Glossary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Absorbed dose: the energy imparted by ionizing radiation per unit mass of irradiated material. The units of absorbed dose are called the gray (gy).
Absorber: any material that stops ionizing radiation. Lead, concrete, and steel attenuate gamma rays. A thin sheet of paper or metal will stop or absorb alpha particles and most beta particles.
Acceptable level of risk: a level of risk associated with a particular activity at which dangers are acceptable to the evaluator.
Accessible environment: the area surrounding a nuclear waste disposal site.
Accident leakage rate: the primary-to-secondary leakage rate occurring during postulated accidents other than a steam generator tube rupture.
Acid rain: also called acid precipitation or acid deposition, acid rain is precipitation containing harmful amounts of nitric and sulfuric acids formed primarily by nitrogen oxides and sulfur oxides released into the atmosphere when fossil fuels are burned. It can be wet precipitation (rain, snow, or fog) or dry precipitation (absorbed gaseous and particulate matter, aerosol particles or dust). Acid rain has a ph below 5.6. Normal rain has a ph of about 5.6, which is slightly acidic. The term ph is a measure of acidity or alkalinity and ranges from 0 to 14. A ph measurement of 7 is regarded as neutral. Measurements below 7 indicate increased acidity, while those above indicate increased alkalinity.
Actinides: elements with atomic numbers from 89 (actinium) or 90 (thorium) to 103 (lawrencium) inclusive.
Action level: a derived media-specific radionuclide-specific concentration or activity level of radioactivity that triggers a response such as seizure of contaminated foodstuffs following a nuclear accident . The action level is called the investigation level and would trigger the response of further investigation or site cleanup if the release criterion is exceeded.
Activation products: nuclides formed through transformation of stable reactor components into radioactive isotopes after intense bombardment with fission products. Radioactivity is thus induced through neutron bombardment or other types of radiation in reactor vessel components and corrosion products (and also in weapons casings) which were stable before the reactor vessel went on-line. The transuranic nuclides Plutonium, americium, curium, etc., are also neutron activation products, originating from neutron capture in Uranium nuclides rather than from the fission of these nuclides. Other important activation products include carbon-14 and tritium as well as activation products derived from activated stainless steel and carbon steel, activated sludge, corrosion deposits and concrete, and contaminated building products e.g. 55fe, 54mn, 65zn, 58co and 60co.
Active degradation mechanisms: new indications associated with defect types that have been identified during inservice inspection.
Activity:rate of disintegration, transformation, or decay of radioactive material. The units of activity are the curie (ci) and the becquerel(bq).
Acute dose: an acute dose means a person received a radiation dose over a short period of time.
Acute exposure: large exposure received over a short period of time.
B&W Babcock &Wilcox: major nuclear manufacturer and maker of pressurized water nuclear reactors(PWRS), fuel rods etc.
Background radiation: radiation from cosmic sources; naturally occurring radioactive materials, including radon (except as a decay product of source or special nuclear material) and global fallout as it exists in the environment from the testing of nuclear explosive devices. "background radiation" does not include radiation from source, byproduct, or special nuclear materials, or devices regulated by the NRC. The radioactivity in the environment including cosmic rays from space and radiation that exists everywhere-in the air, in the earth, and in man-made materials that surround us. In the United States most people receive about 300 millirems of background radiation per year.
Barrel : a volumetric unit of measure for crude oil and petroleum products equivalent to 42 U.S. Gallons.
Base bill: a charge calculated through multiplication of the rate from the appropriate electric rate schedule by the level of consumption.
Baseload capacity : the generating equipment normally operated to serve loads on an around-the-clock basis.
Baseload plant: a plant, usually housing high-efficiency steam-electric units, which is normally operated to take all or part of the minimum load of a system, and which consequently produces electricity at an essentially constant rate and runs continuously. These units are operated to maximize system mechanical and thermal efficiency and minimize system operating costs.
Baseload : the minimum amount of electric power delivered or required over a given period of time at a steady rate.
Bcf : the abbreviation for 1 billion cubic feet.
Beam port: a tube which carries particles from the core of the reactor to an experiment outside of the reactor shielding.
