Experimental and modeling studies of grain size and moisture content effects on radon emanation

Akihiro Sakoda, Yuu Ishimori, Katsumi Hanamoto, Takahiro Kataoka, Atsushi Kawabe, Kiyonori Yamaoka

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

Some models have already been developed to explain the effect of moisture content on the radon emanation fraction of soil. For this purpose, "microscopic" soil models, which are easy to deal with mathematically but cannot take grain size into consideration, have been designed. These previous models consist basically of two opposite grain surfaces and pores between the grains. In the present study, in order to study the effect of not only moisture content but also grain size, we present a simple modeling approach based on two "macroscopic" soil models: (1) a single-grain model and (2) a multiple-grain model. The latter model represents a configuration of spherical grains packed in a simple cubic structure. Based on these soil models and general assumptions, the radon emanation fraction was calculated as a function of grain size or moisture content by Monte Carlo simulation. The results for the multiple-grain model show that the radon emanation fraction is markedly increased with grain sizes ranging from 10 to 100 μm and reaches a constant value of 50% when moisture content is 0% and the radium is uniformly distributed on the grain surface. Moreover, a drastic increase is seen at smaller grain sizes with increasing moisture content. From these results, we concluded that the calculation of radon emanation depends greatly on the pore size between a Ra-bearing grain and a neighboring grain. The validity of the model was also evaluated by comparison to experimental data.

Original languageEnglish
Pages (from-to)204-210
Number of pages7
JournalRadiation Measurements
Volume45
Issue number2
DOIs
Publication statusPublished - Feb 2010

Fingerprint

Radon
radon
moisture content
Moisture
grain size
soils
Soils
Bearings (structural)
Radium
porosity
radium
Pore size

Keywords

  • Grain size
  • Modeling
  • Moisture content
  • Pore gap
  • Radium distribution
  • Radon emanation
  • Soil

ASJC Scopus subject areas

  • Radiation
  • Instrumentation

Cite this

Experimental and modeling studies of grain size and moisture content effects on radon emanation. / Sakoda, Akihiro; Ishimori, Yuu; Hanamoto, Katsumi; Kataoka, Takahiro; Kawabe, Atsushi; Yamaoka, Kiyonori.

In: Radiation Measurements, Vol. 45, No. 2, 02.2010, p. 204-210.

Research output: Contribution to journalArticle

@article{007d57d2d0e2408cb9e0edbd15e1313e,
title = "Experimental and modeling studies of grain size and moisture content effects on radon emanation",
abstract = "Some models have already been developed to explain the effect of moisture content on the radon emanation fraction of soil. For this purpose, {"}microscopic{"} soil models, which are easy to deal with mathematically but cannot take grain size into consideration, have been designed. These previous models consist basically of two opposite grain surfaces and pores between the grains. In the present study, in order to study the effect of not only moisture content but also grain size, we present a simple modeling approach based on two {"}macroscopic{"} soil models: (1) a single-grain model and (2) a multiple-grain model. The latter model represents a configuration of spherical grains packed in a simple cubic structure. Based on these soil models and general assumptions, the radon emanation fraction was calculated as a function of grain size or moisture content by Monte Carlo simulation. The results for the multiple-grain model show that the radon emanation fraction is markedly increased with grain sizes ranging from 10 to 100 μm and reaches a constant value of 50{\%} when moisture content is 0{\%} and the radium is uniformly distributed on the grain surface. Moreover, a drastic increase is seen at smaller grain sizes with increasing moisture content. From these results, we concluded that the calculation of radon emanation depends greatly on the pore size between a Ra-bearing grain and a neighboring grain. The validity of the model was also evaluated by comparison to experimental data.",
keywords = "Grain size, Modeling, Moisture content, Pore gap, Radium distribution, Radon emanation, Soil",
author = "Akihiro Sakoda and Yuu Ishimori and Katsumi Hanamoto and Takahiro Kataoka and Atsushi Kawabe and Kiyonori Yamaoka",
year = "2010",
month = "2",
doi = "10.1016/j.radmeas.2010.01.010",
language = "English",
volume = "45",
pages = "204--210",
journal = "Radiation Measurements",
issn = "1350-4487",
publisher = "Elsevier Limited",
number = "2",

}

TY - JOUR

T1 - Experimental and modeling studies of grain size and moisture content effects on radon emanation

AU - Sakoda, Akihiro

AU - Ishimori, Yuu

AU - Hanamoto, Katsumi

AU - Kataoka, Takahiro

AU - Kawabe, Atsushi

AU - Yamaoka, Kiyonori

PY - 2010/2

Y1 - 2010/2

N2 - Some models have already been developed to explain the effect of moisture content on the radon emanation fraction of soil. For this purpose, "microscopic" soil models, which are easy to deal with mathematically but cannot take grain size into consideration, have been designed. These previous models consist basically of two opposite grain surfaces and pores between the grains. In the present study, in order to study the effect of not only moisture content but also grain size, we present a simple modeling approach based on two "macroscopic" soil models: (1) a single-grain model and (2) a multiple-grain model. The latter model represents a configuration of spherical grains packed in a simple cubic structure. Based on these soil models and general assumptions, the radon emanation fraction was calculated as a function of grain size or moisture content by Monte Carlo simulation. The results for the multiple-grain model show that the radon emanation fraction is markedly increased with grain sizes ranging from 10 to 100 μm and reaches a constant value of 50% when moisture content is 0% and the radium is uniformly distributed on the grain surface. Moreover, a drastic increase is seen at smaller grain sizes with increasing moisture content. From these results, we concluded that the calculation of radon emanation depends greatly on the pore size between a Ra-bearing grain and a neighboring grain. The validity of the model was also evaluated by comparison to experimental data.

AB - Some models have already been developed to explain the effect of moisture content on the radon emanation fraction of soil. For this purpose, "microscopic" soil models, which are easy to deal with mathematically but cannot take grain size into consideration, have been designed. These previous models consist basically of two opposite grain surfaces and pores between the grains. In the present study, in order to study the effect of not only moisture content but also grain size, we present a simple modeling approach based on two "macroscopic" soil models: (1) a single-grain model and (2) a multiple-grain model. The latter model represents a configuration of spherical grains packed in a simple cubic structure. Based on these soil models and general assumptions, the radon emanation fraction was calculated as a function of grain size or moisture content by Monte Carlo simulation. The results for the multiple-grain model show that the radon emanation fraction is markedly increased with grain sizes ranging from 10 to 100 μm and reaches a constant value of 50% when moisture content is 0% and the radium is uniformly distributed on the grain surface. Moreover, a drastic increase is seen at smaller grain sizes with increasing moisture content. From these results, we concluded that the calculation of radon emanation depends greatly on the pore size between a Ra-bearing grain and a neighboring grain. The validity of the model was also evaluated by comparison to experimental data.

KW - Grain size

KW - Modeling

KW - Moisture content

KW - Pore gap

KW - Radium distribution

KW - Radon emanation

KW - Soil

UR - http://www.scopus.com/inward/record.url?scp=77949571641&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77949571641&partnerID=8YFLogxK

U2 - 10.1016/j.radmeas.2010.01.010

DO - 10.1016/j.radmeas.2010.01.010

M3 - Article

AN - SCOPUS:77949571641

VL - 45

SP - 204

EP - 210

JO - Radiation Measurements

JF - Radiation Measurements

SN - 1350-4487

IS - 2

ER -