RE: Radioactive Fossils

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

On Thursday, May 06, 1999, Bernard L Cohen wrote:

> --Why, then, are coal mines low in radon compared to other mines?
> This was a key point in concluding that radon was responsible for lung
> cancer in some miners -- coal miners do not have an excess of lung cancer.
> 
> Also, U in coal averages 1 ppm  vs 2.5 ppm in average rock. I was under
> the impression that geochemistry worked against U and coal depositing
> together
- - - - - - - - -

This reminded me of the following ORNL web posting I found some time ago
(selected bits included below... can't find the URL at the moment).

Jaro
frantaj@aecl.ca
Deep River, Ontario, Canada 

BEGIN QUOTE
> RADIOACTIVITY FROM COAL COMBUSTION
> Alex Gabbard, Metals and Ceramics Division, ORNL
> 
> ....although not as well known, releases from coal combustion contain
> naturally occurring radioactive materials--mainly, uranium and thorium. 
> Former ORNL researchers J. P. McBride, R. E. Moore, J. P. Witherspoon, and
> R. E. Blanco made this point in their article "Radiological Impact of
> Airborne Effluents of Coal and Nuclear Plants" in the December 8, 1978,
> issue of Science magazine. They concluded that Americans living near
> coal-fired power plants are exposed to higher radiation doses than those
> living near nuclear power plants that meet government regulations. This
> ironic situation remains true today and is addressed in this article. 
> The fact that coal-fired power plants throughout the world are the major
> sources of radioactive materials released to the environment has several
> implications. It suggests that coal combustion is more hazardous to health
> than nuclear power and that it adds to the background radiation burden
> even more than does nuclear power. It also suggests that if radiation
> emissions from coal plants were regulated, their capital and operating
> costs would increase, making coal-fired power less economically
> competitive. 
> Finally, radioactive elements released in coal ash and exhaust produced by
> coal combustion contain fissionable fuels and much larger quantities of
> fertile materials..... 
> .....Trace quantities of uranium in coal range from less than 1 part per
> million (ppm) in some samples to around 10 ppm in others. Generally, the
> amount of thorium contained in coal is about 2.5 times greater than the
> amount of uranium. For a large number of coal samples, according to
> Environmental Protection Agency figures released in 1984, average values
> of uranium and thorium content have been determined to be 1.3 ppm and 3.2
> ppm, respectively. 
> ....Using the concentration of uranium and thorium indicated above, the
> graph below illustrates the historical release quantities of these
> elements and the releases that can be expected during the first half of
> the next century, given the predicted growth trends. Using these data,
> both U.S. and worldwide fissionable uranium-235 and fertile nuclear
> material releases from coal combustion can be calculated. 
> ....in 1982 about 616 million short tons (2000 pounds per ton) of coal was
> burned in the United States (from 833 million short tons mined, or 74%),
> the number of typical coal-fired plants necessary to consume this quantity
> of coal is 154. 
> Using these data, the releases of radioactive materials per typical plant
> can be calculated for any year. For the year 1982, assuming coal contains
> uranium and thorium concentrations of 1.3 ppm and 3.2 ppm, respectively,
> each typical plant released 5.2 tons of uranium (containing 74 pounds of
> uranium-235) and 12.8 tons of thorium that year. Total U.S. releases in
> 1982 (from 154 typical plants) amounted to 801 tons of uranium (containing
> 11,371 pounds of uranium-235) and 1971 tons of thorium. These figures
> account for only 74% of releases from combustion of coal from all sources.
> Releases in 1982 from worldwide combustion of 2800 million tons of coal
> totaled 3640 tons of uranium (containing 51,700 pounds of uranium-235) and
> 8960 tons of thorium. 
> Based on the predicted combustion of 2516 million tons of coal in the
> United States and 12,580 million tons worldwide during the year 2040,
> cumulative releases for the 100 years of coal combustion following 1937
> are predicted to be: 
> 
> U.S. release (from combustion of 111,716 million tons): 
> 
> Uranium: 145,230 tons (containing 1031 tons of uranium-235) 
> 
> Thorium: 357,491 tons 
> 
> Worldwide release (from combustion of 637,409 million tons): 
> 
> Uranium: 828,632 tons (containing 5883 tons of uranium-235) 
> 
> Thorium: 2,039,709 tons 
> 
> Radioactivity from Coal Combustion
> 
> The main sources of radiation released from coal combustion include not
