ALARA principle: international principle governing radiation standards. It means As Low As is Reasonably Achievable, economic and social considerations being taken into account.
alpha particles: positively charged particles emitted by certain radioactive substances. They can penetrate only a few inches of air and are not dangerous unless taken into the body.
AECL: Atomic Energy of Canada Limited.
AECB: Atomic Energy Control Board.
background level: the level of radiation in the environment. It comes from naturally radioactive materials, cosmic rays and radioactive fallout. It varies from place to place.
beta particles: elementary particles emitted by some atomic nuclei during radioactive decay. They can be stopped by a thin sheet of metal but can cause skin burns and are harmful if taken into the body. Negatively charged beta particles are called electrons; positively charged beta particles are called positrons.
curie: a unit of radioactivity equal to 37 billion disintegrations per second, about the amount available from one gram of radium.
daughter products: substances into which radioactive nuclei are transformed by radioactive decay.
radioactive decay: the spontaneous transformation that radioactive elements undergo; it involves the emission of alpha particles, beta particles or gamma rays.
ENL: Eldorado Nuclear Limited.
enriched uranium: uranium in which the proportion of uranium-235 has been increased above the naturally occurring 0.7 percent.
gamma rays: high-energy electromagnetic radiation emitted by atomic nuclei. They are very penetrating, can cause damage to the body and are best stopped by lead or depleted uranium shielding. Gamma radiation frequently accompanies alpha and beta emissions.
heavy-water reactor: a reactor which uses heavy water as a moderator and natural uranium as fuel, such as the CANDU.
heavy water: water containing more than the naturally occurring proportion of heavy hydrogen (deuterium) atoms to ordinary hydrogen atoms.
ICRP: International Commission for Radiological Protection.
ion: an electrically charged atom; one that has a deficit of one or more electrons.
ionizing radiation: radiation that can knock electrons off an atom, turning it into an ion. This radiation can damage skin or tissue. Alpha, beta and gamma radiation and X-rays are examples of ionizing radiation.
isotope: atom of an element which is different from other atoms of the same element in terms of atomic weight and nuclear properties but the same in terms of chemical properties.
fissile isotope: an isotope capable of fission; i.e., breaking up into two lighter fragments plus one or more neutrons and accompanied by the release of energy.
microcurie: one-millionth of a curie.
millirem: one-thousandth of a rem.
picocurie: one million-millionth of a curie, or a little more than two disintegrations per second.
pitchblende: a uranium oxide ore containing radium.
rad: (radiation absorbed dose) a unit measure of exposure to radiation which is almost the same as the roentgen.
radium: highly radioactive, alpha-emitting element.
radon gas: alpha-emitting gas given off by radium.
radium bromide: a compound of radium used for medical purposes.
raffiliate: waste material from the solvent extraction production of uranium trioxide.
rem: (roentgen equivalent man) a unit expressing the degree of biological injury caused by radiation; the amount of radiation causing similar biological injury as one roentgen of X-radiation.
roentgen: a unit of exposure to ionizing radiation.
UOinf2: uranium dioxide.
UOinf3: uranium trioxide.
Uinf235: fissionable isotope of natural uranium; natural uranium contains 0.7% U235 and 99.3% U238, a fertile isotope: that is, one not in itself fissionable but which can be made fissionable by irradiation in a reactor.
UFinf6: uranium hexafluoride, a volatile compound of uranium and fluorine used for enrichment.
working level: one way to measure external radiation; the amount of any combination of the short-lived radioactive daughters of radon in one litre of air that will release 1.3 x 105 million electron volts during their decay period; equivalent to 100 picocuries per litre.
working level month: working level x 170 working hours (one month); the product of a working level exposure multiplied by the time of exposure in months or 170 working hours.
WCB: Workmen's Compensation Board.
yellowcake: the mixture of uranium oxides produced by milling uranium ore.