Radiation levels exceed permissible limit
(Monday, April 11, 2011 21:20 +0900 (JST))
The science ministry says the amount of radiation accumulated over about half a month in some areas of Fukushima Prefecture has exceeded the permissible level for a whole year.
Since March 23rd, the ministry has been measuring radiation levels in 15 locations more than 20 kilometers away from the crippled Fukushima Daiichi nuclear power plant.
At one location, in Namie Town about 30 kilometers northwest of the plant, 14,480 microsieverts of radiation had accumulated over the 17-day period to Sunday.
8,440 microsieverts of radiation were observed in Iitate Village.
In another location in Namie, the amount reached 6,430 microsieverts.
People would be exposed to this accumulated amount of radiation if they had stayed outdoors throughout the entire period.
The level at one location was more than 14 times the 1,000 microsieverts that the International Commission on Radiological Protection recommends as the long-term annual reference level for people. The recommended level of 1,000 microsieverts excludes radiation from the natural environment and medical devices.
Hiroshima University Professor Kiyoshi Shizuma says most of the radiation observed in Fukushima is believed to be radioactive cesium that has fallen to the ground.
Shizuma advises residents to wear masks to avoid inhaling radioactive substances mixed with dust.
He points to the need to take samples both from the air and the ground for detailed analyses in order to assess any possible impact on human health.
Monday, April 11, 2011 21:20 +0900 (JST)
Radiation levels in parts of Fukushima over limit
(Tuesday, April 12, 2011 08:52 +0900 (JST))
The Japanese government says the radiation accumulated over a 25-day period at some locations in Fukushima Prefecture has exceeded the permissible level set for a full year.
The government announced the findings on Monday. The calculation is based on data collected from 53 locations, up to 60 kilometers from the Fukushima Daiichi power plant, from the day following the March 11th disasters through April 5th.
34 millisieverts of radiation had accumulated over that period at one location in Namie Town, about 24 kilometers northwest of the plant. This equates to about 314 millisieverts per year, more than 3 times the permissible level of 100 millisieverts.
On Monday, the government expanded its 20-kilometer evacuation zone to include towns where annual exposure is expected to top 20 millisieverts. It asked residents to evacuate within about a month.
Tuesday, April 12, 2011 08:52 +0900 (JST)
Japan to raise Fukushima crisis level to worst
(Tuesday, April 12, 2011 05:47 +0900 (JST))
The Japanese government's nuclear safety agency has decided to raise the crisis level of the Fukushima Daiichi power plant accident from 5 to 7, the worst on the international scale.
The Nuclear and Industrial Safety Agency made the decision on Monday. It says the damaged facilities have been releasing a massive amount of radioactive substances, which are posing a threat to human health and the environment over a wide area.
The agency used the International Nuclear and Radiological Event Scale, or INES, to gauge the level. The scale was designed by an international group of experts to indicate the significance of nuclear events with ratings of 0 to 7.
On March 18th, one week after the massive quake, the agency declared the Fukushima trouble a level 5 incident, the same as the accident at Three Mile Island in the United States in 1979.
Level 7 has formerly only been applied to the Chernobyl accident in the former Soviet Union in 1986 when hundreds of thousands of terabecquerels of radioactive iodine-131 were released into the air. One terabecquerel is one trillion becquerels.
The agency believes the cumulative amount from the Fukushima plant is less than that from Chernobyl.
Officials from the agency and the Nuclear Safety Commission will hold a news conference on Tuesday morning to explain the change of evaluation.
Tuesday, April 12, 2011 05:47 +0900 (JST)
