Open Journal of Safety Science and Technology, 2011, 1, 1- 11
doi:10.4236/ojsst.2011.11001 Published Online June 2011 (http://www.SciRP.org/journal/ojsst)
Copyright © 2011 SciRes. OJSST
Analysis of Instantaneous and Continuous Migration of
Radionuclides from Disposal Facility
Narmine Salah Mahmoud
National Center for Nuclear Safety and Radiation Control, Atomic energy Authority Nasr City, Cairo, Egypt
E-mail: Mnarmine1@hotmail.com
Received April 27, 2011; revised May 30, 2011; accepted June 7, 2011
Abstract
Many disposal sites have been suffered from radionuclide release problems, which lead to land contamina-
tion. Various remediation procedures have been developed during the past decade. Selection of remediation
techniques is dependant mainly on quantity and quality of radioactive contamination. For that reason, the
understanding of the factors that control the degree of contamination of any land should be the start of this
problem. The present work aimed to construct the base of a new mandatory chapter in the safety analysis
report that discuss and predict quantitively and qualitively the possible release from disposal site. The objec-
tive of this chapter is to prevent, restrict, and/or remediate economically the contamination that can be oc-
curred. In the present work, a generic disposal system was evaluated. The radio-elements, which can con-
taminate the area before their decays, are determined by a screening process. Knowing that the mode of ra-
dionuclide migration from a disposal site is one from the important factors that control the contamination
problem; migration activity of the selected radionuclides is assessed by considering instantaneous and con-
tinuous modes release of radionuclides from the disposal site. Finally, the elementary analysis steps demon-
strated in this study will be concluded as the proposed items in the new chapter.
Keywords: Disposal, Land Contamination, Remediation, Safety Analysis Report, Safety Assessment Study,
Instantaneous and Continuous Flow
1. Introduction
Recently disposal site of low and intermediate radioac-
tive waste is represented one of most important radio-
logical installation. Many disposal sites have been suf-
fered from release problems that lead to land contamina-
tion. This contamination is resulted from gradual leach-
ing of radionuclides to the surrounding and subsequent
migration through environmental media. That release
may arise from gradual processes, such as degradation of
barriers, and from discrete events that may affect the
isolation of the waste. Therefore safety analysis report
should be prepared for revision by regulatory committee
before the installation of a disposal facility. Safety as-
sessment study of the disposal site is considered one of
the most important chapters in this report [1]; safety as-
sessment is the procedure for evaluating performance of
disposal system and, as a major objective, its potential
radiological impact on human health and the environ-
ment [2]. This evaluation shall need to project to the fact
that is not practical that remedial action alternative,
which include a surface barrier and institutional controls
remains in perpetuity [3]. In case of land contamination,
various remediation techniques may be applied. However,
these techniques are very expansive processes, and in
some situation they may increase the pollution problem
if improper process is used. Based on this fact, the pre-
sent work aimed to construct the base of a new manda-
tory chapter in the safety analysis report discuss and pre-
dict quantatively and qualitively the possible release
from disposal site to prevent, to restrict, and/or to reme-
diate economically the contamination that have been
occurred.
2. Case Study
2.1. Source Term
The source term considered in this work has been
adopted from the report “Near Surface Radioactive
Waste Disposal Facilities (NSARS)”; an IAEA CRP
project. From NSARS project, twelve radionuclides in
N. S. MAHMOUD
2
homogeneous distribution mixture are represented the
buried waste in a vault disposal structure. The radionu-
clides were selected to be common radionuclides with a
variety of half-life and distribution coefficient and radio-
toxicity as shown in Table 1 [4].
2.2. Site Characteristics and Hydrological
Parameters
Inshas area is assumed the geological site for disposal
system, characteristics and hydrological parameters va-
lues of this area are represented by Table 2. Accordingly,
the absolute level of the ground water are undertaken to
be in the range from 12.5 to 13 m above the sea level.
