Glossary 9-1 Depleted UF6 PEIS

9 GLOSSARY accident: An unplanned sequence of events accident risk: Risk based on both the severity resulting in undesirable consequences, such as of an accident (consequence) and the probability the release of radioactive or hazardous material that the accident will occur. High-consequence to the environment. accidents that are unlikely to occur (low probability) may pose a low overall risk. For accident consequence assessment: An assess- purposes of comparison, accident risk is typically ment of the impacts following the occurrence of calculated by multiplying the accident an accident, independent of the probability of that consequence (e.g., dose or expected fatalities) by accident. The PEIS provides estimates of the the accident probability. consequences of a large number of possible accidents, ranging from those with low proba- accident risk assessment: An assessment that bility (rare) to those with relatively high proba- considers the probabilities and consequences of bility (frequent). a range of possible accidents, including low- probability accidents that have high conse- accident frequency: The likelihood that a quences and high-probability accidents that have specific accident will occur, that is, the proba- low consequences. The overall risk associated bility of occurrence. If an accident is esti- with an accident is generally estimated by mated to happen once every 50 years, the multiplying the accident consequence by the accident frequency is generally reported as probability of occurrence. 0.02 per year (1 occurrence divided by 50 years = 0.02 occurrences per year). For the PEIS, accident source term: The amount of radio- accident frequencies were grouped as follows: active or hazardous material released to the environment in dispersible form following an • I, likely (L) — The average frequency of accident. occurrence is estimated to be greater than or equal to 1 in 100 years. adsorption: Process in which solid surfaces attract and retain a layer of ions from a water • II, unlikely (U) — The average frequency solution. of occurrence is estimated to be 1 in 100 to 1 in 10,000 years. advection: The process by which material is transported by the bulk motion of flowing water. • III, extremely unlikely (EU) — The average frequency of occurrence is esti- air quality: Measure of the health-related and mated to be 1 in 10,000 to 1 in 1 million visual characteristics of the air, often derived years. from quantitative measurements of the concen- trations of specific injurious or contaminating • IV, incredible (I) — The average fre- substances. Air quality standards are the quency of occurrence is estimated to be prescribed level of constituents in the outside air less than 1 in 1 million years. that cannot be exceeded during a specific time in a specified area. Glossary 9-2 Depleted UF6 PEIS

Air Quality Control Region (AQCR): An workforce and the public) and releases of interstate or intrastate area designated by the radioactive material to the environment as low as U.S. Environmental Protection Agency for the social, technical, economic, practical, and public attainment and maintenance of National Ambient policy considerations permit. ALARA is not a Air Quality Standards. dose limit; it is a practice that has as its objective the attainment of dose levels as far below ALARA: see as low as reasonably achievable. applicable limits as possible. alpha particle ("): A positively charged Atomic Energy Act of 1954: The Act that, particle consisting of two protons and two along with other related legislation, provided the neutrons that is emitted during radioactive decay Atomic Energy Commission (a predecessor of from the nucleus of certain nuclides. It is the least the U.S. Department of Energy) with authority to penetrating of the three common types of develop generally applicable standards for radiation (alpha, beta, and gamma). protecting the environment from radioactive materials. ambient air: The surrounding atmosphere as it exists around people, plants, and structures. attainment area: An area considered to have air quality as good as or better than the National American Indian Religious Freedom Act of Ambient Air Quality standards as defined in the 1978: The Act that established national policy to Clean Air Act. An area may be an attainment protect and preserve for Native Americans their area for one pollutant and a nonattainment area inherent right of freedom to believe, express, and for others (see also nonattainment area). exercise their traditional religions, including the rights of access to religious sites, use and Bald and Golden Eagle Protection Act, as possession of sacred objects, and freedom to amended: The Act making it unlawful to take, worship through traditional ceremonies and rites. pursue, molest, or disturb bald (American) and golden eagles, their nests, or their eggs anywhere AQCR: see Air Quality Control Region. in the United States. aquifer: A saturated subsurface geologic forma- beta particle ($): An elementary particle tion that can transmit significant quantities of emitted from a nucleus during radioactive decay; water. it is negatively or positively charged, identical in mass to an electron, and in most cases easily Archaeological and Historic Preservation Act: stopped, as by a thin sheet of metal or plastic. Act directed at the preservation of historic and archaeological data that would otherwise be lost biota: The plant and animal life of a region. as a result of federal construction. It authorizes the U.S. Department of the Interior to undertake blending: The mixing of two quantities of recovery, protection, and preservation of archae- uranium with different levels of enrichment to ological and historic data. produce uranium enriched to a level suitable for manufacture into a fuel. can be as low as reasonably achievable (ALARA): blended with highly enriched uranium to produce An approach to control or manage radiation nuclear reactor fuel. exposures (both individual and collective to the Glossary 9-3 Depleted UF6 PEIS bounding: In the case of accident analysis, graphic dimensions of census tracts vary widely, bounding is a condition, consequence, or risk that depending on population settlement density. provides an upper limit that is not exceeded by Census tracts do not cross county borders. other conditions, consequences, or risks. This term is also used to identify conservative Clean Air Act: The Act that mandates the assumptions that will likely overestimate actual issuance and enforcement of air pollution control risks or consequences. standards for stationary sources and motor vehicles. breach: A general term referring to a hole in a cylinder or container. A breach may be caused by Clean Air Act Amendments of 1990: An Act corrosion or by mechanical forces, such as those that expanded the enforcement powers of the caused by a drop or contact with handling U.S. Environmental Protection Agency and equipment. added restrictions on air toxins, ozone-depleting chemicals, stationary and mobile emissions cancer: A group of diseases characterized by sources, and emissions implicated in acid rain uncontrolled cellular growth. Increased incidence and global warming. of cancer can be caused by exposure to radiation. Clean Water Act of 1972, 1987: The Act that candidate species: Plant or animal species that regulates the discharge of pollutants from a point are not yet officially listed as threatened or source into navigable waters of the United States endangered but are undergoing status review by in compliance with a National Pollution Dis- the U.S. Fish and Wildlife Service. These species charge Elimination System permit. Also are candidates for possible addition to the list of regulates discharges to or dredging of wetlands. threatened and endangered species. Code of Federal Regulations (CFR): The carbon monoxide (CO): A colorless, odorless codified form in which all federal regulations in gas that is toxic if breathed in high concentration force are published. over a period of time. Carbon monoxide is one of six criteria air pollutants specified under Title I of collective dose: Summation of individual the Clean Air Act. radiation doses received by all those exposed to the source or event being considered. The collec- cascade: The process system that is used to tive radiation dose received by a population separate the isotopic streams of uranium-235 and group is usually measured in units of person-rem. uranium-238 in gaseous diffusion plants. collective population risk: A measure of cask: A heavily shielded, typically robust con- possible loss in a group of people that takes into tainer for shipping or storing . account the probability that the hazard will cause Spent nuclear fuel casks are usually cylindrical harm and the consequences of that event. The containers with radiation shielding provided by collective population risk does not express the steel, lead, , or depleted uranium. risk to specific individual members of the population. census tract: An area usually containing between 2,500 and 8,000 persons that is used for committed effective dose equivalent: The sum organizing and monitoring census data. The geo- of the committed dose equivalents to various Glossary 9-4 Depleted UF6 PEIS tissues of the body, each multiplied by its weight- reasonably foreseeable future actions regardless ing factor. It does not include contributions from of what agency (federal or nonfederal), private external doses. Committed effective dose industry, or individual undertakes such other equivalent is expressed in units of rem and actions. Cumulative impacts can result from provides an estimate of the lifetime radiation individually minor but collectively significant dose to an individual from radioactive material actions taking place over a period of time. taken into the body through either inhalation or ingestion. curie (Ci): A measure of the radioactivity of a material, equal to 3.7 × 1010 disintegrations per convection: Process by which heat is trans- second. ferred between a surface and a moving fluid when they are at different temperatures. cylinder: As defined for this PEIS, a large steel

