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Radon transport in fractured soil. Laboratory experiments and modelling

Abstract

Radon (Rn-222) transport in fractured soil has been investigated by laboratory experiments and by modelling. Radon transport experiments have been performed with two sand columns (homogeneous and inhomogeneous) and one undisturbed clayey till column containing a net of preferential flow paths (root holes). A numerical model (the finite-element model FRACTRAN) and an analytic model (a pinhole model) have been applied in simulations if soil gas and radon transport in fractured soil. Experiments and model calculations are included in a discussion of radon entry rates into houses placed on fractured soil. The main conclusion is, that fractures does not in general alter transport of internally generated radon out of soil, when the pressure and flow conditions in the soil is comparable to the conditions prevailing under a house. This indicates the important result, that fractures in soil have no impact on radon entry into a house beyond that of an increased gas permeability, but a more thorough investigation of this subject is needed. Only in the case where the soil is exposed to large pressure gradients, relative to gradients induced by a house, may it be possible to observe effects of radon exchange between fractures and matrix. (au) 52 tabs., 60  More>>
Authors:
Publication Date:
Oct 01, 1997
Product Type:
Thesis/Dissertation
Report Number:
RISO-R-975(EN)
Reference Number:
SCA: 540130; PA: AIX-29:003785; EDB-98:035002; SN: 98001928538
Resource Relation:
Other Information: TH: Thesis (ph.d.).; PBD: Oct 1997
Subject:
54 ENVIRONMENTAL SCIENCES; ADVECTION; CLAYS; DIFFUSION; F CODES; FINITE ELEMENT METHOD; FLOW MODELS; FRACTURES; HOUSES; LAPLACE TRANSFORMATION; MATHEMATICAL MODELS; PERMEABILITY; POROSITY; PRESSURE GRADIENTS; RADON 220; RADON 222; SOILS
OSTI ID:
583868
Research Organizations:
Risoe National Lab., Roskilde (Denmark). Nuclear Safety Research and Nuclear Facilities Dept.
Country of Origin:
Denmark
Language:
English
Other Identifying Numbers:
Other: ON: DE98609894; ISBN 87-550-2315-0; TRN: DK9700154003785
Availability:
INIS; OSTI as DE98609894
Submitting Site:
DKN
Size:
150 p.
Announcement Date:
Apr 23, 1998

Citation Formats

Hoff, A. Radon transport in fractured soil. Laboratory experiments and modelling. Denmark: N. p., 1997. Web.
Hoff, A. Radon transport in fractured soil. Laboratory experiments and modelling. Denmark.
Hoff, A. 1997. "Radon transport in fractured soil. Laboratory experiments and modelling." Denmark.
@misc{etde_583868,
title = {Radon transport in fractured soil. Laboratory experiments and modelling}
author = {Hoff, A}
abstractNote = {Radon (Rn-222) transport in fractured soil has been investigated by laboratory experiments and by modelling. Radon transport experiments have been performed with two sand columns (homogeneous and inhomogeneous) and one undisturbed clayey till column containing a net of preferential flow paths (root holes). A numerical model (the finite-element model FRACTRAN) and an analytic model (a pinhole model) have been applied in simulations if soil gas and radon transport in fractured soil. Experiments and model calculations are included in a discussion of radon entry rates into houses placed on fractured soil. The main conclusion is, that fractures does not in general alter transport of internally generated radon out of soil, when the pressure and flow conditions in the soil is comparable to the conditions prevailing under a house. This indicates the important result, that fractures in soil have no impact on radon entry into a house beyond that of an increased gas permeability, but a more thorough investigation of this subject is needed. Only in the case where the soil is exposed to large pressure gradients, relative to gradients induced by a house, may it be possible to observe effects of radon exchange between fractures and matrix. (au) 52 tabs., 60 ill., 5 refs.}
place = {Denmark}
year = {1997}
month = {Oct}
}