Becquerel (bq): a less unwieldy measurement of radioactivity than curies: one disintegration per second (D.P.S.). A picocurie is 0.037 d.p.s. Or 0.03 bq. The most common reporting unit outside the United States for radionuclide air concentrations is µbq/m3 (microbecquerels).
BEMR/Baseline Environmental Management Report (Baseline Report): congressionally mandated report prepared by the secretary of energy to estimate the cost and schedule of cleaning up the nation's nuclear weapons complex.
Calandria: (in a CANDU reactor) a cylindrical reactor vessel which contains the heavy water moderator. It is penetrated from end to end by hundreds of calandria tubes which accommodate the pressure tubes containing the fuel and coolant.
Calcine : a form of high-level waste produced from defense reactor fuel reprocessing waste (at the idaho chemical processing plant) by heating to a temperature below the melting point to bring about loss of moisture and nonradioactive volatile oxides, thus producing a chemically stable granular powder.
Cancer: an abnormal mass of new tissue growing uncontrollably on or in the body; a disease in which such growths form.<
CANDU: Canadian deuterium Uranium reactor, moderated and cooled by heavy water.
Canister : a metal container used for the storage or disposal of heat-producing, solid, high-level radioactive waste.
Capability: the maximum load that a generating station can carry under specified conditions for a given period of time without exceeding approved limits of temperature and stress. Net summer capability is used in the digest. Measured in watts except as noted otherwise.
Capacity (purchased) : the amount of energy and capacity available for purchase from outside the system.
Capacity charge : an element in a two-part pricing method used in capacity transactions (energy charge is the other element). The capacity charge, sometimes called demand charge, is assessed on the amount of capacity being purchased.
DAC: derived air concentration. The concentration of a given radionuclide that, if inhaled continuously during the work year, would cause a dose of 5 rem.
Data quality indicators: measurable attributes of the attainment of the necessary quality for a particular decision. Data quality indicators include precision, bias, completeness, representativeness, reproducibility, comparability, and statistical confidence.
Daughter products: a synonym for decay products, resulting from the radioactive disintegration of a radionuclide. Daughter products can either be stable or radioactive. Many important radionuclides are components of other nuclides' decay series: e.g. Niobium-95 is a decay product of zirconium-95; neptunium-237 is a decay product of americium-241; americium-241 is a decay product of Plutonium 241. Plutonium-238, the third most common constituent in spent fuel, is a decay product of neptunium 238. All curium nuclides decay to Plutonium isotopes. Also called "growing in." an important daughter product of ubiquitous gaseous stack releases of nuclear reactors is 134Cs, a daughter product of 133Xe.
Daughter : a nuclide formed by the radioactive decay of a different (parent) nuclide.
Decay chain, radioactive : a series of nuclides in which each member decays to the next member of the chain through radioactive decay until a stable nuclide has been formed.
Decay heat: the heat produced by radioactive decay of materials that are primarily the remnants of the chain reaction. /p>
Decay in storage (DIS): an idea whose time has not yet come: instead of dumping virtually uncontained 137Cs (1/2 t = 30 yr) and other intermediate-level wastes into near surface landfills, these wastes would be stored onsite at their point of generation for periods of 50 to 300 years. Now widely accepted by the european community as the only viable waste storage option for intermediate wastes, dis is only coming to the us as a result of failure of the us government to develop a viable waste disposal policy for high-level wastes. As isfsis are constructed for spent fuel, it's only a small step to expand these facilities to add intermediate-level waste storage including gtcc wastes.
Effective action level (fda): following the chernobyl accident, the food and drug administration implemented an unofficial protection action guideline when it observed high levels of chernobyl-derived radiocesium contaminating imported foods approximately one year after the accident. The fda seized and destroyed foods contaminated in excess of 10,000 pci/kg (370 bq/kg) thereby setting an effective action level which was significantly more conservative (lower) than the protection action guidelines promulgated by various U.S. Government agencies before and after the Chernobyl accident.
Effective dose equivalent or effective dose: the sum of the products of the dose equivalent to each organ or tissue and multiplied by their respective tissue weighting factors, and then added to the external whole body dose.
Electric plant (physical) : a facility containing prime movers, electric generators, and auxiliary equipment for converting mechanical, chemical, and/or fission energy into electric energy.