The surficial aquifer is the quaternary water bearing
formation. It composed of loose sand rounded to sub-
rounded very coarse to fine well sorted, occasionally,
with gravel lenses which accelerating the percolation of
groundwater to be detected in shallow wells. The thick-
ness of this aquifer area ranges from few meters in the
extreme west to about 48 m. It is underlined by thin bed
of clay followed by basalt. The permeability coefficients
are ranged from 4.9 × 103 cm/sec to 8.1 × 103 cm/sec,
which indicate a low permeable aquifer. The transmissi-
bility of the aquifer ranges from 56.7 m3/day/m to 100
m3/day/m at the prevailing water temperature [5].
2.3. Scenario Considered
The generic scenario is considered the release of ra-
dionuclide from the disposal area after the institutional
control time of 100 years. The daughters of radionuclide,
the effect of chemical reactions, solubility and dilution
processes, and transport of radionuclides by colloidal
particles are not considered in the present work. Consi-
dering four vaults for the burial of radionuclides are in-
stalled in the site.
Concerning the analysis of the two modes, two dis-
tances 10 and 100 m are selected to be the checked dis-
tance around the disposal site for the calculation of mi-
gration rate of radionuclides within the restricted area
(100 m). Restricted area, defined by the National
Regulator Commission of United State, means an area,
access to which is limited by the licensee for the purpose
of protecting individuals against undue risks from
exposure to radiation and radioactive materials. Res-
tricted area does not include areas used as residential
quarters, but separate rooms in a residential building may
be set apart as a restricted area.The selection distance of
10 m is considered appropriate distance for a beginning
of the remediation technique. The second selection is 100
m, which selected to be the extreme contaminated dis-
tance that should not crossed (the 100 m is known as a
suitable restricted area around the disposal site).
Based on the scenario of land contamination; 1) for
instantaneous flow, an immediately total release of ra-
dionuclides from the site will occur after the institutional
control of 100 years, 2) a continuous flow of radionu-
clides release will occur during additional 100 years in
case of continuous flow study. The unsaturated zone
(vadoze zone) is considered delay time for the radionu-
clides movement and dispersion in this zone is neglected.
Therefore, the evaluation demonstrates the two modes of
migration through the saturated zone of the geological
Table 1. Specifications of rad ionuclides considering in this study.
Radio-nuclide Half-Life (y) Total Inventory (Bq)Distribution coefficient (cm3/g) [4]Ingestion dose factor (Sv/Bq) [5]
H-3 1.24E+01 4.00E+11 0.00E+00 1.70E11
C-14 5.73E+03 4.00E+10 5.00E+00 5.70E10
Co-60 5.30E+00 4.00E+11 1.50E+01 7.30E09
Ni-59 7.50E+04 4.00E+07 4.00E+02 5.70E11
Ni-63 1.00E+02 4.00E+12 4.00E+02 1.50E10
Se-79 6.50E+04 4.00E+07 1.50E+02 2.35E09
Sr-90 2.88E+01 4.00E+12 1.50E+01 3.60E08
Tc-99 2.13E+05 4.00E+07 1.00E01 3.95E10
Ru-106 1.08E+00 4.00E+10 5.00E+01 7.40E09
Cs-134 2.06E+00 4.00E+07 3.00E+02 2.00E08
Cs-137 3.02E+01 4.00E+12 3.00E+02 2.00E08
Th-230 7.70E+04 4.00E+09 3.00E+03 1.50E07
Copyright © 2011 SciRes. OJSST
N. S. MAHMOUD
Copyright © 2011 SciRes. OJSST
3
Table 2. The hydrological parameters of the site.
Factor Value [5]
Vertical distance of unsaturated zon (x) 13 m
Velocity of flow in the unsaturated zone (v) 0.0039 m/s
Effective Porosity of the sand soil (
) 25%
Density of the sand soil (
) 2.6 g/cm3(3)
Seepage velocity in the aquifer 0.04 m/d
Dispersion coefficient in x direction Dx in the aquifer 268.3 m2/year
Dispersion coefficient in y direction Dy 134.1 m2/year
site (aquifer).
