development of comprehensive techniques for coastal site characterisation: part 1—strategic...

Proceedings of The 13th International Conference on Environmental Remediation and Radioactive WasteManagement

ICEM2010October 3-7, 2010, Tsukuba, Japan

ICEM2010-40056

DEVELOPMENT OF COMPREHENSIVE TECHNIQUES FOR COASTAL SITE CHARACTERISATION

(1) STRATEGIC OVERVIEW

Kunio Ota Japan Atomic Energy Agency

Tokai, Ibaraki, Japan

Kenji Amano Japan Atomic Energy Agency Horonobe, Hokkaido, Japan

Tadafumi Niizato Japan Atomic Energy Agency Horonobe, Hokkaido, Japan

W Russell Alexander Bedrock Geosciences Auenstein, Switzerland

Yoshiaki Yamanaka Suncoh Consultants

Tokyo, Japan

ABSTRACT INTRODUCTIONAny assessment of long-term repository safety will require

development of a set of analyses and arguments to demonstrate the persistence of the key safety functions of the geological environment up to several hundred thousand years into the future. However, likely future global climatic and sea-level fluctuations and uplift/subsidence would result in a dramatic change in the location of the current coastline with a subsequent significant change to hydraulic and hydrochemical conditions at coastal sites. It is thus of great importance in the Japanese disposal programme to establish comprehensive techniques for coastal site characterisation.

The assurance of the long-term stability of the geological environment is sine qua non for deep geological disposal. The key safety functions to be served by the geological environment in a geological disposal system will include physically isolating the waste for a sufficiently long period of time, maintaining conditions favourable for the engineered barrier system (EBS), preventing or attenuating potential release of radioactivity and providing sufficient buffering against internal and external perturbations [1]. Consequently, any assessment of repository safety will require development of a set of analyses and arguments not only to define if these functions are currently adequate but also to demonstrate the persistence of the functions, despite external disruptive events and processes, up to several hundred thousand years into the future.

To this end, a systematic framework, which is known as a ‘Geosynthesis Data Flow Diagram’, has been formulated, which outlines a basic roadmap of the geosynthesis methodology for characterising temporal and spatial changes of various properties and processes at coastal sites, with particular focus on the palaeohydrogeology. A basic strategy for stepwise surface-based investigations has also been proposed, which incorporates the geosynthesis methodology in an effective manner. This technique has been introduced in an ongoing collaborative programme for characterising the coastal geological environment around Horonobe in northern Hokkaido, Japan, and now tested and optimised based on accumulated technical knowledge and experience during the progress of the investigations.

In Japan, natural events and processes that could take place over the next several hundred thousand years and affect a geological disposal system include earthquakes and fault movement, volcanic and hydrothermal activity, uplift/ subsidence and climatic and sea-level changes. By applying the Siting Factors, which include criteria for exclusion of certain areas because of increased risk of disturbance of the repository, for the selection of Preliminary Investigation Areas established by the Nuclear Waste Management Organization of Japan (NUMO), significant impacts of earthquakes, fault movement and volcanic and hydrothermal activity could be precluded, thereby excluding areas that would clearly be unsuitable as a repository site [2]. However, in many cases, the potential

Key words: coastal site, site characterisation, geosynthesis methodology, Geosynthesis Data Flow Diagram, basic strategy, palaeohydrogeology, Horonobe

1 Copyright © 20xx by ASME

Proceedings of the ASME 13th International Conference on Environmental Remediation and Radioactive Waste Management

ICEM2010 October 3-7, 2010, Tsukuba, Japan

ICEM2010-40056

1 Copyright © 2010 by ASME

Although the importance of coastal sites in the context of geological disposal is commonly recognised in Japan, there is less practical experiences and technical knowledge, compared with inland areas, with characterising the coastal geological environment. As there exists a significant need to establish comprehensive techniques for coastal site characterisation, a research and development (R&D) task on this has been defined in Phase II (2006-2012) of the national “R&D Programme for the Geological Disposal of High-Level Radioactive Waste” [11]; the goal of the fundamental R&D in Phase II is to establish the technical basis for use in NUMO’s preliminary investigations (PIs) before they begin in earnest. The main component of the task is demonstration of methodologies for characterising the actual coastal geological environment with focus on understanding the evolution of the hydrogeological and hydrochemical environment over geological time and the potential processes involved (e.g. movement of saline/fresh groundwater interface, density-driven flow).

impacts of uplift/subsidence and climatic and sea-level changes will accumulate rather slowly, but constantly, over long time periods in a regional scale and these could not be precluded by siting. It is thus of great importance to develop a set of analyses and arguments for the reliance that can be placed on the key safety functions to assure the long-term stability of the geological environment.

A large number of nuclear facilities are situated in coastal areas: e.g. many nuclear power plants in Japan (Fig. 1) and repositories under construction or to be constructed in Finland, France, South Korea, Sweden and the UK. This is not coincidental; such locations offer ease of transport of bulky or radioactive materials by ship (thus avoiding the transport of hazardous materials by rail or road through densely populated areas) and effectively limitless supplies of cooling water. Such facilities may also be less intrusive in a coastal setting, especially in remote locations, which may have little alternative, e.g. islands/archipelagos with mountainous, tectonically unstable interiors like Japan. Nevertheless, it could be difficult to preclude a risk of some kind of dramatic perturbation at potential coastal sites [3]. Concern presently focusses on a sea-level rise caused by anthropogenic global warming [4] but, within a period of several tens of thousands of years, a return to glacial-period conditions is to be expected, inducing a sea-level fall. Based on previous glaciations, global sea-level could drop by up to 150±10 m [e.g. 5-7], although, during the Last Glacial Maximum, the Japan Sea is estimated to be 125-130 m lower than at present. Although unlikely, melting of the East Antarctic Ice Sheet would increase sea-levels by up to 60 m [8]. Such sea-level changes would result in an extremely dramatic change in the location of coastlines with a subsequent significant change to hydraulic and hydrochemical conditions at coastal repository sites [3, 9, 10].

To this end, Japan Atomic Energy Agency (JAEA) has commenced an R&D programme that involves surface-based investigations in a coastal zone of Horonobe in northern Hokkaido, Japan (Fig. 2), under collaboration with other research organisations [12]. At Horonobe, JAEA’s underground research laboratory (URL) project is currently ongoing with the main aim of establishing and testing relevant techniques for future repository site characterisation in Japan. Throughout surface-based investigations in and around the URL area (i.e. inland), a vast amount of information on the properties and processes of the geological environment within a suite of sedimentary formations has been acquired and relevant investigation techniques developed [13]. These results can thus advantageously provide a basis for efficaciously implementing the new programme. Practical experiences and technical knowledge accumulated not only from the Horonobe URL project but also from the Mizunami URL project for crystalline rock [14] can also be fully utilised. In particular, these experiences indicate that a geosynthesis methodology, initially formalised in a site characterisation programme in Switzerland [15], has proved to be indeed effective throughout the surface-based investigations in both URL projects [16, 17], should be applied.