container used to store depleted UF6. Cylinders cost analysis: The life-cycle cost estimates, are typically about 12 ft long by 4 ft in diameter including estimates of labor and capital, for each and weigh about 10 to 14 tons when full of of the strategy alternatives considered in the depleted UF6. PEIS. cylinder preparation: The activities required to criteria pollutants: Six air pollutants for which prepare depleted UF6 cylinders for transportation. national ambient air quality standards are Cylinder preparation would be required for established by the U.S. Environmental Protection alternatives that involve transport of cylinders to Agency under Title I of the Clean Air Act. The a conversion facility or a long-term storage site. six pollutants are sulfur dioxide (SO2), nitrogen oxides (NOx), carbon monoxide (CO), ozone decay: Natural process by which a radioactive

(O3), particulate matter (PM10, particles with a atom is physically transformed into another form mean diameter of less than 10 microns [µm]), by the release of energy in the form of subatomic and lead (Pb). particles such as alpha or beta particles, or electromagnetic radiation such as gamma rays. critical habitat: Air, land, or water area and constituent elements, the loss of which would decay products, radioactive: The isotopes appreciably decrease the likelihood of sur- produced when another isotope undergoes vival and recovery of a species listed as radioactive decay. The decay products are also threatened or endangered or a distinct segment of typically radioactive. the population of that species. decommissioning: The process of removing a cultural resources: Archaeological sites, facility from operation, followed by decon- architectural structures or features, traditional use tamination, entombment, dismantlement, or areas, and Native American sacred sites or conversion to another use. special use areas. defluorination: The conversion of uranium cumulative impacts: The impacts assessed in hexafluoride to U3O8 accomplished by using an environmental impact statement that could steam. UF6 is chemically decomposed with steam potentially result from the incremental impact of and heat to produce U3O8 and HF, with the action when added to other past, present, and concentrated HF as the direct by-product. Glossary 9-5 Depleted UF6 PEIS

depleted UF6: see depleted uranium hexa- fatalities, as well as other fatal or nonfatal fluoride. adverse impacts to human health. depleted uranium hexafluoride (depleted dose: The amount of energy deposited in body

UF6): A compound of uranium and fluorine tissue due to radiation exposure. Various from which most of the uranium-235 isotope has technical terms — such as dose equivalent, been removed. Isotope separation results in two effective dose equivalent, and collective dose — product “streams.” The stream containing the are used to evaluate the amount of radiation additional uranium-235 is said to be enriched and received by an exposed individual or population. is collected for further processing into other forms of enriched uranium. The remaining UF6 dose rate: Radiation dose delivered per unit of stream is said to be “depleted” and is now stored time and measured in rem per hour. at the Paducah, Portsmouth, and K-25 sites. drain: A device (e.g., a channel or pipe) used to disposal: The emplacement of material in carry away or to empty liquid from a liquid a manner designed to ensure isolation for the source. foreseeable future. Disposal is considered to be permanent, with no intent to retrieve the material drifts: Lateral extensions of belowground for future use. tunnels that are used for storage or disposal of material. disposal facility: A facility or part of a facility into which hazardous, radioactive, or solid waste DUCRETE™: A composite material produced is intentionally placed and at which waste is by combining dense UO2 and concrete. intended to permanently remain after closure of the facility. effective dose equivalent: The sum of the products of the dose equivalent to various organs disproportionately high and adverse envi- or tissues and the weighting factors applicable to ronmental impact: An adverse environ- each of the body organs or tissues that are mental impact determined to be unacceptable or irradiated. The effective dose equivalent includes above generally accepted norms. A dispro- the dose from radiation sources internal and/or portionately high impact refers to an environ- external to the body and is expressed in units of mental hazard with a risk or rate of exposure for rem. a low-income or minority population that exceeds the risk or rate of exposure for the general EIS: see environmental impact statement. population. Emergency Planning and Community Right- disproportionately high and adverse human to-Know Act of 1986: The Act that established health effect: Any effect on human health from programs to provide the public with important exposure to environmental hazards that exceeds information on the hazardous and toxic chemicals generally accepted levels of risk and affects low- in their communities and established emergency income and minority populations at a rate that planning and notification requirements to protect appreciably exceeds the rate for the general the public in the event of a release of hazardous population. Adverse health effects are measured substances. in risks and rates that could result in latent cancer Glossary 9-6 Depleted UF6 PEIS