3. Theoretical Release Models
3.1. Screening Model
The radionuclides that can contribute in the pollution of
land, according to its half-life, radio-activity and/or re-
tardation through the soil, are calculated by conservative
screening model based on 1 mSv/y as a limit value for
personal exposure dose [6]. The screening model is cal-
culated based on the ingestion dose as follows:
I= Io·e−λT*Ding (1)
where:
I is the activity of radionuclides calculated after the
travel time of the unsaturated zone [Bq], Io is the initial
activity of radionuclides in Bq, Ding is the ingestion dose
factor of radionuclide [Sv/Bq]
λ = ln 2/t
where:
λ is the decay constant, dimensionless, t is the ra-
dionuclide half-life [T]
T = T1 + T2
T1 is the institutional control period [T], T
2 is the
travel time of unsaturated [T]
ud
u
X
R
TU
(2)
u
u
v
U
1d
d
K
R

where:
Xu is the thickness of the unsaturated and saturated
zone [L], U
uis the seepage velocity of radionuclides in
unsaturated and saturated zone [L/T], νu and νs are the
velocity of radionuclide in unsaturated and saturated
zone [L/T],
is the effective porosity of the zone.
Rd is the retardation coefficient of radionuclide within
the soil, dimensionless.
(The soil type in the unsaturated zone and the satu-
rated zone is of sand type, so the retardation is equal for
both zones, the same for the density and porosity)
ρ is the density of the soil in [M/L3, Kd is the distribu-
tion coefficient of the radionuclide in [L3/M].
3.2. Modes of Release
The flow in both cases instantaneous and continuous
cases is assessed as linear source in horizontal direction
and analyzed using the equations:
3.2.1. Instantaneous Release
According to the scenario proposed, serious event was
assumed attack the disposal structure leads to rapid re-
lease flow of all buried radionuclides to the surrounding
area. In this case, the equation used to analyze the flow is
as follows [7]:
o
i
ed
C
C
nR
XYZ
(3)

2
1exp 4
4π
d
xd
xd
xUtR
XDt R
Dt R





2
1exp 4
4πyd
yd
y
YDt R
DtR





1
Zb
where:
CI is the activity of radionuclide at x and t [Bq/L3], Co
is the initial concentration [Bq/l3].
ne is the effective porosity dimensionless, D
x is the
dispersion coefficient in the x direction [L2/T], Dy is the
dispersion coefficient in the y direction [L2/T], x is the
distance in x direction [L], y is the distance in y direction
[L], b is the length of the vertical line [L].
t is the time considered during the calculation [T].
3.2.2. Conti nuous Rele ase
A small rupture in the base of the disposal structure is
assumed resulting, which can be formed by ageing effect
of concrete material or from biological attack. That of-
fers a continuous small release flow of radionuclide to
the surrounding area to take place. The movement of the
flow can be treated in this case using the following equa-
tion [8]:
4
io
CC XY (4)
N. S. MAHMOUD
4


12
2x
XerfcxUt Dt







12
12
22
22
y
y
Yerf yzDxV
erfyzD xV






where:
y is the source boundary in the y direction [L], z is the
line source length [L].
The other parameters were defined before.
The equation was modified to take into account the
effect of the retardation coefficient of radionuclides. The
modification in the equation was applied on the seepage
velocity of the contaminant flow in the aquifer [9]. The X
part in the equation is modified as follows:

12
2
dx
XerfcxUtRDt

(5)
The decay of radionuclides is considered in the calcu-
lation in both cases by multiply the Equations (3) and (4)
by the function eλT.
4. Results and Discussions
Table 3 shows the radionuclides resulted from the
screening calculation based on Equation (1), taken in
consideration that the start of evaluation is after the end
of 100 years institutional control period. All radionu-
clides having absorbed dose lower than 1 mSv/y is ex-
cluded from the evaluation.