Of particular importance for this – and the focus of this paper – is the formulation of the ‘Geosynthesis Data Flow Diagram (GDFD)’ that outlines a basic roadmap of the geosynthesis methodology for characterising the evolution of the coastal geological environment. Focus also concentrates on the establishment of a basic strategy, to effectively introduce the geosynthesis methodology in practice, for stepwise surface-based investigations at coastal sites. The applicability of this technique has now been tested during the progress of the surface-based investigations at the Horonobe coastal study area, which serves as a ‘dry run’ and generic test-bed of the PIs for any coastal site.

FIG. 1: Distribution of Nuclear Facilities in Japan


N

Japan Sea

Pacific Ocean

Nuclear power plants in operationNuclear power plant under constructionU-enrichment / fuel fabrication / reprocessing /waste storage / LLW disposal facilities in operation

Rokkasho



FIG. 2: Location of Coastal Study Area of Horonobe, northern Hokkaido, Japan

WHY GEOSYNTHESIS METHODOLOGY? In the repository site characterisation programme, surface-

based investigations in a variety of disciplines aim to derive a comprehensive and consistent overview of the geological environment at a site, as required for repository design (RD) and safety assessment (SA) [18, 19]. A global integration methodology, which clearly defines the goals of individual investigations and interprets and synthesises information from the wide diversity of investigations into a consistent site model, needs to be developed in advance and demonstrated. Once again, experience shows that, for enhancing interactions among different disciplines and ensuring the transparency and traceability of the production of the information needed by the end users, such a methodology is essential.

The geosynthesis methodology is defined as proceeding in the following five steps, which is represented in the GDFD:

i) investigation and data acquisition; ii) data interpretation; iii) conceptual model development; iv) numerical modelling and simulation; v) clarification of the key properties of and processes

ongoing in the geological environment.

Based on previous experiences accumulated both in Japan and Switzerland [13-18], it is clear that iteration of this process, gradually improving understanding of the geological environment in each phase of the stepwise surface-based investigations, can lead to building confidence in output of the geosynthesis. Importantly, the impact of limitations in

knowledge and uncertainties in data can be assessed by the end users to provide feedback to guide optimisation of investigations in the subsequent phases.

FORMULATION OF COASTAL GDFD The key feature of the GDFD is a systematic framework

that can guide efficaciously the surface-based investigations. The GDFD thus illustrates, in a systematic manner, data transformation from initial field-based ‘Investigation’ with ‘Data’ acquisition, through ‘Interpretation/Dataset’ and ‘Conceptualisation/Modelling/Simulation’ of the results from different disciplines, to final clarification of the ‘Key Properties/Processes’ of the geological environment [13, 14].

Identification of Key Properties and Processes The geological environment in which a repository is

constructed is expected to physically isolate the waste for a sufficiently long period of time, provide a suitable environment for installing the EBS and function as a natural barrier to constrain radionuclide migration [1, 20, 21]. A suitable geological environment is expected to have the following properties and functions:

Demonstrated existence over an appropriate location and adequate depth with sufficient spatial extent. Relatively homogeneous stress conditions and low temperatures, to ensure operational safety and ease design, construction and maintenance of the EBS and other underground facilities. Low groundwater flux through the repository horizon, ideally with neutral to slightly alkaline chemistry and reducing conditions, which would serve to restrict erosion of the buffer material, corrosion of overpack, dissolution of the waste glass matrix and radionuclide migration. Slow groundwater movements and long flow paths between the repository and the accessible environment to reduce the rate of radionuclide migration. High dilution and dispersion during migration to the biosphere, resulting in reduction of radionuclide concentrations.

More importantly, the geological environment is required to be sufficiently buffered against natural perturbations, thereby maintaining such properties and functions for a long period of time [1].

To focus the surface-based investigations at coastal sites, the key properties of and processes ongoing in the geological environment to be investigated in relation to RD and SA have been identified, with reference to a variety of FEP (features, events and processes) lists [22-25] and a list of favourable factors and underlying key issues for the PIs [2], as shown in the left column of Table 1. Since characterisation of the overall site evolution over geological time is the focal point of the surface-based investigations at coastal sites, the temporal and spatial (or 4D) changes of various properties and processes are taken into account (see also discussion in [10]).

Shaded relief map (top-left) and base map (bottom) from part of the 1:50,000topographical map (Wakasakanai, Toyotomi, Kamisarufutsu, Teshio, Onobunai,Pinneshiri) published by the Geographical Survey Institute, Japan

45°N

JapanSea

OkhotskSea

Horonobe

Wakkanai

Horonobe Town

10km0 5

Horonobe URL

Japan Sea

Coastal Study Area

(offshore)

URL Area

(onshore)

TokyoTokaiMizunami

N Horonobe


TABLE 1: Key Properties of and Processes Ongoing in the Geological Environment and Key Aspects of Geological, Hydrogeological and Hydrochemical Characterisation at Coastal Sites

Visualisation of Systematic Framework For the identified key properties of and processes ongoing

in the coastal geological environment (Table 1), a range of key aspects to be addressed in the surface-based investigations at coastal sites has been specified in a comprehensive manner. As an example, key aspects – which are particularly sensitive to site uncertainties – to be addressed by geological, hydrogeological and hydrochemical characterisation are also listed in the right column of Table 1. This should serve as a basis for the formulation of the generic GDFD [12].

Based on the key aspects, a wide range of data to be obtained, which is relevant to each key aspect, has been explicitly identified. Then the processing of ‘Data’ into ‘Interpretation/Dataset’, i.e. comprehensively interpreting a range of acquired data and logically deriving the consistent dataset necessary for the key aspects, has been graphically visualised. Application of a palaeohydrogeological

methodology [e.g. 9, 26] is essential for performing this process because the relevance of a combination of data from different disciplines will be ensured and the data compiled in an appropriate manner so as to allow interpreting the evolution of the coastal geological environment.

