head of environment radiation monitoring department. ukrainian hydrometeorological institute. kiev...
TRANSCRIPT
Head of Environment Radiation Monitoring Department.
Ukrainian Hydrometeorological Institute. Kiev Ukraine
Radioecological research during 25 years after the Chernobyl accident
Sweden Society Radioecology Conference , 22-23 of March
Voitsekhovych Oleg
The Dnieper River Aquatic System Radioactive Contamination; 25 Years of
Natural Attenuation and Remediation
Introduction
1. Radionuclide release and deposition
2. Radioactive contamination of the catchments and aquatic environment physical and chemical forms of radionuclides and its transformation
radionuclides in the aquatic systems surface waters (rivers and reservoirs),
groundwaters in the Chernobyl exclusion zone
marine system (Black Sea and global context)
3. Assessment of the water protection countermeasure Initial phase
Intermediate phase
Later phase and current situation
Chernobyl cooling pond decommissioning project
4. Radiation Dose and Risk assessment. Public perception and Assessment of the countermeasure effectiveness.
5. Lesson learned Key natural attenuation processes
Developments and validation of radionuclide transport model
Environment Radiation Monitoring strategies and methods development
Risk Assessment and Risk management at the radioactive contaminated lands.
Emergency preparedness aspects
Chernobyl Isotopes applications as markers for Environment studies
Scope of presentation
Introduction• Twenty five years ago, an unprecedented large amount of radionuclides
were released into the environment due to the major accident at Unit 4 of Chernobyl NPP. As a result, the catchment areas and water bodies of the Dnieper River Basin (third largest aquatic system in a Europe) had been significantly contaminated, primarily due to 137Cs and 90Sr.
• In some cases, the level of radionuclides contamination in the water bodies returned to pre-accident conditions within the first decade following the accident, some aquatic ecosystems remained highly contaminated.
• This report presents the past twenty five year time-series data of water body contamination in Ukraine and the dynamic impacts caused by natural factors and human activities in the Chernobyl affected areas.
• This overview is trying to find answer on a question. What Have We Learned ?, assessing some successes and failures to mitigate water
contamination over post-accidental years
On April, 26 198601:24
6
The information in Media in the first weeks
since the Accident did not described
adequately an actualsituation
Ukraine
Chernobyl Accident is the Highest Single Release of Radionuclides into the Global Environment
• Airborne radionuclide transport >200,000 km2 of Europe with 137Cs >37 kBq/m2 (1 Ci/km2).
• Fuel particles—finely dispersed, low volatility, settled primarily within the ChEZ
• Condensed components—from radioactive gases, settled primarily along the atmospheric flow pathways
• Hot particles—fuel particles, uranium dioxide, with a specific activity >105 Bq/g, size 1 to 100 µm, surface density ~ 1,600 per m2, to ~0.5 m depth
Europe
Uncertainties in Assessment and needs for experimental verification of the accidental consequences.
Radionuclide transport studies due to Runoff, sampling at the contaminated lands and water bodies
Specific phenomenon of the Chernobyl radioactive release --- significant amount of nuclear fuel particles were dispersed to the
environment and deposited on catchment’s soils and bottom sediment of the affected water bodies
[O] = 25.8 0.5 %
[U] = 61.7 0.5 %[Zr] = 7.6 0.2 %[O] = 25.8 0.5 %
[U] = 61.7 0.5 %[Zr] = 7.6 0.2 %[O] = 25.8 0.5 %[O] = 25.8 0.5 %
[U] = 61.7 0.5 %[U] = 61.7 0.5 %[Zr] = 7.6 0.2 %[Zr] = 7.6 0.2 %
UOx matrix fuel particle
U-Zr-O matrix fuel particle
Median size of fuel particles ~ 4-6 mTill 2000 about 70% of radionuclide activity was associated with hot particles particles (2000)
In 2008 most of particles in the soils of river water catchments have been destroyed due to weathering impact and chemical leaching, while significant amount of the “hot particles” still remained in the bottom sediment of lakes around ChNPP. from Kashparov at al, 2003
Fuel particle X-ray microanalysis spectrum of Zr-U-O fuel particles
(Ahamdach 2000)
Geochemical Conceptual Model of the fuel hot particles behavior in soils and bottom sediment
• Low DO and high pH cause a very slow dissolution of fuel particles in bottom sediments.
