Class IB Facilities

Guidance on Deep Geological
Repository Site Characterization
REGDOC-1.2.1

January 2021

Guidance on Deep Geological Repository Site Characterization
Regulatory document REGDOC-1.2.1© Canadian Nuclear Safety Commission (CNSC) 2021
Cat. No. CC172-233/2021E-PDF
ISBN 978-0-660-37087-3
Extracts from this document may be reproduced for individual use without permission provided thesource is fully acknowledged. However, reproduction in whole or in part for purposes of resale orredistribution requires prior written permission from the Canadian Nuclear Safety Commission.
Également publié en français sous le titre : Orientation sur la caractérisation du site pour dépôts
géologiques en profondeur
Document availability
This document can be viewed on the CNSC website. To request a copy of the document in English or
French, please contact:
Canadian Nuclear Safety Commission
280 Slater Street
P.O. Box 1046, Station B
Ottawa, Ontario K1P 5S9
CANADA
Tel.: 613-995-5894 or 1-800-668-5284 (in Canada only)
Fax: 613-995-5086
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Publishing history
January 2021

Version 1.0

January 2021

REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

PrefaceThis regulatory document is part of the CNSC’s regulated facilities and activities series of regulatory
documents. The full list of regulatory document series is included at the end of this document and canalso be found on the CNSC’s website.
Regulatory document REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization,
sets out guidance on site characterization for a deep geological repository (DGR) facility for radioactive
waste. Information gathered for site characterization may be used in subsequent licence applications.
This document supersedes R-72, Geological Considerations in Siting a Repository for Underground
Disposal of High-Level Radioactive Waste, published in September 1987.
For information on the implementation of regulatory documents and on the graded approach, see
REGDOC-3.5.3, Regulatory Fundamentals.
The words “shall” and “must” are used to express requirements to be satisfied by the licensee or
licence applicant. “Should” is used to express guidance or that which is advised. “May” is used toexpress an option or that which is advised or permissible within the limits of this regulatory document.
“Can” is used to express possibility or capability.
Nothing contained in this document is to be construed as relieving any licensee from any otherpertinent requirements. It is the licensee’s responsibility to identify and comply with all applicableregulations and licence conditions.

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REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

Table of Contents
1.

Introduction .................................................................................................................................... 1
1.1

Purpose................................................................................................................................ 1

1.2

Scope................................................................................................................................... 1

1.3

Relevant legislation............................................................................................................. 2

2.

The CNSC’s Waste Management Framework ............................................................................ 2

3.

Background .................................................................................................................................... 3

4.

3.1

Environmental reviews ....................................................................................................... 3

3.2

Public and Indigenous engagement .................................................................................... 4

3.3

Overview of site characterization ....................................................................................... 4

Site Characterization for DGR Facilities ..................................................................................... 5
4.1

Overview ............................................................................................................................. 5

4.2

Role of site characterization in the CNSC regulatory process ............................................ 5

4.3

Site characteristics I: Geological environment ................................................................... 7

4.4

4.3.1

Geological setting .................................................................................................. 7

4.3.2

Hydrogeological setting ......................................................................................... 7

4.3.3

Geochemistry ......................................................................................................... 8

4.3.4

Geological stability ................................................................................................ 8

4.3.5

Geomechanical characteristics ............................................................................... 9Site characteristics II: Surface environment ....................................................................... 9
4.4.1

Climate ................................................................................................................... 9

4.4.2

Aquatic and terrestrial environment..................................................................... 10

4.4.3

Surface water hydrology ...................................................................................... 10

4.4.4

Geomorphology characterization ......................................................................... 11

4.4.5

Geotechnical characterization of surficial deposits ............................................. 11

5.

Human Activities and Land Use ................................................................................................. 12

6.

Data Acquisition and Verification Activities ............................................................................. 12
6.1

Management system ......................................................................................................... 12

6.2

Data management program ............................................................................................... 13

6.3

Sampling and testing procedures ...................................................................................... 13
6.3.1

6.4

Procedures for underground investigation using borehole drilling ...................... 14

Integration and interpretation............................................................................................ 15

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REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

Facilities for Verification and Characterization Activities ...................................................... 16
The Role of Site Characterization in the Siting Process ................................................. 17
A.1

Conceptual and Planning stage ......................................................................................... 17

A.2

Survey Stage ..................................................................................................................... 17

A.3

Site Characterization Stage ............................................................................................... 17

A.4

Site Confirmation Stage .................................................................................................... 18

Glossary ..................................................................................................................................................... 19
References .................................................................................................................................................. 20
Additional Information ............................................................................................................................ 22

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REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization
1.

Introduction
A deep geological repository (DGR) is an engineered facility where radioactive waste isemplaced in a deep, stable, geological formation designed to isolate and contain radioactive waste
over the long term. Site characterization involves detailed technical investigations to increase thestate of knowledge about a particular site. Regional and site-specific information are used to gain
an understanding of a potential site, and the features and processes that might affect the long-term
performance of a DGR facility at that site. These processes involve a number of different
scientific disciplines (such as hydrogeology, rock mechanics and geochemistry) that are
integrated and interpreted together.
1.1

PurposeThis regulatory document provides guidance for site characterization for a DGR facility forradioactive waste.
Site characterization information is integral to licence applications for DGR facilities. The sitecharacterization information used to site and design a DGR facility is re-evaluated over the
lifecycle of the facility, which includes site preparation, construction, operation,
decommissioning and closure.
1.2

