Nuclear vs Coal

Some initial considerations need to be included before looking at the specific areas of pollution when comparing nuclear and coal power production. These include the fact that the burning of coal, along with nuclear power, is also a non renewable source of energy production. Whilst coal combustion has a much greater chemical output into the atmosphere (particularly CO2) there is a much smaller amount of solid bi-product to be disposed of compared to the majority of nuclear power plants. Mining can have significant impact on the environment so the location of the coal vs. uranium ore is important, see Fuel and Waste: Mining processes.

Nuclear vs. Coal: CO2 emissions

When considering the pollution output of any process which requires fuel, the major factor looked at is the release of CO2 into the environment.

The journal "The Nuclear Energy Option" by Professor Bernard Cohen estimates that approximately 15 tonnes of CO2 is produced every minute by large coal burning power stations, where as an equivalent amount of energy can be produced in a nuclear power plant emitting almost five millionths the amount of CO2.

However, similar to coal fired power plants, there are other sources of pollution that must be taken into account when it comes to nuclear energy. Emissions that must be taken into account include those associated with the construction of the plant, mining and processing of the fuel, routine operation of the plant (fuel delivery etc.), the disposal of used fuel and other waste bi-products, and also the decommissioning of the plant.

Along with CO2, coal fired plants also give off other dangerous oxides such as Nitrous Oxide's and Sulfur Dioxide. The table below, supplied by the Nuclear Energy Institute, shows the emissions produced by 1 kWh of electricity based on the life-cycle analysis of different energy sources.

Nuclear vs. Coal: Radiation emissions

Along with the oxides that are released when burning coal for use in power stations it is important to note that releases from coal combustion also contain naturally occurring radioactive materials, mainly uranium and thorium. The levels of uranium and thorium released into the atmosphere, due to the combustion of coal in energy production, is shown in the plot below, taken from the Oak Ridge National Laboratory.

Along with the uranium and thorium, their daughter products produced by the decay of these isotopes, such as radium, radon, polonium, bismuth, and lead also lead to an increase in the radiation output.

J. P. McBride, R. E. Moore, J. P. Witherspoon, and R. E. Blanco showed, through research published in their article "Radiological Impact of Airborne Effluents of Coal and Nuclear Plants", December 8, 1978, issue of Science magazine, that Americans living near coal-fired power plants are exposed to higher radiation doses than those living near nuclear power plants that met government regulations.

The Oak Ridge National Laboratory also gives statistics on the levels of radioactive material given off by a coal fired plant. They estimate that to run your average 1000 megawatt coal-fired power plant, you need to burn about 4 million tonnes of coal. That 4 million tonnes of coal contains 5.2 tonnes of uranium, 12.8 tonnes of radioactive thorium, as well as 0.22 tonnes of radioactive potassium-40.

Along with this it was found by the National Council on Radiation Protection and Measurements (NCRP), that for 1982 the total release of radioactivity from 154 typical coal plants in the United States was approximately 97,318,510 megabecquerels, the equivalent of the radioactivity in 3200 household smoke detectors. They also found that the radiation exposure from an average 1000 MW power plant comes to 4.9 person-sieverts a year for coal-fired power plants and 0.048 person-sieverts a year for nuclear-fired power plants.

This factor of 100 just looks at the nuclear fired power plant by itself. It doesn't include the complete nuclear fuel cycle, which starts with ore mining, goes to fuel processing and operation of the reactor, and finishes with waste disposal. In that case, the radiation dose from a nuclear-fired power plant increases to 1.36 person-sieverts a year.

The sievert is the unit of effective dose of radiation, and so it depends on the biological effects of radiation as opposed to the physical aspects.
The person-Sv/year refers to the amount of radiation received by the entire area's population. To get this in terms of individual effects it needs to be divided by the number of people within the affected area.

The following table shows an estimation of effective dose in millisievert's (1 thousandth of a sievert) of a number of medical uses of radiation. This is to give a quick idea of the amount of radiation that we are looking at.

Diagnostic Procedure	Typical Effective Dose (mSv)1	Number of Chest X rays (PA film) for Equivalent Effective Dose2	Time Period for Equivalent Effective Dose from Natural Background Radiation3
Chest x ray (PA film)	0.02	1	2.4 days
Skull x ray	0.07	4	8.5 days
Lumbar spine	1.3	65	158 days
I.V. urogram	2.5	125	304 days
Upper G.I. exam	3.0	150	1.0 year
Barium enema	7.0	350	2.3 years
CT head	2.0	100	243 days
CT abdomen	10.0	500	3.3 years

http://www.fda.gov/cdrh/ct/risks.html

As shown in the table, the amount of radiation released from a coal fired plant over a year is of a very large amount and is much higher than the levels that we are subjected to under normal atmospheric conditions.

In Australia radiation safety standards are set by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) which are in line with international practice. The annual dose for members of the public (excluding background radiation and medical uses such as X-Rays) is set at 1 millisievert.

When taking into account the populations surrounding power plants the actual dose received by an individual living near a properly operated plant is generally below these levels. Still coal fired power stations end up giving a higher dose to the population than nuclear power plants.