1. Nuclear Waste Disposal
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Nuclear Waste Disposal
Geological Constraints
And Indian Overview

2. Preface Downloaded from CivilDigital.com
Since the development and utilization of nuclear energy during World War II, countries have struggled with the issue of disposing of high-level nuclear waste .
Nuclear waste is one of the biggest downsides to nuclear power, and can remain dangerous for hundreds of thousands of years.
Geological disposal is often stated as the most preferable way of dealing with it, but what does it entail?
In this report we will discuss problems that need to be overcome , ongoing research and try to choose a suitable location in India for disposal.

3. Index Production and types Downloaded from CivilDigital.com
Methods of disposal
Geological constraints
Indian context
Bibliography

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Classification of waste on basis of radioactivity: 1.low level (90%) 2.intermediate level (7%) 3.high level(3%)

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Low-level waste
Generated from hospitals and industry, as well as the nuclear fuel cycle.
Low-level wastes include paper, rags, tools, clothing, filters.
Some high-activity LLW requires shielding during handling and transport but most LLW is suitable for shallow land burial

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7. Intermediate-level waste
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Intermediate-level waste
Intermediate-level waste (ILW) contains higher amounts of radioactivity and in some cases requires shielding
Includes resins, chemical sludge and metal reactor nuclear fuel cladding
It may be solidified in concrete or bitumen for disposal
Short-lived waste (mainly non-fuel materials from reactors) is buried in shallow repositories
Long-lived waste (from fuel and fuel reprocessing) is deposited in geological repository

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High-level waste
It contains fission products and transuranic elements generated in the reactor core.
Though it is only 3% of total volume but it is responsible for 95% of total radioactivity.
It is highly radioactive and often hot.
HLW is the most dangerous and the main candidate for geological disposal
Certain radioactive elements (such as plutonium 239) in “spent” fuel will remain thousands of years
Tc-99 (half-life 220,000 years)
I-129 (half-life 15.7 million years)

9. Management of High-level wastes
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Management of High-level wastes
Immobilization of high level liquid waste into vitrified borosilicate glasses.
Engineered interim storage of vitrified waste for passive cooling in pools near power-plant and surveillance over a period of time qualifying it for ultimate disposal.
Ultimate storage disposal of vitrified waste a deep geological depository
Vitrified waste

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11. Disposal of Waste Downloaded from CivilDigital.com
Depending on level of waste following methods are used
Above ground disposal
Geological disposal
Deep borehole disposal
Disposal at subduction zones
Ocean disposal
Disposal in outer space

12. Impractical methods Downloaded from CivilDigital.com Methods
Main Reasons
Disposal in outer space
Very costly
High risk of space vehicle failure
Ocean Disposal
Declared illegal by international treaty
Disposal at subduction zones
High risk of earthquakes since located on plate boundaries
Rate of subduction is very slow

13. Above ground disposal Downloaded from CivilDigital.com
Generally used for intermediate and high level waste
Waste from a spent fuel pool is sealed (along with an inert gas) in a steel cylinder, which is placed in a concrete cylinder which acts as a radiation shield.
Cheap , relatively easy to construct and monitor.
Dry cask storage area

14. Deep borehole disposal
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Deep borehole disposal
Disposing of high-level radioactive waste from nuclear reactors in extremely deep boreholes
Placing the waste as much as five kilometers beneath the surface of the Earth
Waste is sealed in strong steel containers and lowered down the borehole, filling the bottom one or two kilometers of the hole
Borehole is then sealed with materials, including perhaps clay, cement, crushed rock backfill, and asphalt, to ensure a low-permeability

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16. Advantages of Deep borehole disposal
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Advantages of Deep borehole disposal
A high-temperature scenario involves very young hot waste in the containers which releases enough heat to create a melt zone around the borehole.
As the waste decays and cools, the melt zone re-solidifies, forming a solid granite sarcophagus around the containers, entombing the waste forever.
Environmental impact is small.
Can be carried out near nuclear power-plant eliminating transportation risks.

17. Geological Repository
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Geological Repository
A deep geological repository is a nuclear waste repository excavated deep within a stable geologic environment (typically below 300 m).
Repositories include the radioactive waste, the containers enclosing the waste, other engineered barriers or seals around the containers, the tunnels housing the containers, and the geologic makeup of the surrounding area
Geological disposal can be safe, technologically feasible and environmentally sound

18. Schematics of geological repository
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Schematics of geological repository
C : high level
B :intermediate level
CU : spent fuel(high level

19. Ongoing research Downloaded from CivilDigital.com
Nuclear waste disposal is currently a matter of study. Study is undergoing in many countries related to geological disposal.
European Countries like Finland , Sweden ,Germany ,Belgium have done considerable amount of research and constructing their repositories.
Research was done in USA in Yucca mountains but constructing final repository there was cancelled.
It was stated that cancellation took place due to political reasons ,not technical or safety reasons.
Similarly in India research was done in kolar gold mines in mysore.