Emergency Response Planning Guideline environmental justice: The fair treatment of (ERPG): A hazardous-material personnel people of all races, cultures, incomes, and educa- exposure level or range which, when exceeded tional levels with respect to the development, by a short-term or acute exposure, will cause implementation, and enforcement of environ- adverse reproductive, developmental, or carcino- mental laws, regulations, and policies. Fair genic effects in humans. ERPGs are approved by treatment implies that no population of people a committee of the American Industrial Hygiene should be forced to shoulder a disproportionate Association. share of the negative environmental impacts of pollution or environmental hazards due to a lack endangered species: Any species that is in of political or economic strength. danger of extinction throughout all or a signi- ficant portion of its geographic range. ERPG: see Emergency Response Planning Guideline. Endangered Species Act, as amended: The Act intended to prevent the further decline of evapotranspiration: Loss of water from the endangered and threatened species and to restore soil by both evaporation and transpiration from these species and their habitats. Consultation plants growing in the soil. with the U.S. Fish and Wildlife Service is necessary to determine whether endangered and exposure: The condition of being made subject threatened species or their critical habitats are to the action of radiation, chemicals, or physical known to be in the vicinity of the proposed hazards. Exposure is sometimes used as a action. generic term to refer to the dose of radiation or chemicals absorbed by an individual or engineering analysis: A comprehensive tech- population. nical analysis of depleted UF6 technology options, including conversion, use, trans- external exposure: Exposure to radiation, portation, storage, and disposal. principally gamma radiation, that originates from sources outside of the body. enrichment: An isotopic separation process that increases the portion of the uranium-235 isotope failure: For this PEIS, defined as the release of in relation to uranium-238 in natural uranium. In disposed uranium material from the bottom of addition to the enriched uranium, this process the disposal facility to the surrounding soil. also produces uranium depleted in uranium-235. Failure of a disposal facility would generally Enrichment is accomplished in the United States occur hundreds to thousands of years after through a process called gaseous diffusion. facility closure due to the ultimate penetration of water and natural degradation of engineered environmental impact statement (EIS): A barriers. document prepared in accordance with the requirements of the National Environmental Farmland Protection Policy Act of 1981: An Policy Act. A programmatic EIS (PEIS) is a Act that requires federal agencies to take steps to broad-scope EIS that identifies and assesses the ensure that federal actions do not contribute to environmental impacts of a program or policy. the unnecessary and irreversible conversion of farmland to nonagricultural uses in cases in Glossary 9-7 Depleted UF6 PEIS which other national interests do not override the fugitive emissions: Uncontrolled emissions to importance of protecting the farmland resources. the atmosphere from pumps, valves, flanges, seals, and other process points not vented fault: A fracture in the earth’s crust accom- through a stack. Also includes emissions from panied by displacement of one side of the area sources such as ponds, lagoons, landfills, fracture with respect to the other and in a and piles of stored material. direction parallel to the fracture. gamma radiation ((): High-energy, short- Federal Facilities Compliance Act of 1992: An wavelength electromagnetic radiation (a packet Act that amended the Resource Conservation of energy) emitted from a radioactive nucleus and Recovery Act, with the objectives of bringing during decay. Gamma radiation frequently all federal facilities into compliance with accompanies alpha and beta emissions and applicable federal and state hazardous waste always accompanies fission. Gamma rays are laws, of waiving federal sovereign immunity very penetrating and are best stopped or shielded under those laws, and of allowing the imposition against by dense materials such as lead or of fines and penalties. The law also requires the uranium. Gamma rays are similar to X-rays, but U.S. Department of Energy to submit an are usually more energetic. inventory of all its mixed waste and to develop a treatment plan for mixed waste. gaseous diffusion: The uranium enrichment process first developed in the 1940s as part of the federal-listed species: see threatened, endan- Manhattan Project. In gaseous diffusion, gaseous gered, and candidate species. UF6 is allowed to flow irreversibly through a membrane or diffusion barrier. With holes just fission: The splitting of a heavy atomic nucleus large enough to allow the passage of individual into two nuclei of lighter elements, accompanied molecules without passage of the bulk gas by the release of energy and generally one or through the membrane or diffusion barrier, more more neutrons. Fission can occur spontaneously of the lighter molecules (i.e., those containing or be induced by neutron bombardment. uranium-235 atoms) will flow through the barrier than the heavier molecules (i.e., those containing floodplain: The lowlands adjoining inland and uranium-238 atoms), thus effecting partial coastal waters and relatively flat areas, including separation. Gaseous diffusion results in two at a minimum that area inundated by a 1% or streams of UF6: one enriched in the uranium-235 greater chance flood in any given year. The base isotope and one depleted in the uranium-235 floodplain is defined as the 100-year (1%) flood- isotope. plain. The critical action floodplain is defined as the 500-year (0.2%) floodplain. gelation: A process for conversion of UF6 to

