[Infowarrior] - Japan gov blacks out Fukushima radiation readings

[Richard Forno]

U.S. radiation experts try to decipher reports from Japan

By Steve Sternberg, USA TODAY

Updated 6h 14m ago |

http://www.usatoday.com/news/world/2011-03-17-japanradiate17_ST_N.htm#

The Japanese government's radiation report for the country's 47 prefectures Wednesday had a notable omission: Fukushima, ground zero in Japan's nuclear crisis. Measurements from Ibaraki, just south of Fukushima, were also blanked out.

Radiation experts in the USA say that the lack of information about radioactivity released from the smoldering reactors makes it impossible to gauge the current danger, project how bad a potential meltdown might be or calculate how much fallout might reach the USA.

Japanese nuclear experts are hard at work gathering information, said Fred Mettler, the U.S. representative for the United Nation's committee on the health effects of radiation. "They're monitoring and evaluating and watching the meteorology," he said. "They need to know what the dose rates are in various places, what direction the (radiation is) moving in and what's causing it."

Conflicting accounts of the radiation levels emerged in Tokyo and on Capitol Hill. Japan's Nuclear and Industrial Safety Agency said Wednesday that the radiation detected at the Fukushima plant had fallen steadily over the past 12 hours. But U.S. Nuclear Regulatory Commission (NRC) chief Gregory Jaczko told a House energy subcommittee earlier in the day that radiation levels at the Fukushima plant were "extremely high."

The chief of the U.N. International Atomic Energy Agency, Yukiya Amano, told reporters he will visit Japan to obtain "firsthand information" about the crisis and prod the Japanese government to provide more. Experts from the NRC, led by Charles Casto, were to arrive in the country on Wednesday.

Given accurate readings, U.S. experts can develop computer models of radiation released from the crippled reactors, factoring in prevailing winds, altitude and rainfall, said Owen Hoffman, a radiation expert from SENES Oak Ridge Inc., a consulting firm that calculated risks from Cold War nuclear tests.

One agency equipped to predict where the fallout may travel is the Department of Energy's National Atmospheric Release Advisory Center at Lawrence Livermore National Laboratory. The center has tracked radiation emitted by the meltdowns at Three Mile Island in 1979 and Ukraine's Chernobyl in 1986.

History may offer hints of what's to come. At Three Mile Island, near Harrisburg, Pa., only a small amount of radiation was released before the meltdown was controlled. Chernobyl spewed radiation for days, which rode wind currents worldwide.

Radioactive iodine falls from the plume in rainfall and settles on the grass, where it's eaten by cows and builds up in their milk. Decades after Three Mile Island, no cancers or deaths have been conclusively linked to the U.S. disaster. Researchers have logged 6,000 thyroid cancers in survivors of Chernobyl, all in people who were younger than 18 when they were exposed. That's about one-third of the 14,000 projected to occur.

Thyroid cancer is a major risk because the thyroid needs iodine to make thyroid hormone, which regulates metabolism. For those downwind of Chernobyl, the highest dose exceeded 1 gray, a measure of the radioactivity absorbed in the thyroid.

Children who drank commercial milk during the Cold War nuclear tests received about one-tenth of that, on average, Hoffman said. That was enough to boost their thyroid cancer risk to one in 100, more than twice the usual risk.

The Chernobyl meltdown also contaminated vast tracts of Ukraine, Belarus, Russia and northern Europe with radioactive cesium. "There are still limitations on the export of sheep from Cumbria, in the U.K., and reindeer from Scandinavia," Hoffman said. Cesium also contaminated fish from Scandinavia's northern lakes.

Cesium is absorbed by plants and works its way through the food chain, getting into meat and milk. Unlike radioactive iodine, which has a short half life, cesium lingers in the environment. "Radioactive iodine will be gone in a month," Hoffman said. "Cesium's going to be around for decades."

Contributing: The Associated Press