Second, based on the key aspects of characterisation, types and combination of potentially useful investigation techniques to obtain necessary data have been selected and the correlation between ‘Investigation’ and ‘Data’ defined. Here the investigations involve the survey/review of pre-existing information, aerial, terrestrial and marine exploration and an extensive borehole programme. Finally, the sequence of activities for ‘Conceptualisation/Modelling/Simulation’ towards final production of relevant information on ‘Key Properties/Processes’ of the coastal geological environment has been illustrated, which involves:


Key properties/processesGeology and geological structure• Spatial distribution and geometry of transport pathways• Size and extent of host rock• Heterogeneity within host rock• 4D geomorphological changes; 4D evolution of geological structure

• Spatial distribution and geometry of transport pathways

Spatial distribution, extent and geometry of discontinuities and sedimentary structures

Groundwater flow characteristics• Groundwater flow field and process• Spatial variability of groundwater fluxes• 4D evolution of groundwater flow field and process• 4D evolution of groundwater flux distributionGeochemical characteristics of groundwater• Spatial distribution of saline/fresh groundwater (interface); degree of groundwater mineralisation• Groundwater pH-Eh conditions• 4D evolution of groundwater chemistryTransport/retardation of nuclides• Geometry of transport pathways; depth of diffusion-accessible matrix• Sorption capacity and diffusivity of rock matrix and of transport pathways • Effect of colloid/organics/microbes on nuclide transport/retardationDilution of nuclides• Spatial distribution of higher-permeability rocks, aquifers and surface waters; extent of marine environments• Sorption capacity and diffusivity of rock matrix and of transport pathwaysGeomechanical/hydraulic properties of tunnel near-field environment• Regional and local stress regime• Spatial variability of petrophysical/geomechanical properties of rocks• Volume of inflow into underground tunnels; volume of gas emission from host rock• Size and structure of EDZ; petrophysical/geomechanical properties of EDZ• Distribution of discontinuities intersecting underground tunnels• 4D evolution of stress field at repository depth (NB this will change significantly with water depth above the repository)• 4D evolution of petrophysical/geomechanical properties of rocksSubsurface thermal conditions• Spatial variability of geothermal gradient• Thermal rock properties• 4D evolution of thermal rock properties

• Size and extent of host rock• Heterogeneity within host rock

• 4D geomorphological changes; 4D evolution of geological structure

Spatial distribution and structure of host rock Stratigraphy, thickness and depth of host rock Spatial distribution of discontinuity within host rock Lithological variability within host rock Evolution of regional stress field (tectonics) Changes of style of crustal movement Evolution of geology and geological structure Evolution of petrophysical properties in response to uplift/subsidence and erosion/ sedimentation Evolution of style of topographical changes Palaeo/present climate changes

• Groundwater flow field and process

Groundwater flow system and dominant process

• Spatial variability of groundwater fluxes

Spatial distribution of hydraulic properties of rock and discontinuities Spatial distribution of hydraulic head

• 4D evolution of groundwater flow field and process/ groundwater flux distribution

Evolution of groundwater flow system and process Evolution of hydraulic properties of rock and discontinuities

• Spatial distribution of saline/fresh groundwater (interface); degree of groundwater mineralisation

Spatial distribution of groundwater chemical and isotopic compositions Groundwater flow process

• Groundwater pH-Eh conditions

Spatial distribution of groundwater chemical compositions

• 4D evolution of groundwater chemistry

Spatial distribution of groundwater isotopic compositions and ages Evolution of groundwater flow system and process Changes of groundwater evolution mechanisms

Key properties/processes Key aspects of characterisation


i) building up a conceptual model for the present site conditions and the overall site evolution, based on the relevant dataset;

ii) numerically analysing the present characteristics and processes and their 4D changes, based on the conceptual model and the dataset;

iii) checking the consistency of the simulation results, using data from observation or other disciplines (e.g. groundwater flow and salinity distribution).

The rationale behind the linkages illustrated in the GDFD is discussed in more detail in the underlying research report [12]. Figure 3 shows the section focussing particularly on the data flow for geological, hydrogeological and hydrochemical characterisation to be conducted during terrestrial and marine exploration, as an example of the GDFD for surface-based investigations at coastal sites. Of note is that the data flow for

‘hydrochemical characterisation’ is highlighted. Although impossible to read in detail, but as an example of the complexity of the problem, the entire GDFD is attached (see Annex A).

It is worth noting here that, when conducting exploration onshore or offshore, the potential approaches could be (almost) the same, although the practicalities of exploration and their methods are different. For example, superficial mapping offshore is difficult, but not impossible. Since Charles Darwin’s first voyage on HMS Beagle in 1831 [27], sediment grabs and shallow ‘stab’ corers have allowed samples to be collected from the seabed [e.g. 28] and nowadays a diversity of advanced coring techniques and remote-controlled exploration systems enable more detailed sampling even in deep seas [e.g. 29]. The degree of coverage will, in effect, vary from method to method, depending on the recent advancement of technology and the financial and other constraints on the exploration.

FIG. 3: Data Flow for Geological, Hydrogeological and Hydrochemical Characterisation on Terrestrial and Marine Exploration at Coastal Sites


Geomorphologicalchanges

Palaeoclimatechanges/long-termprediction ofclimate changes

Monitoring ofcrustal movement

Location/flux ofsubmarineseepage

Deep subsurfacehydraulicproperties

Palaeoclimateinvestigations

Shallow sub-surface hydrauliccharacteristics

Geologicaldistribution/structure

Climate changes

Marin

e Exp

lorati

on

Tectonics, crustalstress

Rock mineralogy/chemistry

Petrophysics

Investigations Data Interpretation/Dataset

Geochemicalmodel

Hydraulic headdistribution

Conceptualisation/Modelling/Simulation Key Properties/Processes

Geomorphologicalinvestigations

Surface hydrologi-cal/meteorologicalinvestigations

Surfacehydrochemicalinvestigations

Surfacegeologicalsurveys

Geophysicalsurveys

Trenchexcavationsurvey

Laboratoryexamination/analysis

Seabedgeologicalsurvey

Geophysicalsurveys offshore

Hydrogeologicalinvestigationsoffshore

Hydrochemicalinvestigationsoffshore

Laboratoryexamination/analysis

Terre

strial

Exp

lorati

on

Geomorphology/geodesy

Geomorphologicalchanges

Surface waterchemistry

Sea water/seep-age/porewaterchemistry

Tectonic changes

Palaeogeomor-phological/geo-graphical changes

Hydraulic proper-ties of potentialHR/SU and DC

Evolution ofgeologicalstructure

Evolution ofpetrophysicalproperties

Groundwaterchemistry/origin/age

Recharge rate,water tabledistribution

Recharge ratechange

Evolution ofhydraulic proper-ties of potentialHR/SU and DC

Groundwater flowprocesses inpotential HR/SUand DC

Geomorphologicalmodel

Geomorphologicalchange model

Geological model

Geologicalevolution model

Hydrogeologicalmodel

Hydrogeologicalevolution model

Groundwater flowsimulation

Geochemicalevolution model

Spatial distributionand geometry oftransport pathways

Size and extent ofhost rock

Heterogeneitywithin host rock

4D geomorphologi-cal changes; 4Devolution of geo-logical structure

Groundwater flowfield and process

Spatial variabilityof groundwaterfluxes

4D evolution ofgroundwater flowfield and process

4D evolution ofgroundwater fluxdistribution

4D evolution ofgroundwaterchemistry

Groundwater pH-Eh conditions

Spatial distributionof saline/freshgroundwater(interface); degreeof groundwatermineralisation

