92020B3.MPB Chapter 2. Uranium Releasesto the Environment .. Operationsat SRS involve theuse of uraniumin both researchand productionareas. The isotopic compositionmay varybecauseuraniumthat hasbeen eitherenrichedor depletedin the_sU-isotope andnaturaluranium, which is nativeto the soil andwaterof the SRS, are presentoa the site. Uraniumon the site is presentin manychemical forms,such as the metallicuranium anduranium-aluminumalloy in fuel andtargetassemblies, varioussalts, such as uranylnitrateor uranylsulfate,presentin the separationsprocessstreams,and metal oxides (principallyUO3andU3Os)producedat the end of the separationsprocess. Small amountsof otherchemical forms are presenton the site for use in researchwork, primarilyat the SavannahRiver Laboratory(SRL). Naturallyoccurringuraniumis present in SRS soil andwaterprincipallyas metaloxides. Uraniumreleases haveoccurredprincipallyfromfuel fabricatior andspentfuel processing facilities. Smallerreleases have occurredfromwaste storageandresearchareas. These releases haveoccurredto the atmosphere,site streams,andthe ground.The majorityof these havebeen predictedreleases resultingfromsuch unavoidablesituationsas the natural imperfectionof filtrationmedia. This Chapterdescribesthe origins of documenteduraniumreleases andtheir routes tothe environment. These are releases thatwere anticipatedandwere measuredeitheras uraniumor as partof a gross.alphameasurement. Chapter2. Uranium Releasesto the Environment Specific Uranium Analysesand Unidentified Alpha Some SRS facilities that release uranium also release However,no attemptwas made to scale any data when dual plutonium and other transuranic alpha emitting analyses were not run because no consistent correlations radionuclides. Specific radiochemicalanalyses foruranium between thedata were found. were performed to distinguish uranium releases from releases of the more hazardous transuranium elements. In Mostof the release dataweretaken fromCummins, Hetrick, some facilities, wheresignificant releases of alpha-emitting and Martin, 1991,which summarizesSRS releasescovering radionuclides were not anticipated, only gross-alpha (also the period 1954 through 1989. called unidentified or unknown alpha) analyses were performed to provide an indication of the presence of Releases of radioactivity are expressed in curies. To unexpected alpha emitters. The release tables in this estimate thecorrespondingweightofreleased uranium,the Chapterindicate which values are derived fromuranium-specific activity for the given isotopic mixture must be specific radiochemical analyses and which were derived calculated.For the"natural"uranium(99.27%z_U, 0.7?'_ fromgross-alpha analyses, ln onefacility,theSRLseepage _U, and 0.0055% _U), this specific activity i,, basins, bothanalyses wereperformed overa 10-year period. 692nanocuries pergram(3190pou nds/curie). 1.7 x 10"_-curies.This is the equivalent of about 80 g of (J 4e-5 ,.o natural and depleted uranium during the time of the measurementsor, roughly, 6 rag/day 2e-5 M-Area Releasesto Streams