• Weathering effects, vegetation and microbiological are causing significant effects onto the hot particles physical structure In soils and dried wetlands increasing its dissolution rate.
• Fuel particle dissolution will take ~15–25 years in exposed sediments, and ~100 years in flooded areas
• The physical and chemical form of radionuclide transformation in the catchments' soils and bottom sediment allow to achieve significant progress developing radionuclide water transport models from the contaminated watersheds and river systems
J Environ Radioact. 2009 Apr;100(4):p.329-32..Fuel particles in the Chernobyl cooling pond:
current state and prediction for remediation options.
Bulgakov A, Konoplev A, Smith J, Laptev G, Voitsekhovich O.
0
2
4
6
8
0 5 10 15
Time, years
рН
0.00
0.10
0.20
kl,
yr-1
pHK d
0
25
50
75
100
0 20 40Time, years
90 S
r in
fu
el p
art
icle
s, %
exposed
flooded
Calculated plume formation according to meteorological conditions for instantaneous releases on the following dates and times (GMT): (1) 26 April, 00:00; (2) 27 April, 00:00; (3) 27 April, 12:00; (4) 29 April, 00:00; (5) 2 May, 00:00; and (6) 4 May, 12:00
(Borsilov and Klepikova 1993). 0.00001
0.0001
0.001
0.01
0.1
0 5 10 15
Time since Chernobyl (yrs)
137C
s in
wat
er p
er B
q m
-2 o
f fa
llo
ut
(m-1
)
Kymijoki
Kokemaenjoki
Oulujoki
Kemijoki
Tornionjoki
Dora Baltea
Dnieper
Sozh
Iput
Besed
P ripyat (Mozyr)
Danube
P ripyat (Cher.)
Radioactive contamination of the catchments and aquatic
environment as versus of fallout formation date,
its physical and chemical forms and also the landscapes at the
deposited river watersheds
137Cs activity concentration in different rivers per unit of deposition, Smith, 2004
Radionuclides in RiversAnnual fluxes of 137Cs in the Dnieper River
Ratio of 90Sr and 137Cs in soluble forms in Pripyat River near Chernobyl
1012 Bq Radionuclide inlet to the Kiev reservoir. Pripyat RiverDesna River
Data of Ukr. Hydromet. Institute
Rain flood
Winter ice jam
Spring flo
od
Spring flo
od
0
500
1000
1500
2000
2500
3000
01.01 16.01 31.01 15.02 02.03 17.03 01.04 16.04 01.05 16.05 31.05 15.06 30.06
90 S
r C
on
ce
ntr
ati
on
, B
q m
-3/
Wa
ter
Dis
ch
arg
e,
m3 s-1
102
103
104
105
106
107
108
109
Sr-90, Chernobyl
Sr-90, Input Crossect
Flow Discharge
Water Level
UA Permisible Level
Wa
ter L
ev
el, m
BS
0
500
1000
1500
2000
2500
3000
01.01 16.01 31.01 15.02 02.03 17.03 01.04 16.04 01.05 16.05 31.05 15.06 30.06
137 C
s C
on
ce
ntr
ati
on
, B
q m-3
/ W
ate
r D
isc
ha
rge
, m3 s
-1
102
103
104
105
106
107
108
109
Cs-137, InputCrossectCs-137, Chernobyl
Flow Discharge
Water Level
Wa
ter L
ev
el, m
BS
Pripyat River Flood 1999Pripyat River Flood 1999
0
1
2
3
4
5
6
7
8
9
1987 1989 1991 1993 1995 1997 1999 2001 2003 2005Year
137Cs, ТBq
Inflow to ChEZOutflow from ChEZ
0
2
4
6
8
10
12
14
16
18
20
1987 1989 1991 1993 1995 1997 1999 2001 2003 2005Year
90Sr, ТBq
Inflow to ChEZ
Outflow from ChEZ
Wash-out phenomenon for 137Cs and 90Sr
90Sr
90Cs
Radionuclides runoff budget in the Pripyat river show 10-20% of Cs and 40-70% of Sr have contributing by contaminated waters washed out from the ChNPP zone
Return water running off
from floodplain and drainages
Wash-off Snow melting effect
19861986
19931993
Pripyat River Floodplain around Chernobyl NPP was most heavy contaminated Pripyat River Floodplain around Chernobyl NPP was most heavy contaminated and identified as most significant source of the Dnieper system and identified as most significant source of the Dnieper system 9090Sr-90 secondary Sr-90 secondary
