Radiation levels at Japan nuclear plant reach new highs

Leaked water sampled from one unit Sunday had 100,000 times the radioactivity of normal background levels, although the Tokyo Electric Power Co., which operates the plant, first calculated an even higher, erroneous, figure it didn’t correct for hours.

Tepco apologized Sunday night when it realized the mistake; it had initially reported radiation levels in the leaked water from the unit 2 reactor as being 10 million times the norm, which prompted an evacuation of the building.

After the levels were correctly measured, airborne radioactivity in the unit 2 turbine building still remained so high — 1,000 milli­sieverts per hour — that a worker there would reach his yearly occupational exposure limit in 15 minutes. A dose of 4,000 to 5,000 millisieverts absorbed fairly rapidly will eventually kill about half of those exposed.

The latest confusion in the operation to stave off a full-scale nuclear meltdown at the crippled facility underscores the immense challenges for the several hundred workers in a desperate battle to restart the critical cooling systems. Seventeen workers have been exposed to high levels of radiation, including three who were hospitalized last week, as technicians conducted highly nuanced electrical work in dark conditions that one nuclear industry expert termed “hellish.”

Japanese authorities say efforts to control Fukushima’s overheated reactors will take months and during that time radiation will continue to leak into the environment, extending a nuclear emergency that already ranks as the world’s most serious in a quarter-century. Several hundred workers now shoulder the responsibility for limiting the crisis, amid potentially lethal radiation levels, and on Saturday the chief of Japan’s nuclear agency called on Tepco to improve its worker safety.

On Monday morning, Japan's Chief Cabinet Secretary Yukio Edano made a plea to residents from the 12-mile radius evacuation zone surrounding the crippled nuclear plant to please stay away "until safety is confirmed."