4.1. Instantaneous Release Mode
Figures 1(a) and (b) demonstrates the migration amount
of radionuclides in the saturated zone reaches the dis-
tance 10 and 100 consecutively from the disposal site.
According to the behavior of radionuclide element with
the soil, each element reaches the distance considered at
different time and different concentration. Tc-99, in
Figure 1(a), is the first radionuclide appears at 10 m
before C-14 and the second radionuclide appears at 100
m in Figure 1(b) followed by C-14. That can be ex-
plained by the bulk activity of Tc-99, which moves
without any retention or interaction with soil. In case of
Sr-90; it shows the highest amount of activity followed
by C-14 and Ni-63. Regarding Ni-59, Ni-63, Se-79, and
Cs-137 appear very slowly despite their relatively high
activity. That can be explained by the retention of these
radionuclides on the soil. No appearance is calculated for
Th-230 during the 100 years after the institutional con-
trol of disposal site. That can be referring to its retarda-
tion on soil.
Two radionuclides are selected for more understand-
Table 3. Radionuclides obtained after the screening calcu-
lations.
Radionuclide Half-life (yr) Activity (Bq)
In the four vaults
C-14 5.73E+03 3.95E+10
Ni-59 7.50E+04 4.00E+07
Ni-63 1.00E+02 1.99E+12
Se-79 6.50E+04 4.00E+07
Sr-90 2.88E+01 3.60E+11
Tc-99 2.13E+05 4.00E+07
Cs-137 3.02E+01 3.99E+11
Th-230 7.70E+04 4.00E+09
ing the migration behavior of radionuclides within the
soil; C14 and Cs-137 as shown in Figure 2.
This figure describes the relation between the activity
and the time on 10 and 100 m for the radio-element C-14
and Cs-137. The relation is represented in the form of
area scale. In chart a, C-14 takes a relatively short time
of 1 year after the release to contaminate the 10 m from
the disposal unit and reach maximum concentration after
3 years. C-14 according to his half-life has not loose ac-
tivity during the total duration 0f 200 years starting from
disposal time to the end of the study (the start of the
simulation is after the 100 years institutional control pe-
riod and 100 years for the study). Its maximum concen-
tration is 0.0241% and 0.0238% from initial activity on
10 and 100 m respectively. This reflects its capability to
cross the 100 m without loosing a real activity and pol-
lute longer movement of Cs-137 on 10 m and 100 m, the
Cs-137 appears at 8.5 years (approximate) and reaches
its maximum concentration in 60 years on 10 m. Its
maximum concentration is 1E-06% from initial activity.
In contrary of C-14, Cs-137 looses activity during its
migration by the effect first by time, and by sorption in
soil.
The (c) chart in Figure 2 compares the two radionu-
clides on 10 m. C-14 appears before Cs-137 and reaches
its maximum concentration and its activity decreases to
5.58E06 Bq with the first activity calculated for Cs-137
after 8.5 years. The decrease of activity is represented the
start of migrated flow of radionuclide to the adjacent
distance as shown in chart d as dark area. This early ap-
pearance is expected and can be explained by the lower
retardation factor of C-14 than Cs-137.
Figure 3 describes a deep analysis of the instantane-
ous movement of radionuclides crosses different adjacent
distances and the amount of activity accumulated on each
distance within the time. The charts (a) and (b) represent
the movement of C-14 and Cs-137 respectively. The
Copyright © 2011 SciRes. OJSST
N. S. MAHMOUD
Copyright © 2011 SciRes. OJSST
5
Figure 1. Instantaneous release of radionuclides during 100 years after the end of institutional control period within the
restricted zone, (a) at 10m from the disposal site; (b) at 100m from the disposal site.
movement of C-14, with little tendency to dispose on the
soil, behaves relatively in rapid motion. That is indicated
by the complete similar time-activity curve on the adja-
cent distance (dark area). That is not the case for Cs-137,
which takes higher time to move and can not complete
its migration time-activity curve on the adjacent distance.
