Technical Scope And Approach For The 2004 Composite Analysis Of Low Level Waste Disposal At The Hanford Site

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. Submittal of the draft EIS is currently planned for FY 2008. This data package describes the facility-specific parameters (e.g. location, operational dates, etc.) used to numerically simulate contaminant flow and transport in large-scale Hanford assessments. Kincaid et al. (2004) indicated that the System Assessment Capability (SAC) (Kincaid et al. 2000; Bryce et al. 2002; Eslinger 2002a, 2002b) would be used to analyze over a thousand different waste sites. A master spreadsheet termed the Geographic and Operational Site Parameters List (GOSPL) was assembled to facilitate the generation of keyword input files containing general information on each waste site/facility, its operational/disposal history, and its environmental settings (past, current, and future). This report briefly describes each of the key data fields, including the source(s) of data, and provides the resulting inputs to be used for large-scale Hanford assessments.

Over the past decade significant progress has been achieved in the development of waste characterization and control procedures and equipment as a direct response to ever-increasing requirements for quality and reliability of information on waste characteristics. Failure in control procedures at any step can have important, adverse consequences and may result in producing waste packages which are not compliant with the waste acceptance criteria for disposal, thereby adversely impacting the repository. The information and guidance included in this publication corresponds to recent achievements and reflects the optimum approaches, thereby reducing the potential for error and enhancing the quality of the end product. -- Publisher's description.

Assessing the long term performance of waste disposal facility requires numerical simulation of saturated and unsaturated groundwater flow and contaminant transport. Complex numerical models have been developed to try to realistically simulate subsurface flow and transport processes. These models provide important information about system behavior and identify important processes, but may not be practical for demonstrating compliance with performance standards because of excessively long computer simulation times and input requirements. Two approaches to distilling the behavior of a complex model into simpler formulations that are practical for demonstrating compliance with performance objectives are examined in this paper. The first approach uses the information obtained from the complex model to develop a simple model that mimics the complex model behavior for stated performance objectives. The simple model may need to include essential processes that are important to assessing performance, such as time-variable infiltration and waste emplacement rates, subsurface heterogeneity, sorption, decay, and radioactive ingrowth. The approach was applied to a Low-Level Waste disposal site at the Idaho National Laboratory where a complex three dimensional vadose zone model was developed first to understand system behavior and important processes. The complex model was distilled down to a relatively simple one-dimensional vadose zone model and three-dimensional aquifer transport model. Comparisons between the simple model and complex model of vadose zone fluxes and groundwater concentrations showed relatively good agreement between the models for both fission and activation products (129I, 36Cl, 99Tc) and actinides (238U, 239Pu, 237Np). Application of the simple model allowed for Monte Carlo uncertainty analysis and simulations of numerous disposal and release scenarios. The second approach investigated was the response surface model. In the response surface model approach, the temporal response of a complex model to an instantaneously-released unit mass of a conservative tracer at a defined point is calculated and stored (the response function). A separate response function is needed for each source-receptor pair. The convolution of the response function and estimated contaminant flux from the source then provides an estimate of the media concentration. The response function approach has the advantage of incorporating all processes included in the complex model into a single discrete function that requires only one run of the complex model. Limitations to the response surface model include the assumption of uniform retardation in the model domain and the assumption that radioactive progeny travel at the same rate as their parent. In highly heterogeneous environments where uniform retardation cannot be assumed, contaminant-specific response functions can be calculated. The response surface model was applied to a two-dimensional regional aquifer model to simulate multiple plumes of tritium originating from multiple sources across the Idaho National Laboratory.

Graphite is widely used in the nuclear industry and in research facilities and this has led to increasing amounts of irradiated graphite residing in temporary storage facilities pending disposal. This publication arises from a coordinated research project (CRP) on the processing of irradiated graphite to meet acceptance criteria for waste disposal.

This book presents, for the first time in one place, the results of the latest research regarding water balance covers for solid waste sites, along with case studies drawn from current field testing. Water Balance Covers for Waste Containment: Principles and Practice introduces water balance covers and compares them with conventional approaches to waste containment. The authors give detailed analysis of the fundamentals of soil physics and design issues, introduce applicable ecological concepts and revegetation practices, and then move on to construction, modeling, and maintenance. A viable alternative to conventional landfill cover systems, water balance covers (also known as store-and-release and evapotranspiration covers) cycle water from the soil to the atmosphere during growing season, minimizing the percolation of rainwater through the soil, and thus the production of leachate from land fill contents. This book will be valuable to practicing engineers, as well as regulatory analysts.

At a time when many older facilities are being decommissioned and many more are undergoing major retrofits to extend their lives, there is a wealth of information emerging to guide the design of new facilities. In this publication, the most important lessons learned in recent years are examined.

This report assesses the levels and effects of exposure to ionizing radiation. Scientific findings underpin radiation risk evaluation and international protection standards. This report comprises a report with two underpinning scientific annexes. The first annex recapitulates and clarifies the philosophy of science as well as the scientific knowledge for attributing observed health effects in individuals and populations to radiation exposure, and distinguishes between that and inferring risk to individuals and populations from an exposure. The second annex reviews the latest thinking and approaches to quantifying the uncertainties in assessments of risk from radiation exposure, and illustrates these approaches with application to examples that are highly pertinent to radiation protection.