nuclear-news

Rating the Fukushima damage on a nuclear danger scale

On Saturday, before emergency measures were announced at a second reactor at that plant, Japanese nuclear safety experts rated the accident a four, putting it just behind the Three Mile Island accident in 1979 near Harrisburg, Pa. That accident, the worst in United States history, was designated a five……..The government issued evacuation orders for about 170,000 people in the surrounding area……..

Nuclear Emergency Is Worst in Decades, NYTimes.com, By ANAHAD O’CONNOR  March 12, 2011 The earthquake and tsunami that battered northern Japan on Friday set in motion one of the worst nuclear accidents in over two decades. The International Atomic Energy Agency rates the severity of radiological events, with a scale starting at one, an “anomaly,” and rising to seven, a “major” accident. A six and seven designate full meltdown, where the nuclear fuel or core of a reactor overheats and melts. The scale of the ensuing uncontrolled release of radiation that follows differentiates the two. Partial meltdowns, in which the fuel is damaged, are rated a four or a five.

The accident at Chernobyl in the former Soviet Union in 1986 — which killed 56 people directly and thousands of others through cancer and other diseases — was the only nuclear accident so far to have been designated a seven. Just one other accident has surpassed five on the scale: an explosion of dried radioactive waste at the Mayak Nuclear Power Plant near the Soviet city of Kyshtym in 1957. The blast produced a radioactive cloud that spread for hundreds of miles over what is now Russia, forcing the evacuation of 10,000 people and causing the deaths of at least 200.

The Mayak blast was rated a six on the atomic agency’s scale.

The full extent of the damage at the Fukushima Daiichi Nuclear Power Station in Japan is yet to be determined. On Saturday, before emergency measures were announced at a second reactor at that plant, Japanese nuclear safety experts rated the accident a four, putting it just behind the Three Mile Island accident in 1979 near Harrisburg, Pa. That accident, the worst in United States history, was designated a five……..

Officials monitoring the Daiichi (or No. 2) plant in Fukushima have said they detected a radioactive byproduct, cesium, that could indicate that some of the nuclear fuel in Reactor No. 1 was damaged and a partial meltdown had occurred. Officials at the plant filled the reactor with seawater to prevent a full meltdown. But early Sunday, they were struggling to inject water into Reactor No. 3. The government issued evacuation orders for about 170,000 people in the surrounding area……..

Japan Nuclear Emergency Is Worst in Decades – NYTimes.com

March 13, 2011 - Posted by Christina Macpherson | Japan, safety