Geolo

gy an

d Geo

logica

l Stru

cture

Grou

ndwa

ter flo

w ch

arac

terist

icsGe

oche

mica

l cha

racte

ristic

s of g

roun

dwate

r

Distribution/extent/geometry of poten-tial HR/SU and DC Mineralogical/

chemical proper-ties of potentialHR/SU and DC

Confirmation of consistency

Links not connectedLinks connected

DC: DiscontinuitiesSU: Surrounding unitsHR: Host rock


ESTABLISHMENT OF BASIC STRATEGY The stepwise surface-based investigations in which the

geosynthesis methodology is incorporated in an effective manner will allow chiefly:

addressing key issues that have remained or been newly identified in the previous investigations; ensuring the improvement of understanding of the key properties and processes of the geological environment, which is in many cases represented as the site model; identifying (the degree of) uncertainties in output of the geosynthesis; specifying and prioritising the investigation targets in the subsequent steps; improving techniques for characterising the geological environment by checking their applicability [13-18].

In addition, a stepwise programme is expected to provide flexibility to practically respond to the surprises that inevitably occur during investigations, which could allow enhancing the

opportunity to adopt the investigations to the specific site conditions. Such a stepwise implementation approach is therefore widely accepted and will be planned in NUMO’s site characterisation programme for the PI stage [18].

Based on NUMO’s roadmap developed in a generic manner for implementing RD and SA with interaction with site characterisation during the PI stage [18], practical experience and technical knowledge developed in JAEA’s URL projects [13, 14] and a wide diversity of investigation techniques presented in the generic GDFD, a basic strategy for the stepwise surface-based investigations at coastal sites has been proposed. A general workflow is outlined in Fig. 4, in which several work steps related to planning, geosynthesis and interaction with RD and SA activities are encompassed. In addition, investigation targets in each main step are identified (see the right column of Fig. 4) in the light of understanding the palaeohydrogeological site evolution, which is the focal point of the surface-based investigations at coastal sites.

FIG. 4: Basic Strategy for Surface-Based Investigations at Coastal Sites, with Particular Focus on the Site Palaeohydrogeology

Note that it is implicit within the strategy that, within practical limits, effectively the same methods are applied both onshore and offshore.


Step

Identification of uncertaintiesSpecification/prioritisation of targets

Planning of exploration

Compilation/QA assessment of pre-existing informationEntry into site QMS database

Development of conceptual site model (regional)

Development of conceptual site model (regional)Groundwater flow analysis (regional) Identification of uncertainties

Additionalexploration?

RD/SA

Suitable area?

Specification/prioritisation of targets

Termination of investigation

Establishment of overall programme

Aerial exploration

Marine exploration(2D → 3D)

Terrestrial exploration(2D → 3D)

Revision of overall programme

Complementaryexploration?

No

Yes

No Yes

No Yes

Planning of borehole investigations

Borehole investigations(onshore)

Development of conceptual site model (local)Groundwater flow analysis (local) Identification of uncertainties

RD/SA

Suitable area? Termination of investigation Revision of overall programme

Specification/prioritisation of targets

No

Yes

No Yes

No Yes

Establishment of overall programme

Surv

ey/R

evie

wof

Pre

-exi

stin

gIn

form

atio

nAe

rial/T

erre

stria

l/Mar

ine

Expl

orat

ion

Bor

ehol

e In

vest

igat

ions

NextStage

Geosynthesis RD/SA-Interaction Planning•Site geomorphology•Geomorphological changes•Geological structure•Geophysics•Geological evolution/age•Regional GW flow system•GW chemistry•Global climate/sea-level changes•Uplift/subsidence history•Geomorphological changes•Palaeogeographical changes•Landform distribution/changes•Regional geological structure •Regional GW flow system•Marine seepage distribution•Hydraulic properties of terrestrial –marine superficial sediments•Recharge rate change•SW/GW/marine seepage chemistry•Regional climate/sea-level changes

•Uplift/subsidence history•Local geological structure•Fault distribution/geometry•Lithological variability•Geological age•Hydraulic properties/head distribution•Evolution of hydraulic properties•Evolution of GW flow system•Distribution of GW chemistry•Evolution of GW chemistry•Thermal rock property

Key Input to SitePalaeohydrogeology

GW: Groundwater, SW: Surface water

Borehole investigations(offshore)

Complementaryexploration?

Additionalinvestigations?

Iteration

Iteration


Before looking at the various steps outlined in Fig. 4 in some detail, it is worth noting that, as there has been no choice of host rock or site to date in Japan, this strategy has been proposed in a generic manner; in each step, based on output of the geosynthesis in the preceding step, the investigation targets are to be specified and prioritised, then the investigations carried out iteratively following the GDFD and finally the investigation results assessed in the light of RD/SA for producing output. However, when the areas for the PIs are selected, this strategy needs to be optimised (e.g. defining more specific work steps, avoiding unnecessary repetition of work steps) with refinement of the GDFD, taking into account the known site-specific conditions and the temporal, financial and even societal constraints on the PI programme.

LESSONS LEARNT FROM HORONOBE CASE STUDY The technique described above has been introduced in the

ongoing collaborative programme for characterising the coastal geological environment at Horonobe and now tested and optimised based on practical experiences and technical knowledge developed during the progress of the investigations. Here some lessons learnt to date from the ongoing programme are discussed as are the basic concepts of investigations in each main step.

Survey/Review of Pre-Existing InformationMany of the activities involved in this step are already laid

down in NUMO’s roadmap [19] and this will be followed (with important additions, see below) here. The main aim of this step is to provide a conceptual overview of the area of interest, which should ideally identify the key properties/processes of the geological environment and, at least qualitatively, uncertainties. This will, in fact, serve as the basis for proceeding further with the surface-based investigations. It is thus necessary to compile all available information about the area and develop the database following re-assessment of the quality and reliability of the information.

In this step, the amount of information available will depend on many factors. For example, in the Horonobe area, a significant amount of oil and natural gas exploration has occurred, which means that some basic geological data are available for both onshore and offshore. However, some of the exploration goes back to 1925-1930 [30, 31]; the records are poor and of dubious quality. Even information from more recent work has to be re-assessed in the light of current quality management system (QMS) guidelines.

Because NUMO has currently been developing guidelines for such assessments, here JAEA’s system is being followed and the quality of the pre-existing information evaluated before it is included in the ‘Site QMS Database’ (Fig. 4). Of note in this system is that not only are the data uncertainties taken into account, but also a whole range of additional factors (e.g. the existence or otherwise of a QMS in the original exploration programme) are evaluated to provide a measure of the ‘value’ of the pre-existing information. A final point to note here is that

the general workflow outlined in Fig. 4 implicitly includes temporal variations in the parameters studied where at all possible. This will be discussed further in the next section.

