, the rooftop storage still at risk, still hot. the fire at that reactor was not in fact put out, as it had been reported. instead, officials believe it started a second blaze, which firefighters had to battle today. they had a plan to drop water or acid on it from a helicopter. that seems less likely now. they are considering pumping it through the walls instead. until workers, we should mention, are still missing from yesterday's explosion. we know now that the roof was cracked by the blast. workers today have been unable to approach the storage because of those high levels of radioactivity. again, now those technicians who have been putting their lives at risk to stay at the plant have left. in just the past couple of hours, we have had new reports of white smoke emanating from reactor number three and reactor number four. here in tokyo , 150 miles south of the reactor site, low levels of radiation were detected today. ten times the normal level they would find here in the capital city . some people have been leaving. some international workers have been told to get out. americans at airports, train stations, many of them deciding they are going to leave japan . hundreds of thousands of people, especially in the hardest-hit areas, are facing food stored edges. maybe today's snowfall would help matters, but think again. radioactivity hangs in the air until rain or snow brings it to the ground into the soil, the water, the food supply . thailand, south korea and singapore have now begun checking foods imported from japan , checking for radioactivity. american helicopter crew members were given capacity iodide after flying humanitarian efforts over japan and regulation detectors on the level of contamination. this airline has checked its flights from japan . none has been found so far, but they are recruiting inbound flights away from tokyo anyway. china canceling some flights to tokyo . in evacuating its citizens from its areas of highest rate radiation. workers have had some good news. rescue's continuing today include one elderly man, a 70-year-old woman. both of them trapped for more than 90 hours in the rubble. the ripple effects continue to be felt. japan could be stock market losing more than half a trillion dollars this week, although shares did rebound somewhat at the open this morning. germany could be chancellor ordering checks for every nuclear plant in her country and ordering all seven built before 1980 to be shut down, at least for now. the european union has come to an agreement to stress tests throughout europe as well. in the u.s., house democrats are calling on republicans on the safety issues possibly affecting american nuclear plants . we will have more on the questions being raised in the states later this hour. let's talk about this huge and very disturbing development, the 50 remaining workers leaving the plant. our chief sent correspondence is here. put into context this latest development.

    >> one piece of slightly good news at there were only taken out of their for 45 minutes. the cabinet secretary said that they had left the site. as soon as you left the site, there were a lot of news bulletins. they only work on for 45 minutes. until the radiation levels came down. apparently there is something more ominous. why didn't the regulation levels go up? the chief cabinet secretary said it could have been a breach in containment of reactor no. three. we have not heard much about reactor number three for a few days. there was a breach in containment of reactor no. two, the first breach of containment facility since chernobyl .

    >> people who don't do nuclear speak, help us understand.

    >> it's bad. it's bad and getting worse. does that help?

    >> it's hard not to put it in the context of things like three mile island.

    >> --

    >> when people hear chernobyl , that does not even seem like descriptive enough.

    >> it cannot be that. it will never be that bad. i was there. chernobyl spewed radiation way up into the air. it did not even have containment.

    >> that is the major difference.

    >> they had a small atomic bomb that spread out into the countryside and killed a lot of people instantly. a lot of people over the next few weeks. 4,000 cancers over the next ten years afterward. this is not chernobyl . it is number two in the list of bad nuclear accidents .

    >> that is right now.

    >> that is right now. it is not anywhere near contained. it was a large spike in regulation. this unprecedented break in the containment, this steel and concrete that surrounds and is supposed to contain, if that broke again, it means that all of these systems that were supposed to be so safe are not working. we talk about these people out there. you have to understand those are all volunteers, of course, and they are facing enormous doses of radiation. some have lost their families, homes in the tsunami an earthquake before this happened. they are trying to protect the country from having yet a far more worse situation coming out of the nuclear power plants .

    >> it raises a question for me. when you have someone in that emotional state , making a decision to put their lives at risk, as i have read it, the protection they have is nowhere near what a lot of experts think they need to make what they are doing anywhere near safe.

    >> that is an issue, but the other thing is they have no infrastructure. this all happened because the tsunami knocked out the electrical grid and all the generators. they don't have electricity and structures or enough people. this lacrimal affect with these reactors, they sell one problem here but they do not have a time to pay attention to the reactor over here. we do not know how long this will go on. you have to understand there is no nuclear chain reaction . all these reactions were shut down. some were shut down before the earthquake. all were shot down during the earthquake. you have some hot, radioactive fuel. we need to get it cool enough so it does not burn through. so far, very little has. the amount of radiation that has escaped and is here in tokyo is minuscule. this is not over. until they are stable and cool, which has not happened yet from all the see water they are pumping in and trying to with helicopters, but they realize the fire did not have a whole lot.

