Radioactive Waste
Radioactive waste is what remains after the use or production of radioactive materials. Modern society uses a variety of products and services that depend on radioactive materials. Uses include the production of household smoke alarms, gauges and monitors used in industry to insure quality control, medicinal and pharmaceutical research, and to generate electricity.
Radioactivity consists of highly energetic subatomic particles emitted by atoms from their cores (nuclei). The handling of radioactive waste is a major challenge for modern society, because exposure to high levels of radiation can kill or cause cancer. However, scientists are unsure whether exposure to low levels of radiation has harmful effects. Everyone is exposed to low doses of radiation from the sun and naturally occurring elements in the earth. Levels to which we are exposed every day are called background levels.
Radioactivity decays (decreases) over time. The rate of decay is measured in units called half-lives. If a substance has a radioactive half-life of one hundred years, it will lose 50% of its radioactivity by the end of that time. Some radioactive substances (or isotopes) have half-lives of less than a second, but others have half-lives of hundreds, thousands, or even billions of years. Wastes from those with long half-lives create serious long-term storage problems.
Radioactive waste is categorized according to its half-life and level of radioactivity. Federal regulations are based on two broad categories: low-level radioactive waste (LLRW) and high-level radioactive waste (HLRW). The regulations include more detailed sub-categories and classification criteria. Government definitions of low-level waste are further divided into Classes "A," "B," and "C." Class A LLRW generally includes wastes that have a half-lives of one hundred years or less. Some low-level radioactive waste can be kept in approved confinement areas while waiting for its radioactivity to decay. In most cases, fifty-five gallon drums are used. For example, hospitals are allowed to store waste until it decays to background radiation levels. Then it is placed with non-radioactive medical waste for disposal. Other LLRW cannot be handled in such a manner because of the long-half lives of the kinds of isotopes present in the waste and higher levels of radioactivity. Therefore, some wastes that are categorized as low-level must be sent to another site that is licensed to store them. Low-level radioactive waste includes items that have been contaminated as a result of exposure to radiation such as clothing, rags and mops used for cleaning, medical tubes and injection needles, equipment and tools, and animal tissues used in research. In 1997, about 315,000 cubic feet of commercial low-level radioactive waste were produced in the United States. Sixty-two percent came from nuclear reactors, 26% from industry, 9% from government (other than nuclear weapon facilities), 2.1% from educational institutions, and 0.4% from medical facilities.
High-level radioactive waste are materials that remain at dangerously high levels of radioactivity for hundreds or even thousands of years. High-level waste consists mainly of spent fuel rods from nuclear reactors and waste from the construction and destruction of nuclear weapons.
Radioactive waste is regulated by two federal agencies. The Department of Energy (DOE) regulates radioactive waste from nuclear weapons production and certain kinds of research. The federal Nuclear Regulatory Commission (NRC) regulates radioactive materials from non-military uses of nuclear material, including production of electricity. Some states, called Agreement States, have agreements with the NRC that authorize them to oversee regulation of radioactive materials within their own borders. Handling and storage of low-level radioactive waste requires licenses from the NRC or an Agreement State.
Containment of radioactive wastes is a major challenge. All radioactive waste goes to licensed and regulated facilities, but different facilities are used for differing levels and classifications of waste. As of 1998, there were only two facilities in the United States that accepted a range of low-level radioactive wastes. Sites in four other states that accepted such wastes in the past are closed. Most proposals to establish new LLRW containment facilities have been opposed by the public. Similarly, there is strong public opposition to siting of high-level waste facilities. In 1982, the U.S. Congress passed the Nuclear Waste Policy Act, calling for selection of a site and the construction of a high-level radioactive waste repository by 1998. In 1987, Congress directed the federal government to study one site, Yucca Mountain, Nevada. As of 1998, billions of dollars have been spent on studies of the site and preliminary construction. However, Nevada residents, environmental groups, and others continue to oppose the project. The site has not been officially approved by the NRC, and the estimated date for its opening has been moved to 2010. As of 1998, there were fewer than a dozen approved facilities in the United States that had HLRW on site. In addition, as of 1998 there are 110 nuclear reactors (not all operating) at seventy-three sites in thirty-four states. Each has a temporary storage site for radioactive wastes, each of which is full or nearly full.
Production and handling of radioactive wastes raise many questions that must be addressed. The decision to discontinue or limit certain activities that produce nuclear waste (such as the use of nuclear reactors to produce electricity) must be weighed against the fact that nuclear power provides an energy alternative that reduces the carbon emissions that lead to global warming. Furthermore, sites must be established for containment and long-term storage of radioactive wastes, with shipment of radioactive wastes from temporary storage sites to long-term facilities being done in a manner that maximizes protection for the public.
This is the complete article, containing 908 words
(approx. 3 pages at 300 words per page).
