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Sunday, 3 August 2014

Bringing it Home, Understanding Cesium Deposition at Fukushima and Stirred Up Dust

I like doing this type of calculations that "Bring it Home"

Some others at ENENEWS have gotten good at it. With all the big numbers, scientific notation, various ways of expressing radiation units that the pro-radiation stakeholders use to confuse people....well it's nice when something is presented in an easy to wrap your head around way.

OLDFOOL Since a trillionth of a gram of Cs-137 emits over 3.2 becquerel, a gram of Cs-137 would emit over 3.2 trillion becquerels. So if they are saying that all the dust they created released no more than 4 trillion becquerels, they are implying they only stirred up 1.25 grams of Cs-137 in the dust. I cannot imagine any construction project at that site only stirring up 1.25 grams of Cs-137 in the dust. Most construction projects stir up several kilograms of dust. It would not be pure Cs-137 of course. But it would be more than 1.25 grams. Somebody has made a mistake in their math.

 Securitize July 17, 2014 at 10:04 pm · Reply A Becquerel indicates, on average, an amount of radiation where one radioactive “decay” event occurs each second. 37 billion becquerels are in one curie, or 37 billion disintegrations per second.

Potassium 40 exists in bananas and other fruits and is very weakly radioactive, 71 ten-millionTHs of a curie pure gram. By contrast, cesium 137 has 88 curies per gram. Indeed Cs 137 and Sr 90 emit 10-20 million times more radioactivity than comparable amounts of potassium 40.

Cesium 137 is a significant portion of the long-lasting radioactive isotopes emitted during a nuclear meltdown or other accident. The amount of cesium 137 deposited per square kilometer can thus be used to determine whether that land is fit for human habitation. The lands around the Chernobyl and Fukushima reactors are considered completely uninhabitable for decades based on ~10 curies per square km, or if you like ~25 curies per square mile.

Thus, slightly more than 1/3 of ONE GRAM of cesium 137, deposited across a square mile of land as a smoke or gas, is enough to render that land uninhabitable for decades. Contamination of ~10 curies per square km, ~25 curies per square mile, or ~1/3 of a gram of Cs 137 per sq mi, renders the area unfit for raising crops or livestock. For comparison, dozens of nuclear power plants in the US hold fuel rods containing more than 100 million curies of Cs 137. Remember that just 100 curies can render 1 sq mi uninhabitable.

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