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Kyodo News agency said radioactive caesium had been detected near the site, quoting the Japanese nuclear safety commission. Radioactivity rose 20-fold outside,

by koski 16y ago

Kyodo News agency said radioactive caesium had been detected near the site, quoting the Japanese nuclear safety commission. Radioactivity rose 20-fold outside, reports said. (EDIT: this was before the explosion) The plant "may be experiencing nuclear meltdown", Kyodo and Jiji reported before the explosion, while public broadcaster NHK quoted the safety agency as saying metal tubes that contain uranium fuel may have melted.(AFP)

JonnieCache 16y ago
"Chief cabinet secretary Yukio Edano has told a press conference that he cannot confirm that the explosion at the nuclear power plant was the reactor, saying details of the incident remained unclear. He said authorities were prepared for the worst emergency but urged people to remain calm and not to listen to rumours. He also asked them to conserve electricity." http://www.guardian.co.uk/world/blog/2011/mar/12/japan-tsunami-earthquake-live-coverage#block-41 http://www.guardian.co.uk/world/blog/2011/mar/12/japan-tsuna...
sliverstorm 16y ago
Is 20-fold increase in radioactivity actually hazardous? I was under the impression dangerous levels of radiation are many, many times above normal background radiation and typical 'acceptable' levels of exposure. See http://www.geigercounters.com/Danger.htm http://www.geigercounters.com/Danger.htm for example. Occupational acceptable exposure is 25x that of non-occupational.
- Wientje 16y ago
  The average radioactive dose a person gets per year is about 3,6 to 5 milliSievert a year (for Belgium) of which 2,6 mSv from natural sources, 0,95mSv from medical examinations and 0,05mSv from industry (of which 0,01mSv due to nuclear power) So when they say around the reactor the dose in an hour is about the same as you get a year, then this is about equivalent to two scans in a hospital. Note: this is talking about low levels where the only influence radiation has is increasing the chance of cancer. If there are very high doses >100mSv involved, there will be direct radiological damage which can be strongly compared to damage from burning.
- A1kmm 16y ago
  According to http://www3.nhk.or.jp/daily/english/12_51.html http://www3.nhk.or.jp/daily/english/12_51.html the exposure level measured outside the plant is 1.015 mSv / hr. Exposure to about 1000 times that hourly level in a short time period is needed for life-threatening acute radiation poisoning. Exposure to 1.015 mSv / hour for a year would give a dose equivalent of 8.9 Sv - the excess relative risk of cancer for low dose chronic radiation exposure is about 0.97 per Sv - so the exposure to that level for a year would drastically increase cancer risk. Obviously, people won't be allowed into the areas where radiation levels were that high. I saw a report of a worker acutely exposed to >100 mSv; that single event would be enough to increase that worker's lifetime risk of cancer by about 10%.
  - uvdiv 16y ago
    That report is here (106.3 mSv measured): http://www.tepco.co.jp/en/press/corp-com/release/11031219-e.html http://www.tepco.co.jp/en/press/corp-com/release/11031219-e....

by koski 16y ago

JonnieCache 16y ago

"Chief cabinet secretary Yukio Edano has told a press conference that he cannot confirm that the explosion at the nuclear power plant was the reactor, saying details of the incident remained unclear. He said authorities were prepared for the worst emergency but urged people to remain calm and not to listen to rumours. He also asked them to conserve electricity." http://www.guardian.co.uk/world/blog/2011/mar/12/japan-tsunami-earthquake-live-coverage#block-41 http://www.guardian.co.uk/world/blog/2011/mar/12/japan-tsuna...

sliverstorm 16y ago

Is 20-fold increase in radioactivity actually hazardous? I was under the impression dangerous levels of radiation are many, many times above normal background radiation and typical 'acceptable' levels of exposure. See http://www.geigercounters.com/Danger.htm http://www.geigercounters.com/Danger.htm for example. Occupational acceptable exposure is 25x that of non-occupational.

Wientje 16y ago
The average radioactive dose a person gets per year is about 3,6 to 5 milliSievert a year (for Belgium) of which 2,6 mSv from natural sources, 0,95mSv from medical examinations and 0,05mSv from industry (of which 0,01mSv due to nuclear power) So when they say around the reactor the dose in an hour is about the same as you get a year, then this is about equivalent to two scans in a hospital. Note: this is talking about low levels where the only influence radiation has is increasing the chance of cancer. If there are very high doses >100mSv involved, there will be direct radiological damage which can be strongly compared to damage from burning.
A1kmm 16y ago
According to http://www3.nhk.or.jp/daily/english/12_51.html http://www3.nhk.or.jp/daily/english/12_51.html the exposure level measured outside the plant is 1.015 mSv / hr. Exposure to about 1000 times that hourly level in a short time period is needed for life-threatening acute radiation poisoning. Exposure to 1.015 mSv / hour for a year would give a dose equivalent of 8.9 Sv - the excess relative risk of cancer for low dose chronic radiation exposure is about 0.97 per Sv - so the exposure to that level for a year would drastically increase cancer risk. Obviously, people won't be allowed into the areas where radiation levels were that high. I saw a report of a worker acutely exposed to >100 mSv; that single event would be enough to increase that worker's lifetime risk of cancer by about 10%.
- uvdiv 16y ago
  That report is here (106.3 mSv measured): http://www.tepco.co.jp/en/press/corp-com/release/11031219-e.html http://www.tepco.co.jp/en/press/corp-com/release/11031219-e....