The area under each curve represents the contaminated
area by the radionuclide.
The inside small charts in charts (a) and (b) show this
relation on the same different adjacent distances in area
form. These charts indicate the sequence of movement
with the time. The accumulation of C-14 activity on each
soil layer is not similar as in case of Cs-137 as repre-
sented in chart c and d respectively. The accumulated
quantity on each distance has a sharp pyramided form
with a maximum value which is not the case of Cs-137.
The activity of Cs-137 migrated takes the shape of
smooth large wave. Again, the negative activity values in
the dark area in those charts reflect the migrated activi-
ties to next soil layer.
4.2. Continuous Release Mode
The study assumes continuous release of 0.01% of the
total activity from the disposal site to the surrounding.
That means the flow of release come to end after 100
years from the beginning of the study as it is noted be-
fore. Within the same conditions of time and distance of
instantaneous release from the disposal site, as in case of
instantaneous release on 100 m, C-14 is the beginner to
appear on 10 m in continuous migration followed by
Sr-90 as shown in Figure 4.
However on 50, only the two radionuclides C-14 and
Sr-90 keep their ranks. On 100 m, C-14 is the only nu-
clide can be detected. In contrary of C-14, Cs-137 looses
activity during its migration by the effect first by time,
N. S. MAHMOUD
6
Figure 2. Instantaneous release time taken by radionuclide migrate from the disposal site within the restricted area.
Figure 3. Analysis of the instantaneous movement on different adjacent distances.
Copyright © 2011 SciRes. OJSST
N. S. MAHMOUD7
Figure 4. Release behavior of radinuclide in the continuous mode in the restricted area of the disposal site during the con-
tinuous migration of radionuclides (100 years), (a) On 10 m; (b) On 50 m; (b) On 100 m.
and by sorption in soil. Chart (c) and (d) respectively.
The accumulated quantity on each distance has a sharp
pyramided form with a maximum value which is not the
case of.
Again, the radionuclides C-14 and Cs-137 are selected
for more analyses and understand the continuous mode.
Figure 5 shows the continuous migration of each ra-
dionuclide crosses different adjacent distances and the
amount of activity remains accumulated on each distance.
For C-14, in chart (a), the activity appears increasing
layer to layer. The continuous flow is can be considered
as multi-consecutive instantaneous flows with constant
low concentration or activity of radionuclides. According
to the relatively high motion of C-14, the multi-consecu-
tive instantaneous flow appears on the adjacent soil lay-
ers very quickly. Each flow migrates to a layer before the
leaving of the present flow and without loosing signifi-
cant amount of activity. The addition of more than one
instantaneous flow on the same layers shows a gradually
increasing of the flow. Th-230 has no appearance as in
case of the instantaneous flow based on its long half-life
and distribution coefficient. This is not the case for
Tc-99, which considers to be migrated in a short time.
In chart (b) the situation is opposite; the activity of
Cs-137 flow appears decreasing from layer to layer.
However this isn't the real case. Owing to the fact that
the Cs-137 has a relatively high distribution coefficient
in soil (high retardation), each instantaneous flow moves
very slowly from layer to the adjacent layer loosing ac-
tivity on each layer and before the followed flow reach
the same layer. The small chart in chart (a) and (b) shows
same relation of time-activity in area form for cases of
C-14 and Cs-137, no complete curve is presented during
the 100 years (no maximum values for radionuclides are
presented during this time).
In chart (c) the accumulation of C-14 on each layer is
apparently. Each instantaneous flow reaches an occupied
layer before the escape of the present flow. This indi-
cates by the gradual increasing of each curve simulate
the activity on each layer. However, each curve decreas-
ing with time prove the apparently accumulation and the
escape of each flow to the adjacent distance. In chart (d)
accumulation of Cs-137, which decreases may prove that
charts (b) and (d) describes only one instantaneous flow.
