Hydrologic and Geochemical Controls on the Transport of Radionuclides in Natural Undisturbed Arid Environments as Determined by Accelerator Mass Spectrometry Measurements
This project developed low-level analytical methods for the measurement of radionuclides by accelerator mass spectrometry. The contaminant radionuclides potentially measurable by AMS include: 14C, 36Cl, 59Ni, 63Ni, 90Sr, 93Zr, 99Tc, 129I, 239Np, 239Pu, and other actinides. We chose to concentrate on...
| Main Authors: | , , |
|---|---|
| Other Authors: | |
| Format: | Report |
| Language: | English |
| Published: |
Lawrence Livermore National Laboratory
1999
|
| Subjects: | |
| Online Access: | https://doi.org/10.2172/827420 http://digital.library.unt.edu/ark:/67531/metadc786746/ |
| Summary: | This project developed low-level analytical methods for the measurement of radionuclides by accelerator mass spectrometry. The contaminant radionuclides potentially measurable by AMS include: 14C, 36Cl, 59Ni, 63Ni, 90Sr, 93Zr, 99Tc, 129I, 239Np, 239Pu, and other actinides. We chose to concentrate on 36Cl, 99Tc, 90Sr, and 129I. These nuclides were globally distributed as fallout during the era of atmospheric nuclear testing, and occur today in almost every environment. They also are prominent contaminant nuclides at a variety of DOE sites. There is a need to develop these low-level methods to observe the migration of radionuclides in natural environments. There are at least three advantages of this: (1) the ability to conduct migration studies in locations most like those of concern to public health, e.g., a ''far-field'' environment; (2) migration research does not have to be conducted at sites of multiple contamination, e.g., by VOC's, which can produce hard-to-interpret results; and (3) it becomes unnecessary to collect research samples that are themselves radioactive waste and are therefore difficult to handle and dispose of in the laboratory. Our approach of examining globally distributed, fallout radionuclides provides another advantage: (4) since the nuclides are globally distributed, migration research can be conducted in any chosen environment. Arid environments can be examined for purposes of nuclear waste storage; riverine systems can be examined for the effects of long-range transport; forested or agricultural regions can be examined for the effects of vegetative mediation; even accessible arctic regions could be examined to better understand the fate of radionuclides in remote northern Russia. The innovative aspect of this research project was that it developed methods by which field studies of radionuclide migration could take place virtually anywhere, making the research easier to conduct, less expensive, and better controlled scientifically. Science is still in the process of trying to characterize the mechanisms by which radionuclides migrate in natural environments. It is only by understanding these mechanisms that improved methods for predicting contaminant radionuclide migration can occur. Improved predictions will reduce costs of remediation by indicating where remediative actions will be the most effective, by ensuring that the full extent of remediation required has been accurately determined, by eliminating the need for over-engineered solutions to the problem, and in some cases by demonstrating that natural attenuation near the release will decrease contaminant concentrations below regulatory maximum permissible concentrations (thus eliminating the need for any direct remediative action). Therefore, the development of AMS analytical techniques, which provide strong advantages for scientific characterization of radionuclide migration in all natural environments, thereby providing the means for improved predictive capabilities, will ultimately reduce remediative costs significantly. |
|---|