contaminationcontamination
Flood protective dam has been constructed
19991999
Site characterization studies and modeling results show that most efficient water protection strategy will be to control water level and to mitigate inundation of the most contaminated floodplains by the flood protection sandy dykes constructed at left and right banks of the Pripyat river
Annually averaged 90Sr activities in water of the Pripyat River downstream of Chernobyl town and effects of water contamination
reduction due to construction of the protective dams, preventing flooding of the most contaminated floodplain area near NPP riverside in 1993
Before protective dam constructed
After protective dam constructed in 1993
1986-2009
1987 1993
2009
а
Data of Chernobyl Ecocenter
Radionuclides in water of the Chernobyl cooling pond, 1986-2009
Radionuclides in the closed lakes of the most contaminated areas around Chernobyl
137Cs and 90Sr in Gluboky lake near Chernobyl NPP
TRWDS
Temporary Radioactive Waste Disposal Sites
are significant sources of the shallow ground water
contamination
Its characterization and step by step removal to the specially
organized places for long-term safe storage at the Radioactive
Waste Reprocessing Plant become significant element of
Environment Remediation Strategy at the Chernobyl
Exclusion zone reducing their influence on further long-term ground waters contaminationNNC,2001
Chernobyl Pilot Site – “worst case” scenario of near-surface radioactive waste disposal
Schematic trench cross-sectionBugay at al, 2003.
Trench Studies TRWDS (PVLRO “ Red Forest)
In some places 90Sr activities concentrations in the ground waters adjacent to TRWDS are continuing to growth.
Those, its moving toward the Pripyat river are very slow (1-10 m per year).
90Sr will reach the Pripyat River in ~50-60 yr from now,
However, even in case contaminated groundwater front will reach the river its flux contribution will be insignificant to the Pripyat River radioactive contamination at this time.
In any case observations on the groundwater regime and its contamination trends will be continued for a long time Bugai et al. 1996
90Sr in the groundwater TRWDS “Sand Plato” near Pripyat River (Kiereev et al. 2006)
Monitoring and Simulation of 90Sr Distribution in Groundwater
Effects of the Groundwater level drawdown
The groundwater water table will be reduced at mane places around the ChNPP Cooling pond from 1 to 7 m
of present since it will be decommissioning
The ground water flow directions will be also changed.
The effects of the groundwater level declining in the CP will create positive effects in regarding of the number of temporary waste disposal sites situated
around and also is beneficial for lowering inundation levels at Chernobyl NPP NSC (New Safe Confinement)
site Bugai D., Skalsky A. 2001
8 0 0 9 0 0 1 0 0 0 11 0 0 1 2 0 0 1 3 0 0 1 4 0 0 1 5 0 0 1 6 0 0 1 7 0 0
8 0 0 9 0 0 1 0 0 0 11 0 0 1 2 0 0 1 3 0 0 1 4 0 0 1 5 0 0 1 6 0 0 1 7 0 0
8 0
9 0
1 0 0
11 0
8 0
9 0
1 0 0
11 0
1 .0 E + 0 0 2
1 .0 E + 0 0 3
1 .0 E + 0 0 4
1 .0 E + 0 0 5
1 .0 E + 0 0 6
1 .0 E + 0 0 7
1 .0 E + 0 0 8
1 .0 E + 0 0 9
4 .0 E + 0 0 9
B q /m ^ 3ChNPP NSC
Predicted 90Sr concentrations in the aqueous phase without NSC after 100 yr.