    >> they couldn't get to it.

    >> yeah, they cannot get to the roof. an enormous amount of technical problems. there isn't a guidebook on how to deal with this. this is a routine thing, they do not have control rooms. they don't have all the things you need, valves, electricity to operate them, diesel engines , they are using fire trucks to move the ocean into these reactors.

    >> a couple of those fire trucks coming from the u.s. military . uncharted territory. if you get new information or have new insights during this hour, please come back. we would love to hear from you. bob has been monitoring what has been going on and what we are learning through japanese television . just come on in.

    >> have a good show.

    >> thank you so much. i

Interactive: Japan before and after the disaster

These aerial photos show locations in Japan before and after the 9.0-magnitude earthquake and tsunami that struck March 11. Use the slider below the images to reveal the changes in the landscape.

Explainer: The 10 deadliest earthquakes in recorded history

  • A look at the worst earthquakes in recorded history, in loss of human life. (The March 11, 2011, earthquake and tsumani that affected eastern Japan is not included because the fatalities caused, about 15,000, are fewer than those resulting from the temblors listed below.) Sources: United States Geological Survey, Encyclopedia Britannica

  • 1: Shensi, China, Jan. 23, 1556

    Magnitude about 8, about 830,000 deaths.

    This earthquake occurred in the Shaanxi province (formerly Shensi), China, about 50 miles east-northeast of Xi'an, the capital of Shaanxi. More than 830,000 people are estimated to have been killed. Damage extended as far away as about 270 miles northeast of the epicenter, with reports as far as Liuyang in Hunan, more than 500 miles away. Geological effects reported with this earthquake included ground fissures, uplift, subsidence, liquefaction and landslides. Most towns in the damage area reported city walls collapsed, most to all houses collapsed and many of the towns reported ground fissures with water gushing out.

  • 2: Tangshan, China, July 27, 1976

    Chinese Earthquake
    Keystone  /  Getty Images
    1976: Workers start rebuilding work following earthquake damage in the Chinese city of Tangshan, 100 miles east of Pekin, with a wrecked train carriage behind them. (Photo by Keystone/Getty Images)
    Magnitude 7.5. Official casualty figure is 255,000 deaths. Estimated death toll as high as 655,000.

    Damage extended as far as Beijing. This is probably the greatest death toll from an earthquake in the last four centuries, and the second greatest in recorded history.

  • 3: Aleppo, Syria, Aug. 9, 1138

    Magnitude not known, about 230,000 deaths.

    Contemporary accounts said the walls of Syria’s second-largest city crumbled and rocks cascaded into the streets. Aleppo’s citadel collapsed, killing hundreds of residents. Although Aleppo was the largest community affected by the earthquake, it likely did not suffer the worst of the damage. European Crusaders had constructed a citadel at nearby Harim, which was leveled by the quake. A Muslim fort at Al-Atarib was destroyed as well, and several smaller towns and manned forts were reduced to rubble. The quake was said to have been felt as far away as Damascus, about 220 miles to the south. The Aleppo earthquake was the first of several occurring between 1138 and 1139 that devastated areas in northern Syria and western Turkey.

  • 4: Sumatra, Indonesia, Dec. 26, 2004

    Aerial images show the extent of the devastation in Meulaboh
    Getty Images  /  Getty Images
    MEULABOH, INDONESIA - DECEMBER 29: In this handout photo taken from a print via the Indonesian Air Force, the scene of devastation in Meulaboh, the town closest to the Sunday's earthquake epicentre, is pictured from the air on December 29, 2004, Meulaboh, Aceh Province, Sumatra, Indonesia. The western coastal town in Aceh Province, only 60 kilometres north-east of the epicentre, has been the hardest hit by sunday's underwater earthquake in the Indian Ocean. Officials expected to find at least 10,000 killed which would amount to a quarter of Meulaboh's population. Three-quarters of Sumatra's western coast was destroyed and some towns were totally wiped out after the tsunamis that followed the earthquake. (Photo by Indonesian Air Force via Getty Images)

    Magnitude 9.1, 227,898 deaths.