Electric rate schedule : a statement of the electric rate and the terms and conditions governing its application, including attendant contract terms and conditions that have been accepted by a regulatory body with approp riate oversite authority.
Electric utility : a corporation, person, agency, authority, or other legal entity or instrumentality that owns and/or operates facilities within the United States, its territories, or puerto rico for the generation, transmission, distribution, or sale of electric energy primarily for use by the public and files forms listed in the code of federal regulations, title 18, part 141. Facilities that qualify as cogenerators or small power producers under the public utility regulatory policies act (PURPa) are not considered electric utilities.
Electromagnetic radiation (E.M.R.): energy radiated in the form of a wave which can accelerate charged particles. Electromagnetic radiation can travel through a vacuum. Its energy varies greatly; radio waves have the longest wavelengths and the lowest frequency and energy (1.2398 x 10-10 to 1.2398 x 10-5electron volts. X-rays and gamma rays have the shortest wavelengths and highest frequencies and energies (up to and above 6 x 106 electron volts). For a comprehensive explanation of the public health consequences of ionizing radiation, i.e. Electromagnetic radiation above 155 ev, see gofman, 1981, section 10.
Electromagnetic spectrum - the complete range of frequencies of electromagnetic waves from the lowest to the highest, including radio infrared, visible light, ultraviolet, x-ray, gamma ray, and cosmic ray waves.<
Electron: a subatomic particle with a negative charge. The electron circles the nucleus of an atom.<
Fabrication of weapons components: the machining of Plutonium into warhead components (CO, WA, TN).
Fabrication, fuel : conversion of enriched Uranium hexafluoride (UF6) into pellets of ceramic Uranium dioxide (UO2). These pellets are then sealed into corrosion-resistant tubes of zirconium alloy or stainless steel. The loaded tubes, called fuel elements or rods, are then mounted into special assemblies for loading into the reactor core.
Facility: an existing or planned location or site at which prime movers, electric generators, and/or equipment for converting mechanical, chemical, and/or nuclear energy into electric energy are situated, or will be situated. A facility may contain more than one generator of either the same or different prime mover type. For a cogenerator, the facility includes the industrial or commercial process.
Factor - any of the numbers or symbols in mathematiCs that yield a product when multiplied together. Any related or relevant subject considered to reach a conclusion.<
Fast breeder reactor (fbr): a fast neutron reactor configured to produce more fissile material than it consumes, using fertile material such as depleted Uranium.
Fast neutron reactor: a reactor with little or no moderator and hence utilising fast neutrons and able to utilise fertile material such as depleted Uranium.
FDA: U.S. Food and Drug Administration.
Federal Energy Regulatory Commission (FERC) : a quasi-independent regulatory agency within the department of energy having jurisdiction over interstateelectricity sales, wholesale electric rates, hydroelectric licensing, natural gas pricing, oil pipeline rates, and gas pipeline certification.
Federal Power Act : enacted in 1920, and amended in 1935, the act consists of three parts. The first part incorporated the federal water power act administered by the former federal power commission, whose activities were confined almost entirely to licensing non-federal hydroelectric projects. Parts ii and iii were added with the passage of the public utility act. These parts extended the act's jurisdiction to include regulating the interstate transmission of electrical energy and rates for its sale as wholesale in interstate commerce. The federal energy regulatory commission is now charged with the administration of this law.
Federal Power Commission : the predecessor agency of the federal energy regulatory commission. The federal power commission (fpc) was created by an act of congress under the federal water power act on june 10, 1920. It was charged originally with regulating the electric power and natural gas industries. The fpc was abolished on september 20, 1977, when the department of energy was created. The functions of the fpc were divided between the department of energy and the federal energy regulatory commission.
Ferc : the Federal Energy Regulatory Commission
Gamma camera: remotely operated gamma ray imaging system that generates photos showing radiation areas within the hot side of a nuclear power plant, fuel reprocessing facility or other nuclear installation. The gamma camera is particularly useful during decommissioning and remediation activities for identifying major hot spots in equipment such as reactor vessels, steam generators, or reactor water systems which may contribute to worker exposure.<
Gamma emission: emission from an excited nucleus of a gamma photon
Gamma radiation: e.g. Emitted by zirconium-95: electromagnetic radiation; highly penetrating, very energetic x-rays emitted by an excited nucleus. Will often but not always exit living tissues without depositing its biologically significant electron voltage (ev).