Scope

This document describes the elements of a site characterization program for a DGR facility.
This document is complemented by the requirements and guidance in REGDCOC-2.11.1, Waste
Management, Volume I: Management of Radioactive Waste [1] and REGDOC-2.11.1. Waste
Management, Volume III: Safety Case for the Disposal of Radioactive Waste, Version 2 [2].
Together, these regulatory documents provide requirements and guidance for sitecharacterization. Furthermore, this regulatory document is complemented by other CNSC
regulatory documents.
Note that this document does not:
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provide guidance on finding or selecting a site; site selection is not an activity regulated under
the Nuclear Safety and Control Act (NSCA)
 apply to surface and near-surface waste management facilities, including waste from uranium
mines and mills
 provide guidance on long-term waste management strategies
 provide requirements for safety analysis of the operational phase of DGR facilities
 provide requirements for a post-closure safety case for geological disposal provide guidancefor environmental protection, including environmental assessment (see REGDOC-2.9.1,
Environmental Protection: Environmental Principles, Assessments and Protection Measures)[3]
In this document, the pre-closure period of a DGR encompasses site preparation, construction andoperation of the DGR and the decommissioning and closure of ancillary facilities. The postclosure (or long-term) period is the period that follows the closure of a DGR facility. This longpost-closure time period is a feature of DGR projects, necessitating extensive geological sitecharacterization activities (section 3 this document) and a long-term safety case, as outlined inJanuary 2021

REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

REGDOC-2.11.1, Waste Management, Volume III: Safety Case for the Disposal of Radioactive
Waste, Version 2 [2].
1.3

Relevant legislation

A facility for the long-term management of radioactive waste, such as a DGR, is generally subject
to the licensing requirements of the Class I Nuclear Facilities Regulations. As a facility for the
disposal of a nuclear substance, a DGR meets the definition of a Class IB nuclear facility under
section 1(e) of these regulations. These regulations do not identify a regulatory process forselecting a site. The regulatory process is not triggered until the CNSC receives an application fora licence to prepare a site or for a combined licence to prepare a site and construct a facility.
The Nuclear Safety and Control Act (NSCA) applies once site preparation activities begin.
The following provisions of the NSCA and its associated regulations are relevant to thisdocument:2.

Section 26 of the NSCAClass I Nuclear Facilities Regulations, paragraphs 4(a) and 4(c)The CNSC’s Waste Management Framework
In addition to this regulatory document, the CNSC’s regulatory framework for waste management
includes:

REGDOC-2.11, Framework for Radioactive Waste Management and Decommissioning in
Canada [4]
REGDOC-2.11.1, Waste Management, Volume I: Management of Radioactive Waste [1]
REGDOC-2.11.1, Waste Management, Volume II: Management of Uranium Mine Waste
Rock and Mill Tailings [5]
REGDOC-2.11.2, Decommissioning [6]The following CSA standards complement the CNSC’s regulatory framework:
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CSA N286-12, Management System Requirements for Nuclear Facilities [7]
CSA N288.4, Environmental Monitoring Programs at Class I Nuclear Facilities andUranium Mines and Mills [8]CSA N288.5, Effluent Monitoring Programs at Class I Nuclear Facilities and Uranium
Mines and Mills [9]CSA N288.6, Environmental Risk Assessments at Class I Nuclear Facilities and Uranium
Mines and Mills [10]CSA N288.7, Groundwater Protection Programs at Class I Nuclear Facilities and Uranium
Mines and Mills [11]CSA N292.0, General Principles for the Management of Radioactive Waste and IrradiatedFuel [12]CSA N292.1, Wet Storage of Irradiated Fuel and Other Radioactive Materials [13]
CSA N292.2, Interim Dry Storage of Irradiated Fuel [14]CSA N292.3, Management of Low- and Intermediate-Level Radioactive Waste [15]CSA N292.5, Guideline for the Exemption or Clearance From Regulatory Control ofMaterials That Contain, or Potentially Contain, Nuclear Substances [16]
CSA N292.6, Long-Term Management of Radioactive Waste and Irradiated Fuel [17]January 2021

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REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

CSA N294, Decommissioning of Facilities Containing Nuclear Substances [18]Background
Site characterization data is used to evaluate the suitability of a possible site, inform the design ofa DGR facility, and support the safety case for any potential DGR project. This information isnecessary for detecting potential short- and long-term environmental impacts at various stages
and for tracking what information is used (and how it is used) throughout the CNSC’s licensing
lifecycle. Baseline data provides initial information for evaluating safety at the siting stage andduring initial facility design, and also contributes to determining the effect of features, events andprocesses associated with the DGR system. Data needs include relevant regional- and site-scale
information.
Early in the site selection process for a DGR facility, a prediction of DGR project impacts thatincorporates site characteristic data, typically considers whether the project:

could affect the environment
could adversely affect an Indigenous groups’ potential or established Indigenous and/or treaty
rights, such as the ability to hunt, trap, fish or gather, or conduct cultural ceremonies, as
described in REGDOC-3.2.2, Indigenous Engagement [19]This information, when submitted with a licence application, feeds into any impact assessment.
Early dialogue with the regulator for clarity on regulatory expectations is recommended. Includedin this dialogue is the identification of site characterization activities that may not require alicence from the CNSC. This can be formalized through a service arrangement between theregulator and the proponent.
3.1

Environmental reviews

The CNSC has the mandate to protect the environment. The CNSC assesses the environmental
effects of all nuclear facilities or activities at every phase of their lifecycle. The CNSC requiresthat the environmental effects of all licensed activities be evaluated and considered whenlicensing decisions are made. Environmental reviews are based on the scale and complexity of theenvironmental risks associated with a nuclear facility or activity. Early in the licensing process,
CNSC staff determine which type of environmental review applies by reviewing the information
provided by the applicant or licensee in their application and supporting documentation.
One form of environmental review is an impact assessment. Impact assessments are carried out inaccordance with federal environmental legislation the Impact Assessment Act and its regulations.
The impact assessment is led by the Impact Assessment Agency of Canada, with CNSC
participation. An impact assessment decision must be rendered before a licensing decision can bemade under the NSCA.
Site characterization information is an important consideration for all environmental reviews. The
CNSC reviews this information during the assessment of all licence applications over thefacility’s lifecycle.
For more information on the CNSC’s environmental review and licensing processes, see:January 2021