> only uranium and thorium but also daughter products produced by the decay
> of these isotopes, such as radium, radon, polonium, bismuth, and lead.
> Although not a decay product, naturally occurring radioactive potassium-40
> is also a significant contributor.
> According to the National Council on Radiation Protection and Measurements
> (NCRP), the average radioactivity per short ton of coal is 17,100
> millicuries/4,000,000 tons, or 0.00427 millicuries/ton. This figure can be
> used to calculate the average expected radioactivity release from coal
> combustion. For 1982 the total release of radioactivity from 154 typical
> coal plants in the United States was, therefore, 2,630,230 millicuries.
> Thus, by combining U.S. coal combustion from 1937 (440 million tons)
> through 1987 (661 million tons) with an estimated total in the year 2040
> (2516 million tons), the total expected U.S. radioactivity release to the
> environment by 2040 can be determined. That total comes from the expected
> combustion of 111,716 million tons of coal with the release of 477,027,320
> millicuries in the United States. Global releases of radioactivity from
> the predicted combustion of 637,409 million tons of coal would be
> 2,721,736,430 millicuries. 
> For comparison, according to NCRP Reports No. 92 and No. 95, population
> exposure from operation of 1000-MWe nuclear and coal-fired power plants
> amounts to 490 person-rem/year for coal plants and 4.8 person-rem/year for
> nuclear plants. Thus, the population effective dose equivalent from coal
> plants is 100 times that from nuclear plants. For the complete nuclear
> fuel cycle, from mining to reactor operation to waste disposal, the
> radiation dose is cited as 136 person-rem/year; the equivalent dose for
> coal use, from mining to power plant operation to waste disposal, is not
> listed in this report and is probably unknown. 
> 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. 
> All studies of potential health hazards associated with the release of
> radioactive elements from coal combustion conclude that the perturbation
> of natural background dose levels is almost negligible. However, because
> the half-lives of radioactive potassium-40, uranium, and thorium are
> practically infinite in terms of human lifetimes, the accumulation of
> these species in the biosphere is directly proportional to the length of
> time that a quantity of coal is burned. 
> Although trace quantities of radioactive heavy metals are not nearly as
> likely to produce adverse health effects as the vast array of chemical
> by-products from coal combustion, the accumulated quantities of these
> isotopes over 150 or 250 years could pose a significant future ecological
> burden and potentially produce adverse health effects, especially if they
> are locally accumulated. Because coal is predicted to be the primary
> energy source for electric power production in the foreseeable future, the
> potential impact of long-term accumulation of by-products in the biosphere
> should be considered. 
> 
> References and Suggested Reading 
> 
> J. F. Ahearne, "The Future of Nuclear Power," American Scientist, Jan.-Feb
> 1993: 24-35. 
> E. Brown and R. B. Firestone, Table of Radioactive Isotopes, Wiley
> Interscience, 1986. 
> J. O. Corbett, "The Radiation Dose From Coal Burning: A Review of Pathways
> and Data," Radiation Protection Dosimetry, 4 (1): 5-19. R. R. Judkins and
> W. Fulkerson, "The Dilemma of Fossil Fuel Use and Global Climate Change,"
> Energy & Fuels, 7 (1993) 14-22. 
> National Council on Radiation Protection, Public Radiation Exposure From
> Nuclear Power Generation in the U.S., Report No. 92, 1987, 72-112. 
> National Council on Radiation Protection, Exposure of the Population in
> the United States and Canada from Natural Background Radiation, Report No.
> 94, 1987, 90-128. 
> National Council on Radiation Protection, Radiation Exposure of the U.S.
> Population from Consumer Products and Miscellaneous Sources, Report No.
> 95, 1987, 32-36 and 62-64. 
> Serge A. Korff, "Fast Cosmic Ray Neutrons in the Atmosphere," Proceedings
> of International Conference on Cosmic Rays, Volume 5: High Energy
> Interactions, Jaipur, December 1963. 
> C. B. A. McCusker, "Extensive Air Shower Studies in Australia,"
> Proceedings of International Conference on Cosmic Rays, Volume 4:
> Extensive Air Showers, Jaipur, December 1963. 
> T. L. Thoem, et al., Coal Fired Power Plant Trace Element Study, Volume 1:
> A Three Station Comparison, Radian Corp. for USEPA, Sept. 1975. 
> W. Torrey, "Coal Ash Utilization: Fly Ash, Bottom Ash and Slag," Pollution
> Technology Review, 48 (1978) 136. 
END QUOTE
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