Distance toward the Pripyat River from NSC
90Sr
0
100
200
300
400
500
600
1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002Years
Bq/m3
Vishgorod Novaya Kahovka
90Sr in the waters of the Dnieper’s reservoirs90Sr in the reservoirs of the Dnieper
cascade is still above of its pre-accidental levels observed in 2010 in
range 40-100 Bq m-3 ( the same levels as were observed during 2002
137Сs
1
10
100
1000
1987 1989 1991 1993 1995 1997 1999 2001 Years
Bq/m3
Vishgorod Novaya Kahovka
137Cs in the waters of the Dnieper reservoirs
137Cs activity concentration in water at the lowest reservoir returned to its pre-
accidental level still in 1996-1998.
In 2010 137Cs activities in Kiev (upper reservoir) in a cascade were observing
in range 10-20 Bq m3, while in Kakhovka (lower reservoir) -- 0,5-1,0 Bq m3
137Cs in the bottom sediments of Reservoirs
1991-93
Upper part of Kiev Reservoir
Low part of Kiev Reservoir
2009
137Cs1994
Dni
eper
Pripyat River
Dam near Kiev
Kremetchug reservoir bottom, 1994
137Cs in freshwater fish and other aquatic biota
0
100
200
300
400
500
600
700
800
900
1000
Bq/
kg,
w.w
.
0
200
400
600
800
1000
1200
1400
1600
1800
Bq/
kg, w
.w
137Cs in predatory and non predatory fish species in Kiev reservoir. (after I.Ryabov et al., 2001)
137Cs and 90Sr in predatory and non-predatory fish species. Gluboky Lake
Gudkov, et al. 2008)
Absorbed dose rate caused by incorporated radionuclides in the algae and non-predatory fishes.
Gluboky Lake
Averaged chromosome aberration rates in the fresh water lake mussels in the lakes of the ChNNP area and in the reference clean lakes near Kiev
Published by D.Gudkov et al. 2008
Summary. Long-term doses from aquatic pathways.
Human exposure via the aquatic pathway took place as a result of consumption of drinking water, fish catch in reservoirs and agricultural products grown using irrigation water from Dnieper reservoirs.
In the middle and lower areas adjacent to the Dnieper reservoirs, which were not significantly subjected to direct radionuclide contamination in 1986, a significant proportion (10–20%) of the Chernobyl exposures were attributed to aquatic pathways.
Estimates were that individual doses via aquatic pathways would not have exceeded 1–5 μSv y-1.
Furthermore, in some closed lakes, the concentration of 137Cs remains high and high levels of contamination are found in fish species. People who illegally catch and eat contaminated fish may receive internal doses in excess of 0,5-1 mSv per year from this source.
The most significant individual dose was from 131I and was estimated to be up to 0.5–1.0 mSv for the citizens of Kyiv during the first few weeks after the Chernobyl accident.
Aquatic pathway of Radiation Risk forming and its
Public perception
• In spite of doses were estimated to be very low, there was an inadequate understanding of the real risks of using water from contaminated aquatic systems.
• This created an (unexpected) stress in the population concerning the safety of the water system. This factor made reasonable to provide assessment of collective commitment doses as a basis for justification of some water protection actions
Food product, milk water external inhalation
Actual dose
Public perception about
Dose realization (%) during a 70 years for children born in 1986
From I.Los, O.Voitsekhovych, 2001
For 1-st year about 47 %
For 10 years about 80%
Years
Long-term probabilistic assessment of the Dnieper River contamination -- as a basis for collective dose simulation
0
5
10
15
20
25
30
19941996199920012004200620092011201420162019202120242026202920312034203620392041204420462049205120542056
Year
pC
i/l
Kiev res.
Kakhovka res.Sr- 90
02
46
810
1214
1618
19941996199820002002200420062008201020122014201620182020202220242026202820302032203420362038204020422044204620482050205220542056
Year
pC
i/l
Kiev res.
Kakhovka res.Sr-90
Concentration of 90Sr (1 pCi = 3,7 *10-2 Bq) in water of the upper and downstream reservoirs for the worst (top) and best probabilistic hydrological scenarios to be possible expected at the Dnieper reservoirs (Zheleznyak et al., 1997).
Estimates were made of the collective dose to people from these three pathways for a period of 70 years after the accident, i.e. from 1986 to 2056
A long-term hydrological scenario was analysed using a computer model (Zheleznyak et al 1992).