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3.2

REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

REGDOC-2.9.1, Environmental Protection: Environmental Principles, Assessments andProtection Measures [3]
REGDOC-3.5.1, Licensing Process for Class I Nuclear Facilities and Uranium Mines andMills [20]Public and Indigenous engagement

As set out in as set out in REGDOC-3.2.2, Indigenous Engagement [19], potentially interested
Indigenous groups should be engaged early during the site characterization phase in order todiscuss project plans, gather Indigenous knowledge/land use information and address any
concerns, as appropriate, early in the site characterization and project development process.
Conducting engagement activities with the public and Indigenous groups, early in the sitecharacterization process, is expected to result in more effective and efficient consultation
practices, strengthen relationships with Indigenous communities, assist the Crown in meeting its
obligations regarding any potential duty to consult, and reduce the risk of delays in the regulatory
review process.
Early in the site evaluation process, the applicant should also develop and implement a public
information and disclosure program, per REGDOC-3.2.1, Public Information and Disclosure[21].
Information on public and Indigenous engagement activities is submitted to the CNSC as part of alicence application.
3.3

Overview of site characterization

Site characterization begins before the applicant submits a licence application to the CNSC andcontinues throughout the lifecycle of the DGR facility. The proponent will review and update thissite characterization information, to reflect changes in the vicinity of the site and to incorporate
new scientific data and knowledge. Characterization activities also support the engineering
design.
Site characterization information is presented in this document as follows:
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Site characterization: Section 3 describes the application of site characterization informationin all lifecycle phases, and describes activities to include in a site characterization program: section 3.1 describes the role of site characterization in the CNSC’s regulatory process section 3.2 provides guidance on site characterization for the geological environment
 section 3.3 provides guidance on site characterization for the surface environment
Human activities and land use: Section 4 describes information gathering on past, present
and potential future human activities at or near the site
Data acquisition and verification activities: Section 5 describes information that would
demonstrate, in a licence application, that the results of site characterization activities areaccurate, complete, reproducible, traceable and verifiable
Verification and site characterization: Section 6 provides information about potential
approaches to verification of site characteristics
Siting process for a DGR facility: Appendix A describes the siting process for a DGR
facility, providing more information on the role of site characterization in DGR site selectionthat is consistent with international guidanceJanuary 2021

REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

Information from site characterization should be considered throughout the lifecycle of the
proposed facility to ensure that the facility’s design basis and safety case remain current withchanging environmental conditions or modifications to the facility itself.

4.

Site Characterization for DGR Facilities
4.1

Overview

Site characterization information should be taken into account during the design of a DGR facility
and re-evaluated over the lifecycle of the facility, which includes site preparation, construction,
operation, decommissioning and closure.
Early in the site selection process for a DGR facility, the licensee or applicant should consider
whether the characteristics of a site when used for a DGR could affect the environment, and/or
adversely affect an Indigenous group’s potential or established Indigenous and/or treaty rights.
The licensee or applicant would submit this information, together with a licence application, andensure that it supports any impact assessment.
The licensee or applicant should ensure that information from site characterization is consideredthroughout the lifecycle of the proposed facility to ensure that the facility’s design basis andsafety case remain current with changing environmental conditions or modifications to the facility
itself.
The characteristics of the host rock and geological system (that is, natural barriers) will be uniqueto the site chosen. The geological system refers to the characteristics influencing groundwater
flow, rock mineralogy and structure, the location and properties of discontinuities, andgeochemical processes. The characteristics of the surface environment provide baseline
information for future environmental monitoring and potential mitigation activities.
Specific criteria provided for the collection of characterization data are not exhaustive. Guidanceis presented in no specific order or priority; nor is it limited to the elements, approaches andtechniques identified. Relative relevance of specific criteria will, in some cases, be site specific.
Data and analysis results from site characterization may be used to satisfy information needed insubsequent licensing phases, as specified in the NSCA and associated regulations.
The applicant should reject any unacceptable or inappropriate site before applying for a licence,
without requiring CNSC involvement.
4.2

Role of site characterization in the CNSC regulatory process

Site characterization should be part of the information gathering and initial regulatory submission
activities for the proposed DGR facility. Figure 1 shows where site characterization fits within thesite selection process and the role of site characterization in the CNSC’s regulatory process.
Site characterization data plays a role in detecting potential short- and long-term environmental
impacts at various stages throughout the licensing lifecycle.
The site characteristics are used to demonstrate how the radioactive waste would be adequately
contained and isolated from the environment for an extended period, known as the assessment
time frame. Information on the assessment time frame and the requirements for the long-term

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REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

safety case needed for licensing are provided in REGDOC-2.11.1, Waste Management,
Volume III: Safety Case for the Disposal of Radioactive Waste, Version 2 [2]. As such, sitecharacterization is essential for gathering evidence of whether site attributes will meet
expectations as part of a post-closure safety case. Internationally, assessment time frames
associated with DGRs span tens of thousands of years or more.
Examples of site characterization activities that are carried out after a site preparation licence isobtained include (see figure 1):verification of information gathered and analyzed in earlier phases
establishment of an adequate baseline for future monitoring
information used in updates to the DGR facility post-closure safety case

Where a DGR project receives a licence from the CNSC, ongoing characterization activities may
continue until closure as part of a geoscience verification plan. These activities would serve togather additional geoscientific information to confirm sub-surface conditions originally
understood from surface-based studies.
Further information on the siting process for a DGR, including geological considerations, isavailable in appendix A and in international guidance documents.
Figure 1: Site characterization in the CNSC regulatory process

Figure 1: Site characterization data gathered during site selection should inform impact
assessments and may be included in the initial licence application to the CNSC. Sitecharacterization activities begin in a pre-application period and carry through to subsequent
facility lifecycle phases.