UO2, where the solid uranium is separated from food chain: The scheme of feeding relationships an aqueous solution through chemical reaction. between trophic levels that unites the member species of a biological community. general public: For purposes of analyses in this PEIS, anyone outside the boundary of a site at fugitive dust: The dust released from activities the time of an accident or during normal facility associated with construction, manufacturing, or operations, as well as people along transportation transportation. Glossary 9-8 Depleted UF6 PEIS routes used to ship hazardous chemicals or grout: A cementing or sealing mixture of radioactive materials. cement and water to which sand, sawdust, or other fillers (additives — e.g., waste) may be generic sites: For this PEIS, sites broadly added. defined with very generalized environmental characteristics for the purpose of evaluating the grouted waste: Refers to the solid material impacts of manufacturing, disposal, and long- obtained by mixing waste material with cement term storage in mines. For example, disposal of and repackaging it in drums. Grouting is uranium oxide was analyzed for a wet (or intended to reduce the mobility of the waste eastern) location and a dry (or western) location. material. Such a broad characterization is useful for evaluating an activity that is very generalized in habitat: Area where a plant or animal lives. nature and for which one environmental variable (such as groundwater) is of most importance. hazard index: A summation of the hazard quotients for all chemicals to which an individual geologic repository (mined geologic reposi- is exposed. A hazard index value of 1.0 or less tory): An underground facility for the disposal than 1.0 indicates that no adverse human health of nuclear waste. The waste is isolated by placing effects (noncancer) are expected to occur. it in mined cavities in a continuous, stable geologic formation at depths typically greater hazard quotient: A comparison of an estimated than 300 meters. A surface facility is used to chemical intake (dose) with a reference dose prepare the waste material for placement in the level below which adverse health effects are underground portions of the repository. unlikely. The hazard quotient is expressed as the ratio of the estimated intake to the reference glove box: An airtight box used to work with dose. The value is used to evaluate the potential hazardous material, vented to a closed filtering for noncancer health effects, such as organ system, having gloves attached inside the box to damage, from chemical exposures. protect the worker. hazardous air pollutants: The 189 chemicals greater-than-Class-C waste: Low-level radio- and chemical classes — such as asbestos, active waste generated by the commercial sector beryllium, mercury, benzene, and radionuclides that exceeds U.S. Nuclear Regulatory Commis- — whose emissions are specially regulated by sion concentration limits for Class-C low-level the Clean Air Act. waste, as specified in 10 CFR Part 61. hazardous material: A material that poses a green salt: see uranium tetrafluoride. potential risk to health, safety, and property when transported or handled. groundshine: Gamma radiation emitted from radioactive materials deposited on the ground. hazardous waste: Under the Resource Conser- vation and Recovery Act, a solid waste, or groundwater: Generally, all water contained in combination of solid waste, which — because of the ground; water held below the water table its quantity, concentration, or physical, chemical available to freely enter wells. or infectious characteristics — may (a) cause or significantly contribute to an increase in mortality Glossary 9-9 Depleted UF6 PEIS or an increase in serious irreversible, or the liquid. High-level waste contains a combi- incapacitating reversible, illness; or (b) pose a nation of transuranic waste and fission products substantial present or potential hazard to human in concentrations requiring permanent isolation. health or the environment when improperly High-level waste may include other highly treated, stored, transported or disposed of, or radioactive material that the U.S. Nuclear Regu- otherwise managed. Source material (including latory Commission, consistent with existing law,

UF6), special nuclear material, and by-product determines by rule requires permanent isolation. material, as defined by the Atomic Energy Act, are specifically excluded from the definition of highly enriched uranium (HEU): Uranium solid waste. that contains the isotope uranium-235 in concen- tration of 20% or more. Naturally occurring health risk conversion factors: Estimates of uranium has a uranium-235 content of about the expected number of health effects (i.e., 0.7%. cancer cases, cancer fatalities, or genetic effects) caused by exposure to a given amount of hydrocarbons (HC): Chemical compounds radiation. Health risk conversion factors are containing carbon and hydrogen as the principal multiplied by the estimated radiation dose elements. received by a given population (such as workers or members of the public) in order to estimate the hydrogen fluoride (HF): A colorless, toxic, number of health effects expected to occur as a fuming, corrosive liquid or gas; miscible with result of the exposure. Health risk conversion cold water and very soluble in hot water. HF is factors are derived from data collected from produced when UF6 comes in contact with water, Japanese atomic bomb survivors, historical such as humidity in the air, and is often a by- medical and industrial exposures, and animal product produced when UF6 is converted to experimentation. another chemical form. heels: Residual amounts of nonvolatile material | hygroscopic: A chemical substance with an left in a cylinder following the removal of the | affinity for water; one that will absorb moisture, depleted UF6. usually from the air.

HEU: see highly enriched uranium. Inconel: A metal alloy containing nickel, chromium, and iron, which exhibits good resis- HF: see hydrogen fluoride. tance to corrosion in aqueous environments. high-efficiency particulate air (HEPA) filter: internal exposure: The ingestion or inhalation A filter with an efficiency of at least 99.95% used of radioactive contaminants in air, water, food, or to separate particles from air exhaust streams soil, and the subsequent radiation dose to internal prior to releasing that air into the atmosphere. organs and tissues of the body. high-level (HLW): The involved worker: A worker directly involved in highly radioactive waste material that results the handling or processing of radioactive or from the reprocessing of spent nuclear fuel, hazardous materials. including liquid waste produced directly in reprocessing and any solid waste derived from Glossary 9-10 Depleted UF6 PEIS ion: An atom, molecule, or molecular fragment access to the material until a future use is carrying a positive or negative electrical charge. identified or until a decision is made to dispose of the material. ionizing radiation: Radiation that has enough energy to remove electrons from substances that low-enriched uranium (LEU): Uranium that it passes through, forming ions. contains the isotope uranium-235 in a concen- tration of less than 20% and greater than 0.7%. isotope: One of two or more species of an Most commercial reactor fuel is enriched to 5% element that have the same atomic number but or less uranium-235. different masses. The difference in mass is due to the presence of one or more extra neutrons in the low-income population: Persons of low- nucleus. The number of protons for different income status. This status is based on isotopes of the same element is the same. U.S. Bureau of the Census definitions of Uranium-235 and uranium-238 are examples of individuals living below the poverty line, as isotopes of the element uranium. defined by a statistical threshold that considers family size and income. For 1990, the poverty land disposal restrictions: Restrictions on the line threshold for a family unit of four individuals disposal of waste that is hazardous under the was $12,674 (based on 1989 income). In this Resource Conservation and Recovery Act. The PEIS, low-income population was defined as land disposal restrictions include technology- consisting of any census tract located within a based or performance-based treatment standards 50-mile (80-km) radius of a storage site that has that must be met before hazardous waste can be a proportion of low-income population that is disposed of on land. greater than the respective state average.

