RE: Radioactive Fossils

["Franta, Jaroslav" <frantaj@aecl.ca>]

> ----------
> From: 	Theodore S Bohn[SMTP:BST@inel.gov]
> Reply To: 	radsafe@romulus.ehs.uiuc.edu
> Sent: 	Tuesday, May 11, 1999 1:23 PM
> To: 	Multiple recipients of list
> Subject: 	RE: Radioactive Fossils
> 
> Is it inferred in the articled that the radionuclides (such as uranium and
> thorium and others) are released in the gaseous emission of the combustion
> or
> does a major fraction of them remain in the ash?
> 
ACCORDING TO THE ORNL POSTING:

> Fly ash is primarily composed of non-combustible silicon compounds (glass)
> melted during combustion. Tiny glass spheres form the bulk of the fly ash.
> 
> Since the 1960s particulate precipitators have been used by U.S.
> coal-fired power plants to retain significant amounts of fly ash rather
> than letting it escape to the atmosphere. When functioning properly, these
> precipitators are approximately 99.5% efficient. Utilities also collect
> furnace ash, cinders, and slag, which are kept in cinder piles or
> deposited in ash ponds on coal-plant sites along with the captured fly
> ash. 
...
> During combustion, the volume of coal is reduced by over 85%, which
> increases the concentration of the metals originally in the coal. Although
> significant quantities of ash are retained by precipitators, heavy metals
> such as uranium tend to concentrate on the tiny glass spheres that make up
> the bulk of fly ash. This uranium is released to the atmosphere with the
> escaping fly ash, at about 1.0% of the original amount, according to NCRP
> data. The retained ash is enriched in uranium several times over the
> original uranium concentration in the coal because the uranium, and
> thorium, content is not decreased as the volume of coal is reduced. 
...large quantities of uranium and thorium and other radioactive species in
coal ash are not being treated as radioactive waste. These products emit
low-level radiation, but because of regulatory differences, coal-fired power
plants are allowed to release quantities of radioactive material that would
provoke enormous public outcry if such amounts were released from nuclear
facilities. Nuclear waste products from coal combustion are allowed to be
dispersed throughout the biosphere in an unregulated manner. Collected
nuclear wastes that accumulate on electric utility sites are not protected
from weathering, thus exposing people to increasing quantities of
radioactive isotopes through air and water movement and the food chain. 
....by collecting the uranium residue from coal combustion, significant
quantities of fissionable material can be accumulated. In a few year's time,
the recovery of the uranium-235 released by coal combustion from a typical
utility anywhere in the world could provide the equivalent of several World
War II-type uranium-fueled weapons. Consequently, fissionable nuclear fuel
is available to any country that either buys coal from outside sources or
has its own reserves. The material is potentially employable as weapon fuel
by any organization so inclined. 
....In short, naturally occurring radioactive species released by coal
combustion are accumulating in the environment along with minerals such as
mercury, arsenic, silicon, calcium, chlorine, and lead, sodium, as well as
metals such as aluminum, iron, lead, magnesium, titanium, boron, chromium,
and others that are continually dispersed in millions of tons of coal
combustion by-products. The potential benefits and threats of these released
materials will someday be of such significance that they should not now be
ignored.--Alex Gabbard of the Metals and Ceramics Division 

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