Although the use of nuclear power has several advantages over the burning of fossil fuels, it has several disadvantages also. The inherent danger of a nuclear accident at a power plant is one of these disadvantages. Although the probability of an accident is very low in comparison to other risks we normally encounter, the consequences are significant. Thousands of local citizens could be exposed to radiation levels more than the normal background levels. It is the responsibility of the State to make the necessary decisions regarding the evacuation of its citizens. To make the best decision possible, it is necessary to obtain a large amount of information regarding the concentration of radionuclides being released and to quickly make projections of the exposure to ionizing radiation of the neighbors of the plant. / Master of Science

Thesis (DR. P.H.)--University of Michigan.

Thesis (DR. P.H.)--University of Michigan. / No collective t.p.; title from cover.

Thesis (DR. P.H.)--University of Michigan. / No collective t.p.; title from cover.

Thesis (DR. P.H.)--University of Michigan.

Report (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaf 130). Also available via the Internet.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology and Physical Oceanography, 1982. / Microfiche copy available in Archives and Science / Bibliography: leaves 194-196. / by Joshua Michael Aaron Ryder Wurman. / M.S.

A gas-diffusion tracer experiment was conducted at the ChemNuclear, Inc., nuclear waste burial site near Barnwell, South Carolina, on June 1-10; 1981, testing a new methodology to measure the in situ gaseous diffusion characteristics of unsaturated porous media for the purpose of estimating the diffusive flux of volatile contaminants from the burial ground. The tracers used were CClBrF₂ and SF₆. They were released in the subsurface from permeation devices that closely approximate an ideal point-diffusion source. The permeation devices contain the tracer in liquid form and allow the tracer to escape at a constant rate by diffusion through a Teflon membrane. The release rates for CClBrF₂ and SF6 during the test were 105 and 3.3 nanograms/second, respectively. These compounds were selected on the basis of their compatabi1ity with the permeation-release device, their absence in the subsurface, and detectability in the part-per-tri11ion range in soil gas. Analyses were made in the field on a Varian 3700 series gas chromatograph equipped with an electron-capture detector. The instrument was modified to introduce soil gas through sampling valves and a Nafion tube desiccant. The diffusion sources were placed in the unsaturated soil at depths of 2 meters and 13 meters below land surface. Diffusive movements of tracer were monitored for a period of 7 days and tracer breakthrough was observed at points up to 3.5 meters away. Diffusion was modeled using a three-dimensional, continuous point source, transient-state, analytical model which allowed estimation of the effective diffusion coefficient of the porous media, and an independent assessment of the media's sorptive effects on the tracer gas. The model was calibrated using least squares and curve matching techniques, the latter of which enables a field technician to quickly interpret observed field data. Field values obtained for effective diffusion coefficient ranged from 0.026 to 0.037 cm²/sec. The average tortuosity factor observed for test site was 0.705.

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

Thesis (M. Phil.)--University of Hong Kong, 1991.