Gamma ray: electromagnetic radiation (light) emitted by radioactive decay and having a large amount of energy.
Gas turbine plant : a plant in which the prime mover is a gas turbine. A gas turbine consists typically of an axial-flow air compressor, one or more combustion chambers, where liquid or gaseous fuel is burned and the hot gases are passed to the turbine and where the hot gases expand to drive the generator and are then used to run the compressor.
Gas : a fuel burned under boilers and by internal combustion engines for electric generation. These include natural, manufactured and waste gas.
GE/General Electric: major nuclear contractor and maker of boiling water reactors.(bwrs). Bwrs are much greater contaminators than pwrs.
Geiger counter: a geiger-müller detector and measuring instrument. It contains a gas-filled tube which discharges electrically when ionizing radiation passes through it and a device that records the events.
Generating unit : any combination of physically connected generator(s), reactor(s), boiler(s), combustion turbine(s), or other prime mover(s) operated together to produce electric power.
Half-life: the period required for half of the atoms of a particular radioactive isotope to decay and become an isotope of another element.
Hazardous waste : nonradioactive waste that has at least one of the following characteristiCs: (1) is listed as a hazardous waste in subpart d of 40 CFR part 261, (2) exhibits any of the characteristiCs identified in subpart c of 40 CFR part 261, or (3) contains pcb-containing wastes subject to regulation under the toxic substances control act and 40 CFR parts 702-799.
Health physiCs: that science devoted to recognition, evaluation, and control of all health hazards from ionizing radiation.
Heap leach / in-situ leach: process by which Uranium ore(sometimes others) is leached(in a heap or in place) using a highly toxic acidic solution to extract Uranium.
Heat exchanger: a device used to transfer heat from a flowing fluid on one side of a barrier to a different or separate flowing fluid on the other side.
Heavy oil : the fuel oils remaining after the lighter oils have been distilled off during the refining process. Except for start-up and flame stabilization, virtually all petroleum used in steam plants is heavy oil.
Heavy water reactor: a reactor which uses heavy water as its moderator, eg canadian candu (pressurised hwr or phwr).
Heavy water: water containing an elevated concentration of molecules with deuterium ("heavy hydrogen") atoms.
High radiation area: an area, accessible to individuals, in which radiation levels could result in an individual receiving a dose equivalent in excess of 0.1 rem (1 msv) in 1 hour at 30 centimeters from the radiation source or from any surface that the radiation penetrates.
High-LET: the characteristic ionization patterns by alpha particles, protons or fast neutrons having a high relative specific ionization per unit path length. <
Isometric transition: a mode of radioactive decay where a nucleus goes from a higher to a lower energy state. The mass number and the atomic number are unchanged.
Isotope: an atomic form of an element having a particular number of neutrons. Different isotopes of an element have the same number of protons but different numbers of neutrons and hence different atomic masses, e.g. U235, u238.
Isotopes: forms of the same chemical element that differ only by the number of neutrons in their nucleus. Most elements have more than one naturally occurring isotope. Many isotopes have been produced in reactors and scientific laboratories.
K-capture: the capture by an atom's nucleus of an orbital electron from the first k-shell surrounding the nucleus.
Kilogram - one thoUSAnd grams or 2.2046 pounds.
Kiloton: a measure of the power of an atomic bomb, equal to the detonation of 1000 tons of tnt. The first a-bombs had a size of 10-20 kilotons, now regarded as small, tactical weapons.
Kilowatt (kw) : one thoUSAnd watts.
Kilowatthour (kwh) : one thousand watthours.
LANL/Los Alamos National Laboratory: location where hiroshima and nagasaki bombs were designed & assembled; still designs new warheads(also disassembles).
Leaching : the process of removal or separation of soluble components from a solid by percolating water or other liquids through the solid.
