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Coal vs Nuclear Power

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posted on Jun, 29 2006 @ 11:45 PM
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I'm placing this here, because I'm not really sure where else it should go.

In the United States, approximately 52% of the power grid is made up of coal plants, as opposed to approximately 15% being nuclear. Everybody KNOWS that coal plants are safe, and they're certainly safer than nuclear plants, right? Wrong. Coal plants are FAR more dangerous than nuclear power plants, just from their normal emissions, every day.

Coal is made up of uranium, thorium, aluminum, sulfur, iron and other materials. Coal ash contains oxides of silicon, aluminum, iron, calcium, magnesium, titanium, sodium, potassium, arsenic, mercury, and sulfur plus small quantities of uranium and thorium. A 1984 study puts the Uranium quantities at 1.3 ppm, and Thorium at 3.2 ppm.

IF a coal plant scrubber is working at optimum conditions, it will remove 99.5% of efficiency. This captures the "fly ash" instead of releasing it into the atmosphere. However, even the small portion that is released has radioactive materials in it. And those small quantities add up, and the number of coal plants is expected to increase. Nuclear power plants are actually expected to be replaced with coal plants over time.

Using data from 1982, based on 154 coal plants in the United States, 616 million short tons of coal were burned. Each of these plants released 5.2 tons of Uranium, including 74 pounds of U-235, and 12.8 tons of Thorium. For the entire United States that comes to 801 tons of Uranium (11,371 pounds of U-235) and 1971 tons of Thorium. Worldwide in 1982 there were 3640 tons of Uranium (51, 700 pounds of U-235) and 8960 tons of Thorium released.


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

www.ornl.gov...

These two are not the only radioactive releases from coal plants. There are also daughter products, including radium, radon, polonium, bismuth, and lead. Pottasium-40 is also seen in the exhaust from coal plants.


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.

www.ornl.gov...


An average value for the thermal energy of coal is approximately 6150 kilowatt-hours(kWh)/ton. Thus, the expected cumulative thermal energy release from U.S. coal combustion over this period totals about 6.87 x 10E14 kilowatt-hours. The thermal energy released in nuclear fission produces about 2 x 10E9 kWh/ton. Consequently, the thermal energy from fission of uranium-235 released in coal combustion amounts to 2.1 x 10E12 kWh. If uranium-238 is bred to plutonium-239, using these data and assuming a "use factor" of 10%, the thermal energy from fission of this isotope alone constitutes about 2.9 x 10E14 kWh, or about half the anticipated energy of all the utility coal burned in this country through the year 2040. If the thorium-232 is bred to uranium-233 and fissioned with a similar "use factor", the thermal energy capacity of this isotope is approximately 7.2 x 10E14 kWh, or 105% of the thermal energy released from U.S. coal combustion for a century. Assuming 10% usage, the total of the thermal energy capacities from each of these three fissionable isotopes is about 10.1 x 10E14 kWh, 1.5 times more than the total from coal. World combustion of coal has the same ratio, similarly indicating that coal combustion wastes more energy than it produces.

Consequently, the energy content of nuclear fuel released in coal combustion is more than that of the coal consumed! Clearly, coal-fired power plants are not only generating electricity but are also releasing nuclear fuels whose commercial value for electricity production by nuclear power plants is over $7 trillion, more than the U.S. national debt. This figure is based on current nuclear utility fuel costs of 7 mils per kWh, which is about half the cost for coal. Consequently, significant quantities of nuclear materials are being treated as coal waste, which might become the cleanup nightmare of the future, and their value is hardly recognized at all.

How does the amount of nuclear material released by coal combustion compare to the amount consumed as fuel by the U.S. nuclear power industry? According to 1982 figures, 111 American nuclear plants consumed about 540 tons of nuclear fuel, generating almost 1.1 x 10E12 kWh of electricity. During the same year, about 801 tons of uranium alone were released from American coal-fired plants. Add 1971 tons of thorium, and the release of nuclear components from coal combustion far exceeds the entire U.S. consumption of nuclear fuels. The same conclusion applies for worldwide nuclear fuel and coal combustion.

www.ornl.gov...

It's time to get rid of coal plants. Not only are we wasting MASSIVE amounts of money mining the coal, and wasting what could be fuel for nuclear plants, we're harming the environment, and the people around the plants at the same time. Nuclear power has a bad reputation due to the fear mongering brought on during the 1970s and 1980s. The words Nuclear, and Radiation bring thoughts of horrible mutations, and sickness, and other things along those lines. Nuclear power is actually one of the safest, and most regulated industries in the world. And doesn't have anywhere near the danger from emissions that a coal plant has.




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