Nuclear Surprises?

Which of the following statements is true?

1. A typical coal burning power plant releases more radioactive materials into the air than a typical nuclear reactor plant.

2. Spreading all the nuclear waste equally around the surface of the planet will hardly change the background radiation level at all.

Answer

Both are true statements.

1. The only emissions from a nuclear power plant are (a) water vapor from its cooling towers, (b) thermal energy in the external cooling water, (c) any stray gamma rays not shielded (unlikely to be above normal background), (d) any radioactive isotopes created in the external cooling water (unlikely to be above normal background), and (e) electrical energy.

The emissions and safety procedures at a coal-burning power plant are not as strict and, because all coal naturally contains radioactive material with many isotopes, some of these radioactive isotopes escape into the air when the coal is piled in storage, when the coal is burned, and so on. Measurements at coal-burning plants verify that radioactive atoms and molecules are released.

Scientific researchers in the McBride et al. reference below have concluded from measurements “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. . . . 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.”

G. J. Aubrecht, in the reference below, states that the radioactivity danger from each coal-burning electrical plant is at least 100 times the danger from each nuclear plant.

2. Background radiation levels combining terrestrial (from K-40, Th-232, Ra-226, etc.) and cosmic radiation (photons, muons, etc.) are fairly constant over the world in the range of 8–15 μrads per hour. Assuming maximum damage to human tissue, this present background radiation level corresponds to about 1.8 mSv per year.

If one spreads all the human-produced artificial radioactive materials equally around the surface of Earth, the local increase in radioactivity is expected to be minuscule compared to this indigenous natural radioactive background. Suppose we had a million metric tonnes of human-made radioactive material to be dispersed over Earth of approximately 5 × 10¹⁴ m². Each square meter would acquire an additional 0.2 × 10^–5 kg of radioactive material, compared to the natural amount of radioactive material in the top 10 centimeters of about 2 × 10^–2 kg, producing an insignificant amount of local radiation unless the half-lives were short, on the order of minutes to days. The additional amount adds only 1 part in 10,000 when dispersed around the globe.

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