On each layer this flow of Cs-137 loose activity and de-
creasing from layer to layer. The increasing of each
curve shows the accumulation of activity on each layer is
reflecting the real situation of Cs-137 flow.
Copyright © 2011 SciRes. OJSST
N. S. MAHMOUD
Copyright © 2011 SciRes. OJSST
8
Figure 5. Analysis of the continuous mode of two different element-radionuclides.
4.3. Comparison of the Modes Instantaneous and
Continuous Flow
Table 4 listed the appearance rank of radionuclides in
both case instantaneous and continuous modes and com-
pares these results with the rank obtained before by the
analysis of different parameters. Some radionuclides
have kept, in most rank, their position such as; Sr-90,
C-14 and Tc-99. Meanwhile, no definitive parameter can
be used as indicator for the movement of different ra-
dionuclides.
Table 5 listed the different maximum activity values
obtained in both cases instantaneous and continuous and
their time of appearance. In Both cases, Sr-90 reach the
maximum values of activity migrated nearly within same
values. Except on 100 m in the continuous mode, no ap-
pearance is calculated for Sr-90. In case of instantaneous
mode on 10 and 100 m, the maximum activity calculated
is occurred for all radionuclides around the same time
expect for Tc-99. Tc-99 is detected as the first radionu-
clide migrated in the surrounding and this can be the
situation in case on the 100 m in continuous mode.
Table 6 listed the absorbed dose of maximum activity
values obtained from the radionuclides to consider con-
servatively the contamination of the area, which can be
occurred. C-14, Sr-90, Cs-137 are showed real threat in
most cases. However it should be noted that these values
are case specific according to; geological site character-
Table 4. Appearance of Radionuclides obtained from each
mode of release.
Instantaneous Continuous
10 m 100 m 10 m 100 m
Tc-99 C-14 Tc-99 Tc-99
C-14 Tc-99 C-14 C-14
Sr-90 Sr-90 Sr-90
Se-79 Se-79 Se-79
Cs-137 Cs-137 Ni-63
Ni-63 Ni-63 Cs-137
Ni-59 Ni-59 Ni-59
Th-230 Th-230 Th-230
N. S. MAHMOUD
Copyright © 2011 SciRes. OJSST
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Table 5. Comparison of the maximum activity and their time of appearance on 10m and 100m during 100 years.
Radio-nuclide Initial Activity
(Bq) Maximum Activity
at 10 m in Instant an eo us Mo de Maximum Activity
at 10 m in Continuous Mode
Quantity (Bq) % from initial activityTime (y)Quantity (Bq) % from initial activity Time (y)
C-14 3.95E+10 7.97E+06 2.02E02 5 2.00E+06 5.06E03 30
Ni-59 4.00E+07 9.59E+01 2.40E04 100 1.59E+01 3.98E05 100
Ni-63 1.99E+12 2.39E+06 1.20E04 100 3.96E+05 1.99E05 100
Se-79 4.00E+07 3.36E+02 8.40E04 70 2.64E+02 6.60E04 100
Sr-90 3.60E+11 2.47E+07 6.86E03 5 4.63E+06 1.29E03 30
Tc-99 4.00E+07 1.86E+05 4.65E01 0.1 1.96E+03 4.90E03 1
Cs-137 3.99E+11 2.48E+05 6.22E05 60 4.89E+04 1.23E05 100
Th-230 4.00E+09 s
Radio-
nuclide Initial Activity
(Bq) Maximum Activity
at 100m in Instantaneous Mode Maximum Activity
at 100m in Continuous Mode
Quantity (Bq) %from initial activityTime (y)Quantity (Bq) % from initial activity Time (y)
C-14 3.95E+10 9.51E+06 2.41E02 3 2.4E+04 6.13E05 100
Ni-59 4.00E+07 9.60E+01 2.40E04 100
Ni-63 1.99E+12 2.39E+06 1.20E04 100
Se-79 4.00E+07 3.36E+02 8.40E04 70
Sr-90 3.60E+11 2.56E+07 7.11E03 7
Tc-99 4.00E+07 1.34E+04 3.35E02 3
Cs-137 3.99E+11 2.48E+05 6.22E05 60
Th-230 4.00E+09
ristics, type and quantity of waste buried, and time of
radionuclide release. Additionally, it is important to re-
member that the present study has neglected the effect of
dilution and chemical processes, which is present in real
situations.