latent cancer fatality (LCF): Term used to low-level mixed waste (LLMW): Waste that indicate the estimated number of cancer fatalities contains both hazardous waste under the that may result from exposure to a cancer- Resource Conservation and Recovery Act and causing element. Latent cancer fatalities are radioactive material, including source, special similar to naturally occurring cancers and may be nuclear, or by-product material subject to the expressed at any time after the initial exposure. Atomic Energy Act of 1954. Such waste has to be handled, processed, and disposed of in a lead (Pb): A toxic metal in air, food, water, and manner that considers its chemical as well as its soil. Overexposure to this metal can cause radioactive components. damage to the circulatory, digestive, and central nervous systems. Lead is one of six criteria air low-level radioactive waste (LLW): Waste pollutants specified under Title I of the Clean Air that contains radioactivity but is not classified as Act. high-level waste, transuranic waste, spent nuclear fuel, or “11e(2) by-product material” as LEU: see low-enriched uranium. defined by U.S. Department of Energy Order 5820.2A. Low-level waste is typically disposed long-term storage: The containment of material of using shallow land burial. on a temporary basis or for a period of years, in such a manner as not to constitute disposal of Low-Level Radioactive Waste Policy Act: The such material. Long-term storage would preserve Act, as amended, that established procedures for Glossary 9-11 Depleted UF6 PEIS the implementation of compacts providing for the Modified Mercalli Intensity: A level on the establishment and operation of regional disposal modified Mercalli scale. A measure of the facilities for low-level radioactive waste and that perceived intensity of earthquake ground- made the federal government responsible for shaking with 12 divisions, from I (not felt by ultimate disposal of commercially generated people) to XII (damage nearly total). waste with a classification of greater-than-Class- C (see also greater-than-Class-C waste). Monel: Trade name for a white copper-nickel alloy that is acid- and corrosion-resistant. maximally exposed individual (MEI): A hypothetical individual who — because of multi-purpose unit: A heavily shielded cask proximity, activities, or living habits — could that can be used for storage, transportation, and potentially receive the maximum possible dose of disposal of spent nuclear fuel. radiation or of a hazardous chemical from a given event or process. National Ambient Air Quality Standards (NAAQS): Air quality standards established by Migratory Bird Treaty Act, as amended: Act the Clean Air Act, as amended. The primary intended to protect birds that have common NAAQS are intended to protect the public health migration patterns between the United States and with an adequate margin of safety, and the Canada, Mexico, Japan, and Russia. secondary NAAQS are intended to protect the public welfare from any known or anticipated millirem: A unit of radiation exposure equal to adverse effects of a pollutant. one-thousandth of a rem. National Emission Standards for Hazardous minority population: Persons classified by the Air Pollutants (NESHAPS): A set of national U.S. Bureau of the Census as Negro/Black/ emission standards for listed hazardous pollu- African-American, Hispanic, Asian and Pacific tants emitted from specific classes or categories Islander, American Indian, Eskimo, Aleut, or of new and existing sources. These standards other nonwhite; based on self-classification by were implemented in the Clean Air Act Amend- individuals according to the race with which they ments of 1977. most closely identify. For this PEIS, a minority population was defined as any census tract National Environmental Policy Act (NEPA) of located within a 50-mile (80-km) radius of a 1969: The Act that established the national storage site that has a proportion of minority policy to protect humans and the environment, population that is greater than the respective state requiring environmental reviews of federal average. actions that have the potential for significant impact on the environment. Also established the mixed waste: see low-level mixed waste. Council on Environmental Quality. model: A conceptual, mathematical, or physical National Historic Preservation Act of 1966, as system obeying certain specified conditions, amended: The Act directing federal agencies to whose behavior is used to understand the consider the effects of their programs and physical system to which it is analogous. Models projects on properties listed on or eligible for the are often used to predict the behavior or outcome National Register of Historic Places. It does not of future events. require any permits, but pursuant to federal code, Glossary 9-12 Depleted UF6 PEIS if a proposed action might impact any National Ambient Air Quality Standards for one archaeological, historical, or architectural or more criteria pollutants (see also attainment resource, it mandates consultation with the area and criteria pollutants). proper agencies. nonhazardous waste: Routinely generated National Pollutant Discharge Elimination waste, including general facility refuse such as System (NPDES): Federal permitting system paper, cardboard, glass, wood, plastics, scrap, required for hazardous effluents regulated metal containers, dirt, and rubble. Nonhazardous through the Clean Water Act, as amended. waste is segregated and recycled whenever possible. National Register of Historic Places: A list maintained by the Secretary of the Interior as the noninvolved worker: A worker employed at a official list of historic properties (districts, sites, site who is not directly involved in the handling buildings, structures, and objects) deserving of radioactive or hazardous materials. preservation because of their local, state, or national significance in American history, normal operations: Conditions during which architecture, archaeology, engineering, and facilities and processes operate as expected or culture. Properties listed on or eligible for the designed. In general, the evaluation of normal National Register are protected by the National operations includes the occurrence of some Historic Preservation Act of 1966, as amended. infrequent events that, although not considered routine, are not classified as accidents. For NEPA document: A document prepared example, the identification and repair of breached pursuant to requirements of the National Envi- cylinders, expected to occur infrequently, was ronmental Policy Act or the Council on Environ- considered to be normal operations. mental Quality regulations, including the following: environmental assessment, envi- Nuclear Waste Policy Act of 1982, as ronmental impact statement, Notice of Intent, amended: The Act that authorized federal Record of Decision, and Finding of No Signi- agencies to develop a geologic repository for the ficant Impact. permanent disposal of spent nuclear fuel and high-level radioactive waste. The Act specified

nitrogen oxides (NOx): The oxides of nitrogen, the process for selecting a repository site and primarily nitrogen oxide (NO) and nitrogen constructing, operating, closing, and dioxide (NO2), that are produced in the combus- decommissioning the repository. The Act also tion of fossil fuels and can constitute an air established programmatic guidance for these