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4.3

REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

Site characteristics I: Geological environment

The evaluation of a potential DGR site should include information on:
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containment and isolation characteristics of the host rock and geological system
past and expected/projected future geological stability of the site, including the impacts oforogeny, seismicity, glaciation and volcanism
sufficient extent of suitable host rock at the repository depth
ability of the host rock and geological system to withstand stresses without significant
breachinglocation relative to geological discontinuities
demonstrated isolation of groundwater at selected repository depth from shallow groundwater
systemscharacteristics favourable for limiting contaminant release and transport away from the DGR
low natural resource potential, which would limit the likelihood of inadvertent future human
intrusion by subsequent generations of resource explorers

The geological environment should be used to assess the post-closure safety of a DGR and should
be considered in the engineering design. The geological characteristics combined with theengineered barriers and the design of the DGR should indicate that the proposed DGR, at thechosen site, will remain safe for the entire lifecycle, including the post-closure period.
The evaluation should include quantitative data in addition to qualitative descriptions, where
possible.
The key geological characteristics used to assess the suitability of a DGR site should include theelements set out in subsections 4.3.1 to 4.3.5.
4.3.1

Geological setting

The licensee or applicant should include the following geological setting characteristics:
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tectonic setting
structural geology
stratigraphy
chosen host rock type and extent
fracture characteristics: frequency, orientation, mineralogy and spacing
history of glacial cycles
petrology
geomechanical properties
natural resource potential

The licensee or applicant should include a quantitative assessment of natural resource potentialthat includes historical and current data.
4.3.2

Hydrogeological setting

The licensee or applicant should include the following hydrogeological setting characteristics:
definition of regional hydrogeological regime and/or units

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REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

regional and site-specific groundwater flow conditions (such as flow rate, flow direction,
hydraulic heads and hydraulic gradients)hydrogeology of major rock unitshydrogeological properties (such as porosity and hydraulic conductivity)
recharge and discharge areas
water budget
location of existing and predicted future significant water-use areas (such as groundwater
wells)

This data will help identify preferential pathways, velocities, residence times and otherparameters.
4.3.3

Geochemistry

The licensee or applicant should include the following information to reflect geochemical
conditions:
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mineralogy, including petrography
groundwater/porewater geochemistry
redox conditions
movement of radionuclides (including, but not limited to, information on diffusion, solubility,
speciation and sorption)
movement of non-radioactive species (such as lead, arsenic, chromium and copper)
geochemical impact of groundwater on engineered barriers
microbiology
potential for gas generationwater–rock interaction

Special emphasis should be placed on geochemical properties that can affect the migration ofradionuclides in groundwater. Together with geological and hydrogeological data, thegeochemical conditions provide essential information for predicting how contaminants could
migrate from a DGR to the biosphere.
4.3.4

Geological stability

The licensee or applicant should collect information that reflects the geological stability of thesite and region, including:evidence of recent or historic active tectonic processes (neotectonics) – for example,
information on Quaternary faulting and movement, soil liquefaction and volcanism
record of seismicity at the site, including documentation of historical earthquakes, theirepicentres, magnitude and intensity, and recurrence (link with regional tectonics, structuralgeology)the effect of past glaciation events on the site as a basis for assessing the impact of future
glacial events (in the post-closure period considered in the safety case, per REGDOC-2.11.1,
Waste Management, Volume III: Safety Case for the Disposal of Radioactive Waste,
Version 2 [2]), linking hydrogeological, geochemical and geomechanical rock properties withglacial history

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4.3.5

REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

Geomechanical characteristics

The licensee or applicant should collect information on the geomechanical characteristics toassess the pre-closure and long-term stability of the underground excavations, and the evolutionof the damage zone around those excavations.
The licensee or applicant should include the following information on the geomechanicalcharacteristics:
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the magnitude and orientation of the in situ stressthe stress-strain-strength properties of the intact rock, fractures and rock mass
the influence of time, temperature, scale, anisotropy, pore fluid pressure and other relevant
factors on stress-strain-strength properties
potential to withstand glacial events

4.4

Site characteristics II: Surface environment

The licensee or applicant should characterize surface processes at the site to ensure that natural
hazard events, such as flooding, landslides and erosion, will not impact the ability of theradioactive waste disposal system to function safely. Baseline environmental data is used toassess and predict the effects of a project on the environment.
The characteristics of the surface environment used to assess the suitability of a DGR site should
include the elements set out in subsections 4.4.1 to 4.4.5.
4.4.1

ClimateThe licensee or applicant should characterize the site area meteorological conditions and consider
them in the design of a DGR facility. Meteorological conditions should be determined fromonsite and nearby meteorological stations, where possible. This data should also be used asbaseline data to evaluate the transport of potential airborne releases during the pre-closure periodof the DGR facility.
The licensee or applicant should justify the minimum meteorological data (that is, number ofyears of site-specific data) and demonstrate that it is commensurate with the type of project andthe chosen site. Climate normal data (that is, 30 years of climate data) should also be included.
The licensee or applicant should collect the following specific information:
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local and regional climatic history and expected future trends at both the regional and moreglobal scalemeteorological data, which should be collected at the site, local and regional scales toadequately capture future meteorological conditions that could occur over the time scales ofthe project
regional and local precipitation characteristics
extreme and average data on temperature, precipitation, wind speed and any other relevant
phenomena on a regional basis
wind and atmospheric dispersion characteristics for potential atmospheric releases
potential for rare and extreme weather phenomena, such as hurricanes, tornadoes and severe
winter storms
ground frost and snow coverJanuary 2021

