98-02

Parameters of importance to determine during geoscientific site investigation

Johan Andersson1, Karl-Erik Almén2, Lars O Ericsson3, Anders Fredriksson4, Fred Karlsson3, Roy Stanfors5, Anders Ström3

1 QuantiSci AB 2 KEA GEO-Konsult AB 3 SKB 4 ADG Grundteknik KB 5 Roy Stanfors Consulting AB

June 1998

TECHNICALREPORT

SVENSK KÄRNBRÄNSLEHANTERING ABSWEDISH NUCLEAR FUEL AND WASTE MANAGEMENT CO

P.O.BOX 5864 S-102 40 STOCKHOLM SWEDENPHONE +46 8 459 84 00 FAX +46 8 661 57 19

98–0

2

98-02

Parameters of importance to determineduring geoscientifi c site investigation

Johan Andersson1, Karl-Erik Almén2, Lars O Ericsson3, Anders Fredriksson4, Fred Karlsson3, Roy Stanfors5,Anders Ström3

1 QuantiSci AB2 KEA GEO-Konsult AB3 SKB4 ADG Grundteknik KB5 Roy Stanfors Consulting AB

June 1998

TECHNICALREPORT

SVENSK KÄRNBRÄNSLEHANTERING ABSWEDISH NUCLEAR FUEL AND WASTE MANAGEMENT CO

P.O.BOX 5864 S-102 40 STOCKHOLM SWEDENPHONE +46 8 459 84 00 FAX +46 8 661 57 19

98–0

2

ISSN 0284-3757CM Gruppen AB, Bromma, 1998

ForewordSummaryContents1 Introduction1.1 Purpose and strategy1.1.1 Purpose1.1.2 The term "parameter"1.1.3 Strategy

1.2 Performance and safety assessment1.2.1 Parameters in calculations in performance and safety assessments1.2.2 Favourable, unfavourable and discliminating factors

1.3 Parameters for a geoscientific model description1.3.1 Geoscientific parameters of importance for long-term performance, radiological safety and geoscientific understanding1.3.2 Data needs in planning and design of the rock works1.3.3 Other environmental aspects1.3.4 Evaluation of parameters

1.4 Measurement methods1.4.1 Coupling between measurement methods and possible parameters and generic data1.4.2 Choice of measurement method - geoscientific investigation programme

2 Geology2.1 Overview of parameters, methods and areas of application2.2 Models and areas of application2.2.1 Geological evolution model2.2.2 Soil type model2.2.3 Lithological model2.2.4 Geological structure model2.2.5 Favourable, unfavourable and discriminating factors

2.3 Topography2.4 Soil types - distribution2.5 Lithology and rock type description2.6 Structural geology2.6.1 Plastic structures2.6.2 Brittle structures

2.7 Discontinuities2.7.1 Nomenclature2.7.2 Regional and local discontinuities2.7.3 Local minor discontinuities2.7.4 Individual fractures2.7.5 Measurement methods

3 Rock mechanics - mechanical stability3.1 Overview of parameters, methods and areas of application3.2 Models and areas of application3.2.1 Mechanical stability on repository scale and thermal load3.2.2 Stability in the near field, design questions3.2.3 Assessment of hydrochemical couplings3.2.4 Favourable, unfavourable and discriminating factors

3.3 Discontinuities3.4 Mechanical properties of fractures in different rock masses3.4.1 Deformation properties3.4.2 Strength3.4.3 Evaluation, measurement methods and requirements on precision

3.5 Mechanical properties for intact rock in different rock masses3.5.1 Deformation properties3.5.2 Strength3.5.3 Evaluation, measurement methods and requirements on precision3.5.4 Indentation index, wear index and blastability

3.6 Mechanical properties for different rock masses3.6.1 Deformation properties3.6.2 Strength

3.7 Density and thermal properties3.8 Boundary conditions and supporting data3.8.1 Rock stresses3.8.2 Loads3.8.3 Identified deformations and seismic activity

4 Thermal properties4.1 Overview of parameters, methods and areas of application4.2 Models and areas of application4.2.1 Modelling of thermal evolution4.2.2 Mechanic, hydrological and chemical impact of temperature4.2.3 Design and layout4.2.4 Favourable, unfavourable and discriminating factors

4.3 Parameters4.3.1 Thermal properties of the rock4.3.2 Temperatures

5 Hydrogeology5.1 Overview of parameters, methods and areas of application5.2 Models and areas of application5.2.1 Hydrogeological understanding, boundary conditions and regional changes5.2.2 Inflow during construction period and resaturation5.2.3 Input data to migration models5.2.4 Source term calculations5.2.5 Input data to biosphere models5.2.6 Other near-surface environmental consequences5.2.7 Favourable, unfavourable and discriminating factors

5.3 Hydraulic properties of modelled discontinuities5.3.1 Discontinuities5.3.2 Permeability distribution of discontinuities5.3.3 "Flow porosity" and "storage coefficient"

5.4 Hydraulic properties of the rock mass between deterministically modelled discontinuities5.4.1 Statistical description of discontinuities5.4.2 Permeability distribution5.4.3 Flow porosity, storage coefficient, compressibility

5.5 Salinity and temperature5.6 Hydrogeological data for the soil layers5.7 Boundary conditions and supporting data5.7.1 Regional boundary conditions, historic and future evolution5.7.2 Pressure and head5.7.3 Recharge and discharge areas5.7.4 Large-scale tracer tests5.7.5 Groundwater flow in boreholes

6 Chemistry6.1 Overview of parameters, measurement methods and areas of application6.2 Models and areas of application6.2.1 Assessment of repository performance6.2.2 Groundwater chemistry model6.2.3 Favourable, unfavourable and discriminating factors

6.3 Groundwater chemistry in the repository area6.3.1 Groundwater chemistry parameters of importance for the canister6.3.2 Groundwater chemistry parameters of importance for the bentonite6.3.3 Groundwater chemistry parameters of importance for fuel dissolution

6.4 Groundwater chemistry along flow paths - radionuclide retention6.5 Water chemistry for geoscientific understanding6.6 Quality and requirements on resolution for the groundwater chemistry data

7 Retention properties - radionuclide transport7.1 Overview of parameters, measurement methods and areas of application7.2 Models and areas of application7.2.1 Transport in the near field7.2.2 Transport of radionuclides that have escaped from the repository7.2.3 Transport in the biosphere7.2.4 Ruling out other transport mechanisms7.2.5 Assessment of changes in groundwater chemistry7.2.6 Favourable, unfavourable and discriminating factors

7.3 Properties on a near-field scale7.4 Properties of flow paths7.4.1 Flow paths, groundwater flow, dispersion and porosity7.4.2 "Flow wetted surface"7.4.3 Evaluation, need for precision and measurement methods

7.5 Retention properties of the rock mass along flow paths7.5.1 Sorption7.5.2 Matrix diffusivity, matrix porosity and maximum penetration depth7.5.3 Evaluation, measurement methods and need for resolution

7.6 Transport parameters in soil layers/receptors7.7 Supporting data7.7.1 Geochemical characterization of fracture filling, wall rock and groundwater7.7.2 Tracer tests7.7.3 Groundwater chemistry and estimation of colloids, gas, etc.

8 Conclusions9 ReferencesAppendix A:XList of SKB reports