Life cycle cost estimate: a term used by the department of energy to designate the cost of complete remediation of weapons production facilities within the environmental management program. This term also applies to the decommissioning of nuclear power facilities. It may also be used in reference to the life cycle disposal costs of specific components in a contaminated site, e.g. Spent fuel from a nuclear power plant, gtcc reactor vessel wastes, etc.<
Light oil : lighter fuel oils distilled off during the refining process. Virtually all petroleum used in internal combustion and gas-turbine engines is light oil.
Light water reactor (lwr): a common nuclear reactor cooled and usually moderated by ordinary water.
Light water: ordinary water (h20) as distinct from heavy water.
Lignite : a brownish-black coal of low rank with high inherent moisture and volatile matter (used almost exclusively for electric power generation). It is also referred to as brown coal. Comprises two groups classified according to the following astm specification d388-84 for calorific values on a moist material-matter-free basis
Magnetic field: all magnetic fields are created by moving electric charge. The single moving electron around a nucleus is a tiny electric current. These orbiting electrons create magnetic fields and their net effect is to provide the atom with a magnetic field.
Mass number (a): the total number of protons and neutrons in the nucleus
Maximum demand : the greatest of all demands of the load that has occurred within a specified period of time.
Maximum dependable capacity (gross): dependable main-unit gross capacity, winter or summer, whichever is smaller. The dependable capacity varies because the unit efficiency varies during the year because of temperature variations in cooling water. It is the gross electrical output as measured at the output terminals of the turbine generator during the most restrictive seasonal conditions (usually summer). Measured in watts except as noted otherwise.
Maximum dependable capacity (net): gross maximum dependable capacity minus the normal station service loads. Measured in watts except as noted otherwise.
Mcf : one thoUSAnd cubic feet.
Megaton: 1,000,000 tons of tnt. 1 ton of tnt = 4.184^9 j.
Megawatt (mw): a unit of power, = 106 watts. Mwe refers to electric output from a generator, mwt to thermal output from a reactor or heat source (eg the gross heat output of a reactor itself, typically three times the mwe figure).
Megawatthour (mwh) : one million watthours.
Meltdown: the overheating of a plant's nuclear fuel to such a degree that it reaches the melting point of the Uranium fuel rods, damaging the core and potentially resulting in the release of radiation.
National priorities list: the EPA's list of the most serious uncontrolled or abandoned hazardous waste sites identified for possible long-term remedial action under the CERCLA.
Natural gas : a naturally occurring mixture of hydrocarbon and nonhydrocarbon gases found in porous geological formations beneath the earth's surface, often in association with petroleum. The principal constituent is methane.
Natural Uranium: Uranium with an isotopic composition as found in nature, containing 99.3% U238, 0.7% U235 and a trace of u-234.
Naturally occurring and accelerator-produced radioactive materials : radioactive materials that are considered either naturally occurring and are not source, special nuclear, or by-product material or are produced in a charged particle accelerator
Off-peak gas : gas that is to be delivered and taken on demand when demand is not at its peak.
Ohm : the unit of measurement of electrical resistance. The resistance of a circuit in which a potential difference of 1 volt produces a current of 1 ampere.
Operable nuclear unit : a nuclear unit is operable after it completes low-power testing and is granted authorization to operate at full power. This occurs when it receives its full power amendment to its operating license from the nuclear regulatory commission.
Outage : the period during which a generating unit, transmission line, or other facility is out of service.
Oxide fuels: enriched or natural Uranium in the form of the oxide u02, used in many types of reactor.
Parent : a radionuclide that upon decay yields a specified nuclide (the daughter) either directly or as a later member of a radioactive decay series.
Particle accelerator: device used to accelerate electrons, protons, and alpha particles and other ions to very high speeds
Peak concentration / mean concentration: the peak concentration is the highest reading in a series of samples; the mean concentration is the average of readings in a series of samples.
Peak demand : the maximum load during a specified period of time.
Peak load plant : a plant usually housing old, low-efficiency steam units; gas turbines; diesels; or pumped-storage hydroelectric equipment normally used during the peak-load periods.
Peaking capacity : capacity of generating equipment normally reserved for operation during the hours of highest daily, weekly, or seasonal loads. Some generating equipment may be operated at certain times as peaking capacity and at other times to serve loads on an around-the-clock basis.