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REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

evapotranspiration (that is, evaporation and transpiration from soils, water bodies and plants)
ice dynamics on lakes and streams
air quality

The licensee or applicant should also consider the potential for climate change to impact
processes relevant to the characteristics listed above over the lifecycle of the projects.
4.4.2

Aquatic and terrestrial environment

The licensee or applicant should characterize the ecosystem components in sufficient detail toenable the assessment of their importance, their potential interaction with the project and thepotential for environmental effects arising from the project activities.
The licensee or applicant should characterize the following elements of aquatic ecology, as
applicable:
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surface water characteristics – physical, chemical and biological properties
sediment characteristics – physical, chemical and biological properties
phytoplankton communities
aquatic macrophytes
zooplankton communities
benthic macroinvertebrates
fish
fish habitat
species designated as “at risk”

The licensee or applicant should characterize the following elements of the terrestrial ecology, as
applicable:
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soil quality
vegetation
wildlife
terrestrial habitat
species designated as “at risk”

The level of detail in the description of each of the above components should be in proportion to
the potential for interactions with the DGR (more interaction means more detail).
4.4.3

Surface water hydrology

The licensee or applicant should assess the drainage systems in the area to determine the nature ofsite drainage during the pre-closure DGR period. The importance of this information for a
specific site, including the detail of information needed, should be assessed in a site-specificcontext. Stream, lake, pond and wetland networks in the vicinity of the planned facility should becharacterized to evaluate potential for flooding, erosion, sediment transport and associatedconsequences.
The licensee or applicant should collect and evaluate the following information:

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REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

topography of the site and drainage features, including contributing drainage basin limits(extent, shape)
regional and local precipitation characteristics, including extreme events
size and location of surface water bodies
gradient of the land surface
density of the drainage network
slope of the major stream channels
identification and characterization of groundwater recharge areas and discharge areas(including receiving water bodies)drainage basins’ water balancewater table characteristics and seasonality
magnitude and frequency of floods in the region

The licensee or applicant should consider flood-causing mechanisms, including:

local intense precipitation
flooding
 in rivers and streams
 from upstream dam breaches or failures from storm surges or seiches from tsunamis, tidal and wind waves
 from snow-melting and ice-induced events
 from channel diversions toward the site

The licensee or applicant should also consider the potential for climate change to impact
processes relevant for the characteristics listed above over the lifecycle of the project.
4.4.4

Geomorphology characterization

The licensee or application should characterize the existing geomorphology of a site. This will
permit an understanding of the Quaternary geological history of an area relevant for siting a
DGR. It will also contribute to the geotechnical characterization. This characterization should
include:

distribution of landforms and thickness of surficial material (depth to bedrock)documentation of surface deposits and any existing or potential aggregate resources
Quaternary geological history

4.4.5

Geotechnical characterization of surficial deposits

The licensee or applicant should perform a geotechnical characterization of the surficial deposits
in the area of interest.
The licensee or applicant should consider the following areas of concern:
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slope stability
excavation activities
physical stability and degradation of material stockpiles
stability of facility foundations
quality of human-made barriers constructed using overburden or other materials

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waste settlement
settlement and damage of the facility covers
or any issue that could cause water infiltration and contaminant migration

The licensee or applicant should conduct geotechnical studies that include standard geotechnicalsampling, field investigations and laboratory studies to assess:
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past occurrence of landslides and other potentially unstable slopes in the area
the soil’s physical and index properties (typically grain size, plasticity, dispersion andcohesive properties)
shear strength parameters
bearing capacity of foundation materialliquefaction potential of loose granular material
compaction properties
hydraulic conductivity
other site or facility design-specific properties

Geotechnical characterization of surficial deposits is important, as the integrity of the surface
infrastructure could be affected by the geotechnical properties of overburden materials during thepre-closure period of a DGR facility.

5.

Human Activities and Land Use
The licensee or applicant should collect information on past, present and potential future humanactivities at or near the site and provide an assessment of the likelihood of any impact from those
activities.
To limit adverse impacts on human activities and land use, the licensee or applicant should
consider the following information:
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6.

valuable natural resources (such as groundwater, minerals, surface water or petroleum)
potential for competing land-use activities at the proposed site; surface water use (such asaccess, recreation or hydroelectricity generation)
Indigenous knowledge and historical and current land use by Indigenous communities and the
publiccurrent and historical mineral exploration and mining activities – records of boreholes, shafts
and other features or activities that could represent or cause potential instabilities orradionuclide migration pathways (such as fracking)potential impact of climate change

Data Acquisition and Verification Activities
The licensee or applicant should demonstrate that the results of site characterization activities areaccurate, complete, reproducible, traceable and verifiable.
6.1

Management system

The licensee or applicant should develop and implement a management system for sitecharacterization activities, in accordance with the requirements specified in CSA N286-12,

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Management System Requirements for Nuclear Facilities [7] and in keeping with CNSCREGDOC-2.1.1, Management System [22].
The licensee or applicant should describe the organizational management structure, including theinternal allocation of functions, responsibilities and authority, in accordance with the General
Nuclear Safety and Control Regulations, section 3(1)(k). The management system structure
proposed should include measures to promote and support safety culture for the activity to belicensed, in accordance with section 3(d) of the Class I Nuclear Facilities Regulations. The
licensee’s or applicant’s implementation of a management system should demonstratecompliance, ensure consistency in meeting requirements, set priorities and continuously improvesite characterization activities.
The licensee or applicant should include the generic and specific requirements for sitecharacterization processes and practices under the management system governancedocumentation.
6.2

