Weapons of Mass Destruction (WMD)

Absolute risk

An expression of excess risk based on the assumption that the excess risk from radiation exposure adds to the underlying (baseline) risk by an increment dependent on dose but independent of the underlying natural risk. See Relative risk.

Absorbed dose

The mean energy imparted to matter by ionizing radiation per unit mass. The unit of absorbed dose is the rad, which is equal to 100 erg/g.

Accelerator

An apparatus for imparting high velocities to charged particles.

Activity

The number of nuclear transformations occurring in a given quantity of material per unit time. See Curie; Radioactivity.

Administrative limit

A limit imposed administratively on the quantity of a radionuclide permitted in a building or part of a building.

AIRDOS

A computer code endorsed by the EPA for predicting radiological doses to members of the public due to airborne releases of radioactive material. It accounts for inhalation, external exposure to direct radiation, and food ingestion pathways.

Alpha, alpha particle

A heavy particle consisting of two neutrons and two protons and thus having a charge of +2; the nucleus of a helium-4 atom.

As low as reasonably achievable (ALARA)

A philosophy of protection that controls and maintains exposures to individuals and to the work force and general public as low as technically and economically feasible below the established limits.

Background radiation

Radiation arising from radioactive material other than that directly under consideration. Background radiation due to cosmic rays and natural radioactivity is always present. There may also be external background radiation from the presence of radioactive substances in building material itself and internal radiation from natural radioactive substances such as potassium-40 in the body.

Best estimate

An estimate made with the numerical inputs that are believed to be representative of the real situation, not biased conservatively.

Beta particle

Charged particle emitted from the nucleus of an atom, with a mass and charge equal in magnitude to that of the electron.

Bioassay

Urinalysis used to monitor the intake of tritium and plutonium in an individual.

Carcinogen

A substance that directly or indirectly causes cancer.

Collective (effective) dose equivalent

The sum of the doses to all exposed groups of people times the number of individuals receiving each dose. For example, if 20 persons receive a dose of 5 rem, 10 a dose of 10 rem, and 5 a dose of 20 rem, the collective dose is (20×5)+(10×10)+(5×20)=100+100+100=300 person-rem.

Committed dose

The time integral of the dose equivalent rate for a specified time period.

Committed Effective Dose Equivalent (CEDE)

"The sum of the committed dose equivalents to various tissues in the body, each multiplied by its weighting factor. It does not include contributions from external dose. Committed dose equivalent is expressed in units of rem (or sievert)" (DOE Order 5480.11, section 8e(8)).

Curie (Ci)

A special unit of activity. One curie equals 37 billion nuclear transformations per second.

Decibel (dB)

A unit measure of a sound pressure ratio. The reference sound pressure is 0.0002 dynes per square centimeter, or the equivalent of 200 micro-bar or 20 Pascal (Pa). This is the smallest sound a human can hear.

Depleted uranium

Uranium from which most of the uranium-235 isotope has been removed.

Dose

A general term denoting the quantity of radiation or energy absorbed. For special purposes, it must be appropriately qualified.

Dose equivalent

"The product of absorbed dose in rads (or gray) in tissue, a quality factor, and other modifying factors. Dose equivalent is expressed in units of rem (or sievert)" (DOE Order 5480.11, section 83(2)). The relative biological effectiveness of different kinds of radiation is expressed in the quality factor. (Note: The International Commission on Radiological Protection now uses the term, radiation weighting factor, to replace the term, quality factor.)

Dosimeter

An instrument or device used to detect and measure accumulated radiation exposure.

Effective Dose Equivalent (EDE)

The dose equivalent from irradiation of an organ or part of the whole body that bears the same risk of cancer as uniform irradiation of the whole body. "The sum over specified tissues of the products of the dose equivalent in a tissue and the weighting factor for that tissue. The effective dose equivalent is expressed in units of rem (or sievert)" (DOE Order 5480.11, section 8e(5)). (Note: The International Commission on Radiological Protection (ICRP) decided in ICRP Publication 60 to use the term effective dose to replace effective dose commitment.)

Emergency Response Planning Guidelines

Estimates of concentration ranges at which adverse effects can be expected if exposure to a specific chemical last more than 1 hour.

Ergonomic factors

Environmental stresses such as repetitive motion and mental or physical fatigue that can create health concerns when uncontrolled. Ergonomics is also known as human engineering.

Explosives

See High explosives.