The absorbed doses calculated and presented in Table
6 for some cases are not expected. For example Tc-99 in
spite of quickly migration, its dose calculated does not
generate real pollution derived from the ingestion dose
conversion factor. The same situation is shown in all
case for Ni-59, Ni-63, and Se-79.
Figure 6 evaluates the difference in movement and
quantity of activity migration in both cases instantaneous
and continuous modes. In case of C-14, the movement in
continuous mode shows slow movement than in instant-
taneous mode. The quantity of activities is higher in case
of instantaneous case within limited distance. For Cs-137,
the activity in the flow, which moves from layer to layer,
is higher in case of instantaneous mode. On the other
hand, the accumulation of activity on any layer can be
higher than the flow migrated on it. This can be ex-
plained by the property of continuous mode to offer
multi-contact time of the waste multi-instantaneous
flows in continuous mode with each soil increment. On
other words, instantaneous release crossed each incre-
ment of soil once time; that increment does not the
enough time to retain radionuclides.
5. Conclusions
The objective of the study is not only to evaluate the two
modes and compare, but to estimate possible pollution,
which can occur for a disposal site. This estimation gives
an early overview for keeping the performance of dis-
posal sites until the buried radionuclide reach certain
decay, which does not leads to any pollution. Addition-
ally, the study tries to establish basis for the preparation
of remediation actions in case of any release. The present
study concludes the following:
The safety analysis for a disposal site should contain
a separate chapter study the possible land pollution
and the suitable remediation techniques [10-17].
N. S. MAHMOUD
Copyright © 2011 SciRes. OJSST
10
Table 6. Calculated absorbed dose in both cases instantaneous and continuous modes.
Dose from Instantaneous mode
(mSv/y) Dose from Continuous mode
(mSv/y)
Radionuclide Ingestion dose conversion factor
(Sv/Bq) 10 m 100 m 10 m 100 m
C-14 5.7E10 4.54E+00 5.42E+00 1.14E+00 1.32E02
Ni-59 5.7E11 5.47E06 5.47E06 9.06E07
Ni-63 1.5E10 3.59E01 3.59E01 5.94E02
Se-79 2.35E09 7.90E04 7.90E04 6.20E04
Sr-90 3.6E08 8.89E+02 9.22E+02 1.67E+02
Tc-99 3.95E10 7.35E02 5.29E03 7.74E04
Cs-137 2E08 4.96E+00 4.96E+00 9.78E01
Th-230 1.5E07
Figure 6. Comparison of the modes instantaneous and continuous modes.
The pollution of the area should be monitoring to not
exceed the restricted area around the disposal site.
The study should be within a reasonable enough pe-
riod of time for performing good results.
Detail analysis of different parameters and factors
affect the rate of release from the disposal site should
be considered.
Possible pollution should be evaluated considering
different factors
The mode of release is from the important should be
undertaken in this chapter.
The instantaneous mode can pollute a long distance
N. S. MAHMOUD11
but with low activity.
The continuous mode pollutes a restricted area within
high concentration.
The appearance of each radionuclide should be
monitored at selected distance within the restricted
area around the burial area.
Some radionuclide moves very quickly but does not
require any remediation because it does not reflect a
real pollution case. Some radionuclide moves very
slowly enough to detect and to perform suitable
remediation techniques.
Decontaminations and remediation plans should be
demonstrated in this chapter for assessment by regu-
latory bodies.
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