Radiation (Ionizing)

DOE-HDBK-1188-2006

144. RADIATION (IONIZING). Particles (alpha, beta, neutrons, and other subatomic particles) or

photons (i.e., gamma, x-rays) emitted from the nucleus of unstable atoms as a result of radioactive

decay. Such radiation is capable of displacing electrons from atoms or molecules in the target material

(such as biological tissues), thereby producing ions. [NRC Glossary]

145. RADIOACTIVE WASTE. In general, waste that is managed for its radioactive content. Waste

material that contains source, special nuclear, or by-product material is subject to regulation as

radioactive waste under the Atomic Energy Act. Also, waste material that contains

accelerator-produced radioactive material or a high concentration of naturally occurring radioactive

material may be considered radioactive waste.[Derived from DOE O 435.1, DOE 5820.2A]

146. RADIOACTIVITY. Defined as a process:

The spontaneous transformation of unstable atomic nuclei, usually accompanied by the emission of

ionizing radiation. [Derived from NCRP 65]

Defined as a property:

The property of unstable nuclei in certain atoms to spontaneously emit ionizing radiation during nuclear

transformations. [Derived from BEIR III, RHH, ASD]

147. RADIOISOTOPE OR RADIONUCLIDE. An unstable isotope that undergoes spontaneous

transformation, emitting radiation. (See isotope.) [HPRH]

148. REASONABLY ACHIEVABLE CONTROL TECHNOLOGY (RACT). Technology for control

of pollutant emissions from existing sources in areas that are not in attainment of National Ambient Air

Quality Standards (NAAQS). RACT may include devices, systems, process modifications, or other

apparatus or techniques that are reasonably achievable taking into account: (1) the necessity of

imposing such controls in order to attain and maintain a NAAQS; (2) the social, environmental, and

economic impact of such controls; and (3) alternative means of providing for attainment and

maintenance of such a standard. [See National Ambient Air Quality Standards (NAAQS).] [Derived

from 40 CFR 51.100(o)]

149. RECORD OF DECISION (ROD). A concise public document that records a federal agency's

decision(s) concerning a proposed action for which the agency has prepared an environmental impact

statement (EIS). The ROD is prepared in accordance with the requirements of the Council on

Environmental Quality NEPA regulations (40 CFR 1505.2). A ROD identifies the alternatives

considered in reaching the decision, the environmentally preferable alternative(s), factors balanced by

the agency in making the decision, whether all practicable means to avoid or minimize environmental

harm have been adopted, and if not, why they were not. [See environmental impact statement (EIS).]

[Derived from 40 CFR 1505.2]

150. REM. A unit of dose equivalent. The dose equivalent in rems equals the absorbed dose in rads in

tissue multiplied by the appropriate quality factor and possibly other modifying factors. Derived from

"roentgen equivalent man," referring to the dosage of ionizing radiation that will cause the same

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