Historical data were used to account for the natural variability in river flow.
Dose-assessment studies were carried out to estimate the collective dose from the three main pathways (Berkovski et al 1996),.
0%
20%
40%
60%
80%
100%
1 6 11
16
21
26
31
36
41
46
51
56
61
66
Com
pone
nts
of c
olle
ctiv
e do
se, %
0
10
20
30
40
50
Ann
ual c
olle
ctiv
e do
se,
man
Sv
Орошение Рыба Питьевая вода Годовая коллективная дозаIrrigation Fish Drinking water Annual collective dose
0%
20%
40%
60%
80%
100%
1 6 11
16
21
26
31
36
41
46
51
56
61
66
Co
mp
on
ents
of
coll
ecti
ve
do
se,
%
0
10
20
30
40
50
An
nu
al
coll
ecti
ve
do
se,
ma
n S
v
Орошение Рыба Питьевая вода Годовая коллективная дозаIrrigation Fish Drinking water Annual collective dose
Collective effective dose for Kyiv region population due to water consumption from Kiev reservoir usage pathways as a function of years after 1986
Collective effective dose for Poltava region population due to water usage pathways from Kremetchug reservoir as a function of years after 1986
COLLECTIVE DOSE COMMITMENT (CDC70) CAUSED BY 90SR AND 137CS FLOWING FROM THE PRIPYAT RIVER (BERKOVSKY ET AL. 1996)
Dose estimates for the Dnieper system show that if there had been no action to reduce radionuclide fluxes to the river, the collective dose commitment for the population of Ukraine (mainly due to Cs and Sr) could have reached 3000 man Sv.
Protective measures, which were carried out during 1992–1993 on the left-bank flood plain of the Pripyat River and later on right bank (1999) decreased exposure by approximately 1000 man Sv. (Voitsekhovich et al. 1996).
Water protection and Remediation • Many remediation measures during initial period after the accident (1986-1988)
were put in place, but because actions were not taken on the basis of dose reduction, most of these measures were ineffective.
• Because of the importance of short lived radionuclides, early intervention measures, particularly changing supplies, can significantly reduce doses to the population, mainly because 131I. However this opportunity has been missed during first month since the accident.
• During first months after the accident restrictions on fishery and irrigation from the contaminated water bodies have been established. The number of water regulation actions at the small river in the Chernobyl exclusion zone were applied.
• Numerous countermeasures put in place in the months and years after the accident to protect water systems from transfers of radioactivity from contaminated soils were, in general, ineffective and expensive and led to relatively high exposures to workers implementing the countermeasures.
• The water regulation at the most contaminated floodplains and water runoff regulation from the wetlands in the close zone around ChNPP only can be considering as effective.
Decommissioning means:
Restore Monitoring network
Stop water pumping from the river
• Separating the inflow and outflow channels (to use as fire reservoir)
• Construct alternative source of cooling water--groundwater pumping wells
• Declining water from the CP (filtration)
• Remediation of the remained bottom area if needed. Institutional control.
ChNPP
Prip
yat River
Decommissioning of the Chernobyl Cooling Pond
PripyatRiver
Monitoring well
Quaternary unconfinedaquifer
Eocene aquitard
Eocene confined aquifer
Subsurfacedischarge
Cooling pond
Drainagedischarge
North drainagechannelSouth drainage
channel
104
105
106
107
108
109
110
111
0 365 730 1095 1460 1825 2190 2555 2920 3285
Время, сутки
Ур
ов
ен
ь в
од
ы в
ВО
, м Б
СВ Сухий сценарій
Нормальнийсценарій
Water level above the sea
Days after start point
As the result of the water level decline the area covered
about 60-70% of the bottom sediment territory may be
dried and exposed for wind human access.
The new artificially forming bottom sediment relief will be
created by the 3 types - always dry
- always covered by water - intermediate wetland (dried
or wet) depend of water mode and climate conditions)
0
10
20
30
40
50
60
70
0 50 100 150 200 250 300
Время, годы
90S
r, Б
к/л
Bottom Sediment landscape
transformationThe geochemistry of the wetland lakes will be transformed.
