Radiation near Japan reactors too high for workers

21:39, Apr 18 2011
Nuclear reactor
A helicopter flies past Japan's Fukushima Daiichi No.1 Nuclear reactor earlier on Saturday, the day after the deadly quake and tsunami.
Fukushima Daiichi power plant
In this video image taken from NTV Japan via APTN, smoke is seen above Fukushima Daiichi power plant's Unit 1.
Fukushima Daiichi power plant
NUCLEAR EMERGENCY: Smoke rises from Fukushima Daiichi power plant's Unit 1 in Okumamachi.
Japanese earthquake, tsunami aftermath
The damaged roof of reactor number No. 1 at the Fukushima Daiichi nuclear plant after an explosion that blew off the upper part of the structure.
Officials in protective gear stand next to people from the evacuation area near the Fukushima Dai-ichi nuclear plant.
Officials in protective gear stand next to people from the evacuation area near the Fukushima Daini nuclear plant.
An official in protective gear talks to a woman who is from the evacuation area near the Fukushima Daini nuclear plant.
An official in protective gear talks to a woman who is from the evacuation area near the Fukushima Daini nuclear plant.
Radiation patients
Futaba Kosei Hospital patients disembark after being evacuated from a hospital near the troubled Fukushima Dai-ichi nuclear complex. They might have been exposed to radiation while waiting for evacuation.
Girl in isolation
A girl at a makeshift facility to screen, cleanse and isolate people with high radiation levels, looks at her dog through a window in Nihonmatsu.
Fukushima Dai-ichi power plant's Unit 3
This image from Japan's NHK public television via Kyodo News shows the Fukushima Dai-ichi power plant's Unit 3 after Monday's explosion.
An official scans for signs of radiation
An official scans for signs of radiation in Nihonmatsu City after radiation leaked from the earthquake-damaged Fukushima Daini nuclear station.
Smoke rises from Fukushima Daiichi nuclear power complex in this still image from video footage.
Smoke rises from Fukushima Daiichi nuclear power complex in this still image from video footage.
A doctor checks uses a giger counter to check the level of radiation on a woman while a soldier in gas mask looks on at a radiation treatment centre in Nihonmatsu city in Fukushima prefecture.
A doctor checks uses a giger counter to check the level of radiation on a woman while a soldier in gas mask looks on at a radiation treatment centre in Nihonmatsu city in Fukushima prefecture.
The No.3 nuclear reactor of the Fukushima Daiichi nuclear plant is seen burning after a blast following an earthquake and tsunami in this handout satellite image.
The No.3 nuclear reactor of the Fukushima Daiichi nuclear plant is seen burning after a blast following an earthquake and tsunami in this satellite image.
A radiation dosimeter indicates 0.6 microsieverts in Shibuya, Tokyo, on Tuesday.
A radiation dosimeter measures radiation levels in Shibuya, Tokyo.
Tokyo Electric Co. employees in charge of public relations use a photo of the Fukushima Daiichi nuclear complex to explain the situation during a press conference.
Tokyo Electric Co. employees in charge of public relations use a photo of the Fukushima Daiichi nuclear complex to explain the situation during a press conference.
Medical staff use a Geiger counter to screen a woman for possible radiation exposure at a public welfare centre in Hitachi City, Ibaraki.
Medical staff use a Geiger counter to screen a woman for possible radiation exposure at a public welfare centre in Hitachi City, Ibaraki.
Fukushima Dai-ichi
Damage to the No. 4 reactor at the Fukushima Daiichi nuclear power complex.
Fukushima Dai-ichi
Steam rises from the No.3 reactor at the Fukushima Dai-ichi nuclear power complex, March 16.
Fukushima Dai-ichi
Damage to the No. 4 reactor at the Fukushima Daiichi nuclear power complex.
Japan's nuclear fallout
Yumi Sugiura, who evacuated from Iitate town in Fukushima, receives a screening test for traces of nuclear radiation at a welfare center in Yamagata, northern Japan.
Japan's nuclear fallout
Yumi Sugiura, centre, and her husband, who evacuated from Iitate town in Fukushima, look at a list of detected nuclear radiation levels in communities at a welfare center in Yamagata, northern Japan.
Japan Maritime Self-Defense Force personnel, wearing protective suits, operate on JMSDF auxiliary multi-purpose support ship Hiuchi near the Tokyo Electric Power Co.'s Fukushima Daiichi nuclear power plant.
Japan Maritime Self-Defense Force personnel, wearing protective suits, operate on JMSDF auxiliary multi-purpose support ship Hiuchi near the Tokyo Electric Power Co.'s Fukushima Daiichi nuclear power plant.
TEPCO's crippled Fukushima Daiichi Nuclear Power Plant No.4 reactor is seen in this still image taken from a video shot by an unmanned helicopter on April 10, 2011.
TEPCO's crippled Fukushima Daiichi Nuclear Power Plant No.4 reactor is seen in this still image taken from a video shot by an unmanned helicopter on April 10, 2011.
TEPCO's crippled Fukushima Daiichi Nuclear Power Plant No. 3 reactor in Fukushima prefecture, northern Japan is seen in this still image taken from a video shot by an unmanned helicopter on April 10, 2011.
TEPCO's crippled Fukushima Daiichi Nuclear Power Plant No. 3 reactor in Fukushima prefecture, northern Japan is seen in this still image taken from a video shot by an unmanned helicopter on April 10, 2011.
Japan Fallout
A girl wearing a hat sits in her stroller as she takes part in an anti-nuclear protest with her mother in Tokyo.
Japan Fallout
The crippled Fukushima Daiichi Nuclear Power plant is seen in Fukushima Prefecture in this undated handout photo.
Japan Fallout
Four-year-old girl Saki Watanabe is tested for possible nuclear radiation at an evacuation centre in Koriyama.
Japan Fallout
A man is tested for radiation in Koriyama.
Japan Fallout
Hiromi Kobayashi, who is eight months pregnant, is tested for possible nuclear radiation exposure at an evacuation center in Koriyama.