Aerial/Terrestrial/Marine Exploration This step involves marine and terrestrial exploration by

aerial means which is to be conducted based on the targets defined in the previous step, but concerns most likely surface mapping (2D) and geophysical investigations (preferably 3D). The main aims of this step are to check and revise the conceptual overview (or site model) – three-dimensionally where possible – and, based on this, to specify key aspects of characterisation and the degree of uncertainties so as to allow determining the targets and their priorities.

Of specific interest in the Horonobe area is that the availability of the pre-existing geophysical data means that temporal changes in some site parameters can also be assessed using true time-lapse (or 4D) imaging. Although this seismic methodology has been confined to oil exploration or CO2disposal studies to date [e.g. 32], it would seem the perfect tool to follow changes in the saline/fresh groundwater interface over the decades since the original survey lines have been shot during the period of hydrocarbons exploration.

For example, during the exploration of the coastal area for the construction of the Seikan Tunnel (the world’s longest undersea tunnel) between Hokkaido and north-east Japan, onshore geophysical lines have been extended offshore by means of ships using towed arrays [33]. Some advances have recently been demonstrated in onshore – offshore integrated geophysical survey at the Horonobe coastal zone [34]; such technological advancement could allow more precise subsurface imaging in the onshore – offshore transition zone, becoming, no doubt, an essential technique for coastal site characterisation. However the survey offshore is more prone to disruption by bad weather or, as here, very strong tidal currents.

Borehole Investigations Borehole investigations are likely to be more targeted,

which would explore potential problematic areas as identified in the aerial survey and focus very much on particularly important issues specified after assessing the results of the previous step. After completion of this step, a more detailed site model is to be built up, updating the model in the previous step, and the degree of uncertainties quantified.

Of great importance in this step is borehole investigations offshore which should be combined with the geophysical survey in the previous step. Drilling offshore is, of course, extremely expensive compared with that onshore, particularly as water depth increases (although, as a rule, this is not a major problem for the near-coastal zone of the Japan Sea). However, modern controlled directional drilling technology – being developed worldwide and also in the Horonobe area [35, 36] – means that a significant volume of the sub-seabed can be explored from a drilling rig situated on the coast and drilling out to sea [e.g. 37].

7 Copyright © 20xx by ASME 7 Copyright © 2010 by ASME

[2] Nuclear Waste Management Organization of Japan, 2004, “Evaluating Site Suitability for a HLW Repository”, NUMO-TR-04-04, NUMO, Tokyo, Japan.

CONCLUSIONS AND FUTURE PERSPECTIVES JAEA’s generic GDFD has been originally developed

based on the surface-based investigation expertise both in Japan and Switzerland for inland areas. However, considering the likely attractiveness of coastal sites, it is now being reviewed and updated to address those features of site characterisation which are unique to coastal repositories. This update is based on the practical experiences and technical knowledge developed during the surface-based investigations in the Horonobe coastal study area. This attraction of coastal sites is not coincidental, especially in islands/archipelagos with mountainous, tectonically unstable interiors such as Japan. Such locations clearly offer ease of transport of bulky or radioactive materials by ship and effectively limitless supplies of cooling water. Such facilities may also be less intrusive in a coastal setting, especially in remote locations, e.g. the Drigg site in the UK, Rokkasho in Japan (Fig. 1).

[3] McKinley, I.G. and Alexander, W.R., 2010, “Coastal Repositories”, Volcanism, Tectonism and the Siting of Nuclear Facilities, C. Conner, L. Conner and N.A. Chapman, eds., Cambridge University Press, Cambridge, UK. [4] Intergovernmental Panel on Climate Change, 2007, Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the IPCC, Cambridge University Press, Cambridge, UK. [5] Yokoyama, Y., Lambeck, K. et al., 2000, “Timing of the Last Glacial Maximum from Observed Sea-Level Minima”, Nature, 406, pp. 713-716. [6] Rabineau, M, Berné, S. et al., 2006, “Paleo Sea Levels Reconsidered from Direct Observation of Paleoshoreline Position during Glacial Maxima (For the Last 500,000 Yr)”, Earth Planet. Sci. Lett., 252, pp.119-137. Iteration of the geosynthesis methodology with the new

GDFD for surface-based investigations at coastal sites will lead to the build-up of experiences and eventually establishing, in a systematic manner, comprehensive techniques for characterising stepwise the coastal geological environment. The first phase of this process has been the development of site characterisation techniques [9] and palaeohydrogeological conceptualisation tools [10] based on the geological environment in the Horonobe coastal study area. The second phase of work will be to test the developed methodologies on other sites on Japan’s western seaboard, to build confidence in their applicability to other coastal sites on the Japan Sea. This will enable rationales behind the update to be accumulated, reinforcing the knowledge base being developed in the Japanese national disposal programme. The third, and final, phase of work will see the methodologies being applied to other coastal sites, both in Japan and worldwide, eventually leading to a refined GDFD which is optimised for application to NUMO’s future PIs.

[7] Clark, P.U., Dyke, A.S. et al., 2009, “The Last Glacial Maximum”, Science, 325, pp. 710-714. [8] Hambrey, M., Bamber, J. et al., 2010, “Glaciers – No Nonsense Science”, Geosci., 20 (6), pp. 18-23. [9] Amano, K., Niizato, T. et al., 2010, “Development of Comprehensive Techniques for Coastal Site Characterisation: (2) Integrated Palaeohydrogeological Approach for Development of Site Evolution Models”, Proc. 13th

International Conference on Environmental Remediation and Radioactive Waste Management (ICEM2010), Tsukuba, Japan, 3-7 Oct. 2010, ASME. [10] Niizato, T., Amano, K. et al., 2010, “Development of Comprehensive Techniques for Coastal Site Characterisation: (3) Conceptualisation of Long-Term Geosphere Evolution”, Proc. 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM2010),Tsukuba, Japan, 3-7 Oct. 2010, ASME. [11] Agency for Natural Resources and Energy and Japan Atomic Energy Agency, 2009, “Research and Development Programme for the Geological Disposal of HLW”, Jul. 2009 (version H20), ANRE, Tokyo and JAEA, Tokai, Japan. (in Japanese)

This programme of transparent, rigorous testing, refining and polishing of JAEA’s coastal GDFD will build confidence, not only within NUMO but also within the Japanese regulators and any volunteer communities, in the applicability of the procedure and should serve as a significant contribution to the safety case for assuring the long-term stability of the geological environment at a coastal site.

[12] Osawa, H., Ota, K. et al., 2008, “Establishment of Advanced Integration Technology for Site Characterization of Deep Geological Repository: Development of Information Synthesis and Interpretation System”, JAEA-Research 2008-085, JAEA, Tokai, Japan. (in Japanese with English abstract) ACKNOWLEDGEMENTS

The authors would like to thank our numerous colleagues at JAEA Horonobe for their contribution to this programme.

