[ RadSafe ] Fukushima - "Spewing" 200 million Bq/hr vs. Soil Release of natural Rn-222 from 2 km^2

[Brennan, Mike (DOH)]

Indeed, the continuous production of a noble gas causes both a larger population dose and, even for most people exposed to detectable contamination from Fukushima, a large dose to a critical organ than the contamination from Fukushima will produce.  And to the extent individuals shelter in buildings with poor air exchange (in an attempt to limit exposure to fallout), they quite possibly will increase their exposure to radon, and the negative consequences.  

  

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Witold Matysiak
Sent: Monday, August 29, 2011 9:35 AM
To: The International Radiation Protection (Health Physics) Mailing List
Subject: Re: [ RadSafe ] Fukushima - "Spewing" 200 million Bq/hr vs. Soil Release of natural Rn-222 from 2 km^2

I agree with Dr. Busby, half lives are key here.
Since 222-Rn is in equilibrium with its predecessors in the chain,
alpha radiation due to 222-Rn, 218-Po etc will stay several log decade
years after all 137-Cs from Fukushima decays away.

W

On Fri, Aug 26, 2011 at 4:08 AM, Busby, Chris <C.Busby at ulster.ac.uk> wrote:
> Half lives
> Chris
>
>
> -----Original Message-----
> From: radsafe-bounces at agni.phys.iit.edu on behalf of Stewart Farber
> Sent: Fri 26/08/2011 01:19
> To: The International Radiation Protection (Health Physics) Mailing List
> 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:
>           <http://www.globalsecuritynewswire.org/gsn/nw_20110818_8989.php>
>
>
> 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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