Re: radioactivity from fossil fuel power stations

[BERNARD L COHEN <blc+@PITT.EDU>]

	Hopefully my previous message covers this. If not, please ask for

more explanation.



Bernard L. Cohen

Physics Dept.

University of Pittsburgh

Pittsburgh, PA 15260

Tel: (412)624-9245

Fax: (412)624-9163

e-mail: blc+@pitt.edu





On Fri, 3 Aug 2001, Susan Gawarecki wrote:



> 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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