pollution problem. When NO2 combines with activities. volatile organic compounds in sunlight, ozone is produced. Nitrogen oxides are one of six criteria nuclear weapon: The general name given to air pollutants specified under Title I of the Clean any weapon in which the explosion results from Air Act. energy released by reactions involving atomic nuclei — either fission, fusion, or both. nonattainment area: An Air Quality Control Region (or a portion thereof) for which the Occupational Safety and Health Adminis- U.S. Environmental Protection Agency has deter- tration (OSHA): The agency that oversees and mined that ambient air concentrations exceed Glossary 9-13 Depleted UF6 PEIS regulates workplace health and safety, created by Options, Disposal: Options for disposal of the Occupational Safety and Health Act of 1970. depleted uranium material as low-level radio- active waste. The disposal options in the PEIS Options, Continued Cylinder Storage: An are defined by the chemical form of the uranium option for all alternative management strategies and the type of disposal facility. Two disposal considered in the PEIS that would involve the options were considered in the PEIS: continued storage of depleted UF6 cylinders at • Disposal of U3O8 — Depleted uranium the Paducah, Portsmouth, and K-25 sites for could be disposed of as U3O8 following some period of time. Continued cylinder storage conversion. Disposal of both ungrouted was assumed to occur at these three sites through and grouted U3O8 was considered. Poten- 2028 for all alternatives and to extend through tial disposal facilities included shallow 2039 for the no action alternative. earthen structures, belowground vaults, and an underground mine.

Options, Conversion: Conversion of depleted • Disposal of UO2 — Similarly to disposal

UF6 to another chemical form. The conversion of U3O8, depleted uranium could be options considered in the PEIS were conversion disposed of as UO2 following conversion, to U3O8, conversion to UO2, and conversion to in either grouted or ungrouted form. The metal. Several representative technologies were disposal facilities considered were the considered within each option. same as those considered for U3O8: shallow earthen structures, belowground Options, Cylinder Preparation: The activities vaults, and an underground mine. necessary to prepare depleted UF6 cylinders for off-site transportation. Depleted UF6 cylinders Options, Manufacture and Use: Options that were designed, built, tested, and certified to meet involve the manufacture and use of depleted requirements of the U.S. Department of Trans- uranium as radiation shielding material, as portation (DOT) for shipment by truck and rail. follows: However, after several decades in storage, some • Use as Uranium Oxide Shielding — The cylinders no longer meet these requirements. manufacture and use of uranium oxide- Two options for preparing these cylinders for shielded storage casks for spent nuclear shipment were considered in the PEIS: fuel. • Cylinder Overcontainers — Protective • Use as Uranium Metal Shielding — The metal “overcontainers” in which cylinders manufacture and use of uranium metal- not meeting DOT requirements could be shielded casks for spent nuclear fuel. placed for shipment. These reusable over- containers would be slightly larger than a Options, Storage: Storage of depleted uranium cylinder and would be designed to meet all until use at a later date. Storage options were DOT requirements. defined by the chemical form of the uranium and • Cylinder Transfer — New cylinders into the type of storage facility. Three storage options

which the depleted UF6 in cylinders not were considered in the PEIS:

meeting DOT requirements would be • Storage as UF6 — Storage of UF6 in transferred for shipment. cylinders similar to those currently used. Storage facilities considered included yards, buildings, and an underground mine. Glossary 9-14 Depleted UF6 PEIS

• Storage as U3O8 — Storage of depleted turbulence. Categories range from extremely

uranium in drums as U3O8 following con- unstable (A) to extremely stable (F). Unstable version. Storage facilities considered conditions promote the rapid dispersion of included buildings, belowground vaults, atmospheric contaminants and result in lower air and an underground mine. concentrations compared with stable conditions.

• Storage as UO2 — Similar to options for

U3O8, storage of depleted uranium as UO2 pathway: A route or sequence of processes by in drums in buildings, belowground vaults, which radioactive or hazardous material may or an underground mine. move through the environment to humans or other organisms. For example, one potential OSHA: see Occupational Safety and Health exposure pathway involves the contamination Administration. and subsequent use of surface water or groundwater. overcontainer: Container used for transporting cylinders not meeting U.S. Department of Trans- PCBs: see polychlorinated biphenyls. portation (DOT) requirements. An overcontainer is a container into which a cylinder would be PEIS: see programmatic environmental impact placed for shipment. The metal overcontainer statement. would be designed, tested, and certified to meet all DOT shipping requirements and would be PELs: see permissible exposure limits. suitable to contain, transport, and store the cylinder contents regardless of cylinder condition. permeability: In hydrology, the capacity of a The type of overcontainer evaluated in the PEIS medium (rock, sediment, or soil) to transmit was a “clamshell” vessel. groundwater. Permeability depends on the size and shape of the pores in the medium and how ozone (O3): The triatomic form of oxygen. In they are interconnected. the stratosphere, ozone protects the Earth from the sun’s ultraviolet rays, but in lower levels of permissible exposure limits (PELs): Occupa- the atmosphere, ozone is considered an air tional exposure limits established for worker pollutant and can cause irritation of the eyes and exposures to various chemicals, endorsed by the respiratory tract. Ozone is one of six criteria air Occupational Safety and Health Administration. pollutants specified under Title I of the Clean Air Permissible exposure limits are defined so as to Act. protect worker health and may be for short-term or 8-hour duration exposure. palustrine: Nontidal wetlands dominated by trees, shrubs, or persistent emergent vegetation plume: The spatial distribution of a release of or small shallow wetlands. airborne or waterborne material as it disperses in the environment. particulates: Particles in an aerosol stream, the larger of which usually can be removed by filtration.

Pasquill stability categories: Classification scheme that describes the degree of atmospheric Glossary 9-15 Depleted UF6 PEIS

plutonium (Pu): A heavy, radioactive, metallic depleted UF6. The PEIS considers six alternative element with the atomic number 94. Plutonium is approaches to accomplish that action. produced artificially in a reactor by bombardment of uranium with neutrons and is used primarily in public: see general public. the production of nuclear weapons. rad: see radiation absorbed dose.

