April 3, 2011

U.S. robot to survey Japan plant

TOKYO - Cool water powered by diesel generators or firetruck pumps continued to circulate around nuclear fuel rods in reactors at the tsunami-stricken Fukushima Dai-ichi nuclear-power plant Tuesday, limiting the potential for further releases of toxic particles, as workers struggled to contain the spread of radioactive contamination.

Crews piled sandbags and concrete blocks around the mouths of flooded tunnels to keep contaminated water from spilling into the sea and slowly pumped stagnant radioactive water out of dark turbine rooms.

To help survey the facility, the U.S. Energy Department is sending a robot and several radiation-shielded cameras, a spokeswoman said Tuesday. The tank-treaded robot, called Talon, is being dispatched from the Idaho National Laboratory and will scout the most radioactive areas of the plant with cameras and radiation sensors.

At the same time, scientists - under orders from Japanese nuclear regulators - painstakingly increased their documentation of the damage that explosions from the malfunctioning reactors and probable leaks from one or more reactor cores have begun to inflict on the country's food and water supply and its environment.

"Monitor," "measure," "follow" and "study" have become the mantras of government officials who have only the earliest glimpses of how the disaster will evolve.

At a meeting of the Japanese parliament, Prime Minister Naoto Kan criticized plant operator Tokyo Electric Power Co. for failing to adequately protect the facility from disaster. The plant was flooded by a wave that easily swept over its 20-foot-high protective wall.

When asked about whether contaminated water on the site is continuing to spread, Hidehiko Nishiyama, director general for the Nuclear and Industrial Safety Agency, said he had no data to show that it was.

But Tokyo Electric should "strengthen surveillance and monitoring," Nishiyama said. The same goes for tracking the extent of plutonium found in five soil samples taken at the plant or the path of radioactive iodine that has been traced in the ocean.

On Monday, the utility reported that underground tunnels outside the building were filled with water.

Radiation doses in both buildings near the second reactor measured in excess of 1,000 millisieverts per hour, potent enough to cause serious illness after several hours of exposure. The limit on workers there is 250 millisieverts of radiation per year, which they would reach in 15 minutes at the most radioactive sites in the facility.

Government officials said they would work to improve conditions for the hundreds of workers who are risking their lives to bring the plant under control. An inspector for the nation's nuclear regulator on Monday offered a picture of harsh and chaotic work conditions: The workers eat only two meals a day because of sporadic shipments of food and sleep in one large room or hallways at a headquarters near the plant. They have limited fresh water and no outside phone lines.

Nuclear regulators and Tokyo Electric officials say they still do not know the precise source of the leak. They believe it is a broken pipe or a crack in a condensation chamber near the base of the reactor building, and that seepage has come into contact with partially melted nuclear fuel rods in the reactor's core.

Meanwhile, in Washington, U.S. officials expressed concern about the limited information shared by the Japanese. Citing "many gaps in our knowledge," Peter Lyons, acting assistant secretary at the Department of Energy, told the Senate Environment and Public Works Committee, "It appears all three reactor cores are damaged" but to unknown extent.

Washington Post Mar. 30, 2011 12:00 AM

U.S. robot to survey Japan plant

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