Global Security Newswire

Radioactive cesium emitted by Japan's damaged Fukushima Daiichi atomic facility has turned up in atmospheric readings in 18 of the nation's prefectures, according to figures issued on Friday by the Japanese Science Ministry (see GSN, Nov. 11).

The six-reactor power plant was damaged by the March 11 earthquake and tsunami that left more than 20,000 people missing or dead in Japan. Radiation releases on a level not seen since the 1986 Chernobyl disaster forced the evacuation of about 80,000 residents from a 12-mile ring exclusion zone surrounding the site in Fukushima prefecture.

Government sources said the boundary between Gunma and Nagano prefectures marked the westernmost point of the contaminant's dispersal, while southern Iwate prefecture was the northernmost point of its spread, the Asahi Shimbun reported. Cesium 134 and cesium 137 isotopes had reached levels in excess of 30,000 becquerels per square meter in sections of southern Iwate and eastern Nagano prefectures.

Levels higher than 60,000 becquerels per square meter turned up close to the boundary dividing the cities of Oshu and Ichinoseki and near the division between the jurisdictions of Saku and Sakuho.

The newly released contaminant dispersal figures were the first to include data on six prefectures: Gifu, Iwate, Nagano, Toyama, Shizuoka and Yamanashi (Asahi Shimbun I, Nov. 12).

Separately, conditions at the Fukushima plant could complicate efforts to measure the heat of broken-down nuclear fuel in site reactors, the Asahi Shimbun reported (Hidenori Tsuboya, Asahi Shimbun II, Nov. 14).