[13] Ota, K., Abe, H. et al., 2007, “Horonobe Underground Research Laboratory Project: Synthesis of Phase I Investigations 2001 – 2005”, Volume “Geoscientific Research”, JAEA-Research 2007-044, JAEA, Tokai, Japan. (in Japanese with English abstract; English version in press)

REFERENCES[1] Nuclear Energy Agency, 2009, Stability and Buffering Capacity of the Geosphere for Long-Term Isolation of Radioactive Waste: Application to Crystalline Rock, Workshop Proc., Manchester, UK, 13-15 Nov. 2007, OECD/NEA, Paris, France.

[14] Saegusa, H., Seno, Y. et al, 2007, “Final Report on Surface-Based Investigation (Phase I) at the Mizunami Underground Research Laboratory Project”, JAEA-Research 2007-043, JAEA, Tokai, Japan. (in Japanese with English abstract; English version in press)

8 Copyright © 20xx by ASME 8 Copyright © 2010 by ASME


[15] National Cooperative for the Disposal of Radioactive Waste, 1997, “Geosynthese Wellenberg 1996, Ergebnisse der Untersuchungsphasen I und II”, NTB 96-01, Nagra, Wettingen, Switzerland. (in German with English abstract) [16] Hatanaka, K. Osawa, H. and Umeki, H., 2009, “Geosynthesis: Testing a Safety Case Methodology at Generic Japanese URLs”, Approaches and Challenges for the Use of Geological Information in the Safety Case for Deep Disposal of Radioactive Waste, Third AMIGO Workshop Proc., Nancy, France, 15-17 Apr. 2008, OECD/NEA, Paris, France, pp. 134-153.[17] Niizato, T. Yasue, K.-I. et al., 2009, “Synthesising Geoscientific Data into a Site Model for Performance Assessment: A Study on the Long-Term Evolution of the Geological Environment in and around the Horonobe URL, Hokkaido, northern Japan”, Approaches and Challenges for the Use of Geological Information in the Safety Case for Deep Disposal of Radioactive Waste, Third AMIGO Workshop Proc., Nancy, France, 15-17 Apr. 2008, OECD/NEA, Paris, France, pp. 222-234. [18] Vomvoris, E., Sprecher, C. et al., 2008, “Geosynthesis: Application in Switzerland and Elsewhere – What’s Next?”, Proc. 12th International High-Level Radioactive Waste Management Conference (IHLRWM), Las Vegas, USA, 7-11 Sep. 2008, ANS, pp. 120-126. [19] Kurikami, H., Suzuki, S. et al., 2009, “Study on Strategy and Methodology for Repository Concept Development for the Japanese Geological Disposal Project”, NUMO-TR-09-04, NUMO, Tokyo, Japan. [20] National Cooperative for the Disposal of Radioactive Waste, 1994, “Kristallin-1, Safety Assessment Report”, NTB 93-22, Nagra, Wettingen, Switzerland. [21] Japan Nuclear Cycle Development Institute, 2000, “H12: Project to Establish the Scientific and Technical Basis for HLW Disposal in Japan”, Project Overview Report, JNC TN1410 2000-001, JAEA, Tokai, Japan. [22] Nuclear Energy Agency, 2000, Features, Events and Processes (FEPs) for Geologic Disposal of Radioactive Waste: An International Database, OECD/NEA, Paris, France. [23] Mazurek, M., Pearson, F.J. et al., 2003, Features, Events and Processes Evaluation Catalogue for Argillaceous Media,OECD/NEA, Paris, France. [24] Miller, B., Arthur, J. et al., 2002, “Establishing Baseline Conditions and Monitoring during Construction of the Olkiluoto URCF Access Ramp”, Posiva 2002-07, Posiva, Olkiluoto, Finland. [25] Alexander, W.R. and Neall, F.B., 2007, “Assessment of Potential Perturbations to Posiva’s SF Repository at Olkiluoto Caused by Construction and Operation of the ONKALO Facility”, Working Report 2007-35, Posiva, Olkiluoto, Finland. [26] Chapman, N.A. and McEwen, T.J., 1993, “The Application of Palaeohydrogeological Information to Repository Performance Assessment”, Palaeohydrogeological Methods and their Applications, Proc. NEA Workshop, Paris, France, 9-11 Nov. 1992, OECD/NEA, Paris, France, pp. 23-35.

[27] FitzRoy, R., 1839, Narrative of the Surveying Voyages of His Majesty’s Ships Adventure and Beagle between the Years 1826 and 1836, Volume 2. Henry Colburn Publishers, London, UK.[28] Searle, R.C. Schultheiss, P.J. et al., 1985, “Great Meteor East (Distal) Madeira Abyssal Plain: Geological Studies of its Suitability for Disposal of Heat-Emitting Radioactive Wastes”, IOS Report 193, IOS, Godalming, UK. [29] Japan Agency for Marine-Earth Science and Technology homepage, http://www.jamstec.go.jp/e/index.html [30] Nagao, S. and Makino, T., 1959, “Report on the Omagari Oil-Field Investigation in the Teshio District”, Rep. Investigation of Mineral Deposits in Hokkaido, No. 49, Hokkaido Development Agency, Sapporo, Japan. (in Japanese) [31] Mitani, K., Hayakawa, F. et al., 1971, “Natural Gas Reservoir in the Toyotomi Anticline Area”, Rep. Investigation of Mineral Deposits in Hokkaido, No. 125, Hokkaido Development Agency, Sapporo, Japan. (in Japanese) [32] Fenwick, C., 2010, “Seismic Fleet Targets 3D and 4D High-End Surveys”, Hydrogr. Seism. Mag., Aug. 2009, Setform Ltd., London, UK, pp. 25-26.[33] Inoue, T., 1986, “The Seikan Tunnel: Survey of the Seikan Tunnel”, Tunnelling Underground Space Technol., 1, pp. 333-340.[34] Radioactive Waste Management Funding and Research Center, 2009, “Development of Advanced Technology for Characterisation of Seawater/Freshwater Interface and Fault in Coastal Zone”, Annual Rep. 2008, METI, Tokyo, Japan. (in Japanese)[35] Kiho, K., Shin, K. et al., 2006, “Development of Controlled Drilling Technology and Measurement Method in the Borehole (Phase 1)”, Civil Engineering Research Laboratory Rep., No. N01, CRIEPI, Abiko, Japan. (in Japanese with English abstract) [36] Kiho, K., Shin, K. et al., 2009, “Development of Controlled Drilling Technology and Measurement Method in the Borehole (Phase 2): Upgrading of Drilling and Measurement System and its Application to the Fault”, Civil Engineering Research Laboratory Rep., No. N03, CRIEPI, Abiko, Japan. (in Japanese with English abstract) [37] Holmöy, K.H., Lien, J.E. and Palmström, A., 1999, “The Frøya Tunnel – Going Sub-Sea on the Brink of the Continental Shelf”, Tunnels Tunnelling, May 1999, pp. 25-30.


