World
Engineers attempt to plug nuke plant leak
Updated: 2011-04-04 07:58
By Ryan Nakashima and Mari Yamaguchi (China Daily)
A 20-cm split allows radioactive water to spill into the Pacific Ocean
TOKYO - Highly radioactive water was still gushing into the Pacific Ocean from Japan's tsunami-crippled nuclear plant despite efforts to stop it with a chemical substance mixed with sawdust and shredded newspaper on Sunday.
The new approach was employed after concrete failed to seal a crack at a Japanese nuclear power plant incapacitated by last month's earthquake-spawned tsunami. A search of site found no other leaks.
The tsunami left a trail of destruction up and down the country's northeastern coast and is believed to have killed 25,000 people.
The first deaths at the Fukushima Daiichi nuclear plant itself, though, were confirmed on Sunday by the operator, Tokyo Electric Power Co (TEPCO). A 21-year-old and a 24-year-old were conducting regular checks at the complex when the 9.0-magnitude earthquake hit Japan on March 11.
"It pains us to have lost these two young workers who were trying to protect the power plant amid the earthquake and tsunami," TEPCO Chairman Tsunehisa Katsumata said in a statement.
The bodies were not discovered until Wednesday and had to be decontaminated from radioactive materials. The announcement was delayed while authorities notified the families, TEPCO spokesman Kazufumi Suzuki said.
Since the tsunami knocked out the plant's cooling systems and reactors began to dangerously overheat, a series of almost daily problems has led to substantial amounts of radiation leaking into the atmosphere, ground and sea in the world's worst nuclear crisis since the 1986 meltdown at Chernobyl in the former Soviet Union.
On Saturday, authorities discovered a crack from which radioactive water was spilling into the Pacific. It was the first time they had identified a direct source of sea contamination. The source of the water is believed to be the reactor cores.
A picture released by TEPCO shows water shooting some distance away from a wall and splashing into the sea, though the amount of water was not clear. The contaminated water will quickly dissipate in the ocean but could pose a danger to workers at the plant.
The crack, 20 centimeters in length, is in a maintenance pit from which water containing levels of radioactive iodine far above the legal limit spilled into the ocean, said Hidehiko Nishiyama of Japan's Nuclear and Industrial Safety Agency.
Workers filled the pit with concrete but couldn't get it to dry.
Next, they injected polymer into a pipe that connects the pit to the rest of the system. The polymer can absorb enormous amounts of water and expands to 50 times its original size. It's not yet known if that has stemmed the leak.
The crack is believed to have been caused by the earthquake, though that is still under investigation. The reactor buildings and other structures in more sensitive parts of the plant were built to stricter codes and thus were better able to withstand earthquakes than the pit, according to Nishiyama.
"Even if the crack in the pit was caused by the quake, the reactors must have withstood the temblor," he said.
Over the past 10 days, pooling water at the nuclear complex has repeatedly forced technicians to pull back and suspend their work.
A search of the plant on Sunday found no similar leaks leading directly to the ocean. "We believe that's the only crack," said another TEPCO spokesman, Naoki Tsunoda.
People living within 20 kilometers of the plant have been evacuated, but, as with previous leaks, it could pose a danger to workers.
Radiation - as well as debris and several explosions - slowed the search for the bodies of the two workers who had been listed as missing since just after the quake struck.
Overhead, and throughout the coastal region, helicopters and planes roared by as US and Japanese forces ended their all-out search for bodies.
The effort was probably the final hope for retrieving the dead, though limited operations may continue. The search turned up more than 70 bodies during the course of the weekend.
In all, 12,000 deaths have been confirmed, and another 15,400 people are missing.
Associated Press
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