PM10: Particulate matter with a mean aero- dynamic diameter equal to or less than 10 microns | radiation: The particles (alpha and beta

(µm). PM10 is one of six criteria air pollutants particles) or photons (gamma rays) emitted from specified under Title I of the Clean Air Act. the nuclei of radioactive atoms. Some elements are naturally radioactive; others are induced to Pollution Prevention Act of 1990: The Act become radioactive by bombardment in a reactor. establishing the national policy that pollution Naturally occurring radiation, such as that from should be prevented or reduced at the source or uranium, is indistinguishable from induced recycled in an environmentally safe manner and radiation. that pollution that cannot be prevented or recycled should be, as a last resort, treated and disposed of radiation absorbed dose (rad): The basic unit in an environmentally safe manner. of absorbed dose equal to the absorption of 0.01 joule per kilogram of absorbing material. polychlorinated biphenyls (PCBs): A class of chemical substances formerly manufactured as an radioactivity: The spontaneous decay or disin- insulating fluid in electrical equipment. PCBs are tegration of unstable atomic nuclei, accompanied highly toxic to aquatic life and, in the environ- by the emission of radiation. ment, exhibit many of the characteristics of dichloro diphenyl trichloroethane (DDT). PCBs radionuclide: An atom that exhibits radioactive persist in the environment for a long time and properties. Standard practice for naming a radio- accumulate in animals. nuclide is to use the name or atomic symbol of the element followed by its atomic weight (e.g., polycyclic aromatic hydrocarbons (PAHs): A cobalt-60 [Co-60], a radionuclide of cobalt with group of organic compounds, some of which are an atomic weight of 60). known to be potent human carcinogens. recharge: Replenishment of water to an aquifer. population dose: see collective dose. Record of Decision (ROD): A document programmatic environmental impact state- prepared in accordance with the requirements of ment (PEIS): A type of EIS that deals with 40 CFR 1505.2 that provides a concise public broad strategies and decisions, such as those that record of the U.S. Department of Energy’s are regional or national in scope. decision on a proposed action for which an EIS was prepared. A ROD identifies the alternatives proposed action: The term used in an EIS to considered in reaching the decision, the refer to the activity planned by a federal agency environmentally preferable alternative(s), and the that generates the need to prepare an EIS. The factors balanced by the U.S. Department of proposed action for this PEIS is to select a Energy in making the decision. The ROD also strategy for the long-term management of identifies whether all practicable means to avoid Glossary 9-16 Depleted UF6 PEIS or minimize environmental harm have been Safe Drinking Water Act, as amended: An Act adopted and, if not, why they were not. that protects the quality of the public water supplies and all sources of drinking water. region of influence (ROI): The physical area that bounds the environmental, sociological, sanitary waste: Waste generated by normal economic, or cultural feature of interest for the housekeeping activities, liquid or solid (includes purpose of analysis. sludge), that is not hazardous or radioactive. rem: The dosage of an ionizing radiation that will schoepite: A yellow secondary uranium mineral cause the same biological effect as one roentgen that has the chemical formula UO3@2H2O. of X-ray or gamma-ray exposure. scope: The range of actions, alternatives, and repository: see geologic repository. impacts to be considered in a document prepared pursuant to the National Environmental Policy representative sites: For this PEIS, sites defined Act of 1969. with data for actual conditions at sites that, although not proposed for that activity, might be scoping: The process of inviting public somewhat similar to an eventual site. comment on what should be considered prior to Representative sites were used for analysis of preparation of an environmental impact state- conversion and long-term storage in yards, ment. buildings, and vaults. This more narrow charac- terization of potential future sites was used when severe accident: An accident with a frequency the activity was technically better defined. Use of of less than 1 in 1 million (10-6) per year that representative sites results in a more realistic would have more severe consequences than a assessment and comparison of options and design-basis accident in terms of damage to the alternatives than generic sites. In this PEIS, the facility, off-site consequences, or both. conditions at the current storage sites were used to define the range of conditions at the representative shielding: Any material that is placed between sites. a source of radiation and people, equipment, or other objects, in order to absorb the radiation and Resource Conservation and Recovery Act thereby reduce radiation exposure. Common (RCRA), as amended: An Act that provides a shielding materials include concrete, steel, water, “cradle-to-grave” regulatory program for and lead. In general, for shielding gamma hazardous waste that established, among other radiation sources, the denser a material is, the things, a system for managing hazardous waste more effective it is as a shield. from its generation until its ultimate disposal. shielding manufacturing facility: A plant retardation: The process by which dissolved where depleted uranium shielding is generated material moves more slowly through the soil and assembled with nonradioactive shielding than the velocity of the bulk fluid (i.e., water). components to produce casks.

risk: A quantitative or qualitative expression of sinter: To form a homogenous mass by heating possible loss that considers both the probability without melting. that a hazard will cause harm and the consequences of that event. Glossary 9-17 Depleted UF6 PEIS socioeconomic analysis: Analysis of those parts stakeholder: Any person or organization inter- of the human environment in a particular location ested in or potentially affected by activities and that are related to existing and potential future decisions of the U.S. Department of Energy. economic and social conditions. storage: The temporary holding of material in a socioeconomic impacts: For this PEIS, impacts controlled and monitored facility. expressed in terms of regional economic impacts (notably changes in local employment, income, strategy: For this PEIS, a set of actions for and economic output [sales]), impacts to public handling depleted UF6, from its current storage services and finance in local jurisdictions, and condition at three U.S. Department of Energy impacts to local housing markets. sites — Portsmouth, Ohio; Paducah, Kentucky, and Oak Ridge, Tennessee — to ultimate Soil and Water Conservation Act of 1977: An disposition. These broad strategies focus on act to establish a program administered by the material use, storage, and disposal. Secretary of Agriculture to further the conser- vation of soil, water, and related resources consis- sulfur dioxide (SO2): A compound of sulfur tent with the roles and responsibilities of other produced by the burning of sulfur-containing federal agencies and state and local governments. compounds and considered to be a major air pollutant. Sulfur dioxide is one of six criteria air Solid Waste Disposal Act: An Act that regulates pollutants specified under Title I of the Clean Air the treatment, storage, or disposal of solid, both Act. nonhazardous and hazardous, waste, as amended by the Resource Conservation and Recovery Act sulfur oxides (SOx): A general term used to and the Hazardous and Solid Waste Amendments describe the oxides of sulfur — pungent, of 1984. colorless gases formed primarily by the combustion of fossil fuels. Sulfur oxides, which source: Any physical entity that may cause are considered major air pollutants, may damage radiation exposure, for example, by emitting the respiratory tract as well as vegetation. ionizing radiation or releasing radioactive material. Examples of radiation sources include technology assessment report: A document X-ray machines and radionuclides such as (Lawrence Livermore National Laboratory 1995) uranium. that identified and assessed the recommendations received in response to the “Request for source term: The amount of radioactive or Recommendations” for uses and management hazardous material released to the environment technologies for depleted UF6. following an accident. terrestrial: Pertaining to plants or animals spent nuclear fuel: Fuel that has been with- living on land rather than in the water. drawn from a nuclear reactor following irradiation, the constituent elements of which have not been threatened species: Any species that is likely to separated by reprocessing. become an endangered species within the foreseeable future throughout all or a significant stability class: see Pasquill stability categories. portion of its range. Glossary 9-18 Depleted UF6 PEIS