A pair of thin robots on treads sent to explore buildings inside Japan's crippled nuclear reactor have come back 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 stabilising 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 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.

Angry at the slow response to the nuclear crisis and to the catastrophic earthquake and tsunami that caused it, lawmakers tore into Prime Minister Naoto Kan.

"You should be bowing your head in apology. You clearly have no leadership at all," Masashi Waki, a lawmaker from the opposition Liberal Democratic Party, shouted at Kan.

"I am sincerely apologising for what has happened," Kan said, stressing the government was doing all it could to handle the unprecedented disasters.

TEPCO's president, Masataka Shimizu, appeared ill at ease as lawmakers heckled and taunted him.

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 US nuclear industry are allowed an upper limit of 50 millisieverts per year. Doctors say radiation sickness sets in at 1000 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 analyse 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 minimising 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.

NISA also sent a report to the government watchdog Nuclear Safety Commission, saying that some fuel pellets and rods in the reactors in Units 1, 2 and 3 had become overheated and melted, the first time it had provided details of the damage to the fuel. Nishiyama said the agency can only say "more than 3 percent" of the fuel rods have melted. That figure had previously been given as the minimum core damage suspected.

A pool of stagnant radioactive water was also discovered in the basement of Unit 4.

With evacuees' ordeal stretching into the long-term, some began moving out of school gymnasiums into temporary housing. Hundreds who have not found apartments or relatives to take them in began filling up inns at hot springs.

"The government has asked us to be ready to take in as many as 200 evacuees for the next four months at least," said Masaki Hata, whose family has run the Yoshikawaya Hot Springs Inn on the outskirts of Fukushima for seven generations.

Michiaki Niitsuma, a 27-year-old office worker, said he was glad to have a comfortable place to stay while he waited to go home.

"My kids got sick in the shelter. It was cold. It's much better here. It's a relief," he said.

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A radio-controlled PakBot robot opens a door inside housing for the reactor of Unit 3 during inspection of the tsunami-damaged facilities at the Fukushima Dai-ichi Nuclear Power Plant.
GOING IN: A radio-controlled PakBot robot opens a door inside housing for the reactor of Unit 3 during inspection of the tsunami-damaged facilities at the Fukushima Dai-ichi Nuclear Power Plant.

AP