March 24, 2011
By DAVID JOLLY and HIROKO TABUCHI
TOKYO — Japan’s effort to contain the crisis at the Fukushima Daiichi nuclear plant suffered a setback, an official said on Friday, citing evidence that the reactor vessel of the No. 3 unit may have been damaged.
The development, described at a news conference by Hidehiko Nishiyama, deputy director-general of the Japan Nuclear and Industrial Safety Agency, raises the possibility that radiation from the mox fuel in the reactor — a combination of uranium and plutonium — could be released.
One sign that a breach may have occurred in the reactor vessel, Mr. Nishiyama said, took place on Thursday when three 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 in a reactor. The No. 3 unit, the only one of the six reactors at the site that uses the mox fuel, was damaged by a hydrogen explosion on March 14. Workers have been seeking to keep it cool by spraying it with seawater along with a more recent effort to restart the reactor’s cooling system.
In another development on Friday, the Japanese government said it would help people who wish to leave the area around the crippled plant, a sign that efforts to reassure frightened residents have failed to persuade people to stay.
There is no evacuation order for a zone from 12 to 19 miles around the nuclear plant, the chief cabinet secretary, Yukio Edano, said in a televised news conference, but officials recognize that some people may wish to leave and it will assist them. The government has ordered all people living within about 12 miles of the plant to evacuate, but has only advised those in the outer zone to stay indoors.
That advice has not changed, Mr. Edano said. The United States has recommended that its citizens stay at least 50 miles away from the plant.
Levels of a radioactive isotope found in Tokyo’s water supply fell by more than half on Thursday, testing below the country’s stringent maximum for infants. The lower readings were made hours after Mr. Edano said the isotope, iodine 131, had been detected in the water supply of Kawaguchi City, just north of Tokyo, as well as in those of two of Tokyo’s neighboring prefectures, Chiba and Saitama. On Wednesday, the authorities cautioned those in the affected areas not to give infants tap water.
The problem is not likely to end soon; nuclear workers will have to keep venting radioactive gases from the damaged reactors, adding to the plume of emissions carried by winds and dispersed by rain. The public has been warned not to consume food and milk from the area near the plant.
Mr. Edano said the three injured workers at Reactor No. 3 had sustained radiation burns to their legs while dragging an electrical cable through contaminated water in an effort to restore the crucial pump. The workers were burned as contaminated water poured over the tops of their boots, soaking their feet and ankles, the Asahi Shimbun newspaper reported, citing sources with the Tokyo Electric Power Company, the plant’s operator.
Two workers were taken to Fukushima Medical University Hospital and were expected to be transferred to the National Institute of Radiological Sciences in Chiba City. Hiro Hasegawa, a Tokyo Electric spokesman, said the third worker had not been hospitalized.
Mr. Edano said the three were employed by a subcontractor of Tokyo Electric. Halting progress was reported in the efforts to restart cooling systems at the plant that were knocked out in the earthquake and tsunami on March 11.
A Tokyo Electric official said workers had managed to restore lighting in the central control room of Reactor No. 1, an important step toward restarting its cooling system. The temperature in the reactor pressure vessel has been showing a worrisome increase, and Mr. Edano said efforts were being focused on resolving the problem.
Takeshi Takizawa contributed reporting.
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