Site Characterization and Data Requirements for BDC Implementation

1. Site characterization and data requirements for implementing the BDC Presenter Name School of Drafting Regulations for Borehole Disposal of DSRS 2016 Vienna, Austria

2. Outline • Step by step development of the BDC • The nature of site characterization • Site characterisation techniques • Site characterization data and their uses 2

3. Main references Requirements for disposal Guidance for borehole disposal TECDOC 1644 Technology of the BDC

4. Step by step development of the BDC 4

5. Crossl Retrieve, transfer, condition and store sources Borehole construction Collection and transfer of sources from store Source containerization Emplacement & backfilling Casing removal, seal emplacement i i i i i i i i Site decommissioning Possible Borehole programme 3. Pre-disposal -site specific 1. Pre-requisites 4. Disposal DECISION POINT approve site DECISION POINT –license disposal at recommended site Regulatory framework Regulator, implementer established Define national inventory HOLD POINT Characterise favoured site Site-specific design & safety assessments 2. Pre-disposal generic Define inventory for disposal adapt design to suit Define site selection process Site screening Site walkover & evaluation Draw up ranked shortlist Government decisions and inputs i Waste management implementer actions Regulatory Body decisions & inspections i

6. Decision points • First decision: site approval. Supporting information: • preliminary safety case based on IAEA generic safety assessments • inventory • Site data based on existing information/ desk studies • Second decision: approval for borehole construction and disposal of sources but with hold point following construction. • Supporting information: • Site specific safety case • Inventory • Site characterization data Step-by-step development 6

7. The nature of site characterization 7

8. Multi-disciplinary 8

9. Use of safety assessment • Safety assessment is the main driver for research and development (R&D) and site characterization Identify key uncertainties Safety assessment Facility design R&D/ Site characterization to resolve uncertainties Update design Update data 9

10. Site characterization techniques 10

11. Use of existing information • It is likely that a great deal will already be known about the properties of the site, especially • Geology/ hydrogeology • Hydrology • Meteorology From national institutes etc • Ecology • Transport & utilities • All existing information needs to be collected • Local centres of expertise consulted and integrated into the project • Identify key missing data /inconsistencies 11

12. Scope of Site Investigations • Scope defines activities to be undertaken, e.g. • How many investigation boreholes? • How deep? • Type and amount of sampling and testing, etc? • Scope of required investigations depends on: • The geological environment eg how complex is it? • The inventory of wastes for disposal - esp. mobility and longevity of radionuclides; • The national regulations and approaches to authorisation; • The local availability of resources

13. Investigation Strategy • Take maximum advantage of existing information; • Use techniques for site investigations that are: • Best suited to obtain the required information; and • Are available locally at reasonable cost. • Use of specialist contractors, hence the need to specify the work ie technical specifications

14. Technical Specifications • The generic TS define genericrequirements that need to be followed for undertaking the different investigation activities; • Responsibility for providing more detailed information on how activities are undertaken rests with the implementing organisation • These detailed requirements should take account of: • Local regulations and approaches to undertaking site investigations; • Available local resources; and • Local language

15. Activities included in Generic Technical Specifications • Surface-based geophysical surveys; • Exploratory boreholes: • Interpretation; • Investigation management (if above activities are undertaken by multiple contractors) • Ecological survey

16. Important Considerations • Investigations are designed to gather the information needed for the project - it is important to keep focus; • Multidisciplinary – may require collaboration between a range of contractors; and • Contractors may need to wait whilst other activities are being undertaken, e.g.: • Drilling halted whilst testing is being carried out • Investigatory drilling is not like drilling a water well

17. Surface-based geophysical surveys • Provide data and information on the subsurface environment: • lithological contrasts; • Geological structures (e.g. faults); and • Depth to groundwater. • Identify prospective locations for siting: • Investigation boreholes (one or more); and • Disposal boreholes (one or more). • Use of seismic surveys, ground penetrating radar

18. Exploratory boreholes • Are likely to be smaller diameter than the disposal borehole • Define geological succession; • Define characteristics of the geological materials, e.g. geo-mechanical, geochemical and hydrogeological properties; • Define groundwater chemistry; • Establish groundwater pressures/ flow directions; and • Provide information to calibrate geophysical surveys

19. Core drilling

20. Specific down-hole techniques • Geophysical wireline logging • Hydrogeological Testing • Groundwater sampling and testing

21. Typical wireline log Example of a wireline log that provides data (bottom to top) for borehole diameter (calliper log), density and resistivity

22. Interpretation • Critically evaluate the results of the investigations; • Establish characteristics of site, including geological materials present and associated uncertainties; • Identify and describe information related to geological evolution/ change; and • Define geological conditions that may influence: • Borehole construction • Depth of borehole disposal; and • Location of disposal borehole

23. Uses of site characterization data 23

24. Site characterization – possible data uses • Site selection • Borehole design optimization • Borehole construction • Post-closure safety • Understanding the geological evolution of the site

25. Site selection Site location may be determined by site properties but is more often a political decision

26. Design Optimization Necessary adaptation to individual country/ site conditions: number of packages, hence length of disposal zone determined by inventory geometry of borehole(s) tuned to optimize use of the site Aim to dispose at depth of at least 30m Avoid phreatic surface Avoid any heavily weathered rocks near the surface Aim to preserve isolation, taking account of long-term erosion

27. Disposal borehole construction • Construction of the disposal borehole will be facilitated by the presence of competent rock ie rock that does not lose cohesion or fracture heavily when the borehole is drilled • Such effects can be caused by the presence of low strength rocks caused, perhaps, by extensive weathering rocks (often near the surface) or by high rock stresses at depth causing breakout • Warning of such possibilities will be provided by site characterization

28. Post-closure safety • Strong reliance on long-term physical containment - hence key inputs relate to groundwater chemistry • Longer term radionuclides will escape – hence key inputs relate to flow and transport of contaminants into the human environment

29. Geological evolution The licensee will be expected to have a good overall understanding of the geological evolution of the site because it is this that informs about its likely future evolution Hence key inputs could relate to past climate conditions, seismicity, geomorphology etc

30. Summary • The presentation has covered • Step by step development and implementation of the BDC • The nature of site characterization • Site characterization techniques • Uses of site characterization data

31. Thank you!