The Catholic University of America

Radiation Safety Manual

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9.6 - GLOSSARY

Absorbed Dose -- The energy imparted by ionizing radiation per unit mass of irradiated material with a unit of rad or gray. (1 rad = 0.01 gray = 0.01 joule/kilogram)

Airborne Radioactive Material -- Radioactive material dispersed in the air in the form of dusts, fumes, particulates, mists, vapors, or gases.

Airborne Radioactivity Area -- A room, enclosure, or area in which airborne radioactive materials exist in concentrations in excess of the derived air concentrations (DACs) specified in 10 CFR 20, Appendix B.

ALARA -- Acronym for "as low as reasonably achievable".

Annual limit on intake (ALI) -- The derived limit for the amount of radioactive material that can be ingested or inhaled by an adult radiation worker in a year. ALIs for various nuclides are listed in 10 CFR 20, Appendix B, Table 1.

Approved Exhaust Ventilation -- A hood, glove box, or local exhaust facility which has been approved by the RSO for work with specific radioactive isotopes and activity concentrations. Approval is designated by printed labels attached to the ventilation unit by the RSO.

Authorization -- Authority granted by the RSC to a CUA investigator to use radioactive material of specified type(s) and quantities for stipulated purposes, as stated in Part D of Form RSO-2 "Application for Possession and Use of Radioactive Material."

Authorized User -- An individual granted an Authorization by the RSC.

Background Radiation -- Radiation from cosmic sources, naturally occurring radioactive materials, and global fallout as it exists in the environment. Background radiation does not include radiation from licensed or regulated source, byproduct, or special nuclear materials.

Bioassay -- The determination of the kind, quantity, concentration, and location of radioactive material in the human body by direct (in vivo) measurement, or by analysis (in vitro) of materials excreted or removed from the human body.

Byproduct Material -- Radioactive material yielded in or made radioactive by the process of producing or utilizing special nuclear material. A more detailed explanation of the term is provided in 10 CFR 20.

CFR -- Code of Federal Regulations

Consumable Radioactive Material -- Radioactive material withdrawn incrementally from a stock container for user-determined end use.

Contaminated Casualty -- An individual who has (or is suspected to have): ingested or inhaled radioactive materials, had radioactive materials come into contact with the eyes or an open wound, or been injected with radioactive materials.

Contamination -- An unwanted presence of radioactive material on an object or person.

Controlled Area -- An area, outside of a restricted area but inside the site boundary, access to which can be limited by the licensee for any reason.

CUA -- The Catholic University of America.

Decontamination -- The removal of contamination to an acceptable level or activity concentration.

Declared Pregnant Woman -- A woman who has voluntarily informed her employer, in writing, of her pregnancy and the estimated date of conception.

Derived Air Concentration (DAC) -- the concentration of a given radionuclide in air which, if breathed by the reference man for a working year of 2,000 hours under conditions of light work (inhaling 1.2 cubic meters of air per hour), would result in an intake of one ALI. DAC values for specific nuclides are listed in 10 CFR 20, Appendix B, Table 1, Column 3.

DC -- The District of Columbia.

DHS -- the U.S. Department of Homeland Security.

DHHS -- The U.S. Department of Health and Human Services.

DOE -- The U.S. Department of Energy.

Dose Equivalent -- The product of the absorbed dose in tissue, quality factor of the radiation, and all other necessary modifying factors at the location of interest. The units of dose equivalent are the rem and the sievert.

dpm -- disintegrations per minute.

Embryo/fetus -- The developing human organism from conception until the time of birth.

Emergency (Radiation) -- Any incident resulting from the use of one or more sources of ionizing radiation that creates an internal or external hazard to personnel.

Exposure -- Being exposed to ionizing radiation or radioactive material.

External Dose -- That portion of the dose equivalent received from radiation sources outside the body.

Extremity -- The hand, elbow, arm below the elbow, foot, knee, or leg below the knee.

Eye Dose Equivalent -- Applies to the external exposure of the lens of the eye and is taken at a tissue depth of 0.3 centimeter (300 mg/cm²).

High Radiation Area -- An area, accessible to individuals, in which radiation levels could result in an individual receiving a dose equivalent in excess of 100 mrem (1 mSv) in one hour at 30 centimeters from the radiation source or any surface that the radiation penetrates.

Individual User -- Any person who works with sources of ionizing radiation under the supervision of an Authorized User.

Internal Dose -- That portion of the dose equivalent received from radioactive material taken into the body.

Licensed Material -- Source material, special nuclear material, or byproduct material received, possessed, used, transferred, or disposed of under a general or specific license issued by the NRC.

Limits (dose limits) -- The permissible upper bounds of radiation exposures or doses.

LSC -- Liquid scintillation counter.