рН will be reduced and NH4 will be increased
The radionuclides in the water column will be increased
53
105
340
780
720
9467
43
44
35
7
31
31
571
48
50
150
56
139
990
30
53
2700
48
30
76
210
55
188
52
143
205
63
70
33
280
57
200
51
51200
54
66
45
100
64
30
30
57
75
35
33
180
39
30
65
33
55
250
71
252
42
40
33
55
40
6
174
108
157
55
45
170
42
94
18
40
73
61
41
40
24
210
40
76
72
50
27
29
42
104
71 90
133
97
79
311
45
145
100
56
262
50
75
64
52
300
158
75
302
57
86
27
67
15
100
140
350
350
760
57
380
1327
152
3360
90
551
100
5000
453
256
809
400
200
1780
928
50
51
320
682
1195
75
234
50
600
481
230
200
2000
75
3600
800
200
80
1200
1900
231
1200
2300
2350
200
2101
2150
780
1400
4780
800
1984
2720
615
1706
991
200
1376
230
25
50
75
100
150
250
500
750
1200
2000
Chernobyl NPP Cooling PondCs-137, Ci km -2
Scale 1cm :500m
0 500 1000 1500 2000
Ci km -2
87
243
28
44
19
22
5
3
3514
4
9
16
4
13
7
5
16
23
17
35
38
103
30
7
515
4
2
17
200 260
455
940
302
480
5
147
3
40
10
220
254
100
340
330
72
137
20
147
980
1
5
10
25
50
100
250
500
750
1000
Chernobyl NPP Cooling PondSr-90, Ci km2
Scale 1cm:500m
0 500 1000 1500 2000
Ci km-2
0.67
2.6
0.35
0.52
0.18
0.15
0.041
0.04
0.30.097
0.024
0.09
0.12
0.028
0.12
0.06
0.06
0.12
0.28
0.18
0.35
0.51
0.050.011
0.84
0.071
4.7
8
16
3.5
6
0.1
3.5
0.074
0.97
0.42
6.3
5.8
2.4
11
11
0.01
0.05
0.1
1
5
10
Chernobyl NPP Cooling PondTotal Pu, Ci km 2
Scale 1cm :500m
0 500 1000 1500 2000
Ci km -2
137Cs 90Sr 239,240Pu
137Сs 90Sr 239,240Pu
According to UHMI report in the CP is currently accumulated about
280 TБк 137Cs, 42 TБк 90Sr and 0,75 TБк Pu
The major activities of these radionuclides accumulated at the depth deeper of 7 meters and will remain flooded in a new transformed water ecosystem
Radionuclides in the bottom sediment (UHMI, 2005)
Possible effects of soil particles atmospheric dispersion and fire
• The effects of re-suspension to be local and may increase contamination of the surrounding areas no more then 5 % of existing contamination level.
• NO significant effects for personnel, working at the Chernobyl NPP site due to effect of wind re-suspension or grass fire at the CP (less 1 mSv a year)
Conclusions• Radiological Risks associated with decommissioning of ChNPP for
population living along the Dnieper River is negligible.
• Transition period of the water infiltration may take 5-7 years, since the current CP will be transformed in to the new ecosystem
Preliminary assessment show that combination of OPTIONS
• Do nothing and “Partial Remediation”, i.e. remediation of the most contaminated sediments ( relatively small areas 0,1-0,5 km2 by removing them and placing in the waste disposal site can be reasonable .
• Natural attenuation process such as natural vegetation covers of the exposed sediment to be most reasonable selected remediation strategy.
• New transformed ChNPP cooling pond ecosystem will pose a unique natural ecosystem laboratory.
• It is still uncertain understanding how fast new transformed ecosystem will be restored as wetlands with a new sustainable conditions
From Chernobyl Forum, 2005 to 2011
What has been changed ?
International Conference 25 Years after Chernobyl, Kiev
Radionuclides in the Black Sea• After Chernobyl 137Cs inventory in
the 0-50 m layer increased by a factor of 6-10 and the total 137Cs inventory in the whole basin increased by a factor of at least 2 ( pre-Chernobyl value of 1.40.3 PBq)
• 137Cs input from the Danube and the Dnieper rivers (0.05 PBq in the period 1986-2000) was insignificant in comparison with the short-term atmospheric fallout.
