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Fukushima

New information posted 18th March is in bold. Thanks David G in Tokyo for the info.

Important Links 

International Atomic Energy Agency Updates.

David from Tokyo says - "The press releases at http://www.nisa.meti.go.jp/english/index.html seem to have the most up to date info. Not as sexy as the headlines on CNN or CBC. The story that should be making the headlines is http://edition.cnn.com/2011/WORLD/asiapcf/03/18/japan.disaster/index.html"

NISA Nuclear Industry Safety Agency


TheOilDrum.com Contains important information regarding zirconium (Zircaloy) fuel cladding.

Why I am not worried about Japans nuclear reactors  started as an email, went viral but contains some good explanations of the safety features but should be read in conjunction with TheOilDrum.com

See Wikipedia - Fukushima_I_Nuclear_Power_Plant for fairly up to date news but without details of the dangers.

More detailed news at - Nuclear Street

Weather Satallite Japan  the wind seems to blow East thank god! (Corrected this!)

Google Map Japan  Fukushima 250Km North of Tokyo

Physics

Radiation Measurement

A number of things need to be understood when talking about radiation. First there is radiation and contamination. Then there is radiation does and the current level of radiation.
  • Contamination is when a substance that is a source of radioactivity gets some place it shouldn't be like in you or in your garden!
  • Radioactive substances give off radiation just like a torch gives out light. The strength of radiation is like the strength of the light.
  • The dose of radiation a person received is the strength times how long they were exposed to it.
Human radiation dose is measured in a funny unit called "Sieverts" and you would normally get a does of typically 0.0024 Sievert in a year or 0.273 micro Sieverts per hour. Radiation in daily-life  (PDF:815KB) The unit is based on the biological damage the radiation can cause. For acute (that is, received in a relatively short time, up to about one hour) full body equivalent dose of;
  • 1 Sievert causes nausea,
  • 2-5 Sieverts causes epilation or hair loss, hemorrhage and will cause death in many cases.
  • More than 3 Sieverts will lead to death in 50% of cases within 30 days, and
  • over 6 Sv survival is unlikely. (For more details, see radiation poisoning.)
Often radiation strength is measured in Sieverts per unit time.

Main Contaminants

Radiation poisoning was a major concern after the Chernobyl reactor accident. Thirty-one people died as an immediate result. Of the 100 million curies. () of radioactive material, the short lived radioactive isotopes such as 131I Chernobyl released were initially the most dangerous. Due to their short half-lives of 5 and 8 days they have now decayed, leaving the more long-lived 137Cs (with a half-life of 30.07 years) and 90Sr (with a half-life of 28.78 years) as main dangers.

Fukushima

16th March

"RMonitoring outputs by MEXT out of 20km Zone of Fukushima Dai-ichi NPP and Dai-ni NPP “NEW”
MEXT is monitoring the radiation dose rate out of 20km Zone of Fukushima Dai-ichi NPP and Dai-ni NPP and deliver the output as needed for the safety of the evacuees and the residents in the vicinity.  
Readings at Monitoring Post out of 20 Km Zone of Fukushima Dai-ichi NPP

13th March

"Radiation levels have been monitored across the Fukushima Daiichi and Daini sites. As of 10.00pm 13 March 2011, Tepco said that radiation levels were lower and stable.

13th March

"Radiation levels have been monitored across the Fukushima Daiichi and Daini sites. As of 10.00pm 13 March 2011, Tepco said that radiation levels were lower and stable.

Potential contamination of the public is being studied by Japanese authorities as over 170,000 residents are evacuated from within 20 kilometres of Fukushima Daini and Daiichi nuclear power plants. Nine people's results have shown some degree of contamination. See  World Nuclear News

12th March

The maximum level detected on the 12 March was at 3.29pm when levels reached 1015 microsieverts per hour which is about 1 Sieverts per hour." i.e. if you were across the Fukushima Daiichi and Daini sites for 3 hours at that time, you have a 50% chance of being dead in 30 days.

There does appear to have been contamination in the area according to the article below from  World Nuclear News.

Chernobyl Compared

Chernobyl was a more serious incident in that the core of the reactor exploded scattering material all over the place. However the current situation at Fukushima is still very serious indeed in that we have a number of reactor failures and cooling with seawater pumped in seems one an improvised solution.





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