Image: Remote-controlled robot in the crippled Fukushima Dai-ichi No. 2 reactor building
Reuters
A remote-controlled robot is seen in the crippled Fukushima Dai-ichi No. 2 reactor building in Fukushima.
msnbc.com news services
updated 4/18/2011 1:00:00 PM ET 2011-04-18T17:00:00

A pair of thin robots on treads sent to explore buildings inside Japan's crippled nuclear reactor came back Monday with disheartening news: Radiation levels are far too high for repair crews to go inside.

Nevertheless, officials remained hopeful they can stick to their freshly minted "roadmap" for cleaning up the radiation leak and stabilizing the Fukushima Dai-ichi plant by year's end so they can begin returning tens of thousands of evacuees to their homes.

"Even I had expected high radioactivity in those areas. I'm sure (plant operator Tokyo Electric Power Co.) and other experts have factored in those figures when they compiled the roadmap," Chief Cabinet Secretary Yukio Edano said.

Officials said Monday that radiation had spiked in a water tank in Unit 2 and contaminated water was discovered in other areas of the plant. They also described in detail for the first time the damage to fuel in three troubled reactors, saying pellets had melted.

That damage — sometimes referred to as a partial meltdown — had already been widely assumed, but the confirmation, along with the continued release of radiation from other areas, serves to underscore how difficult and how long the cleanup process will be. In fact, government officials themselves have acknowledged that there are still many setbacks that could crop up to slow down their timeline.

Slideshow: Triple tragedy for Japan (on this page)

Most Japanese want a new prime minister to lead rebuilding after last month's earthquake and tsunami, newspaper polls showed on Monday. Nearly 70 percent of people surveyed by the Nikkei business daily said Prime Minister Naoto Kan should be replaced, and a similar number said the government's response to the nuclear crisis was not acceptable.

Kan was criticized again in parliament on Monday for his response to the nuclear disaster. An opposition lawmaker suggested he had been ill-prepared from the start, pointing to Kan's admission that he could not recall the details of a drill last year that simulated a Fukushima-type incident.

"Prime Minister Kan is working hard and he must be experiencing difficulties. But many people have questions about his leadership," opposition Liberal Democratic Party lawmaker Masashi Waki told the upper house budget committee.

Kan said he and his government were doing their best.

"Japan has experienced many crises in the past, but I believe this is the biggest crisis in the 65 years since the end of World War Two," he told a parliamentary panel on Monday.

"From now on ... we must persist with our strategy on two fronts, and I want to make every effort on both issues," he said, referring to rebuilding the country and resolving the nuclear crisis.

Workers have not been able to enter the reactor buildings at the stricken plant since the first days after the cooling systems were wrecked by the March 11 earthquake and tsunami that left more than 27,000 people dead or missing. Hydrogen explosions in both buildings in the first few days destroyed their roofs and scattered radioactive debris.

On Sunday, a plant worker opened an outer door to one of the buildings and two Packbots, which resemble drafting lamps on tank-like treads, entered. After the worker closed the door, one robot opened an inner door and both rolled inside to take readings for temperature, pressure and radioactivity. They later entered a second building.

The robots reported radioactivity readings of up to 49 millisieverts per hour inside Unit 1 and up to 57 inside Unit 3, levels too high for workers to realistically enter.

"It's a harsh environment for humans to work inside," said Hidehiko Nishiyama of Japan's Nuclear and Industrial Safety Agency.

Japanese authorities more than doubled the legal limit for nuclear workers since the crisis began to 250 millisieverts a year. Workers in the U.S. nuclear industry are allowed an upper limit of 50 millisieverts per year. Doctors say radiation sickness sets in at 1,000 millisieverts and includes nausea and vomiting.

The robots, made by Bedford, Massachusetts, company iRobot, which also makes the Roomba vacuum cleaner, explored Unit 2 on Monday, but TEPCO officials had yet to analyze that data.

The radioactivity must be reduced, possibly with the removal of contaminated debris and stagnant water, before repair crews would be allowed inside, said NISA official Masataka Yoshizawa.

