REPORTING FROM SEOUL -– More environmental damage has likely occurred at Japan’s stricken nuclear reactor after more than 45 tons of highly radioactive water leaked from the Fukushima Daiichi power station this weekend, with some of the water possibly reaching the nearby Pacific Ocean, the utility that operates the plant said.
The leak counteracts assurances that the Tokyo Electric Power Co., or Tepco, has largely controlled damage at the coastal nuclear plant, located about 220 miles northeast of Tokyo, which it plans to bring to a total shutdown by year's end.
On March 11, the 1970s-era plant was hit by a massive earthquake-triggered tsunami that knocked out its cooling system, eventually leading to several reactor-core meltdowns. The catastrophe, which experts have called the largest single release of radioactivity into the ocean, has threatened fisheries in the region and caused the evacuation of 80,000 residents near the facility.
Since March, utility engineers have attempted to cool the ailing plant's reactors by flooding them with water, which becomes contaminated with radioactivity in the process.
Tepco installed a new circulatory cooling system in September, with filters that decontaminate and recycle the cooling water. However, the company acknowledges that some water has already leaked into the ocean and that thousands of tons more remains in the flooded basements of the plant's reactor buildings.
According to a statement on the utility’s website, workers discovered Sunday morning that radioactive water was pooling in a runoff container near one of those purification devices.
The system was shut down and the leak apparently ceased, but workers later found highly radioactive water leaking from cracks in the container’s concrete wall into a gutter that leads to the ocean.
Employees stemmed the leak with sandbags.
The newspaper Asahi Shimbun quoted Tepco officials as saying that as much as 220 tons of water may now have leaked from the damaged facility since the disaster struck nearly nine months ago.
The water from Sunday's leak was measured at 16,000 becquerels per liter of cesium-134, and 29,000 becquerels per liter of cesium-137, the utility said. Those numbers are 270 times and 322 times higher, respectively, than government safety limits, experts say.
Both substances are readily absorbed by living tissue and can greatly increase the risk of developing cancer.
In another development, Japanese media quoted an interim report, released by Tepco last week, that captures the desperation workers faced when the Fukushima Daiichi plant was struck by the tsunami in March.
"I felt I could do nothing. Other operators appeared anxious, and said, 'When we cannot control [the reactors] and are helpless, is there any point in us staying here?' " the chief of the reactors' central control room is quoted as saying in the utility's internal investigation report released Friday. "So, I bowed my head and asked them to stay."
Another worker interviewed by officials was part of an effort to vent the containment vessels around the nuclear cores to prevent an explosion.
"I heard some big weird popping sounds ... and when I tried to start working ... my black rubber boots melted [because of the heat]," he said.
-- John M. Glionna