AN

NEX

A: G

ener

ic G

DFD

for S

urfa

ce-B

ased

Inve

stig

atio

ns a

t Coa

stal

Site

s


Survey/Review of Pre-existing Information

Terrestrial Exploration

Geom

orph

ologic

al ch

ange

s

In sit

u roc

k mec

hanic

al tes

ts

Core

logg

ing, in

vesti

gatio

nsof

drilli

ng m

ud

Bore

hole

wall i

magin

g

Geop

hysic

al log

ging

Tren

ch ex

cava

tion s

urve

y

Distr

ibutio

n/exte

nt/ge

ometr

yof

disco

ntinu

ities

Distr

ibutio

n/geo

metry

/thi

ckne

ss/de

pth/ge

ologic

aldo

main

of ho

st ro

ck

Distr

ibutio

n/geo

metry

/thick

-ne

ss of

surro

undin

g unit

s

Evolu

tion o

f geo

logica

lstr

uctur

e

Evolu

tion o

f petr

ophy

sical

prop

ertie

s (up

lift/su

bside

nce

histor

y)

Palae

ogeo

morp

holog

ical/

geog

raph

ical c

hang

es

Palae

oclim

ate ch

ange

s, lon

g-ter

m pr

edict

ion of

clim

atech

ange

s

Geolo

gical

rock

/fault

form

ation

Crus

tal m

ovem

ent to

date,

evolu

tion o

f reg

ional

stres

sfie

ld

Borehole InvestigationsGe

omor

pholo

gy, g

eode

sy;

aeria

l/sate

llite i

mage

s etc

Tecto

nics,

geolo

gy,

geolo

gical

struc

ture e

tc

Mine

ralog

ical/c

hemi

cal/p

etro-

phys

ical/tr

ansp

ort p

rope

rties

Geom

orph

ologic

al inv

estig

a-tio

ns; la

ndfor

m ma

pping

Surfa

ce hy

drolo

gical/

mete-

orolo

gical

inves

tigati

ons

Surfa

ce ge

ologic

al su

rveys

;lith

ostra

tigra

phy,

fault e

tc

Geop

hysic

al su

rveys

; gra

vity,

electr

omag

netic

, seis

mic e

tc

Lab e

xami

natio

n/ana

lysis;

petro

grap

hy, m

icrofo

ssil,

age,

petro

phys

ics/m

echa

nics e

tc

VSP

surve

y, cro

ss-h

oletom

ogra

phy s

urve

y

Hydr

aulic

pack

er te

sts; s

ingle

hole,

cros

s-hole

etc

Lab e

xami

natio

n/ana

lysis;

petro

grap

hy, m

icrofo

ssil,

pore

water

chem

istry,

sorp

tion/

diffus

ion, r

ock m

echa

nics e

tc

Geolo

gical

surve

y; dr

edge

in-

vesti

gatio

ns, p

iston

corin

g etc

Lab e

xami

natio

n/ana

lysis;

pore-

water

chem

istry,

micr

ofoss

il etc

Hydro

geolo

gical

inves

tigati

ons;

hydra

ulics

of se

dimen

ts etc

Fluid

loggin

g

Long

-term

grou

ndwa

ter le

vel/

pres

sure

chan

ges

Loca

tion/f

lux of

subm

arine

seep

age

Deep

subs

urfac

e hyd

rauli

cpr

oper

ties;

water

pres

sure

,K,

De e

tc

Rech

arge

rate,

wate

r tab

ledis

tributi

on

Rech

arge

rate

chan

ge

Evolu

tion o

f hyd

rauli

c pro

p-er

ties o

f roc

k/disc

ontin

uities

Grou

ndwa

ter flo

w sim

ulatio

n(ta

king s

alinit

y, de

nsity

etc

into a

ccou

nt)

Grou

ndwa

ter flo

w sim

ulatio

n(ta

king g

eolog

ical/h

ydro

-ge

ologic

al/ch

emica

l evo

lution

into a

ccou

nt)

Palae

oclim

ate in

vesti

gatio

ns;

diatom

, dep

osits

, age

etc

Long

-term

hydr

aulic

/hydr

o-ch

emica

l mon

itorin

g

Trac

er ex

perim

ents

Mine

ralog

ical/c

hemi

cal p

rop-

ertie

s of h

ost r

ock;

chem

ical/

isotop

ic co

mpos

itions

Mine

ralog

ical/c

hemi

cal p

rop-

erties

of su

rroun

ding u

nits;

chem

ical/is

otopic

comp

ositio

nsMi

nera

logica

l/che

mica

l pro

p-er

ties o

f disc

ontin

uities

; che

m-ica

l/isoto

pic co

mpos

itions

Grou

ndwa

ter ch

emist

ry in

host

rock

; che

mica

l/isoto

picco

mpos

itions

, age

Grou

ndwa

ter ch

emist

ry in

surro

undin

g unit

s; ch

emica

l/iso

topic

comp

ositio

ns, a

geGr

ound

water

chem

istry

indis

conti

nuitie

s; ch

emica

l/iso

topic

comp

ositio

ns, a

ge

Shall

ow su

bsur

face h

ydra

ulic

char

acter

istics

; rive

r flux

,pr

ecipi

tation

, eva

po-

trans

pirati

on, v

egeta

tion e

tc

Crus

tal m

ovem

ent a

nalys

is

Initia

l stre

ssIni

tial s

tress

state

Stre

ss/ex

cava

tion a

nalys

is

Surfa

ce hy

droc

hemi

cal in

ves-

tigati

ons;

prec

ipitat

ion et

c

Hydr

oche

mica

l inve

stiga

tions

;gr

ound

water

chem

istry/

isotop

es, in

situ

phys

ico-

chem

ical m

easu

reme

nt etc

Hydr

oche

mica

l inve

stiga

tions

;se

epag

e che

mistr

y etc

Rock

mec

hanic

al/the

rmal

prop

ertie

s; un

iaxial

comp

ress

ive st

reng

th,ge

other

mal g

radie

nt etc

Petro

phys

ical/m

echa

nical/

therm

al pr

oper

ties o

f hos

tro

ck/su

rroun

ding u

nits

Evide

nce o

f long

-term

solut

etra

nspo

rt in

host

rock

and

disco

ntinu

ities

Grou

ndwa

ter flo

w pr

oces

ses

in ro

ck/di

scon

tinuit

ies

Solut

e tra

nspo

rt co

ncep

tual

mode

l

Tran

spor

t pro

cess

es in

host

rock

/disc

ontin

uities

;ad

vecti

on, d

iffusio

n, co

lloid-

facilit

ated,

two-

phas

e

Geom

etry o

f path

ways

/po

rosit

ies, s

orpti

on/di

ffusio

npr

oper

ties o

f hos

t roc

k/dis

conti

nuitie

s

Surfa

ce w

ater c

hemi

stry;