Rad (radiation absorbed dose) : a measurement of the energy deposited in any material by ionizing radiation. One rad is equal to the absorption of 100 ergs of energy in every gram of the material exposed to the radiation.
Radiation : energy that moves through space in the form of particles or electromagnetic waves.<
Radiation counters : machines used to detect and count the energy of the radiation given off by a given object.
Radiation dose: generic term that means absorbed dose, dose equivalent, effective dose equivalent, committed dose equivalent, committed effective dose equivalent, or total effective dose equivalent.
Radiation equivalent man (rem): the conventional unit of dose equivalent. The corresponding international system (si) unit is the sievert (sv); 1 sv = 100 rem.
Safstor: a method of decommissioning in which the nuclear facility is placed and maintained in such condition that the nuclear facility can be safely stored and subsequently decontaminated (deferred decontamination) to levels that permit release for unrestricted use.
Sales for resale : energy supplied to other electric utilities, cooperatives, municipalities, and federal and state electric agencies for resale to ultimate consumers.
Sales : the amount of kilowatthours sold in a given period of time; usually grouped by classes of service, such as residential, commercial, industrial, and other. Other sales include public street and highway lighting, other sales to public authorities and railways, and interdepartmental sales.
Salt cake : a salt form of high-level waste stored in tanks, which is produced from neutralizing acidic liquid waste from defense reactor fuel reprocessing with an alkaline agent (caustic soda).
Saltstone : a low-level waste by-product from the solidification of high-level waste at the savannah river site. Saltstone is retained in trenches at the savannah river site.
Sample: a part or selection from a medium located in a survey unit or reference area that represents the quality or quantity of a given parameter or nature of the whole area or unit; a portion serving as a specimen.
Teratogenic effects: teratogenic effects are effects from some agent, that are seen in the offspring of the individual who received the agent. The agent must be encountered during the gestation period.
Terrestrial radiation : the portion of natural radiation (background) that is emitted by naturally occurring radioactive materials in the earth. <
Thermal column : a part of the reactor that can be used to produce low energy or thermal neutrons for special irradiation experiments.
Thermal power : a measure of the rate of heat-energy emission that results from the radioactive decay of a material. A unit of thermal power commonly used is the watt (w).
Ultraviolet light: light with wavelength shorter than visible light, but longer than x-rays.
UMTRAP/Uranium Mill Tailings Remedial Action Program: DOE program to provide disposal, or stabilization and control of Uranium mill tailings piles and vicinities.
Unconditional free release of a nuclear facility withdrawal of the facility from the list of licensed facilities according to national regulations. This free release allows the consideration of the facility, its buildings, its equipment and the site, or part of the site on which the facility is built, as non-nuclear.
Voltage reduction : any intentional reduction of system voltage by 3 percent or greater for reasons of maintaining the continuity of service of the bulk electric power supply system.
Waste isolation pilot plant : a facility, located near Carlsbad, New Mexico, to be used for demonstrating the safe disposal of transuranic wastes from DOE defense-related activities.
Waste: high-level waste (hlw) is highly radioactive material arising from nuclear fission. It can be recovered from reprocessing spent fuel, though some countries regard spent fuel itself as hlw and plan to dispose of it in that form. It requires very careful handling, storage and disposal.
Waste: low-level waste is mildly radioactive or contaminated material, typically from medical or industrial applications of radioactivity, and usually disposed of by incineration and burial.
Watt:the electrical unit of power. The rate of energy transfer equivalent to 1 ampere flowing under a pressure of 1 volt at unity power factor.
X-rays: penetrating electromagnetic radiation(photon) having a wavelength that is much shorter than that of visible light. These rays are usually produced by excitation of the electron field around certain nuclei. In nuclear reactions, it is customary to refer to photons originating in the nucleus as x-rays.
Yellowcake: a Uranium oxide concentrate that results from milling (concentrating) Uranium ore. It typically contains 80 to 90 wt % U3o8. Ammonium diuranate, the penultimate Uranium compound in U308 production, but the form in which mine product was sold until about 1970. See also Uranium oxide.
Zirconium: a metallic element, highly resistant to corrosion, used to make the fuel rods that contain the fuel pellets.
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