Authors: P Zhao Q Hu T P Rose G J Nimz M Zavarin
Publish Date: 2008/05/02
Volume: 276, Issue: 3, Pages: 755-761
Abstract
99Tc and 129I are important contributors to risk assessment due to their long halflives and high mobility as aqueous anionic species We analyzed 99Tc and 129I in groundwater samples in and near 11 underground nuclear tests and in melt glass and rock samples retrieved from the Chancellor test cavity Nevada Test Site The 129I/127I ratio ranges from 10−3 to 10−6 in cavity water and 10−4 to 10−9 in satellite wells The 99Tc concentration ranges from 3 to 10−4 Bq/l in cavity waters and from 03 to 10−4 Bq/l in satellite wells Downstream migration is apparent for both radionuclides However it is affected by both retardation and initial distribution Insitu 99Tc and 129I K d s calculated using rubble and water concentrations are 3 to 22 ml/g and 0 to 012 ml/g respectively and are suggestive of mildly reducing conditions 129I distribution in the melt glass rubble and groundwater of the Chancellor test cavity is 28 24 and 48 respectively for 99Tc it is 65 35 and 03 respectively Our partitioning estimates differ from those of underground tests in French Polynesia implying that fission product distribution may vary from test to test Factors that may influence this distribution include geologic conditions eg lithology water and CO2 content and the cooling history of the test cavity
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