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21. Geological constraints
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Geological constraints
Circulation of water
Properties of Host Rock Depending on type.
Erosion.
Hazards like earthquake / volcanic eruption.

22. Water circulation Downloaded from CivilDigital.com
Water circulation, as well as providing a path for soluble waste to escape to the surface, will increase the speed at which engineered barriers such as metal casing will degrade.
Groundwater circulates in two distinct places within the bedrock, within the pores and within fractures.
Crystalline rocks like granite ,basalt /tuff have very low permeability but are often highly fractured.
In clays, such as those investigated in French and Belgian underground laboratories, the permeability is higher but fractures are much rarer.

23. Geo-hydrological study of area:
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Geo-hydrological study of area:
Potential groundwater pathways defined by top soil, weathered rock, fracture networks, interflow porous layers should be identified.

24. Host rocks Downloaded from CivilDigital.com
Each rock type has different geomechanical property.
Moreover these property vary from site to site.
So in following slides we will look upon research done in different types of host rock.

25. Research in granitic rocks
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Research in granitic rocks
In Finland research was done at onkalo .
While in Sweden research was done at underground Äspö Hard Rock Laboratory.
Tunnels and other excavations in hard granitic rocks are stable over long period of time.
But excavation results in stress release and opening of fractures.
Permeability is very low unless water conducting joints or open fractures are present.

26. Research in Tuff Downloaded from CivilDigital.com
Volcanic tuffs are also candidates for nuclear waste depositories, such as the Yucca Mountain site in the U.S.A.
Welded tuffs can have low permeabilities, but the most attractive property of tuffs is their ability to trap some radionuclides through sorption.
Yucca mountain range

27. Research in clay based rocks
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Research in clay based rocks
In France Andra (French National Radioactive Waste Management Agency) is the public body responsible for the long-term management of all radioactive waste.
Research was done at Meuse/Haute-Marne underground research laboratory which is in clay formation.
Meuse/Haute-Marne is underground laboratory, located at a depth of 490 meters in the heart of a very stiff (indurated) clay formation (argillite).
Over 10 years of research was done using:
> 1,300 km of seismic profiles studied
> 27 deep boreholes
> 4.2 km of cored boreholes
> 2.3 km of argillite cores

28. Meuse/Haute-Marne underground research laboratory
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Meuse/Haute-Marne underground research laboratory

29. Properties of the rock formation
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Properties of the rock formation
the geological environment is stable; very low seismic risk.
the clay layer is regular and homogeneous over a large surface area.It does not present any fault
Argillite has excellent properties. It is a stiff (indurated) sedimentary rock with very low permeability
Radioactive or nonradioactive elements dissolved in water move very slowly through this rock
the rock can withstand mining excavation work.

30. Bentonite clay Downloaded from CivilDigital.com
These layers are placed between host rock and waste to restrict groundwater flow and retard migration of radionuclides.
Their swelling properties helps in sealing the fractures in host rock.
Bentonite clay being used in sealing waste overpack

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Indian context
India has extensive & varied experience in the operation of near surface disposal facilities (NSDFs) in widely different geo-hydrological and climatological conditions by BARC.
There are seven NSDFs currently operational within the country.
In India, the most promising formation is granitic rocks.
A program for development of a geological repository for vitrified high level long lived wastes is being pursued actively, involving In-situ experiments, site selection, characterization and laboratory investigations

32. In-situ underground experiments
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In-situ underground experiments
For assessment of the rock mass response to thermal load from disposed waste , an experiment of 8-years duration was carried out.
At a depth of 1000 m in an abandoned section of Kolar Gold mine.

33. Choosing a location Downloaded from CivilDigital.com
absence of seismic risks in the long term.
absence of significant water circulation inside the repository,
rock suitable to underground installations excavation.
confinement property for radioactive substances.
sufficient depth to keep the waste safe from potential aggressions.
absence of nearby rare exploitable resources.

34. Choosing low risk seismic zone
Choosing low risk seismic zone. And avoiding high population density areas.
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35. Overlap of seismic and population level.
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Overlap of seismic and population level. 1. 2. 3. 4.
Western Rajasthan
Lower Chhattisgarh
Western Andhra Pradesh
Eastern Karnataka

36. Choosing arid areas i.e. low rainfall.
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Lower Chhattisgarh ruled out because of high rainfall

37. Further research required on:
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Conclusion
Based on above study these three regions in India can be used for disposal Western Rajasthan, Western Andhra Pradesh, Eastern Karnataka.
Since this is very preliminary study , further research in these narrowed down regions can be carried out.
Further research required on:
This sub-surface information by drilling and lithological studies.
Geophysical surveys using Ground Penetration Radar (GPR).
Water circulation study.
Absence of exploitable natural resource.

38. Bibliography Downloaded from CivilDigital.com Wikipedia Andra.fr
barc.gov.in