throughput: A general term that refers to the triuranium octaoxide (U3O8): An oxide form amount of material handled or processed by a of uranium that is the most common chemical facility in a year. form found in nature. U3O8 is very stable and has a low solubility in water. tiering: The process of first addressing general

(programmatic) matters in a broad PEIS, followed UF4: see uranium tetrafluoride. by more narrowly focused (project-level) environmental documentation that incorporates by UF6: see uranium hexafluoride. reference the more general document.

For the Depleted Uranium Hexafluoride UO2: see uranium dioxide. Management Program, the PEIS addresses the potential impacts of broad strategy alternatives. At U3O8: see triuranium octaoxide. the second level, documents will address specific siting issues, construction and operation decisions, ungrouted waste: For this PEIS, defined as and the impacts of transport between identified U3O8 or UO2 in the powder or pellet form origins and destinations. produced during the conversion process. topography: Physical shape of the ground uranium: A heavy, silvery-white, naturally surface. radioactive, metallic element (atomic number 92). Its two principally occurring total effective dose equivalent: The sum of the isotopes are uranium-235 and uranium-238. effective dose equivalent from external exposure Uranium-235 is indispensable to the nuclear and the 50-year committed effective dose equiv- industry because it is the only isotope existing in alent from internal exposure. nature to any appreciable extent that is fissionable by thermal neutrons. Uranium-238 is Toxic Substances Control Act of 1976 (TSCA): also important because it absorbs neutrons to The Act authorizing the U.S. Environmental produce a radioactive isotope that subsequently Protection Agency (EPA) to secure information on decays to plutonium-239, an isotope that also is all new and existing chemical substances and to fissionable by thermal neutrons. control any of these substances determined to cause an unreasonable risk to public health or the uranium dioxide (UO2): A black crystalline environment. This law requires that the health and powder that is widely used in the manufacture of environmental effects of all new chemicals be fuel pellets for nuclear reactors. Pressed and reviewed by the EPA before they are manu- sintered, it is stable when exposed to water or air factured for commercial purposes. below 300EC.

transuranic waste: Waste contaminated by uranium hexafluoride (UF6): A chemical | alpha-emitting transuranic radionuclides (i.e., | composed of one atom of uranium combined | radionuclides with atomic numbers greater than | with 6 atoms of fluorine. UF6 is a volatile white | 92) with half-lives of more than 20 years and con- | crystalline solid at ambient conditions. This form centrations higher than 100 nanocuries per gram of uranium is used as feed for gaseous diffusion (nCi/g) at the time of assay. enrichment plants. Glossary 9-19 Depleted UF6 PEIS uranium metal: A heavy, silvery-white, waste minimization: An action that econom- malleable, ductile, softer-than-steel metallic ically avoids or reduces the generation of waste element. One of the densest materials known, it is by source reduction, reducing the toxicity of 1.6 times more dense than lead and slightly less hazardous waste, improving energy usage, or toxic. Uranium metal is not as stable as U3O8 or recycling.

UF4 because it is subject to surface oxidation. It tarnishes in air, with the oxide film preventing wastewater: Water that typically contains less further oxidation of massive metal at room than a 1% concentration of organic hazardous temperature. waste materials.

uranium tetrafluoride (UF4): A green crystal- Water Quality Act of 1987: An act amending line solid that melts at about 960EC and has an the Federal Water Pollution Control Act to make insignificant vapor pressure. It is very slightly National Pollutant Discharge Elimination System soluble in water; generally an intermediate in the requirements applicable to storm-water conversion of UF6 to either uranium oxide (U3O8 discharges. or UO2) or uranium metal. It is formed by the reaction of UF6 with hydrogen gas in a vertical wetlands: Lands or areas exhibiting hydric tube-type reactor or by the action of hydrogen soils, saturated or inundated soil during some fluoride on uranium dioxide. Also known as green portion of the plant growing season, and plant salt. species tolerant of such conditions (includes swamps, marshes, and bogs). uranyl fluoride (UO2F2): A yellow hygroscopic (i.e., moisture-retaining) solid that is very soluble Wild and Scenic Rivers Act: An Act providing in water. In accidental releases of UF6, UO2F2 is for protection of the free-flowing, scenic, and a solid particulate compound that may deposit on natural values of rivers designated as the ground over a large area. components or potential components of the National Wild and Scenic Rivers System. vacuum: A pressure less than atmospheric. Depleted uranium hexafluoride is stored in a World Wide Web site: A collection of informa- | vacuum in cylinders. tion — possibly including text, figures, pictures, audio, and video — that can be accessed by volatile organic compounds (VOCs): A broad computer through the Internet computer network. range of organic compounds (such as benzene, These sites are intended to communicate and chloroform, and methyl alcohol), often distribute information to anyone having access to halogenated, that vaporize at ambient or relatively the Internet. low temperatures. waste management: The planning, coordination, and direction of those functions related to generation, handling, treatment, storage, transportation, and disposal of waste, as well as associated pollution prevention and surveillance and maintenance activities. Glossary 9-20 Depleted UF6 PEIS