Geochemical Data Package for the 2005 Hanford Integrated Disposal Facility Performance Assessment

摘要: CH2M HILL Hanford Group, Inc. (CH2M HILL) is designing and assessing the performance of an integrated disposal facility (IDF) to receive low-level waste (LLW), mixed (MLLW), immobilized low-activity (ILAW), failed or decommissioned melters. The project assess this IDF Performance Assessment (PA) activity. goal PA activity provide a reasonable expectation that protective general public, groundwater resources, air surface-water inadvertent intruders. Achieving will require prediction contaminant migration from facilities. This expected occur primarily via movement water through facilities, consequent transport dissolved contaminants in vadose zone where may be re-introduced receptors drinking wells mixing Columbia River. Pacific Northwest National Laboratory (PNNL) assists their assessment activities. One PNNL tasks estimates geochemical properties materials comprising IDF, disturbed region around facility, physically undisturbed sediments below (including sedimentsmore » aquifer upper unconfined aquifer). are expressed as parameters quantify adsorption solubility constraints might apply for those exceed constraints. common used distribution coefficient (Kd) thermodynamic product (Ksp), respectively. In data package, we approximate using more simplified construct, called solution concentration limit, constant value. Kd values limits each direct inputs subsurface flow codes predict system. addition best-estimate values, conservative value range provided. package does not list uncertainty. However, different both spatial zones system supply time-varying cement solidified waste. presented were previously report prepared by Kaplan Serne (2000) 2001 ILAW PA, have been updated include applicable investigations completed since issuance improvements our understanding geochemistry specific Hanford. A discussion also included evolution recommended original 1999 2003 Supplement PAs current 2005 key concern: Cr(VI), nitrate, 129I, 79Se, 99Tc, U(VI). provides rationale why certain changed with time.« less