Description

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Description

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This example illustrates the use of the program for lateral migration of a radioactive contaminant in a fractured porous rock with a single set of parallel fractures. It considers advective-dispersive transport along the fractures and diffusion into the rock matrix. The deposit is assumed to extend a considerable distance from the source (effectively an infinite distance) but we are only interested here in what happens over the first 50 m after 30 years..

 

It is assumed that the source concentration, co, is 1 unit and that the half life of the radioactive species is 100 years. The source is considered to have a sufficiently large supply that there is no significant change in source concentration due to mass movement into the rock. However the source does experience radioactive decay.

 

This example is also being used to illustrate the Maximum Sublayer Thickness Special Feature, for specifying sublayer thicknesses that are greater than 5 units.

 

The following parameters are defined for this example:

 

Property

Symbol

Value

Units

Darcy Velocity

va

0.08

m/a

Fractured Rock Thickness

HT

50

m

Number of Sub-layers

 

5

-

Fracture spacing

2H1

0.05

m

Fracture opening

2h1

10

µm

Dispersion along fractures

Df

6

m2/a

Fracture Distribution Coefficient

Kf

0

cm3/g

Matrix Diffusion Coefficient

Dm

0.0018

m2/a

Matrix Distribution Coefficient

Km

0

cm3/g

Matrix Porosity

nm

0.05

-

Dry Density of Matrix

 

2

g/cm3

Source Concentration

co

1

 

Half life of contaminant

 

100

a

Time period of interest

 

30

a