Sturdier robots can remove some of the debris, but workers are needed to test the integrity of the equipment and carry out electrical repairs needed to restore the cooling systems as called for in the road map, Yoshizawa said.

"What robots can do is limited, so eventually, people must enter the buildings," TEPCO official Takeshi Makigami said.

The robots, along with remote-controlled miniature drones, have enabled TEPCO to photograph and take measurements of conditions in and around the plant while minimizing workers' exposure to radiation and other hazards.

Separately, readings from a water tank attached to the spent fuel pool in Unit 2 showed a severe spike in radiation that NISA officials said might have been caused by the escape of radioactive vapor from a nearby containment vessel. They said, however, the possibility of damage to spent fuel rods could not be ruled out.

Meanwhile, Toyota Motor Corp. resumed car production at all of its plants in Japan on Monday for the first time since the quake and tsunami, but said the factories will run at half capacity due to parts shortages.

The world's No. 1 automaker said it was still struggling to secure around 150 types of auto components. The magnitude-9.0 earthquake and ensuing tsunami destroyed parts factories in northeastern Japan, causing severe shortages.

The twin disasters forced Toyota to shut down all output in Japan except at three plants, which have been running at limited capacity since late March and early April to produce hot-selling Prius, Lexus and Corolla cars.

The 900 workers at Toyota's auto plant in Miyagi, one of the worst-hit areas in the disasters, observed a minute's silence for tsunami victims before starting work Monday.

Copyright 2011 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Video: Cherry blossoms offer solace in Japan

Photos: Triple tragedy for Japan

loading photos...
  1. Office workers in Tokyo look at smoke rising over the skyline after the magnitude 9.0 earthquake off Japan's northeast coast on March 11, 2011. (Xinhua via Getty Images) Back to slideshow navigation
  2. Waves pour over a seawall and roar into a seaside village near the mouth of Hei River on March 11 as the tsunami generated by the massive earthquake hits shore. (Mainichi Newspaper via EPA) Back to slideshow navigation
  3. Hotel employees squat around a pillar at the hotel's entrance in Tokyo after the powerful earthquake on March 11. (Itsuo Inouye / AP) Back to slideshow navigation
  4. A tsunami wave sweeps away homes in its path in Natori, Miyagi prefecture, on March 11. (Kyodo News via AP) Back to slideshow navigation
  5. One house bursts into flames after the tsunami swept it and many of its neighbors off their foundations in Natori on March 11. (Kyodo News via Reuters) Back to slideshow navigation
  6. Shaken evacuees gather in Shinjuku Central Park in Tokyo on March 11. (Kyodo News via Reuters) Back to slideshow navigation
  7. An aerial photo shows Sendai Airport being inundated by a tsunami on March 11. Later reports said the first wave hit 26 minutes after the quake struck at 2:46 p.m. local time. (Kyodo News via Reuters) Back to slideshow navigation
  8. A swirling pattern is evident in this aerial photo of the tsunami as it hit a port in Oarai, Ibaraki prefecture on March 11. (Kyodo News via AP) Back to slideshow navigation
  9. Toya Chiba, a reporter for local newspaper Iwate Tokai Shimbun, is swept away while taking pictures at the mouth of the Owatari River during the tsunami at Kamaishi port, Iwate prefecture. Chiba managed to survive in the rush of water by grabbing a dangling rope and climbing onto a coal heap around 30 feet high after being swept away for about 100 feet, Kyodo News reports. (Kamaishi Port Office / Kyodo via Reuters) Back to slideshow navigation
  10. Natural gas containers burn in Chiba Prefecture near Tokyo, on March 11. The massive earthquake triggered many fires, posing additional problems for first responders. (Kyodo News via Reuters) Back to slideshow navigation
  11. Containers for cargo are strewn about like giant Legos in Sendai, Miyagi prefecture, on March 12. (Itsuo Inouye / AP) Back to slideshow navigation
  12. People use a floating container to ferry survivors to higher ground in Kesennuma City, Miyagi prefecture, on March 12. (Kyodo News via Reuters) Back to slideshow navigation
  13. Cars swept into a jumble by the tsunami are seen in Hitachi City, Ibaraki prefecture, on March 12. (Yomiuri via Reuters) Back to slideshow navigation
  14. A line of residents seeking water snakes across the playground of a school in Sendai, Miyagi prefecture, on March 13, two days after the earthquake. (Kyodo News via AP) Back to slideshow navigation
  15. Japanese firefighters rescue tsunami survivors in Natori, Miyagi prefecture, on March 13. (EPA) Back to slideshow navigation
  16. A Japanese home drifts in the Pacific Ocean off the coast of Sendai in this photograph taken on March 13. (Dylan McCord / U.S. Navy via Reuters) Back to slideshow navigation
  17. A woman cries while sitting on a road in the devastated city of Natori, Miyagi prefecture, on March 13. (Asahi Shimbun / Reuters) Back to slideshow navigation
  18. An "SOS" signal scrawled on the sports field of a high school beckons potential rescuers on March 13 in the town of Minami Sanriku, Miyagi prefecture. (Kyodo News via Reuters) Back to slideshow navigation
  19. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

