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BULATOM June 9-11 2010 1
Site selection and design basis of the National Disposal Facility for LILW
Geological and engineering barriers
Sergey Boyanov
BULATOM June 9-11 2010 2
Content• Site selection• Characteristics of the “Radiana” site
- Location- Geological structure- Physical and mechanical properties- Hydro-geological conditions
• Design basis of the Disposal Facility• Migration analysis• Safety assessment approach• Conclusion
BULATOM June 9-11 2010 3
Concept, Region Analyses
Site Characterization
Site Confirmation
PSAREIA
Operation
OrderPermit
доклад
Permit, 05.05.2006
Design
Civil Construction Works
Institutional control
300
OrderPermit
Permit for commissioning
License for Operation
Permit for Closure
ISAR
2015-20652012-20142010-201106.06-06.08 201012.2008
Site Selection
Establishment of National Disposal Facility for LIL-SL waste
TIME SCHEDULE Strategy on management of spent nuclear fuel and radioactive waste,
Council of Ministers, December 2004
The safety of the disposal facility during operational and post-operational phase is assured by engineered and natural barriers and doesn’t depend on any active measures according to the safety criteria
1. Development of Concept 2. Data Collection & Analyses of areas3. Site Characterization4. Site Confirmation
BULATOM June 9-11 2010 4
Stage 1. Development of concept of the NDFVolumeVolume: 138200 : 138200 мм33
Total activityTotal activity: 2,4: 2,4хЕхЕ+14+14 BqBq
BULATOM June 9-11 2010 5
Stage 2. Data collection and areas analysis
78 sites 78 sites –– 12 sites 12 sites –– 4 sites4 sites
BULATOM June 9-11 2010 7
Stage 3 Sites Characterization
The regional and detailed geological,geophysical, geochemical, civil-geological, geotechnical and hydrogeological researches on four sites - Radiana, Brestowa
padina, Marichin valog and Varbitca were carried out
BULATOM June 9-11 2010 8
Length 1700 m, width in middle part 350 m, elevation 55 m
Radiana site was selected as more preferable on result of comparative technical-economical analysis and safety assessment
BULATOM June 9-11 2010 9
GEOLOGICAL STRUCTURE OF THE SITE
Layer No Lithology Thicness[m]
Layer 1 Loess and loess clay 6.50- 41.40Layer 2 Sandy and gravel clay 1.6 – 7.0Layer 3 Silty to sandy clay 24-50Layer 4 Sand and sandy clay 2-10
BULATOM June 9-11 2010 10
№ Lithology ρ w Ro E φ Cu
g/cm3 % MPa MPa degree kPa1aа Silty loess 1.62 10.2 0.17 10.2 21.5 28.7
1b Loess clay and burred soil 1.76 15.0 0.19 17.0 19.8 32.8
2а Gravel and sandy clay 2.02 15.6 0.30 18.0 20.5 45.3
2b Silty-sandy clay 2.09 8.6 0.35 16.3 21 33.3
3 Silty clay 2.05 19.3 0.27 25.0 23.8 76.6
4 Sand and sandy clay 2.02 16.1 0.27 21.5 27.8 40.0
ρ - volume densityw – water contentRo – conditional computing loading
E – Module of common deformationφ – angle of internal frictionC – cohesion (undrained)
Physical and mechanical properties
BULATOM June 9-11 2010 12
Map of underground water level
The depth of water level is more that 40 meters below terrain surface.
BULATOM June 9-11 2010 13
Design basis of the NDF
8 modules with sizes 35.5m х 117m х 10 m5-8 galleries with size 1400 m х ф 6-8 m
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Stress-strain condition of both structures and host rock
0,00
0,20
0,40
0,60
0,80
1,00
1,20
0 0,3 1,3 2,2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 30
Време, t, години
Коеф
ициент
Kt, зави
сещ
от
врем
ето
0,0
5,0
10,0
15,0
20,0
25,0
100 200 300 400 500 600 700 800 900 1000
Реакция на крепежа, KN/m2
Дебел
ина на
пла
стич
ната
зон
а,
m
C=0,15 MPa
C=0,20 MPa
C=0,30 MPa
C=0,45 MPa
Development of loading on reinforces in the time
Depend of the geomechanical parameters(Р* и b ) of cohesion С
Diagram of torsion moments
The deformations in a massif around galleries develop in a calming down mode during the first 30 years. After then the equilibrium condition is established
- on Fellenius method Кst = 0.654;-on Morgenshtern method Кst = 0.680
In massif and in structures is develop critical stress-strain state
BULATOM June 9-11 2010 15
Migration analysis
Parameters of the hydraulic model Coefficient of distribution Kd
The maximal concentration of radionuclides, reaching up to underground water, as 129I, 94Nb, 59Ni, 239Pu are less of admitted volume activity
for drinking water even if used most conservative approach for calculation.