Data management program

The licensee or applicant should ensure the consistency and quality of the data used to develop
the safety case submitted in support of any formal licence application. The integrity, accuracy andcompleteness of the information and data generated as a result of site characterization activities
are of the utmost importance.
The licensee or applicant should establish quality assurance and quality control programs toensure high data quality and traceability. The programs should be focused on the production of
documentary evidence to demonstrate that the required data quality has been achieved. Datashould be collected, presented, stored and archived in a suitably standardized controlled fashion.
Data should be compiled in a format that facilitates examination, comparison, identification of
information gaps and independent review. The licensee or applicant should ensure that the
documentation for each site characterization component clearly indicates the properties being
investigated, the data collection and investigation methods used, the results, and the associatedassumptions and uncertainties.
The licensee or applicant should ensure that review and verification activities are undertaken byindependent individuals or groups (that is, third-party reviewers) that are different than those who
initially did the work. The reviews should be carried out at different stages, in accordance withthe work instructions and procedures. The process of data evaluation and establishment of thesite-related parameters involves technical and engineering analyses and judgments, which require
extensive experience and knowledge. In many cases the parameters and analyses may not lendthemselves to direct verifications through inspections and tests, or to other techniques that can be
precisely identified and controlled.
6.3

Sampling and testing procedures

The licensee or applicant should obtain the data necessary to guide later development phases andupdates to safety assessments and the safety case, including:geoscientific data compilation
airborne geophysical (such as magnetic or gravity) surveys and seismic surveys
shallow seismic techniques and drilling (which may be used to characterize the overburden)
geological mapping

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bedrock mapping
surficial mapping (that is, landforms, depth to bedrock, surface deposits or aggregate
resources, Quaternary geological history)
environmental characterization
topographical mapping
aerial photograph interpretationsoil sampling to assess soil deposition and transportation processes
geochemical rock property testing
borehole drilling

Site characterization information is necessary to first develop interpretations, and to later confirm,
refine and adapt interpretations based on data acquired from earlier characterization activities.
6.3.1

Procedures for underground investigation using borehole drilling

The licensee or applicant should develop a site characterization program that describes thefollowing:
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number, locations and types (that is, diamond drill vs. air percussion) of boreholes to be
drilled on the site
purpose of each borehole and its intended orientation, length and diametertypes of drilling lubricants and drilling fluid tracers that will be used during drillingtypes of and schedule for borehole deviation monitoring to control orientationcore recovery specifications, sampling intervals, and core logging and storage procedures, orchip sampling, logging and storage procedures
number and types of physical tests to be done on core samples or chip samples
schedule for drilling and testingtypes of hydrogeologic testing (such as drill stem shut-in testing, pulse testing or tracer
testing) to be performed during the drilling program
groundwater samples that will be collected during drilling and the types of analyses of thegroundwater that will be done
record of the types of analysis performed, analytical instrumentation used, and the time
between sampling and analysis
borehole development and completion procedures (flushing, casing and grouting)borehole sealing procedures that will be followed should a borehole require abandonment

The licensee or applicant should have a borehole quality assurance and quality control program toensure that the objectives of the drilling program are achieved and controlled. It should include
the following:

maintenance of a drilling journal by a qualified drill-site geologist who records drilling andrelevant drilling-related activities such as: the cleaning of drill rods before drilling starts
 surface casing installation and grouting procedures
 drilling penetration rates
 core recovery
 presence of water-producing intervals and flow rates
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additions of drilling lubricantsborehole development related to the removal of residual drill cuttings and drilling fluid,and core or chip sample information
recording of static water-level information during shutdowns in drilling operations and thefield chemistry of groundwater that is airlifted to the surface during the drilling of air
percussion boreholes, and the procedures followed to collect and preserve such water samples
post-drilling borehole surveys to confirm that the borehole has been drilled to the prescribed
depth, diameter and orientation
establishment of an electronic record that documents all borehole drilling activities andmeasurements

The licensee or applicant should conduct site characterization activities in consultation with therelevant regulatory bodies early in the process to ensure that regulatory expectations, permitting,licensing or other requirements are clearly understood and that potential issues associated withdata acceptance are identified and mitigated.
Site characterization for DGRs involves the collection of reliable information on the sub-surface
conditions. In the pre-application stage (figure 1), much of the data is collected from various tests
conducted in and between boreholes drilled specifically for this purpose. Other regulators will
have jurisdiction over site characterization activities carried out before a site is selected and before
an applicant engages in activities that would require a licence from the CNSC (see section 3.1).

6.4

Integration and interpretation

The licensee or applicant should amalgamate the results of site characterization integration andinterpretation in a site model which would constitute important supporting information to thepost-closure safety case.
The licensee or applicant should use site characterization information to develop a detailed
conceptual understanding of the site, through the analysis of a large number of physical andenvironmental components that interact with each other. This results in several independent
systems of related components, where the components in each system can be interpreted todevelop a conceptual site model. For example, the stratigraphy, lithology and spatial distributionof in situ stress can be interpreted to give a conceptual model of both the current and evolutionary
structural geology of the site, while the distribution of mineralogy in the rock matrix and in
fracture infilling can be interpreted to give a separate model of the site’s geological evolution.
Different site models developed from different surveys and disciplines should be integrated into asingle, consistent conceptual model of the site’s geological and hydrogeological history, current
conditions and expected (unperturbed) evolution.
The history of the site should inform how the site has responded to past perturbations;
extrapolating historical site information through to current site conditions can provide a model of
how the site is expected to evolve in the future. Perturbations that may be imposed by the planned
facility, together with the information about the site response to past events, should inform any
model of the expected future evolution of the site. The model of current conditions at a site
provides the necessary information for design purposes.

