Hanford groundwater scenario studies

Abstract

This report documents the results of two Hanford groundwater scenario .* studies. The first study examines the hydrologic impact of increased 3 groundwater recharge resulting from agricultural development in the Cold Creek Valley located west of the Hanford Reservation. The second study involves recovering liquid radioactive waste which has leaked into the groundwater flow system from a hypothetical buried tank containing highlevel ,radioactive waste. The predictive and control capacity of the onsite Hanford modeling technology is used to evaluate both scenarios. The results of the first study indicate that Cold Creek Valley irrigation is unlikely to cause significant changes in the water table underlying the high-level waste areas or in the movement of radionuclides already in the ground water. The hypothetical tank leak study showed that an active response (in this case waste recovery) can be modeled and is a possible alternative to passive monitoring of radionuclide movement in the unlikely event that high-level waste is introduced into the ground water. iii ARH-SA-292

Guidelines for selecting codes for ground-water transport modeling of low-level waste burial sites. Volume 1. Guideline approach

“…In a general context, the answer clearly depends on the simulation study objectives and whether or not one believes that a three-dimensional process is ever reasonably represented by a lower spatial 1.11 dimensionality. In the case of the study by Ahlstrom et al (1977) and Arnett et al (1977), the answer seems affirmative, in view of the large areal extent, when compared with the aquifer thickness involved. In this example, issues about field-scale dispersion, however, are probably unresolved.…”

“…Both Figures 4 and 5 constitute a two-dimensional viewpoint of a burial site. Figure 5 is the region over which tritium migration in an aquifer was modeled (Ahlstrom et al 1977;Arnett et al 1977). Both of these reports are essential for understanding all aspects of the conceptual model associated with Figure 5.…”

“…Many of these technical issues are discussed in Chapter 2, because their treatment will determine the modeling outcome and predictions. For instance, an issue associated with the modeling described by Ahlstrom et al (1977} andArnett et al (1977) might be the question: "Is a two-dimensional areal description of transport adequate?" In a general context, the answer clearly depends on the simulation study objectives and whether or not one believes that a three-dimensional process is ever reasonably represented by a lower spatial 1.11 dimensionality.…”

“…Previous cited examples that are pertinent to this discussion are the transport simulations performed by Ahlstrom et al (1977) and Arnett et al (1977) which coupled a ground-water flow code with a solute transport code to model tritium migration.…”

Guidelines for selecting codes for ground-water transport modeling of low-level waste burial sites. Executive summary

“…Both Figures 4 and 5 constitute a two-dimensional viewpoint of a burial site. Figure 5 is the region over which tritium migration was modeled (Ahlstrom et al 1977;Arnett et al 1977}. These reports together are essential for understanding all aspects of the conceptual model associated with Figure 5.…”