[ RadSafe ] Fukushima - "Spewing" 200 million Bq/hr vs. Soil Release of natural ... Thank you

parthasarathy k s ksparth at yahoo.co.uk
Fri Aug 26 00:19:38 CDT 2011


Thank you for the analysis. Useful numbers.

----- Original Message -----
From: Stewart Farber <SAFarber at optonline.net>
To: The International Radiation Protection (Health Physics) Mailing List <radsafe at health.phys.iit.edu>
Sent: Friday, 26 August 2011, 5:49
Subject: [ RadSafe ] Fukushima - "Spewing" 200 million Bq/hr vs. Soil Release of natural Rn-222 from 2 km^2

Hello all,
I read an article recently: "Fewer Contaminants Seen Escaping From Japan Nuclear Plant", Aug. 18, Global Security Newswire. See:

This recent article  mentioned that the Fukushima complex was now releasing 200 million Bq per hour. Most members of the media and public don't know a Becquerel from a Pickerel, but 200 million of anything must be a very huge amount that poses a major risk. Right??  How do you make people understand that 200E6 Bq per se is not the end of the world? Of course the isotopes and exposure pathways are vital in assessing significance of any activity released, but let's not go there.

200E6 Bq got me thinking about natural background radiation, and what is released from soil to air.    Let me know how the following strikes you as a point of comparison.

An average value for Rn-222 gas flux from the earth's surface [due to the average concentration of U-238 in soil leading to Rn-222 gas release] is roughly 30 milliBq/m^2/sec. Do the math and you'll see that give or take, any random 2  km^2 of the earth's surface will release 200 million Bq per hour of Rn-222, equal to the total amount of radioactivity being emitted recently by the nuclear reactors 1, 2, and 3 at Fukushima as it is brought to a cold shutdown. As the Global Security Newswire article noted the reactors were "previously hemorrhaging five times that amount" . As we all know radiation is not released from a facility -- it is either "spewed" or "hemorrhaged".

Five times more than 200 million Bq would be equal to the routine Rn-222 release by nature from about 10 km^2 - an area 3 km x 3 km - which will continue due to natural radioactivity for billions of years given the half life of U-238.

Further, based on average wind farm capacity density  [ about 6.5 MWe per km^2 ], the 2 km^2 of land currently "spewing" 200 million Bq/hr will support the wind generation of only about 13 MW of electricity.

An area of land necessary to site and generate 2,000 MW[e] of wind power [an area of 285 km^2  or 11 miles by 11 miles ] would be needed to equal the pre-accident combined output of Fukushima 1, 2, and 3. This 285 km^2 of land to site 2,000 MW[e] of wind generation will release about 32 billion Bq of  Rn-222 per hour.  32 billion Bq of Rn-222 per hour from nature being "spewed" from a windfarm generating 2,000 MWe vs. only about 200 million Bq from Fukushima 1, 2, 3. Do we need to evacuate the area around any large windfarm?

Thoughts on the above comparisons?

Stewart Farber, MS Public Health
SAFarber at optonline.net
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