Shallow land burial in vadose zone sediment at the Hanford Site in Washington is being
considered for the disposal of Category 3 low-level waste. A series of column
experiments were conducted to evaluate and model the performance of the soil
surrounding the trench encasement material for iodine-129 and technetium-99 by
evaluating the mobility of these nuclides through the surrounding Trench 8 soil. These
experiments were designed to determine effective diffusion coefficients for ¹²⁷I and ⁹⁹Tc
through the following system: from contaminated soil into uncontaminated soil. The
tests were performed at two different soil moisture contents to evaluate the effects of soil
moisture content on diffusion. This thesis describes the experimental methods and
presents the diffusion results for this media type. It was found that as the moisture
content increased the diffusion increased by an order of magnitude (iodine 4% and 7%
moisture content soil effective diffusion coefficients were 8.90E-08 and 1.84E-07 cm²/s
respectively, and technetium 4% and 7% moisture content soil diffusion coefficients were
7.61E-08 and 1.45E-07 cm²/s respectively). These results, in combination with other
diffusion systems results, will allow the development of release models and contaminant
migration models that can be used to estimate the long-term fate of dose-controlling
radionuclides that are or will be buried in solid waste burial trenches. / Graduation date: 2004
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/30314 |
| Date | 17 October 2003 |
| Creators | Schwab, Kristen E. |
| Contributors | Istok, Johnathan, Higley, Kathryn A. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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