I received the following e-mail today from my Dad, who worked in General Electric’s nuclear power division in the 50’s and 60’s. Although he has no direct knowledge of the Fukushima Dai-Ichi reactor, his knowledge of nuclear power is well above that of the average citizen. With his permission, this might put the fall-out from the Japanese nuclear power problems in perspective. As always, it is presented here unedited and unfiltered.
This memorandum explains a little about radiation exposure. It is difficult to simplify since it depends on where you live, the type of radiation you are receiving (alpha, beta, gamma) and the period of exposure. Nonetheless, here are some examples of average radiation from various sources. Do not be concerned about understanding the units since all numbers are relative.
Transcontinental airline flight up to 0.05 milliSievert (mSv)
Chest X-ray 0.06 mSv
Radiation level 3.7 miles from
Fukushima Dai-Ichi reactor 0.09 mSvDental X-ray 0.09 mSv
Largest possible off-site dose from
Three-Mile Island accident 0.46 mSvMammogram 0.70 mSv
Abdominal X-ray 1.20 mSv
Head Cat-Scan 2 mSv
Radiation released to sea from first
venting of Fukushima Dai-Ichi 3 mSvAnnual Background radiation from
earth and sky 3 mSvChest Cat-Scan 8 mSv
Abdominal Cat-Scan 10 mSv
NRC annual limit for nuclear energy
workers 50 mSvEstimated dose to increase cancer
risk by less than 1 percent 100 mSvEPA voluntary maximum for
emergency non-life-saving work 250 mSvEPA voluntary maximum for
emergency life-saving work 750 mSvFifty percent likelihood of death 4,800 mSv
Instead of publishing this type of data by government sources, the hype continues in the newspapers with no idea of what they are talking about. People in California are buying potassium-iodide tablets and the Chinese are hording food since responsible people are not speaking out.
The wind along the Japanese east coast blows inland part of the day and out to sea for part of the day. The operator-controlled venting of the containment building, even though hydrogen burning caused an explosion, was undoubtedly performed when the wind was blowing out to sea.
The evacuation of all other people from a 12-mile radius around the plant was cautionary in the event the plant problems worsened. The subsequent requirement for people within a 19-mile radius remain indoors was also cautionary. The Japanese expect to restore electric power to the plants today to restore cooling to the reactors and pump water into the spent fuel storage pools.
Admittedly, some of these numbers are from the very newspapers and other media sources that are quoting Japanese officials. If the numbers being reported from Japan are even close to what is actually happening, there’s clearly nothing to worry about here.
Most of these numbers come from U.S. government sources, and may be equally suspect, depending on your view of government honesty.
