CHAPTER 9 GLOSSARY absorbed dose – The energy imparted to matter active fault – A fault where another earthquake by ionizing radiation per unit mass of the is likely sometime in the future. Faults are irradiated material (e.g., biological tissue). The commonly considered to be active if they units of absorbed dose are the rad and the have moved one or more times in the last gray. (One rad equals 0.01 grays, which equals 10,000 years. (See fault.) 100 ergs per gram of material.) (See erg, gray, ionizing radiation, irradiated, and radiation activity – (1) A measure of the amount of absorbed dose [rad].) radiation emitted from a radioactive material, expressed in either becquerels or curies. accelerator (particle) – An apparatus for (See becquerel and curie.) (2) An action, imparting high velocities by electromagnetic or operation, or effort. electrostatic means to charged particles (as electrons) that are generated in the apparatus, Acute Exposure Guideline Levels (AEGLs) – accelerated in controlled paths to a state of high Threshold values published by the National energy, and focused continuously until they Research Council and National Academy of emerge as a stream of high-speed projectiles. Sciences for use in chemical emergency (See electron.) planning, prevention, and response programs. AEGLs represent threshold exposure limits for accident – In the context of this environmental the general population, including susceptible impact statement, a specific, identifiable, individuals, and are developed for exposure unexpected, unusual, and unintended event or periods of 10 minutes, 30 minutes, 1 hour, sequence of events that results in undesirable 4 hours, and 8 hours. AEGL values are defined consequences. for varying degrees of severity of toxic effects, as follows: accident sequence – In regard to nuclear facilities, an initiating event followed by system AEGL-1: The airborne level of concentration failures or operator errors that could result in of a substance above which the exposed significant core damage, confinement system population could experience notable failure, and/or radionuclide releases. discomfort, irritation, or certain asymptomatic nonsensory effects. However, the effects acid – A chemical compound with a pH value would not be disabling and would be transient lower than 7.0. (See pH.) and reversible upon cessation of exposure. actinide – Any member of the group of AEGL-2: The airborne level of concentration elements with atomic numbers 89 (actinium) of a substance above which the exposed to 103 (lawrencium), including uranium and population could experience irreversible or plutonium. All members of this group are other serious, long-lasting adverse health radioactive. (See atomic number and effects or an impaired ability to escape. radioactivity.) AEGL-3: The airborne level of concentration activation energy – The minimum amount of of a substance above which the exposed energy required to initiate a chemical reaction. population could experience life-threatening health effects or death. activation product – An element that is formed by absorption of neutrons, protons, or other additive – The property whereby the total effect nuclear particles and thus may be radioactive. of multiple agents is the sum of effects of the (See neutron and proton.) agents acting separately under the same conditions. 9–1 Tank Closure and Waste Management Environmental Impact Statement for the Hanford Site, Richland, Washington administrative control – Provisions related to alpha particle – A positively charged particle organization and management, procedures, ejected spontaneously from the nuclei of some record-keeping, assessment, and reporting that radioactive elements. It is identical to a helium are necessary to ensure safe operation of a nucleus and has a mass number of 4 and an facility. electrostatic charge of +2. It has low penetrating power and a short range (a few centimeters in adsorption – A “taking up” by physical or air). (See alpha radiation.) chemical forces of the molecules of gases, dissolved substances, or liquids by the surfaces alpha radiation – A strongly ionizing, but of solids or liquids with which they are in weakly penetrating, form of radiation consisting contact. of positively charged alpha particles emitted spontaneously from the nuclei of certain AEGL-1, -2, and -3 – See Acute Exposure elements during radioactive decay. Alpha Guideline Levels. radiation is the least penetrating of the three common types of ionizing radiation (alpha, beta, affected environment – The existing biological, and gamma). Even the most energetic alpha physical, social, and economic conditions of an particle generally fails to penetrate the dead area that are subject to direct and/or indirect layers of cells covering the skin and can be changes as a result of a proposed human action. easily stopped by a sheet of paper. Alpha radiation is most hazardous when an air pollutant – Generally, an airborne substance alpha-emitting source resides inside an that, in sufficiently high concentrations, could organism. (See alpha particle, ionizing harm living things or cause damage to materials. radiation, and radioactive decay.) From a regulatory perspective, air pollutants are substances for which emissions or atmospheric alternative – One of two or more actions, concentrations are regulated or for which processes, or propositions from which a maximum guideline levels have been established decisionmaker will determine the course to to enable assessment of their potential for be followed. The National Environmental harmful effects on human health and welfare. Policy Act (NEPA) of 1969, as amended, states that in preparing an environmental impact air quality – The cleanliness of the air as statement (EIS), an agency “shall ... study, measured by the levels of pollutants relative to develop, and describe appropriate alternatives to the standards or guideline levels established to recommended courses of action in any proposal protect human health and welfare. which involves unresolved conflicts concerning alternative uses of available resources” (Title 42 air quality control region – Geographic of the United States Code, Section 4322(2)(E)). subdivisions of the United States that were Council on Environmental Quality NEPA- established to deal with pollution on a regional implementing regulations indicate that the or local level. Some regions span more than one alternatives section in an EIS is “the heart of the state. environmental impact statement” (Title 40 of the ALARA – See as low as is reasonably Code of Federal Regulations, Section 1502.14) achievable. and include rules for presenting the alternatives, including no action, and their estimated impacts. alkaline – Having the properties of a soluble mineral salt capable of neutralizing acids. ambient – Surrounding. alluvium (alluvial) – Unconsolidated, poorly ambient air – The atmosphere surrounding sorted detrital sediments deposited by streams people, plants, and structures. and ranging in size from clay to gravel. alpha activity – The emission of alpha particles by radioactive materials. (See alpha particle.) 9–2 Chapter 9 ▪ Glossary ambient air quality standards – As prescribed area use factor – The ratio of the size of an by regulations, the level of pollutants in the air organism’s home, breeding, or feeding/foraging that may not be exceeded during a specified time range to the size of a contamination area; if the in a defined area. Air quality standards are used home range is larger than the contamination to provide a measure of the health-related and area, then the area use factor is unity (1). visual characteristics of the air. artifact – An object produced or shaped by amphibian – Class of cold-blooded, scaleless human workmanship that is of archaeological or vertebrates that usually begin life with gills and historical interest. then develop lungs. as low as is reasonably achievable (ALARA) – anadromous – Fish (such as salmon) that An approach to radiation protection used to ascend freshwater streams from saltwater bodies manage and control worker and public of water to spawn. exposures (individual and collective) and releases of radioactive material to the ancillary equipment – Structures associated environment to as far below applicable limits as with tank operations, including miscellaneous social, technical, economic, practical, and public underground storage tanks; the waste transfer policy considerations permit. ALARA is not a system (diversion boxes, valve pits, and transfer dose limit; it is instead a process for minimizing piping); tank pits; tank risers; in-tank equipment; doses to as far below limits as is practicable. and miscellaneous facilities used in the treatment, transfer, or storage of tank waste. atmospheric dispersion – The distribution of (See miscellaneous underground storage tanks.) pollutants from their source into the atmosphere by wind, turbulent air motion attributable to anion – A negatively charged ion. (See ion.) solar heating of Earth’s surface, or air movement over rough terrain and variable land and water annulus – The space between the inner and surfaces. outer shells of a double-shell tank. (See double- shell tank.) Atomic Energy Act – A law enacted in 1946 and amended in 1954 (Title 42 of the United antagonistic – Opposing or counteracting the States Code, Part 2011 et seq.) that placed effects of something else. nuclear production and control of nuclear materials under the oversight of a civilian aquatic – Living or growing in, on,