    The body of a victim of the twin disaster lays on the stairs of a destroyed house in Sendai, Miyagi prefecture, on March 13. (David Guttenfelder / AP) Back to slideshow navigation
  20. Sixty-year-old Hiromitsu Shinkawa waves to members of Japan Maritime Self-Defence Force preparing to rescue him about 9 miles off Fukushima prefecture on March 13. Shinkawa survived by clinging to a piece of roof after the tsunami hit his hometown of Minamisoma. (Japanese Defense Forces via AFP - Getty Images) Back to slideshow navigation
  21. People walk along a flooded street in Ishimaki City, Miyagi prefecture on March 13. (Kyodo News via Reuters) Back to slideshow navigation
  22. An explosion at the Fukushima Dai-ichi nuclear power plant sends a plume of smoke skyward on March 14. The blast was believed to have been caused by a buildup of hydrogen inside the reactor building, caused by the partial meltdown of nuclear fuel inside. The plant was crippled after the earthquake cut power to the station and tsunami waves knocked out backup generators. (NTV / FCT) Back to slideshow navigation
  23. A 1-year-old boy is re-checked for radiation exposure after being decontaminated in Nihonmatsu, Fukushiima prefecture, on March 14. (Toru Nakata / Asahi Shimbun via AP) Back to slideshow navigation
  24. Officers examine a Mitsubishi F-2 fighter jet of the Japanese Air Self-Defense Force on March 14. The warplane was swept by the tsunami into a building at Matsushima base in Higashimatsushima, Iwate prefecture. (Kyodo News via Reuters) Back to slideshow navigation
  25. Japanese rescue team members carry the body of a man out of the village of Saito on March 14. (David Guttenfelder / AP) Back to slideshow navigation
  26. A woman survivor is reunited with her relatives at a shelter in Rikuzentakata in Iwate prefecture, on March 15. (Lee Jae-Won / Reuters) Back to slideshow navigation
  27. A bicyclist wheels across a hellish landscape in what was the city of Minami Sanriku, Miyagi prefecture, on March 15. (David Guttenfelder / AP) Back to slideshow navigation
  28. Tsunami survivors cook on an open fire in front of their damaged house in Ishinomaki, Miyagi Prefecture, on March 15. (Kyodo News via AP) Back to slideshow navigation
  29. Vehicle headlamps illuminate a devastated section of Yamada town, Iwate prefecture, on March 16. (Jiji Press via AFP - Getty Images) Back to slideshow navigation
  30. Evacuees carry bowls of pork soup from a soup kitchen to a makeshift shelter in Minami Sanriku, Miyagi prefecture, on March 16. (Tsuyoshi Matsumoto / The Yomiuri Shimbun via AP) Back to slideshow navigation
  31. Refugees, including 53 people who were rescued from a retirement home during the tsunami, take shelter inside a school gym in the leveled city of Kesennuma, Miyagi prefecture, on March 17. (David Guttenfelder / AP) Back to slideshow navigation
  32. Members of Japan Self-Defense Force pray over the body of a tsunami victim in Onagawa, Miyagi prefecture, on March 20. (Shuji Kajiyama / AP) Back to slideshow navigation
  33. Tomoko Yagi looks at two firetrucks that were tossed around like toys in the tsunami in Kamaishi, Iwate prefecture, on March 20. (Lee Jae-Won / Reuters) Back to slideshow navigation
  34. Survivors relay boxes of relief supplies arriving at their evacuation center in Ishinomaki, Miyagi prefecture, on March 21. (Kunihiko Miura / The Yomiuri Shimbun via AP) Back to slideshow navigation
  35. A boat juts out from the top of a building in Otsuchi, Iwate prefecture, on March 22. (Hiroto Nomoto / The Yomiuri Shimbun via AP) Back to slideshow navigation
