Characterization of stored defense production spent nulcear fuel and associated materials at Hanford Site, Richland Washington: Environmental assessment

Abstract

DISCLAIMERPortions of this document may be illegible in electronic image products. Images are produced from the best available original document. GLOSSARY OF TERMS ACTIVITYActivity i s a measure of quantity of a radioactive substance. The SI u n i t of measure i s the becquerel (B ) which i s equal t o the amount of substance from which one disintegration 9 nuclear transformation) per second i s obtained. The common unit of activity is the curie (Ci) which i s equal t o 37 billion disintegrations per second -t h a t number of disintegrations i s approximately the disintegration rate of one gram (0.04 oz) of radium from which the original definition came. One Ci equals 3.7 x 10" Bq.While activity gives a measure of rate of radioactive decays of a substance, i f used alone i t may be misleading. The half-life of the substance, or the time i t takes for one half of the activity t o have disappeared i s also important. For example one unit of activity of cesium-137 (half-life about 30 years) will have diminished t o about 1% of the i n i t i a l amount in 200 years, whereas one u n i t of activity of iodine-129 (half-life about 16 million years), for a l l practical purposes, will not have diminished a t a l l .BECQUEREL See Activity. CR I T I CALI TYCriticality typically refers t o a condition where masses o f f i s s i l e material have exceeded the size, geometry and neutron moderation t o result in a spontaneous self-sustaining nuclear chain reaction in which there i s an exact balance between production and loss of neutrons in the absence of extraneous sources. The result i s emission of radiation and release of considerable quantities of fission products. the usual sense, however dose rates near a c r i t i c a l i t y event can be very high t o lethal. Extraordinary precautions are taken t o assure that the . conditions for accidental c r i t i c a l i ty do not exi s t .The event i s not explosive in CURIE See Activity . DEFENSE PRODUCTION SPENT NUCLEAR FUELDefense'production spent nuclear fuel i s nuclear fuel t h a t has been irradiated in a nycl ear reactor for production of speci a1 nuclear materi a1 , principally plutonium-239 t o be used in national defense programs, t h a t has been removed from the reactor, b u t has not been reprocessed for recovery o f urani um and pl utoni um. HEPA FILTERA HEPA f i l t e r i s a high efficiency particulate air f i l t e r . HEPA f i l t e r will remove 99.95+% of airborne particulates per stage of f i l t e r . of radioactive material from a i r . Typically aThese f i l t e r s are often used i n series t o obtain greater removal MASS SPECTROMETRY Mass spectrometry i s an analytical technique used t o determine the mass number per u n i t charge of elements contained i n a gas sample. particularly useful for quantitatively determining reaction products resulting from chemical reactions. This i s M ETA LLOG RAPHA technique of recording images using photographic equipment i n conjunction with optical or electron microscopes t o investigate microstructural features ...