Principles Of Radioactivity

Radioactivity in the environment provokes public reaction faster than any other environmental occurrence. The mere word radioactivity evokes fear in most people, even trained and skilled workers in the field. This fear has been etched in the public mind by such names as Hiroshima, Three Mile Island, and Chernobyl. This legacy of fear has made it difficult for proponents of the usefulness of radioactivity to gain the public trust.

Handling radioactivity in the environment was formerly the territory of the nuclear engineer. This has changed dramatically during the past twenty-five years. Today, individuals working in the environmental arena may be required to deal with radiological issues as one part of a broad environmental program. The aim of this section, and the remainder of the chapter, is to help such individuals grasp the principles of radioactivity as they pertain to environmental engineering.

The following questions must always be answered when one encounters or suspects the presence of radiation:

• What type and how much radioactive material is present?

• How can it be contained and/or disposed, including classification and transportation?

Radioactivity enters the environment from natural and man-made sources. Radioactivity can exist as gaseous, liquid or solid materials. Radon is a well-known example of a radioactive gas. Water often contains dissolved amounts of radium and uranium. Solid radioactive waste is produced from many sources, including the uranium and rare earth mining industries, laboratory and medical facilities, and the nuclear power industry.

The Environmental Protection Agency (EPA) has the authority to develop federal radiation protection guidelines for release of radioactivity into the general environment and for exposure of workers and the public. The Nuclear Regulatory Commission (NRC) and individual states authorized by the NRC, called agreement states, see Figure 11.21.1, implement the EPA's general environmental standards through regulations and licensing actions. These standards are usually based on recommendations developed by the International Atomic Energy Agency (IAEA).

FIG. 11.21.1 States with NRC-licenses or agreements for possession of radioactive materials.

FIG. 11.21.1 States with NRC-licenses or agreements for possession of radioactive materials.

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