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REGDOC-1.2.1, Guidance on Deep Geological Repository Site Characterization

Facilities for Verification and Characterization Activities
The licensee or applicant should discuss plans for verification with the CNSC at an early stage.
This includes plans for an underground research facility (URF) or a similar facility. Early
discussions help clarify the regulatory approval process and identify site characterization
activities related to verification. This dialogue is also necessary to identify those sitecharacterization activities that may be conducted before a CNSC licence is obtained to prepare asite and/or to construct.
A URF is a facility typically constructed at a depth that provides a representative environment toacquire knowledge and provide training, to further characterize the geology, conduct experiments,
test equipment and designs, and help demonstrate feasibility of a DGR.
Geoscientific characteristics of the subsurface cannot be obtained from surface-based activities
alone (such as geophysical surveys, mapping, and deep borehole drilling), which are limited
simply because they are surface-based observations of features that exist at depth. Therefore,
verification and characterization activities (such as underground excavation and research) in a
URF are considered as an international best practice for DGRs for high-level radioactive waste,
including used nuclear fuel. These activities reduce uncertainties, by providing more data toinclude in a safety case, and may be carried out at a generic and/or site-specific URF.
Setting up a URF is time consuming. There may be a significant time lapse between selection of apotential site and construction of a URF at that site. It also takes time to build research andsupport capacity by participating in URF activities in other countries. Therefore, a best practice isto plan for URF activities as early as possible in the siting process.

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The Role of Site Characterization in the Siting Process
The process for selecting a site and the decision to choose a particular site are the responsibility of thelicence applicant.
The International Atomic Energy Agency (IAEA) identifies four stages to the siting process for a DGR:
1. conceptual and planning stage
2. area survey stage
3. site investigation stage
4. detailed site characterization and site confirmation stage
Site characterization begins at stage 1 during the investigation of a site and is expected to become more
intensive as the siting process progresses through to confirmation of the site. The transition from one
stage to the next is somewhat arbitrary owing to the inevitable overlap in siting activities.
Characterization activities also support the engineering design.
Characterization activities would be expected to continue through the various CNSC licensing phases –site preparation, construction, operation, decommissioning and closure – should a project obtainregulatory approvals.

A.1

Conceptual and Planning stage

An overall plan for the site selection process is developed at this stage. Activities include desktop datacompilation and interpretation. They include the identification of desirable features as a basis for thesecond stage, as well as the conceptualization of a generic facility design based on the type, volume andradionuclide content of the radioactive waste to be managed. (For guidance, see REGDOC-2.11.1, Waste
Management, Volume III: Safety Case for the Disposal of Radioactive Waste, Version 2 [2] and CSA
N292.0-14, General Principles for the Management of Radioactive Waste and Irradiated Fuel [12]). Site
screening criteria should be developed for selecting or rejecting potential sites and, eventually, identifying
a preferred site.

A.2

Survey Stage

The survey stage involves the screening of identified potential siting areas and regional geologicalmapping and other regional-scale characterization activities (such as airborne geophysical surveys).
Engineering design may evolve based on acquired site information. The goal of activities carried out at
the surveying stage is to inform the screening process, which may narrow down potential sites.

A.3

Site Characterization Stage

The site characterization stage involves extensive field work and laboratory studies, usually to gather sitespecific data on a range of site conditions, including a site’s geology, geochemistry and geomechanicalsuitability.
Early-stage site characterization activities involve scientific studies and desktop data compilation work,
and include activities such as geophysical surveys and borehole drilling, though such activities would stop
short of breaking the ground to excavate a shaft.

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A preliminary post-closure safety case (including long-term models) should be completed at this time totest the site’s suitability to host a DGR facility, as well as to guide further characterization andconfirmation activities. A preliminary safety case may also form part of a comparative analysis ofremaining sites (if applicable), which would lead to the next stage of site confirmation, in which detailed,extensive work would focus on one or more sites.

A.4

Site Confirmation Stage

Site confirmation generally consists of detailed field and laboratory studies at the selected site. At thisstage it may be necessary to evaluate whether sinking a shaft or constructing an underground researchfacility are needed to obtain more information.
A post-closure safety case should be prepared based on all of the data gathered during prior siting stages
and in combination with information such as geology and hydrogeology, and information about otherbarriers such as the engineered barrier system, canister design, and radioactive waste characteristics. This
information may be used to develop the safety case for licensing.

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Glossary
For definitions of terms used in this document, see REGDOC-3.6, Glossary of CNSC Terminology, which
includes terms and definitions used in the Nuclear Safety and Control Act and the regulations made underit, and in CNSC regulatory documents and other publications. REGDOC-3.6 is provided for reference andinformation.
The following terms are either new terms being defined, or include revisions to the current definition forthat term. Following public consultation, the final terms and definitions will be submitted for inclusion in
the next version of REGDOC-3.6, Glossary of CNSC Terminology.
containment
The function of the barrier to prevent or control releases of radioactive or hazardous wastes. For deep
geological disposal, this refers to the functions of both the natural barrier (such as the host rock) and theengineered barrier to limit radionuclide releases.
isolation
The physical separation of radioactive waste from people and the environment to make accessing thewaste difficult. For deep geological disposal, isolation is provided mainly by the depth of the repository.

