This report presents the f i r s t iteration of the Composite Analysis for Low-Level Wmte Disposal in the 200 Area Plateau of the Hmford Site (Composite Analysis) prepared in response to the U.S. Department of Energy Implementation Plan for the Defense Nuclear Facility Safety Board Recommendation 94-2. The Composite Analysis is a companion document to published analyses of four active or planned lowlevel waste disposal actions: the solid waste burial grounds in the 200 West Area, the solid waste burial grounds in the 200 East Area, the Environmental Restoration Disposal Facility, and the disposal facilities for immobilized lowractivity waste. A single Composite Analysis was prepared for the W o r d Site considering only sources on the 200 Area Plateau. The performance objectives prescribed in U.S. Department of Energy guidance for the Composite Analysis were 100 mrem in a year and examination of a lower dose (30 mrem in a year) to ensure the "as low as reasonably achievableyy concept is followed. The 100 mrem in a year limit was the maximum allowable all-pathways dose for 1000 years following Hanford Site closure, which is assumed to occur in 2050. These performance objectives apply to an accessible environment defined as the area between a buffer zone surrounding an exclusive waste management area on the 200 Area Plateau, and the Columbia River.Estimating doses to hypothetical future members of the public for the Composite Analysis was a multistep process involving the estimation or simulation of inventories; waste release to the environment; migration through the vadose zone, groundwater, and atmospheric pathways; and exposure and dose. Doses were estimated for scenarios based on agriculture, residential, industrial, and recreational land use.The radionuclides included in the vadose zone and groundwater pathway analyses of future releases were carbon-14, chlorine-36, selenium-79, technetium-99, iodine-129, and uranium isotopes. In addition, tritium and strontium-90 were included because they exist in groundwater plumes. Radionuclides considered in the atmospheric pathway included tritium and carbon-14.Most of the radionuclide inventory in past-practice liquid discharge and solid waste burial sites on the 200 Area Plateau was projected to be released in the f i r s t several hundred years following H d o r d Site closure and a significant fraction of the inventory was projected to be released prior to closure. The maximum predicted agricultural dose outside the buffer zone was less than 6 mrem in a year in 2050 and declined thereafter. The maximum doses estimated for the residential, industrial, and recreational scenarios, were 2.2,0.7, and 0.04 mrem in a year, respectively, and also declined after 2050. The radiological doses for all of the exposure scenarios outside the buffer zone were well below the performance . objectives.. Significant uncertainties exist in the f i r s t iteration Composite Analysis, with the largest uncertainty associated with the inventories of key mobile radionuclides. Other sources of...

Example Time Periods and Analysis Considerations 4.3 Cline et al. (1980) noted that most of the disturbed areas at the Hanford Site have developed irregular stands of cheatgrass, tumbleweed, and rabbitbrush. All three of these plants have been

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A Composite Analysis is required by U.S. Department of Energy (DOE) Order 435.1 to ensure public safety through the management of active and planned low-level radioactive waste disposal facilities associated with the Hanford Site. A Composite Analysis is defined as "a reasonably conservative assessment of the cumulative impact from active and planned low-level waste disposal facilities, and all other sources from radioactive contamination that could interact with the low-level waste disposal facility to affect the dose to future members of the public." At the Hanford Site, a Composite Analysis is required for continued disposal authorization for the immobilized low-activity waste (ILAW), spent vitrification plant melter components, low-level waste in the 200 East and 200 West Solid Waste Burial Grounds or the Integrated Disposal Facility to be located in the 200 East Area, and Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) waste in the Environmental Restoration Disposal Facility (ERDF). The 2004 Composite Analysis will be a site-wide analysis, considering final remedial actions for the Columbia River Corridor and the Central Plateau. The river corridor includes waste sites and facilities in each of the 100 Areas as well as the 300, 400, and 600 Areas. The "Central Plateau" describes the region associated with operations and waste sites of the 200 Areas. DOE is developing a strategy for closure of the Central Plateau area by 2035. At the time of closure, waste management activities will shrink to a Core Zone within the Central Plateau. The Core Zone will contain the majority of Hanford's permanently disposed waste. Figure 1.1 shows the Core Zone, Central Plateau, Hanford Site (also known as the Columbia River Corridor), and Hanford Reach National Monument. The 2004 Composite Analysis will be a companion site-wide assessment to waste-specific and sitespecific assessments. The 2004 Composite Analysis also will provide supporting information on a regional or site-wide basis for use in important Hanford assessments and decisions such as the CERCLA 5-year review in 2005, tank closure decisions, decisions on final groundwater remedies for the 200 Areas, decisions on final groundwater remedies for the 100 Areas, and the Columbia River corridor final record of decision. The purpose of this document is to describe the technical scope of the 2004 Composite Analysis for the Hanford Site and the approach to perform this analysis. This document describes the performance and data quality objectives, region involved, contaminants of concern, waste sites to be included, scenarios to be evaluated, spatial and temporal domains for the Composite Analysis, and incorporates information from related studies associated with the 2004 Composite Analysis. The 2004 Composite Analysis will be a site-wide evaluation of the potential long-term impact on the health of a hypothetical future member of the public. The human health impact will be evaluated from combined radionuclide releases to groundwater, surface w...

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PNL-4260 UC-94e Publication of these verification studies completes the first phase of the establishment of a responsive simulation capability for the program. Validation against recorded field data sets is the next step for the CFEST code. Following validation studies, CFEST will be employed in the evaluation of ongoing field studies of the Seasonal Thermal Energy Storage Program.

This data package was originally prepared to support a 2004 composite analysis (CA) of low-level waste disposal at the Hanford Site. The Technical Scope and Approach for the 2004 Composite Analysis of Low Level Waste Disposal at the Hanford Site (Kincaid et al. 2004) identified the requirements for that analysis and served as the basis for initial preparation of this data package. Completion of the 2004 CA was later deferred, with the 2004 Annual Status Report for the Composite Analysis of Low-Level Waste Disposal in the Central Plateau at the Hanford Site (DOE 2005) indicating that a comprehensive update to the CA was in preparation and would be submitted in 2006. However, the U.S. Department of Energy (DOE) has recently decided to further defer the CA update and will use the cumulative assessment currently under preparation for the environmental impact statement (EIS) being prepared for tank closure and other site decisions as the updated CA.

Vadose zone hydrology has received increased attention in recent years as a result of environmental concerns over potential groundwater pollution from buried wastes. Funding agencies have supported several comprehensive field studies designed to improve and test models that describe flow and transport of contaminants in heterogeneous field soils. Extensive data bases, containing measured hydraulic properties and observations of flow and transport, have been established and have been useful for model testing and comparison. Improvements in stochastic and deterministic modeling capabilities for the vadose zone have been made. The stochastic models provide a way to account for site variability. The improved deterministic models conserve mass and are computationally efficient. This paper discusses recent progress in the areas of model validation, stochastic and deterministic analysis, multiphase flow and transport, preferred pathway analysis, and other related topics.