Prognostic migration of isotope 129I for calculation time 100, 250 and 500 year, after his passed in underground water - 4150 years
after closed of disposal facility
BULATOM June 9-11 2010 16
Reference: At degradation of concrete its hydraulic conductivity is increased, but because preservation of high pH the geochemical conditions of the cement of medium continue to be very favorable concerning high sorption and low solubility of radionucleides (Atkinson at al., 1985; Alcorn et al., 1990; Mallants and Volckaert, 2003ô; Richet et al., 2004 IAEA - ASAM, 2005);
Conservative or engineer approach?• The conservative approach is based on use references and requirements
of international organizations. It reflects a a level of ignorance or misunderstanding of conditions and processes
• The engineering approach is based on research of processes and phenomena impacted on both degradation of engineer barriers and migration of radionuclide
BULATOM June 9-11 2010 17
Research of near surface concrete facility
Average compressive strength is 140 kg/cm2
Vp = 3350m/s – 4015m/s
BULATOM June 9-11 2010 18
Sample № 1 2 3
Pore volume, cm3/g 0.0829 0.0783 0.116
10 20 30 40 500
200
400
600
800
1000
1200
1400
W
VVVV, O
V, W
VO
W
XX
V
XV
O
Rostovsky - pr.1, 02.11.09
V - SiO2
O - Ca(OH)2
X - CaAl2Si2O8
W - CSH(B)
imp/
sec
angle,deg
10 20 30 40 500
200
400
600
800
1000
1200
1400
1600
W
VVVV, WV, W
V
W
X
V
V
Rostovsky - pr.2, 02.11.09
V - SiO2
X - CaAl2Si2O8
W - CSH(B)
imp/
sec
angle,deg10 20 30 40 50
0
200
400
600
800
1000
1200
1400
W1W1
V
VV
XXXX
VXX
V, XXXX
XXXX
V
XXX
V
Rostovsky - pr.3, 02.11.09
V - SiO2
X - CaAl2Si2O8
XX - CaCO3
W1 - C2SH
imp/
sec
angle,deg
The volume of pore in concrete is increased. The contents of calcium hydroxide is insignificant. In sample 3 calcium hydroxide is carbonated and passed to calcium carbonate .
• The process of degradation assumes reduction of pH, but preservation of mechanical properties of concrete.
• After degradation the cement mixes cannot be considered as geochemical barrier which could be to restrict the radionuclide migration
• For maintenance of reliability of concrete barriers they need in maximal isolation of water
BULATOM June 9-11 2010 19
1. Favorable hydro-geological condition2. Applicable technical design3. Technology of building and geotechnical fastening
Factors, determining both degradation of facility and migration of radionuclides
BULATOM June 9-11 2010 20
4 6 8 10 12 14 16 18 20 22water content [%]
-24
-22
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
dept
h [m
]
4 6 8 10 12 14 16 18 20 22water content [%]
-24
-22
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
dept
h [m
]
0
10
20
30
40
50
60
70
80
I II III IV V VI VII VIII IX X XI XII
месеци
сред
на сум
а на
вал
ежите,
mm
0
10
20
30
40
50
60
70
80
90
I II III IV V VI VII VIII IX X XI XII
месеци
отно
сителн
а вл
ажно
ст, %
Monthly relatively air humiditymonthly precipitation
July: precipitation 49 mm, evaporation 112 mm December: precipitation 42 mm evaporation 3.6 mmAll year: precipitation 550 mm evaporation 440 mm
P + E + F + W = 0
Water balance?
BULATOM June 9-11 2010 21
Changes of the humidity contain in depth
0 1 2 3 4 5 6depth 1m
4
8
12
16
20
0 1 2 3 4 5 6depth 4m
4
8
12
16
20
0 1 2 3 4 5 6depth 12m
4
8
12
16
20
0 1 2 3 4 5 6depth 22m
4
8
12
16
20
The both content and dispersion of the humidity decrease in depth
4 8 12 16 20
-24
-22
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
4 8 12 16 20 4 8 12 16 20 4 8 12 16 20 4 8 12 16 20 4 8 12 16 20
BULATOM June 9-11 2010 22
• Artificial cover has worse isolated property than multy-layer undisturbed massif• The atmospheric and underground water will be entered in zone of disposal modules or below it• The additional water will decreased quality of mechanical properties of soil nearest and under facility• In a structure of facility and in a host soil around it the critical stress-deformation state are created in the time
Characteristics of the trench type design
110 mm/m2 per year
BULATOM June 9-11 2010 23
•The tunnels are protected from both atmospheric and underground water by number of clay layers•The cylindrical constructions of galleries do not create concentration of stress or forces•The structures are in a condition of three-dimensional stress that provides long-term stability •The concrete is very steady against three-dimensional stress•The miner technology for concrete stacking provides his extremely high density•The filling around of packings provides stability of walls and limits distribution of radionuclides•Geotechnical injection of clay or silicone solutions around galleries provides additional protection of concrete against water.•At degradation of waste form in packings the stress-strain condition of a structures practically does not change
Characteristics of the gallery type design
BULATOM June 9-11 2010 24
Children’s imagine of the National Disposal Facility for LILW
CONCLUSION
Children trust that they will live safety and we try to justify this trust