    This was the third largest earthquake in the world since 1900 and the largest since the 1964 Prince William Sound, Alaska temblor. In total, 227,898 people were killed or were missing and presumed dead and about 1.7 million people were displaced by the earthquake and subsequent tsunami in 14 countries in South Asia and East Africa. (In January 2005, the death toll was 286,000. In April 2005, Indonesia reduced its estimate for the number missing by over 50,000.)

  • 5: Haiti, Jan 12, 2010

    Haitians walk through collapsed building
    Jean-philippe Ksiazek  /  AFP/Getty Images
    Haitians walk through collapsed buildings near the iron market in Port-au-Prince on January 31, 2010. Quake-hit Haiti will need at least a decade of painstaking reconstruction, aid chiefs and donor nations warned, as homeless, scarred survivors struggled today to rebuild their lives. AFP PHOTO / JEAN-PHILIPPE KSIAZEK (Photo credit should read JEAN-PHILIPPE KSIAZEK/AFP/Getty Images)

    Magnitude 7.0. According to official estimates, 222,570 people killed.

    According to official estimates, 300,000 were also injured, 1.3 million displaced, 97,294 houses destroyed and 188,383 damaged in the Port-au-Prince area and in much of southern Haiti. This includes at least 4 people killed by a local tsunami in the Petit Paradis area near Leogane. Tsunami waves were also reported at Jacmel, Les Cayes, Petit Goave, Leogane, Luly and Anse a Galets.

  • 6: Damghan, Iran, Dec. 22, 856

    Magnitude not known, about 200,000 deaths.

    This earthquake struck a 200-mile stretch of northeast Iran, with the epicenter directly below the city of Demghan, which was at that point the capital city. Most of the city was destroyed as well as the neighboring areas. Approximately 200,000 people were killed.

  • 7: Haiyuan, Ningxia , China, Dec. 16, 1920

    7.8 magnitude, about 200,000 deaths.

    This earthquake brought total destruction to the Lijunbu-Haiyuan-Ganyanchi area. Over 73,000 people were killed in Haiyuan County. A landslide buried the village of Sujiahe in Xiji County. More than 30,000 people were killed in Guyuan County. Nearly all the houses collapsed in the cities of Longde and Huining. About 125 miles of surface faulting was seen from Lijunbu through Ganyanchi to Jingtai. There were large numbers of landslides and ground cracks throughout the epicentral area. Some rivers were dammed, others changed course.

  • 8: Ardabil, Iran, March. 23, 893

    Magnitude not known, about 150,000 deaths

    The memories of the massive Damghan earthquake (see above) had barely faded when only 37 years later, Iran was again hit by a huge earthquake. This time it cost 150,000 lives and destroyed the largest city in the northwestern section of the country. The area was again hit by a fatal earthquake in 1997.

  • 9: Kanto, Japan, Sept. 1, 1923

    Kanto Damage
    Hulton Archive  /  Getty Images
    1923: High-angle view of earthquake and fire damage on Hongokucho Street and the Kanda District, taken from the Yamaguchi Bank building after the Kanto earthquake, Tokyo, Japan. (Photo by Hulton Archive/Getty Images)
    7.9 magnitude, 142,800 deaths.

    This earthquake brought extreme destruction in the Tokyo-Yokohama area, both from the temblor and subsequent firestorms, which burned about 381,000 of the more than 694,000 houses that were partially or completely destroyed. Although often known as the Great Tokyo Earthquake (or the Great Tokyo Fire), the damage was most severe in Yokohama. Nearly 6 feet of permanent uplift was observed on the north shore of Sagami Bay and horizontal displacements of as much as 15 feet were measured on the Boso Peninsula.

  • 10: Ashgabat, Turkmenistan, Oct. 5, 1948

    7.3 magnitude, 110,000 deaths.

    This quake brought extreme damage in Ashgabat (Ashkhabad) and nearby villages, where almost all the brick buildings collapsed, concrete structures were heavily damaged and freight trains were derailed. Damage and casualties also occurred in the Darreh Gaz area in neighboring Iran. Surface rupture was observed both northwest and southeast of Ashgabat. Many sources list the casualty total at 10,000, but a news release from the newly independent government on Dec. 9, 1988, advised that the correct death toll was 110,000. (Turkmenistan had been part of the Soviet Union, which tended to downplay the death tolls from man-made and natural disasters.)


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