chem

ical/is

otopic

comp

ositio

ns,

collo

ids/or

ganic

s/micr

obes

etc

Grou

ndwa

ter ch

emist

ry;ch

emica

l/isoto

pic co

mpos

itions

,co

lloids

/orga

nics/m

icrob

es et

cSe

a wate

r/see

page

/pore

water

chem

istry;

chem

ical/

isotop

ic co

mpos

itions

etc

Geolo

gical

distrib

ution

;lith

ostra

tigra

phy,

depo

sition

alfac

ies et

cGe

ologic

al str

uctur

e;lin

eame

nt, fa

ult, fo

lding

,ac

tive s

tructu

re et

c

Geom

orph

ologic

al ch

ange

s;up

lift/su

bside

nce r

ate,

palae

otopo

grap

hyCl

imate

chan

ges;

globa

lcli

mate

chan

ges,

palae

o-cli

mate/

palae

oveg

etatio

n

Solut

e tra

nspo

rt/re

tarda

tion;

Kd, D

e, α,

pore

stru

cture

etc

Confi

rmati

on of

cons

isten

cy

Links

not c

onne

cted

Links

conn

ected

Long

-term

pred

iction

ofglo

bal c

limate

chan

ges e

tc

Surfa

ce hy

drau

lics;

river

flux,

prec

ipitat

ion, w

ater t

able

etc

Deep

subs

urfac

e hyd

rauli

cs;

water

pres

sure

, K et

c

Hydr

oche

mistr

y; gr

ound

water

chem

istryl

/isoto

pes e

tc

Rock

mec

hanic

s, the

rmal

prop

ertie

s, str

ess e

tc

Remo

te se

nsing

Aeria

l geo

phys

ical s

urve

y;ma

gneti

c, ra

diome

tric et

c

AerialExploration

Crus

tal m

ovem

ent m

onito

ring;

GPS/

seism

ic ob

serva

tion e

tc

Marine ExplorationGe

omor

pholo

gy/ge

odes

y;alt

itude

/land

form/

drain

age

syste

m dis

tributi

on

Tecto

nics;

faultin

g/de

posit

ional

ages

,de

forma

tion/d

isplac

emen

t

Crus

tal st

ress

, foca

lme

chan

ism so

lution

s

Rock

mine

ralog

y/che

mistr

y;pe

trogr

aphy

, mine

ral/c

hemi

-ca

l com

posit

ions,

alter

ation

textur

e, or

ganic

s etc

Petro

phys

ics; P

/S-ve

locity

,po

rosit

y, de

nsity

, res

istivi

ty etc

Inves

tigati

ons

Data

Inter

preta

tion/D

atase

t

Geom

orph

ologic

al mo

del

Geom

orph

ologic

al ch

ange

mode

l

Geolo

gical

mode

l

Geolo

gical

evolu

tion m

odel

Hydr

ogeo

logica

l mod

el

Hydr

ogeo

logica

l evo

lution

mode

l

Geoc

hemi

cal m

odel

Hydr

aulic

prop

ertie

s of h

ost

rock

Hydr

aulic

prop

ertie

s of

surro

undin

g unit

s

Hydr

aulic

prop

ertie

s of

disco

ntinu

ities

Hydr

aulic

head

distr

ibutio

n

Geoc

hemi

cal e

volut

ion m

odel

Rock

mec

hanic

al mo

del

Conc

eptua

lisati

on/M

odell

ing/S

imula

tion

Key P

rope

rties/P

roce

sses

Groundwater flowcharacteristics

Spati

al va

riabil

ity of

grou

ndwa

ter flu

xes

Grou

ndwa

ter flo

w fie

ld an

dpr

oces

s

4D ev

olutio

n of g

roun

dwate

rflo

w fie

ld an

d pro

cess

4D ev

olutio

n of g

roun

dwate

rflu

x dist

ributi

on

Geochemical charac-teristics of groundwater

4D ev

olutio

n of g

roun

dwate

rch

emist

ry

Grou

ndwa

ter pH

-Eh c

ondit

ions

Spati

al dis

tributi

on of

salin

e/fre

sh gr

ound

water

(inter

face)

;de

gree

of gr

ound

water

mine

ralis

ation

Transport/retardationof nuclides

Effec

t of c

olloid

/orga

nics/

micro

bes o

n nuc

lide

trans

port/

retar

datio

n

Sorp

tion c

apac

ity an

ddif

fusivi

ty of

rock

matr

ix an

dof

trans

port

pathw

ays

Geom

etry o

f tran

spor

tpa

thway

s; de

pth of

diffu

sion-

acce

ssibl

e matr

ix

Dilution of nuclides

Spati

al va

riabil

ity of

wate

rflu

xes i

n high

er-p

erme

abilit

yro

cks,

aquif

ers a

nd su

rface

water

s

Spati

al dis

tributi

on of

high

er-

perm

eabil

ity ro

cks,

aquif

ers

and s

urfac

e wate

rs; ex

tent o

fma

rine e

nviro

nmen

ts

Geomechanical/hydraulic properties of tunnelnear-field environment

Size

and s

tructu

re of

EDZ

;pe

troph

ysica

l/geo

mech

anica

lpr

oper

ties o

f EDZ

Volum

e of in

flow

into u

nder

-gr

ound

tunn

els; v

olume

ofga

s emi

ssion

from

host

rock

Spati

al va

riabil

ity of

petro

phys

ical/g

eome

chan

ical

prop

ertie

s of r

ocks

Regio

nal a

nd lo

cal s

tress

regim

e

4D ev

olutio

n of s

tress

field

atre

posit

ory d

epth

4D ev

olutio

n of p

etrop

hysic

al/ge

omec

hanic

al pr

oper

ties o

fro

cks

Distr

ibutio

n of d

iscon

tinuit

iesint

erse

cting

unde

rgro

und

tunne

ls

Geology andGeological Structure

4D ge

omor

pholo

gical

chan

ges;

4D ev

olutio

n of

geolo

gical

struc

ture

Heter

ogen

eity w

ithin

host

rock

Size

and e

xtent

of ho

st ro

ck

Spati

al dis

tributi

on an

dge

ometr

y of tr

ansp

ort

pathw

ays

Subsurfacethermal conditions

Ther

mal ro

ck pr

oper

ties

4D ev

olutio

n of th

erma

l rock

prop

ertie

s

Spati

al va

riabil

ity of

geoth

erma

l gra

dient

Geop

hysic

al su

rveys

; gra

vity,

electr

omag

netic

, seis

mic e

tc


development of comprehensive techniques for coastal site characterisation: part 1—strategic...

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