Major Spill -- A spill of radioactive material which entails a risk of airborne contamination in excess of the isotope specific maximum permissible concentration listed in 10 CFR 20, Appendix B Table 1, Columns 2 and/or 3; or entails risk of radiation exposure rates in excess of 50 mrem/hr (500 µSv) at 30 centimeters.

mrem -- millirem, 1/1,000th of a rem

mSv -- millisievert, 1/1,000th of a Sievert

NRC -- The U.S. Nuclear Regulatory Commission.

Occupational Dose -- The dose received by an individual in the course of employment in which the individual’s assigned duties involve exposure to radiation and to radioactive materials. Occupational dose does not include dose received from background radiation, as a patient from medical practices, from voluntary participation in medical research programs, or as member of the general public.

Potentially Exposed Personnel -- Includes at a minimum, all persons authorized to work in the same room with radioactive material. If x-ray or gamma radiation generates dose rates in adjoining rooms that exceed the levels permissible in an unrestricted area, the personnel occupying those adjacent spaces would be included.

Principal Investigator -- The applicant named in an “Application for Possession and Use of Radioactive Material.” The principal investigator becomes an Authorized User upon approval of the application by the RSC..

Principal User -- A person authorized by the RSC for unsupervised operation of a radiation producing machine.

Radiation -- Ionizing radiation in the form of alpha particles, beta particles, gamma rays, x-rays, neutrons, high speed electrons, high-speed protons, and other particles capable of producing ions. Radiation, as used in this manual, does not include non-ionizing radiation, such as radio- or microwaves, or visible, infra-red, or ultraviolet light.

Radiation Area -- An area, accessible to individuals, in which radiation levels could result in an individual receiving a dose equivalent in excess of 5 mrem (50 µSv) in one hour at 30 centimeters from the radiation source or from any surface that the radiation penetrates.

Radiation Producing Equipment (RPE) or Machine (RPM) -- Any machine or equipment whose primary purpose is to produce ionizing radiation, or which produces ionizing radiation coincidental to its primary purpose.

Radiation Worker -- An individual, including Authorized User, employee, or student, who is permitted to work with one or more sources of ionizing radiation on the CUA campus in accordance with the administrative procedures set forth in this manual.

Radioactive Material -- Material which emits alpha particles, beta particles, gamma rays, x-rays, neutrons, high speed electrons, high-speed protons, and other particles capable of producing ions.

Radioactive Waste (Radwaste) -- (1) Unsealed radioactive material whose retention is no longer desired by the responsible Authorized User, (2) Material/equipment presumed to be contaminated.

Rem -- Acronym for "Roentgen equivalent man," the special unit of dose equivalent (1 rem = 0.01 Sievert).

Restricted Area -- An area, access to which is limited by the licensee for the purpose of protecting individuals against undue risks from exposure to radiation and radioactive materials.

RMIC -- Radioactive Material Inventory Control.

RSC -- Radiation Safety Committee

RSL -- Radiation Safety Laboratory

RSO -- Radiation Safety Officer

Sievert -- The SI unit of any of the quantities expressed as a dose equivalent. (1 Sv = 100 rems).

Source of Ionizing Radiation -- Any isotope, regardless of chemical or physical form, which naturally or artificially radioactive, and whose quantity, total activity, or specific activity exceeds the limits established by law or regulation for exemption from controls established to protect the public health, or (2) Any radiation producing machine or equipment, as defined herein.

Source Material -- ((1) Uranium or thorium or any combination of uranium and thorium in any physical or chemical form; or (2) Ores that contain, by weight, 0.05 percent or more, of uranium or thorium or any combination of uranium and thorium. Source material does not include special nuclear material.

Special Nuclear Material -- (1) Plutonium, uranium-233, uranium enriched in the isotopes 233 or 235, or (2) Any material artificially enriched by any of the foregoing.

Stock Container -- A bulk or storage container from which material is incrementally withdrawn for user- determined end use.

Survey -- An evaluation of the radiological conditions and potential hazards incident to the production, use, transfer, release, disposal, or presence or radioactive material or other sources of radiation. When appropriate, such an evaluation includes a physical survey of the location of radioactive material and measurements or calculations of levels of radiation, or concentrations or quantities of radioactive material present.

Technical Member -- A member of the RSC, qualified by training and experience in the use of radioactive material or radiation producing equipment, appointed from a Department or Laboratory which uses sources of ionizing radiation.

Technician -- An individual authorized to operate a radiation producing machine under the supervision of a Principal User.

Total Effective Dose Equivalent (TEDE) -- The sum external and internal exposures.

Unrestricted Area -- An area, access to which is neither limited nor controlled by the licensee.

Unsealed Container -- A container of radioactive material which is open to the atmosphere or which has a closure intended for manual manipulation.

Whole Body -- For purpose of external exposure, the head, trunk, gonads, arms above the elbow and legs below the knee.