TOKYO — News signs emerged on Friday that parts of the crippled Fukushima Daiichi nuclear plant are so damaged and contaminated that it will be harder to bring the plant under control soon.
Kyodo/Reuters
Authorities in protective clothing at a hospital in Fukushima Prefecture on Friday prepared to transfer to another hospital workers who were exposed to radiation at the Fukushima Daiichi nuclear plant.
At the same time, Japanese officials began encouraging people to evacuate a larger swath of territory around the complex.
Speaking to a national audience at a news conference Friday night two weeks after the magnitude 9.0 earthquake and the devastating tsunami that followed it, Prime Minister Naoto Kan dodged a reporter’s question about whether the government was ordering a full evacuation, saying officials were simply following the recommendation of the Japan Nuclear Safety Commission.
“The situation still requires caution,” Mr. Kan, grave and tired-looking, told the nation. “Our measures are aimed at preventing the circumstances from getting worse.” The authorities said that they would now assist people who want to leave the area from 12 to 19 miles outside the plant and that they were now encouraging “voluntary evacuation” from the area. Those people had been advised March 15 to remain indoors, while those within a 12-mile radius of the plant had been ordered to evacuate.
The United States has recommended that its citizens stay at least 50 miles away.
“The state of the plant is still quite precarious,” Mr. Kan said. “We’re working hard to make sure it doesn’t get worse. We have to ensure there’s no further deterioration.”
One sign of possible deterioration came at reactor No. 3. Workers who were trying to connect an electrical cable to a pump in a turbine building next to the reactor were injured when they stepped into water that was found to be significantly more radioactive than normal. On Friday officials and experts offered conflicting explanations of what went wrong — but all pointed to greater damage to the reactor’s systems and more contamination there than officials indicated earlier.
Two workers were exposed to radiation and burned when water poured over the top of their boots and down around their feet and ankles, officials said.. A third worker was wearing higher boots and did not suffer the same exposure.
Like the injured workers, many of those risking their lives are subcontractors of Tokyo Electric, paid a small daily wage for hours of work in dangerous conditions. In some cases they are poorly equipped and trained for their task.
A Japanese physicist, who asked not to be identified so as not to damage his relations with the establishment, said it was “ridiculous” that the workers had not been wearing full protective gear.
The National Institute of Radiological Sciences said that the radioactivity of the water that the three workers had stepped in was 10,000 times the level normally seen in coolant water at the plant. It said that the amount of radiation the workers are thought to have been exposed to in the water was 2 to 6 sievert. Even 2 sievert is eight times the new 250 millisievert annual exposure limit set for workers at Daiichi in the days after the disaster; the previous limit was 100. Tokyo Electric officials said that water with an equally high radiation level had been found in the No. 1 reactor building, The Associated Press reported.
Skin exposures of 2 to 6 sieverts will cause severe burns, according to Dr. David J. Brenner, Director of the Center for Radiological Research at Columbia University. But if those doses reach the whole body and not just the skin “you’re at a very high risk of dying,” he said. At a dose of 4 sieverts half of the people exposed will die, Dr. Brenner said. But he said that from the information that had been provided it was not clear whether the dose to the workers reached their skin only, or penetrated their bodies.
Concerns about Reactor No. 3 have surfaced before. Japanese officials said nine days ago that the reactor vessel may have been damaged.
Hidehiko Nishiyama, deputy director-general of the Japan Nuclear and Industrial Safety Agency, mentioned damage to the reactor vessel on Friday as a possible explanation of how water in the adjacent containment building had become so radioactive. A senior nuclear executive who insisted on anonymity but has broad contacts in Japan said that there was a long vertical crack running down the side of the reactor vessel itself. The crack runs down below the water level in the reactor and has been leaking fluids and gases, he said.
The severity of the radiation burns to the injured workers are consistent with contamination by water that had been in contact with damaged fuel rods, the executive said.
“There is a definite, definite crack in the vessel — it’s up and down and it’s large,” he said. “The problem with cracks is they do not get smaller.”
But Michael Friedlander, a former nuclear power plant operator in the United States, said that the presence of radioactive cobalt and molybdenum in water samples taken from the basement of the turbine building raised the possibility of a very different leak.
Both materials typically occur not because of fission but because of routine corrosion in a reactor and its associated piping over the course of many years of use, he said.
The aggressive use of saltwater to cool the reactor and its storage pool for spent fuel may mean that more of these highly radioactive corrosion materials will be dislodged and contaminate the area in the days to come, posing further hazards to repair workers, Mr. Friedlander added.
Whichever explanation is accurate, the contamination of the water in the basement of the turbine building poses a real challenge for efforts to bring crucial cooling pumps and other equipment back online.
“They can’t even figure out how to get that out, it’s so hot” in terms of radioactivity, the senior nuclear executive said.
One other major worry about reactor No. 3 is the mox fuel it uses. It is an especially dangerous blend of reprocessed fuel and can be more radioactive when melted than pure uranium fuel as used in other reactors, experts say.
The news Friday and the discovery this week of a radioactive isotope in the water supplies of Tokyo and neighboring prefectures punctured the mood of optimism with which the week began, leaving a sense that the battle to fix the damaged plant will be a long one.
No one is being ordered to evacuate the second zone around the plant, officials said, and people may choose to remain, but many have already left of their own accord, tiring of the anxiety and tedium of remaining cooped up as the nuclear crisis simmers just a few miles away. Many are said to be virtual prisoners with no access to shopping and immobilized by a lack of gasoline.
“What we’ve been finding is that in that area life has become quite difficult,” Noriyuki Shikata, deputy cabinet secretary for Mr. Kan said in a telephone interview. “People don’t want to go into the zone to make deliveries.”
Mr. Shikata said the question of where those who chose to leave would go was still under consideration. The effort to move people comes at a time when there are already hundreds of thousands of Japanese displaced by the quake and tsunami.
Officials continue to be dogged by suspicions that they are not telling the entire story about the radiation leaks. Shunichi Tanaka, former acting chairman of the country’s Atomic Energy Commission, told The Japan Times in an interview published Friday that the government was being irresponsible in forcing people from their homes around the damaged plant without explaining the risks they were facing.
“The government has not yet said in concrete terms why evacuation is necessary to the people who have evacuated,” he said.
The National Police Agency said Friday that the official death toll from the March 11 earthquake and tsunami had passed 10,000, with nearly 17,500 others listed as missing.
Lee Jae-Won/Reuters
Levels of a radioactive isotope in Tokyo's water supply fell.
There was some good news. Levels of the radioactive isotope found in Tokyo’s water supply fell Friday for a second day, officials said, dropping to 51 becquerels per liter, well below the country’s stringent maximum for infants.
On Wednesday Tokyo area stores were cleaned out of bottled water after the authorities said the isotope, iodine 131, had been detected in the city’s water supply and cautioned those in the affected areas not to give infants tap water. On Thursday cities in two of Tokyo’s neighboring prefectures, Chiba and Saitama, also reported disturbing levels of radiation in their water.
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