OF DEFENSE’ 00 B20. JOINT CFFICs OF TEST iNFCXMATION 326 US ATOMIC ENERGY RG “RUT ION: COMMISSION ¢ So, — SRUICBEIEFING TEXT pants A Location { : 410494 AELEASE ON DELIVERY EFPECTOOOFONUCLEAR wiar ON. PESTING AT THE ENIWETOK FROVING GhUUNLS C NOTE: What follows is the approxirate text that Dr. Gordon Dunning of the Civision of biology and Medicine, Ata Energy Commission, will use in his oriefing: lecture # unclearei Observer Group at Eniwetok on. the “abbye s a ~ 4 Nature and Gis tribution of Falrou, i‘ As the instant of detonation of a nuclear weapor there is produced a tlast tion. The blast ant initicl gamma effects are limited to eo The intensity of the light might be hérwful to, ws areas relatively ciose in to the atoll where the detonation .% occurs. the eyes out to the maximum straight- line-of-sight distance me if viewed without protective glasses. > :a r The effect that may result at zreat, distance is that of radiation exposure from fallout. At the time of detonation @ large number of cifferent raaioactive substances are preduced witn half-lives rar-ing from a frace : * = tion of a second te many years (the half-life is the time Bal tolose one-half of its railoactivity). gs high in the air these radioisotopes Bied with fine particles that settle rela= Meeco the earth thus providing time for the | eT “the short-lived isotopes to decoy and also for rhe wide cdisoersal of the particulate nattar. when _« the firebal: intersects the Eg round during & detonation ® the radioisotcces will become associated principally wiun the larger »articles wnich fall relatively rapidly, BEST COPY AVAILABLE (more) . Re ge a: . ‘ . "ae foherepiepe a & wave and thermal and initipl gemma radi sage : mON . Ot ape wy geoe geteo &

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