Novel Experiments for Understanding the Shallow Land Burial of Low-Level Radioactive Wastes
- PDF / 306,813 Bytes
- 7 Pages / 420.48 x 639 pts Page_size
- 55 Downloads / 195 Views
Inc.
441
NOVEL EXPERIMENTS FOR UNDERSTANDING THE SHALLOW LAND BURIAL OF LOW-LEVEL RADIOACTIVE WASTES G. L. DePOORTER AND T. E. HAKONSON Los Alamos National Laboratory, Group LS-6, MS-495, P. 0. Box 1663, Los Alamos, NM 87545 ABSTRACT Data on the basic processes that occur in the shallow land burial of low-level radioactive wastes are needed to engineer facilities with guaranteed performance, to validate models for system predictions, and to provide input to models that consider contaminant pathways out of the facility. Two types of novel experiments that will provide experimental data on the basic processes in shallow land burial facilities are described in this paper. Generic experiments that give data on the movement of water and radionuclides and an experiment that is particularly important for semi-arid sites are described. INTRODUCTION Experiments to provide data on the processes that occurr in the shallow land burial of low-level radioacive wastes are necessary to engineer facilities with guaranteed performance, to validate models for system predictions, and to provide input to models that include contaminant pathways out of the facility. Experimental results from appropriately sized field experiments will become available from two sets of novel experiments to be described in this paper. Generic experiments that give data on the movement of water and radionuclides and a moisture cycling experiment that is particularly important for semi-arid sites are described. GENERIC EXPERIMENTS Water flux is an important component in the performance of a shallow land burial waste disposal facility. Therefore, the generic experiments are designed to understand the movement of water and radionuclides and to understand how to move the water in a controlled manner. An ideal way to study water movement would be to have a profile that could be considered typical of that in a burial pit, and to examine the movement of water and radionuclides in this typical profile in great detail. The two experiment clusters in the Experimental Engineered Test Facility at the Los Alamos National Laboratory allow precisely this [1,2]. The experiment clusters are a modification of an experimental unit designed by Phillips and co-workers [3] and are shown schematically in plan and section views in Figure 1. Each experiment cluster provides six caissons, 3 m in diameter and 6 m deep, for experiments under controlled and measurable hydrologic conditions. Ports between the instrument and access caisson and the experiment caissons allow the emplacement of instrumentation in a horizontal plane. The detailed movement of water and elements typical of those found in low-level waste disposal facilities will be studied in experiments constructed in the large caissons as shown in Figure 2 (drawn to scale). Aluminum neutron moisture probe access tubes will be placed as shown in Figure 2. Two arrays of copper-constantan thermocouples will be emplaced approximately 0.5 and 2.3 m beneath the surface of the filled unit. These arrays will measure the temperature
Data Loading...