Exponential notation

A means of expressing large or small numbers in powers of ten. For instance, 4.3×106=4,300,000 and 4.3×10-5 =0.000043. This relationship is also sometimes expressed in the form 4.3E+6=4,300,000 and 4.3E-5=0.000043.

Exposure assessment

The determination of the magnitude, frequency, duration, and route of exposure.

External exposure

Radiation exposure from sources outside the body: cloud passage, material deposited on the ground, and nearby surfaces.

Fission

The splitting of a heavy atomic nucleus into two nuclei of lighter elements, accompanied by the release of energy and generally one or more neutrons. Fission can occur spontaneously or be induced by neutron bombardment.

Gamma radiation

Shortwave-length electromagnetic radiation emitted from the nucleus with typical energies ranging from 10 keV to 9 MeV. Individual gammas considered as particles are also called photons.

Gamma spectroscopy

Analysis of the radionuclides in a sample by measurement of the intensities of the various gammas given off.

Glovebox

A sealed box in which workers, while remaining outside and using gloves attached to and passing through openings in the box, can safely handle and work with radioactive materials, other hazardous materials, and nonhazardous air-sensitive compounds.

Gross alpha

The concentration of all alpha-emitting radionuclides in a sample.

Gross beta

The concentration of all beta-emitting radionuclides in a sample.

Half-life

Time required for a radioactive substance to lose 50 percent of its activity by decay.

Hazard Index (HI)

The ratio between the intake of a chemical and an acceptable health-based reference level. A hazard index of less than 1 indicates a safe level of intake.

Hazardous waste

Any solid, semisolid, liquid, or gaseous waste that is ignitable, corrosive, toxic, or reactive as defined by RCRA and identified or listed in 40 C.F.R. part 261.

Health-conservative scenario

Refers to a scenario in which the highest possible source parameters are used to predict the highest offsite concentrations. Also called the worst-case scenario.

HEPA filter (High Efficiency Particulate Air)

Filter material that captures entrained particles from an air stream, usually with efficiencies in the range of 99.95 percent and above for particle sizes of 0.3 micron. Filter material is usually a paper or fiber sheet that is pleated to increase its surface area.

High explosives (HE)

Chemically energetic materials with the potential to react explosively; nuclear explosives are not included.

Immediately-Dangerous-to-Life-or-Health (IDLH)

Exposure concentrations established by the National Institute for Occupational Safety and Health/Occupational Safety and Health Administration Standards Completion Program to be used as guidelines for selecting respirator protection for some chemicals. An IDLH condition is one that poses an immediate danger to life or health or that poses an immediate threat of severe exposure to contaminants such as radioactive materials that are likely to have adverse cumulative or delayed effects on health.

Internal exposure

Radiation exposure from sources inside the body: from materials ingested, inhaled, or (in the case of tritium) absorbed through the skin.

Inventory

The amount of a radioactive or hazardous material present in a building or laboratory.

Low specific activity

"'Low Specific Activity material (LSA)' means any of the following:

"(1) Uranium or thorium ores and physical or chemical concentrates of those ores.

"(2) Unirradiated natural or depleted uranium or unirradiated natural thorium.

"(3) Tritium oxide in aqueous solutions provided the concentration does not exceed 5.0 millicuries per milliliter.

"(4) Material in which the radioactivity is essentially uniformly distributed and in which the estimated average concentration of contents does not exceed:

"(i) 0.0001 millicurie per gram of radionuclides for which the A2 quantity* is not more than .05 curie;

"(ii) 0.005 millicurie per gram of radionuclides for which the A2 quantity* is more than .05 curie, but not more than 1 curie; or

"(iii) 0.3 millicurie per gram of radionuclides for which the A2 quantity* is more than 1 curie.

"(5) Objects of nonradioactive materials externally contaminated with radioactive material, provided that the radioactive material is not readily dispersible and the surface contamination, when averaged over an area of 1 square meter, does not exceed 0.0001 millicurie (220,000 disintegrations per minute) per square centimeter of radionuclides for which the A2 quantity* is not more than .05 curie, or 0.001 millicurie (2,200,000 disintegrations per minute) per square centimeter for other radionuclides" (49 C.F.R. section 173.403(n)).

* "'A2 quantities are the maximum activities of radioactive material permitted in the package being transported. These quantities are listed in 49 C.F.R. 173.435; they depend on the isotopes included."

Melanoma

A skin cancer characterized by black pigmentation, given to metastasis.

MeV

A unit of energy equal to 1.6×10-6 ergs or 1.6×10-13 joules. Short for million electron volts, an electron volt being the energy acquired by an electron when it is accelerated through a potential drop of one volt.

