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Title: INITIAL SINGLE SHELL TANK (SST) SYSTEM PERFORMANCE ASSESSMENT OF THE HANFORD SITE

Abstract

The ''Initial Single-Shell Tank System Performance Assessment for the Hanford Site [1] (SST PA) presents the analysis of the long-term impacts of residual wastes assumed to remain after retrieval of tank waste and closure of the SST farms at the US Department of Energy (DOE) Hanford Site. The SST PA supports key elements of the closure process agreed upon in 2004 by DOE, the Washington State Department of Ecology (Ecology), and the US Environmental Protection Agency (EPA). The SST PA element is defined in Appendix I of the ''Hanford Federal Facility Agreement and Consent Order'' (HFFACO) (Ecology et al. 1989) [2], the document that establishes the overall closure process for the SST and double-shell tank (DST) systems. The approach incorporated in the SST PA integrates substantive features of both hazardous and radioactive waste management regulations into a single analysis. The defense-in-depth approach used in this analysis defined two major engineering barriers (a surface barrier and the grouted tank structure) and one natural barrier (the vadose zone) that will be relied on to control waste release into the accessible environment and attain expected performance metrics. The analysis evaluates specific barrier characteristics and other site features that influence contaminant migration by themore » various pathways. A ''reference'' case and a suite of sensitivity/uncertainty cases are considered. The ''reference case'' evaluates environmental impacts assuming central tendency estimates of site conditions. ''Reference'' case analysis results show residual tank waste impacts on nearby groundwater, air resources; or inadvertent intruders to be well below most important performance objectives. Conversely, past releases to the soil, from previous tank farm operations, are shown to have groundwater impacts that re significantly above most performance objectives. Sensitivity/uncertainty cases examine single and multiple parameter variability along with plausible alternatives to ''reference'' cases to judge how the proposed closure system performs when changes to important assumptions are made to the hydrogeologic and engineered systems. The estimated impacts from these cases are generally consistent with ''reference'' case results (i.e., performance objectives are exceeded by contaminants from past releases but not tank residuals). This document and its future iterations will play a critical role in the decision making process for the closure of the Hanford Tank Farms. It will support interim decisions related to tank retrievals and interim corrective measures, in addition to supporting the major closure decisions of tanks and tank farms. Hence, it is imperative that the review process of this document is inclusive of the decision makers as well as the Hanford Stakeholders.« less

Authors:
Publication Date:
Research Org.:
Hanford Site (HNF), Richland, WA
Sponsoring Org.:
USDOE - Office of Environmental Management (EM)
OSTI Identifier:
897768
Report Number(s):
CH2M-32267-FP Rev 0
TRN: US0701516
DOE Contract Number:  
DE-AC27-99RL14047
Resource Type:
Conference
Resource Relation:
Conference: WM07 WASTE MANAGEMENT SYMPOSIA INC 02/25/2007 THRU 03/01/2007 TUCSON AZ
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; CLOSURES; DECISION MAKING; ECOLOGY; ENVIRONMENTAL IMPACTS; FARMS; METRICS; RADIOACTIVE WASTE MANAGEMENT; REGULATIONS; STORAGE FACILITIES; TANKS; US EPA; WASTE MANAGEMENT; WASTES

Citation Formats

JARAYSI, M.N. INITIAL SINGLE SHELL TANK (SST) SYSTEM PERFORMANCE ASSESSMENT OF THE HANFORD SITE. United States: N. p., 2007. Web.
JARAYSI, M.N. INITIAL SINGLE SHELL TANK (SST) SYSTEM PERFORMANCE ASSESSMENT OF THE HANFORD SITE. United States.
JARAYSI, M.N. Mon . "INITIAL SINGLE SHELL TANK (SST) SYSTEM PERFORMANCE ASSESSMENT OF THE HANFORD SITE". United States. doi:. https://www.osti.gov/servlets/purl/897768.
@article{osti_897768,
title = {INITIAL SINGLE SHELL TANK (SST) SYSTEM PERFORMANCE ASSESSMENT OF THE HANFORD SITE},
author = {JARAYSI, M.N.},
abstractNote = {The ''Initial Single-Shell Tank System Performance Assessment for the Hanford Site [1] (SST PA) presents the analysis of the long-term impacts of residual wastes assumed to remain after retrieval of tank waste and closure of the SST farms at the US Department of Energy (DOE) Hanford Site. The SST PA supports key elements of the closure process agreed upon in 2004 by DOE, the Washington State Department of Ecology (Ecology), and the US Environmental Protection Agency (EPA). The SST PA element is defined in Appendix I of the ''Hanford Federal Facility Agreement and Consent Order'' (HFFACO) (Ecology et al. 1989) [2], the document that establishes the overall closure process for the SST and double-shell tank (DST) systems. The approach incorporated in the SST PA integrates substantive features of both hazardous and radioactive waste management regulations into a single analysis. The defense-in-depth approach used in this analysis defined two major engineering barriers (a surface barrier and the grouted tank structure) and one natural barrier (the vadose zone) that will be relied on to control waste release into the accessible environment and attain expected performance metrics. The analysis evaluates specific barrier characteristics and other site features that influence contaminant migration by the various pathways. A ''reference'' case and a suite of sensitivity/uncertainty cases are considered. The ''reference case'' evaluates environmental impacts assuming central tendency estimates of site conditions. ''Reference'' case analysis results show residual tank waste impacts on nearby groundwater, air resources; or inadvertent intruders to be well below most important performance objectives. Conversely, past releases to the soil, from previous tank farm operations, are shown to have groundwater impacts that re significantly above most performance objectives. Sensitivity/uncertainty cases examine single and multiple parameter variability along with plausible alternatives to ''reference'' cases to judge how the proposed closure system performs when changes to important assumptions are made to the hydrogeologic and engineered systems. The estimated impacts from these cases are generally consistent with ''reference'' case results (i.e., performance objectives are exceeded by contaminants from past releases but not tank residuals). This document and its future iterations will play a critical role in the decision making process for the closure of the Hanford Tank Farms. It will support interim decisions related to tank retrievals and interim corrective measures, in addition to supporting the major closure decisions of tanks and tank farms. Hence, it is imperative that the review process of this document is inclusive of the decision makers as well as the Hanford Stakeholders.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 08 00:00:00 EST 2007},
month = {Mon Jan 08 00:00:00 EST 2007}
}

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