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References
1. CNSC. REGDOC-2.11.1, Waste Management, Volume I: Management of Radioactive Waste. Ottawa,
2021.
2. CNSC. REGDOC-2.11.1, Waste Management, Volume III: Safety Case for the Disposal ofRadioactive Waste, Version 2. Ottawa, 2021.
3. CNSC. REGDOC-2.9.1, Environmental Protection: Environmental Principles, Assessments andProtection Measures. Ottawa, 2020.
4. CNSC. REGDOC-2.11, Framework for Radioactive Waste Management and Decommissioning in
Canada. Ottawa, 2018.
5. CNSC. REGDOC-2.11.1, Waste Management, Volume II: Management of Uranium Mine Waste
Rock and Mill Tailings. Ottawa, 2018.
6. CNSC. REGDOC-2.11.2, Decommissioning. Ottawa, 2021.
7. CSA Group. CSA N286-12, Management System Requirements for Nuclear Facilities. Toronto, 2012.
8. CSA Group. CSA N288.4, Environmental Monitoring Programs at Class I Nuclear Facilities andUranium Mines and Mills. Toronto, 2019.
9. CSA Group. CSA N288.5, Effluent Monitoring Programs at Class I Nuclear Facilities and Uranium
Mines and Mills. Toronto, 2011.
10. CSA Group. CSA N288.6, Environmental Risk Assessments at Class I Nuclear Facilities andUranium Mines and Mills. Toronto, 2012.
11. CSA Group. CSA N288.7, Groundwater Protection Programs at Class I Nuclear Facilities andUranium Mines and Mills. Toronto, 2015.
12. CSA Group. CSA N292.0-14, General principles for the management of radioactive waste andirradiated fuel. Toronto, 2014.
13. CSA Group. CSA N292.1, Wet Storage of Irradiated Fuel and Other Radioactive Materials. Toronto,
2016.
14. CSA Group. CSA N292.2, Interim Dry Storage of Irradiated Fuel. Toronto, 2013.
15. CSA Group. CSA N292.3, Management of Low- and Intermediate-Level Radioactive Waste. Toronto,
2014.
16. CSA Group. CSA N292.5, Guideline for the Exemption or Clearance From Regulatory Control ofMaterials That Contain, or Potentially Contain, Nuclear Substances. Toronto, 2011.
17. CSA Group. CSA N292.6, Long-Term Management of Radioactive Waste and Irradiated Fuel.
Toronto, 2018.

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18. CSA Group. CSA N294, Decommissioning of Facilities Containing Nuclear Substances. Toronto,
2009.
19. CNSC. REGDOC-3.2.2, Indigenous Engagement. Ottawa, 2019.
20. CNSC. REGDOC-3.5.1, Licensing Process for Class I Nuclear Facilities and Uranium Mines andMills. Ottawa, 2017.
21. CNSC. REGDOC-3.2.1, Public Information and Disclosure. Ottawa, 2018.
22. CNSC. REGDOC-2.1.1, Management System. Ottawa, 2019.

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Additional Information
The CNSC may recommend additional information on best practices and standards such as thosepublished by CSA Group. With permission of the publisher, CSA Group, all nuclear-related CSA
standards may be viewed at no cost through the CNSC web page “How to gain free access to all nuclearrelated CSA standards”.
The following documents provide additional information that may be relevant and useful forunderstanding the requirements and guidance provided in this regulatory document:









Western European Nuclear Regulators’ Association. Report: Radioactive Waste Disposal
Facilities Safety Reference Levels. 2014.
CSA Group. CSA N292.0-14, General Principles for the Management of Radioactive Waste
and Irradiated Fuel. Mississauga, 2014.
WM2015 Conference. March 15–19, 2015, Need for and Use of Generic and Site-SpecificUnderground Research Laboratories to Support Siting, Design and Safety Assessment
Developments – 15417. USA, 2015.
International Atomic Energy Agency (IAEA). IAEA Safety Standards Series, No. SSR-5,
Disposal of Radioactive Waste. Vienna, 2011.
IAEA. IAEA Safety Glossary: Terminology Used in Nuclear Safety and Radiation Protection,2018 Edition. Vienna, 2018.
IAEA. IAEA Safety Standards Series, No SSG-23, The Safety Case and Safety Assessment
for the Disposal of Radioactive Waste. Vienna, 2012.
IAEA. IAEA Safety Standards Series, No GSG-1, Classification of Radioactive Waste.
Vienne, 2009.
IAEA. IAEA Safety Standards Series, No SSG-14, Geological Disposal Facilities forRadioactive Waste. Vienna, 2011.

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CNSC Regulatory Document Series
Facilities and activities within the nuclear sector in Canada are regulated by the CNSC. In addition to the
Nuclear Safety and Control Act and associated regulations, these facilities and activities may also be
required to comply with other regulatory instruments such as regulatory documents or standards.
CNSC regulatory documents are classified under the following categories and series:
1.0

Regulated facilities and activities

Series 1.1
Reactor facilities
1.2
Class IB facilities
1.3
Uranium mines and mills
1.4Class II facilities
1.5
Certification of prescribed equipment
1.6
Nuclear substances and radiation devices
2.0
Safety and control areas
Series 2.1
Management system
2.2
Human performance management
2.3
Operating performance
2.4
Safety analysis
2.5
Physical design
2.6
Fitness for service
2.7
Radiation protection
2.8
Conventional health and safety
2.9
Environmental protection
2.10
Emergency management and fire protection
2.11
Waste management
2.12
Security
2.13
Safeguards and non-proliferation
2.14
Packaging and transport
3.0
Other regulatory areas
Series 3.1
3.2
3.3
3.4
3.5
3.6

Reporting requirements
Public and Indigenous engagement
Financial guarantees
Commission proceedings
CNSC processes and practices
Glossary of CNSC terminology

Note: The regulatory document series may be adjusted periodically by the CNSC. Each regulatory
document series listed above may contain multiple regulatory documents. Visit the CNSC’s website forthe latest list of regulatory documents.