Mutagen

A substance that causes genetic or inheritable defects.

Negligible individual risk level

A level of average excess risk of fatal health effects attributed to irradiation below which further effort to reduce radiation exposure is unwarranted. The value recommended by the National Council on Radiation Protection (NCRP) is 1 mrem.

Noble gas

In this EIS/EIR, neon, argon, krypton, or xenon. With rare exceptions, these gases do not enter into chemical reactions.

Nonionizing radiation

Electromagnetic radiation of wavelengths greater than 10-7 m (1000Å), such as laser, thermal, or radio-frequency radiation.

Order of magnitude

A factor of ten. When a measurement is made with a result such as 3×107, the exponent of 10 (here 7) is the order of magnitude of that measurement. To say that this result is known to within an order of magnitude is to say that the true value lies (in this example) between 3×106 and 3×108.

Person-rem

A unit of collective dose.

pH

The negative logarithm of the concentration of hydrogen ions in a liquid measured in gram equivalents per liter. A pH of 7 is neutral; smaller numbers indicate an acid condition, larger ones a basic condition.

Population exposure

The collective radiation dose received by a population group. See Collective dose equivalent.

Pyrotechnic material

A combustible substance such as gunpowder that gives off a display of sparks when burning.

Rad

A unit of absorbed dose equal to 100 erg/g. The equivalent SI unit is the gray, abbreviated Gy; 1 Gy=100 rad.

Radioactivity

The properties that certain nuclides have of spontaneously emitting particles, gamma radiation, or x radiation.

Relative risk

An expression of excess risk based on the assumption that the excess risk from radiation exposure depends on the underlying natural risk.

Rem

The special unit of dose equivalent that expresses the effective dose calculated for all radiation on a common scale. It is the absorbed dose in rads multiplied by certain modifying factors (e.g., the quality factor). The equivalent SI unit is the sievert, abbreviated Sv; 1 Sv=100 rem.

Risk assessment or analysis

Integration of the toxicity and exposure assessment into qualitative and quantitative expressions of risk.

Risk estimator

A number used to convert the measured or calculated effective dose equivalent to estimates of latent fatal cancers that can be attributed to the exposure.

Scenario

A particular chain of hypothetical circumstances that could, in principle, release radioactivity or hazardous chemicals from a storage and handling site, or during a transportation accident.

Screening-level assessment

An assessment of potential health effects used to determine relative risks of various procedures and/or hazards.

Sievert

A unit of dose equivalent equal to 100 rem.

Thermoluminescent

detector (TLD)

A dosimeter that operates on the principle that energy absorbed from ionizing radiation raises the molecules of the detector material to a metastable state until they are heated to a temperature high enough to cause the material to return to its normal state accompanied by the emission of light. The amount of light emitted is proportional to the energy absorbed.

Thermonuclear

Related to the fusion process.

Threshold Limit Values/Time-Weighted Average (TLV/TWA)

Guidelines or recommendations that refer to airborne concentrations of potentially hazardous substances. A time-weighted average TLV is an average for a normal 8-hour workday or 40-hour workweek, to which all workers may be repeatedly exposed, day after day, without adverse effect.

Tiger Team

A team set up by the Secretary of Energy in 1989 to assess the environment, safety, and health operations at all DOE facilities to determine whether changes were needed to improve the protection of the environment, safety, and health.

Total detriment

The total number of deleterious effects (fatal and nonfatal cancers, severe hereditary effects, other deleterious effects, and the associated morbidity) that would eventually be experienced by persons exposed to ionizing radiation and by their descendants.

Toxicity assessment

Identification of the types of adverse health effects associated with exposures and the relationship between the magnitude of the exposure and of the adverse effects.

Tritiated water

Water in which one of the hydrogen atoms has been replaced by a tritium atom; sometimes shown as HTO.

Tritium

A radioactive isotope of the element hydrogen, with two neutrons and one proton in its nucleus. Common symbols for the isotope are 3H and T.

Valley fever

(coccidioidomycosis)

A fungal disease of the lungs endemic to the southwest United States characterized in severe cases by high fever and extreme fatigue.

Volatile organic compound (VOC)

A compound containing carbon and hydrogen in combination with any other element that has a vapor pressure of 1.5 psi absolute (77.6 mm Hg) or greater under storage conditions.

Whole-body radiation

Radiation to the whole body, as opposed to individual organs or parts of the body.