  36. Manami Kon, 4, uses the Japanese "hiragana" characters she just learned to write a letter to her missing mother in the devastated city of Miyako, Iwate prefecture, on March 22 . "Dear Mommy. I hope you're alive. Are you OK?" read the letter, which took about an hour to write. Also missing were the little girl's father and sister. (Norikazu Tateishi / The Yomiuri Shimbun via AP) Back to slideshow navigation
  37. Tokyo Electric Power Co. workers collect data in the control room for the Unit 1 and 2 reactors at the crippled Fukushima Dai-ichi nuclear power plant on March 23. (Nuclear and Industrial Safety Agency via AP) Back to slideshow navigation
  38. An aerial photo taken by an unmanned drone shows the damaged units of the Fukushima Dai-ichi nuclear plant on March 24. (Air Photo Service via EPA) Back to slideshow navigation
  39. Two residents exchange words as they are reunited two weeks after the earthquake and tsunami in a makeshift public bath set up outside a shelter in Yamamoto, Miyagi prefecture, on March 25. (Shuji Kajiyama / AP) Back to slideshow navigation
  40. A Japanese funeral parlor worker shovels dirt onto the coffins of victims of the earthquake and tsunami at a mass funeral in Yamamoto, Miyagi prefecture, on March 26. (David Guttenfelder / AP) Back to slideshow navigation
  41. A lone pine tree stands in a devastated area iof Rikuzentakaka, Iwate prefecture, on March 27. It was the only one among tens of thousands of other pine trees forming "Takata Matsubara," or Takata seaside pine forest, standing after the March 11 tsunami washed away all the others, local media said. (Kyodo News via AP) Back to slideshow navigation
  42. A woman whose house was washed away loses control of her emotions on March 29 as she talks about the disaster that befell her hometown of Kesennuma, Miyagi prefecture. (Kuni Takahashi) Back to slideshow navigation
  43. Japanese Emperor Akihito and Empress Michiko, left, talk with evacuees at Tokyo Budoh-kan evacuation center on March 30. (Issei Kato / Pool via AFP - Getty Images) Back to slideshow navigation
  44. Officials of the Tokyo Electric Power Co., (TEPCO), including Chairman Tsunehisa Katsumata, center, Vice President Takashi Fujimoto, second from left, bow before a news conference at the company's head office in Tokyo on March 30. (Itsuo Inouye / AP) Back to slideshow navigation
  45. A man rides a bicycle in between the ships that were washed ashore by the March 11 tsunami, on March 30, in Kesennuma, Miyagi prefecture. (Eugene Hoshiko / AP) Back to slideshow navigation
  46. An elderly woman waves to her grandchildren in Minamisanriku, Miyagi prefecture, on April 3, as authorities began a mass evacuation of approximately 1,100 homeless survivors to shelters elsewhere. (Jiji Press via AFP - Getty Images) Back to slideshow navigation
  1. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  2. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  3. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  4. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

Timeline: Crisis in Japan

How events have unfolded since a 9.0 earthquake struck northeast Japan, triggering a deadly tsunami and nuclear power disaster.

  1. Image: The wave from a tsunami crashes over a street in Miyako City, Iwate Prefecture in northeastern Japan
    Ho / Reuters
    Above: Timeline Crisis in Japan
  2. Interactive Japan before and after the disaster

Discuss:

Discussion comments

,

Most active discussions

  1. votes comments
  2. votes comments
  3. votes comments
  4. votes comments