• • The contribution of Chernobyl-
origin 137Sr from atmospheric fallout was estimated at 0.1-0.3 PBq.
• At the same time, a relatively important input of 90Sr from the Dnieper and Danube Rivers was observed.
Sediments/Water FluxesSediments/Water Fluxes Sediments/Water FluxesSediments/Water Fluxes
137s
137Cs and 90Sr vertical distributions in the Western Black Sea deep-water basin (1998 and 2000)
0 10 20 30
0
50
100
150
200
0 200 400 600 800 1000
C(z)=C0+a/(1+exp(-(z-z0)/b))
R = 0.91 St. Error = 2.61
Depth
, m
TOTAL INVENTORY
(0-200m layer) -1173+/-181 TBq
137Cs, Bq m-3
137Cs, TBq
- BS98-16- BS2K-37
Stations:
90Sr, Bq m-3
0 5 10 15 20 25
Dep
th, m
0
50
100
150
200
250
500
750
1000
1250
1500
1750
2000
90Sr, TBq0 100 200 300 400 500 600 700 800
C(z)=C0+a/(1+exp(-(z-z0)/b))
R = 0.93 St. Error = 1.42
- BS2K - 37- BS2K - 23- BS2K - 11- BS98 - 16- BS98 - 15
TOTAL INVENTORY
in the whole volume -1765+/-792 TBq
Stations:
0 250 500 750 1000
137Cs activity, Bq.kg-1 dw
Dep
th, c
m
1
2
3
7
8
4
5
6
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
238Pu/239,240Pu
Dep
th, c
m
1
2
3
4
5
6
7
Fuel
rep
roce
ssin
g
Wea
pons
test
ing
Che
rnob
yl
8
0
5
10
15
20
25
30
0 100 200 300 400 500 600
137Cs, Bq kg-1
Depth
, cm
137Cs in core BS98-03 illustrate a history of sedimentation
typical of riverine suspended particles deposited near the
Danube River Delta
137Cs activity and 238Pu/ 239,240Pu activity ratio profiles in deep-sea sediment core BS2K-11
(water depth 1880 m), 2002
Vertical profile of Radiotracers
Resolution of the core Resolution of the core cutting method is 5-7 cutting method is 5-7 slices for slices for 1 cm of the 1 cm of the
bottom sediment core bottom sediment core
0 500 1000 1500 2000
0-0.15
0.30-0.50
0.70-0.90
1.00-1.20
1.40-1.60
1.80-2.00
2.25-2.50
2.75-3.00
137Cs activity, Bq/kg
Slic
e, c
mThe result illustrates the low sedimentation rates, the upper peak of The result illustrates the low sedimentation rates, the upper peak of
137137Cs corresponding to the Chernobyl input (1986) and the lower one to Cs corresponding to the Chernobyl input (1986) and the lower one to the time of maximum input from global fallout in the early 1960s. the time of maximum input from global fallout in the early 1960s.
The result illustrates the low sedimentation rates, the upper peak of The result illustrates the low sedimentation rates, the upper peak of 137137Cs corresponding to the Chernobyl input (1986) and the lower one to Cs corresponding to the Chernobyl input (1986) and the lower one to
the time of maximum input from global fallout in the early 1960s. the time of maximum input from global fallout in the early 1960s.
BLACK SEA CORE BS-4Depth versus Age
0
1
2
3
4
5
6
70 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220
Age (y)
Dep
th (
cm)
0.000
0.005
0.010
0.015
0.020
0.025
0.030
Sed
imen
tati
on
Rat
e (g
cm
2 y-1
)
CRS Pb-210 Dates
CIC Pb-210 Dates
Cs-137/Am-241 Dates
CRS SedimentationRates
1986
1963
ChNPP
NW Tests
Black Sea Cruise 1998
1963 (66)
1986 (89)
Environment Radiation Monitoring Findings ERM should be a tool for decision making
ERM should be Task and Site specific
Sampling programs to be based on screening assessment and also have adequately designed according to the tasks, expected way of the data utilization and regulatory requirements
Parameters for analytical measurements have to be corresponded with source term analyses and strategies for Safety or Environment Assessment .
