nuclear efficiency The ratio (expressed as a percentage) between the number of atoms that fission and the total number of fissionable atoms available in a specific atomic weapon, muclear safing system The portion of an atomic weapon that contains integrally all the apparatus which, on receipt of proper signals from the arming system, or by manual operation, functions so as to place the nuclear system in an armed or "safed" condition, overpressure The transient pressure, usually expressed in pounds-per-square-—inch, exceeding atmospheric pressure, manifested in the blast wave from the explosion, The exact distribution is a function of time and of the weapon yield and the medium in which the weapon is detonated, plasma physics The science of dealing with the study of fully ionized gases, ~ predetonation 1. The premature explosion of the high explosive charge in an atomic weapon of the implosion-type, or of the propellant in an atomic weapon of the gun-type, before the weapon has reached the predesignated point of burst in its trajectory. 2, The premature commencement of fission of the active material in an atomic weapon before the designed criticality is achieved, preinitiation The premature commencement of fission of the active material in an atomic weapon before the designed criticality is achieved, Rad-Safe Program (Radiological Safety) The prescribed (by AEC) system of insuring safe control of radioactivity received by personnel; included handling, decontamination, pilot and crew exposure, radiac Radioactive. When used in connection with "instruments" or "detector," indicates device to measure and/or record radiation exposure. roentgen The quantity of X or gamma radiation such that the associated corpuscular emission per 0.001293 grams of air produces, in air, ions carrying one electrostatic unit of electricity of either sign, 326 AFWILYHO SWEH-2~-003h, a “ Vin