Re: radioactivity from fossil fuel power stations

[Susan Gawarecki <loc@ICX.NET>]

Technically, once the coal is gone and burned, nothing "replaces" it in

the ground.  For strip mines, the landscape is permanently altered

because material is missing.  For subsurface mines, voids remain that

may fill with water or that may collapse causing subsidence at the

surface.



I doubt that an area mined for coal would then become a higher radon

source.  In fact, that coal itself contains uranium and thorium means

that coal is at least a minor radon source.  Most important rock types

for radon are granites, phosphates, and various sedimentary rocks (such

as shales, sandstones, and limestones) that have become somewhat

enriched in radionuclides via exposure to uranium-bearing groundwater

(generally due to a significant organic content which seems to

preferentially capture uranium).



Only if the other rock types associated with coal have relatively high

uranium contents, and these are fractured or exposed to the extent that

trapped radon is released, might your argument hold much weight.  These

negative effects are probably negligable compared to the acidification

of groundwater and surface water caused by the exposure of the iron

sulfides commonly associated with coal.



Regards,

Susan



Bernard L Cohen wrote:

> 

> On Fri, 3 Aug 2001, Susan Gawarecki wrote:

> 

> > Dr. Cohen,

> >

> > I'm a geologist, but I don't understand what you mean by this statement:

> >

> > > When coal is mined out of the ground and

> > > made to "disappear" as carbon dioxide, its carbon is replaced in the

> > > ground by other rock which contains U, Th, Ra.....

> 

>         -- My statement here is a simplification of a much more

> complicated analysis, given in the paper cited, but I will try.

>         When the carbon in the coal is burned, it disappears from the

> ground. The volume of the ground that it occupied is then taken by other

> rock or soil which contains uranium, and therefore eventually serves as a

> source of radon. The carbon in the coal cannot serve as a source of radon.

> The uranium impurity in the coal is returned to the ground eventually.

>         In other words, the carbon in the coal takes up a volume in the

> ground which produces no radon, while the rock that takes up that volume

> when the coal is removed does produce radon.



-- 

.....................................................

Susan L. Gawarecki, Ph.D., Executive Director

Oak Ridge Reservation Local Oversight Committee

                       -----                       

A schedule of meetings on DOE issues is posted on our Web site

http://www.local-oversight.org/meetings.html - E-mail loc@icx.net

.....................................................

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