QA/QC principles to be obligatory for all partners of the ERM programs
Data reporting and Data management should be well coordinated, agreed and based on DPSIR principles
DPSIR = Drivers, Pressures, States, Impacts and Responses
09.09.2009
Network of Monitoring Stations and Wells in the ChNPP close-in zone.
Schematic of Monitoring Wells
нниийй””
• 40 cross sections and aerosol pump stations;• 138 wells, 2 water supply stations;• 4 stations of surface water and bottom sediments
Chernobyl Ecocenter, S. Kireev.
Groundwater Modeling
• VisualModflow and MT3D96 codes
• Regional model of the Chernobyl exclusion zone and a 2D cross-section model
Pond
Infiltration model After Bugai et al.
Surface Water ModelingWater Quality Analysis Simulation Program (WASP)--EPA framework for modeling contaminant fate and transport in surface water.
Radionuclide transport modeling codes RIVTOX, COASTOX and THREETOX developed in IMMSP of the National Academy of Sciences
of Ukraine
Kd depends on the N ammonia concentration (M. Zheleznyak et al., (2005)—INTAS-2001-0556 Project Report “Radionuclide and Sediment Transport Modelling
Within the Cooling Pond Ecosystem“) Zheleznyak et al., 2002; Maderich et al, 2005
Microbial communities
Dissolved radionuclides
Radionuclides in suspended sediments
Radionuclides in bottom sediments
Advection
Diffusion/Dispersion
Adsorption Desorption
Adsorption
Desorption
Sedimentation
Resuspension
Uptake
Processes Affecting Radionuclide Transport in the lake-reservoir systems
Suspended sediments
Do We Have Reliable Monitoring and Modeling Tools?
Modified after M.Zheleznyak
FloodplainChernobyl
NPP
Cooling pond
Modeling of Cooling pond Dam Break and Sr-90 release
00,050,1
0,150,2
0,250,3
0,350,4
0,450,5
1 19
37
55
73
91
10
9
12
7
14
5
16
3
18
1
19
9
21
7
23
5
25
3
27
1
28
9
30
7
32
5
34
3
36
1
time (day)
Sr
90 c
on
c. in
solu
t. (
Bq
/l)
Kiev
Kanev
Krem
Dndz
Dnepr
Kahovka
M. Zheleznyak et al. 2005
Some conclusive comments
Basic knowledge of geological, hydrological and ecosystem peculiarities at the area of potential radiation impact allows to select right strategy on imitative and environment protection
Any countermeasure and remediation planning must be based on detailed monitoring data and exhausting site characterization results.
Scientifically defensive assessment tools and required data must be developed and applied
Countermeasure and remediation selection must be based on a cost-risk analyses that directly connects the main physical and chemical processes to environment (ecosystem) or human heath risks and costs
Decision makers must be knowledgeable on phenomena being evaluating, they should efficient use expert’s experience and expert’s analytical and modeling systems, which can help to accept right and reasonable decisions aiming to mitigate or prevent expose of people and also allow to safe as always limited resources available , when measures can not be justified or may be postponed.
Decision makers must communicate facts quickly and honestly to the affected public
Acknowledgements
This this comprehensive overview is based on the results taken from number of previous national and international projects, which have been implementing with contribution of many people during recent 25 years.
Special thanks to:.G. Laptev, V.Kanivets, A. Kostezh, L.Pirnach, S.Todosienko (UHMI)
• and also appreciate to our colleagues:• D.Bugay, A.Skalsky (Institute Geological Sciences) • S. Kireev ( Chernobyl Centre), • V. Kashparov (Institute agriculture radioecology)• Konoplev, A. Bulgakov, (SPA, “Typoon”)• M.Zheleznyak, (IPMMS)• V.Berkovsky ( IRP)• O.Nasvit and D.Gudkov (IGB)
Many thanks to all analyst, engineers and technicians, which contribution to field and analytical studies make possible this syntheses and analyses
Many thanks to Chernobyl NPP authority and Administration of the Chernobyl Exclusion zone for supporting remediation projects and monitoring programs at the Chernobyl exclusion zone
Thank you very much for your attention
UHMI, Nauki prospect, 37. Kiev 03028. Ukraine