Toward resolving model-measurement discrepancies of radon entry into houses
- Univ. of California, Berkeley, CA (United States)
Analysis of the literature indicated that radon transport models significantly and consistently underpredict the advective entry into houses of soil-gas borne radon. Advective entry is the dominant mechanism resulting in high concentrations of radon indoors. My dissertation research investigated the source of the model-measurement discrepancy via carefully controlled field experiments conducted at an experimental basement located in natural soil in Ben Lomond, California. Early experiments at the structure confirmed the existence and magnitude of the model-measurement discrepancy, ensuring that it was not merely an artifact of inherently complex and poorly understood field sites. The measured soil-gas entry rate during structure depressurization was found to be an order of magnitude larger than predicted by a current three-dimensional numerical model of radon transport. The exact magnitude of the discrepancy depends on whether the arithmetic or geometric mean of the small-scale measurements of permeability is used to estimate the effective permeability of the soil. This factor is a critical empirical input to the model and was determined for the Ben Lomond site in the typical fashion using single-probe static depressorization measurements at multiple locations. The remainder of the dissertation research tests a hypothesis to explain the observed discrepancy: That soil permeability assessed using relatively small-scale probe measurements (0.1--0.5 m) does not reflect bulk soil permeability for flows that is likely to occur at larger scales of several meters or more in real houses and in the test structure. The idea is that soil heterogeneity is of a nature that, as flows occur over larger scales, larger scales of heterogeneity are encountered that facilitate larger flux rates, resulting in a scale dependence of effective soil permeability.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 10183521
- Report Number(s):
- LBL-34244; ON: DE93040290
- Resource Relation:
- Other Information: TH: Thesis (Ph.D.); PBD: Jun 1993
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
RADON
ENVIRONMENTAL TRANSPORT
HOUSES
CONTAMINATION
SOILS
RADIONUCLIDE MIGRATION
INDOOR AIR POLLUTION
CALIFORNIA
PERMEABILITY
POROSITY
DYNAMICS
DIFFUSION
PRESSURE GRADIENTS
560101
540230
320107
DOSIMETRY AND MONITORING
RADIOACTIVE MATERIALS MONITORING AND TRANSPORT
BUILDING SYSTEMS