site selection and design basis of the national disposal ... 3/report... · site selection and...

BULATOM June 9-11 2010 1

Site selection and design basis of the National Disposal Facility for LILW

Geological and engineering barriers

Sergey Boyanov


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


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


Stage 1. Development of concept of the NDFVolumeVolume: 138200 : 138200 мм33

Total activityTotal activity: 2,4: 2,4хЕхЕ+14+14 BqBq


Stage 2. Data collection and areas analysis

78 sites 78 sites –– 12 sites 12 sites –– 4 sites4 sites


Preferable sites


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


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


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


№ 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


Host-soil

Loess clay

Sandy clay

Gravel-clay


Map of underground water level

The depth of water level is more that 40 meters below terrain surface.


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


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


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


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


Research of near surface concrete facility

Average compressive strength is 140 kg/cm2

Vp = 3350m/s – 4015m/s


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


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


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


1. Favorable hydro-geological condition2. Applicable technical design3. Technology of building and geotechnical fastening

Factors, determining both degradation of facility and migration of radionuclides


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?


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


• 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


•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


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


Thank you for your attention


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site selection and design basis of the national disposal ... 3/report... · site selection and...

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