Technical Report

TR-10-51

Model summary report forthe safety assessment SR-Site
Svensk Kärnbränslehantering AB

December 2010

Svensk Kärnbränslehantering AB

Box 250, SE-101 24 Stockholm
Phone +46 8 459 84 00

TR-10-51

CM Gruppen AB, Bromma, 2011

Swedish Nuclear Fueland Waste Management Co

ISSN 1404-0344
Tänd ett lager:
SKB TR-10-51
P, R eller TR.

Model summary report forthe safety assessment SR-Site
Svensk Kärnbränslehantering AB

December 2010

A pdf version of this document can be downloaded from www.skb.se.

Preface
This document gives an overview of computer codes used in the safety assessment SR-Site and thequality assurance procedures and documents relating to the codes. It supports the safety assessment
SR-Site, which will support the licence application for a final repository in Sweden.
The report has been produced by Fredrik Vahlund, SKB (project leader) in collaboration with
Lena Zetterström Evins, SKB and Maria Lindgren, Kemakta Konsult AB.
Stockholm, December 2010
Allan Hedin
Project leader SR-Site

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Summary
This document is the model summary report for the safety assessment SR-Site. In the report, thequality assurance (QA) measures conducted for assessment codes are presented together with thechosen QA methodology.
In the safety assessment project SR-Site, a large number of numerical models are used to analyse
the system and to show compliance. In order to better understand how the different models interact
and how information are transferred between the different models Assessment Model Flowcharts,
AMF’s, are used. From these, different modelling tasks can be identify and the computer codes used.
As a large number of computer codes are used in the assessment the complexity of these differs
to a large extent, some of the codes are commercial while others are developed especially for theassessment at hand. QA requirements must on the one hand take this diversity into account and on
the other hand be well defined. In the methodology section of the report the following requirements
are defined for all codes:••••

It must be demonstrated that the code is suitable for its purpose.
It must be demonstrated that the code has been properly used.
It must be demonstrated that the code development process has followed appropriate procedures
and that the code produces accurate results.
It must be described how data are transferred between the different computational tasks.

Although the requirements are identical for all codes in the assessment, the measures used to showthat the requirements are fulfilled will be different for different types of codes (for instance due tothe fact that for some software the source-code is not available for review).
Subsequent to the methodology section, each assessment code is presented together with a discussion on how the requirements are met.

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Contents
1
1.1
1.2
1.3
1.4

Introduction
Objectives and scope of the SR-Site assessment
Objectives and scope of the current report
Key reports in the assessment
Outline of the report

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2.1
2.2
2.3
2.4
2.5

Principles for quality assurance of computer codes
Assessment model flow chart
Computer codes and AMF activities
Types of codes used in the assessment
Requirements on assessment codes
Template used for reporting the codes in Chapter 3
2.5.1 Introduction
2.5.2 Suitability of the code
2.5.3 Usage of the code
2.5.4 Development process and verification
2.5.5 Handling of input data, computational results and scripts
2.5.6 Rationales for using the code in the assessment

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3.1

Description of the codes
3DEC
3.1.1 Introduction
3.1.2 Suitability of the code
3.1.3 Usage of the code
3.1.4 Development process and verification
3.1.5 Handling of input data, computational results and scripts
3.1.6 Rationales for using the code in SR-Site
Abaqus
3.2.1 Introduction
3.2.2 Suitability of the code
3.2.3 Usage of the code
3.2.4 Development process and validation
3.2.5 Handling of input data, computational results and scripts
3.2.6 Rationales for using the code in SR-Can
Analytical model for quantification of buffer erosion and canister corrosion
3.3.1 Introduction
3.3.2 Suitability of the code
3.3.3 Usage of the code
3.3.4 Development process and verification
3.3.5 Handling of input data, computational results and scripts
3.3.6 Rationales for using the code in the assessment
CODE_BRIGHT
3.4.1 Introduction
3.4.2 Suitability of the code
3.4.3 Usage of the code
3.4.4 Development process and verification
3.4.5 Handling of input data, computational results and scripts
3.4.6 Rationales for using the code in the assessment
ConnectFlow
3.5.1 Introduction
3.5.2 Suitability of the code
3.5.3 Usage of the code
3.5.4 Development process and verification
3.5.5 Handling of input data, computational results and scripts
3.5.6 Rationales for using the code in SR-Site

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3.2

3.3

3.4

3.5

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3.6

DarcyTools
3.6.1 Introduction
3.6.2 Suitability of the code
3.6.3 Usage of the code
3.6.4 Development process and verification
3.6.5 Handling of input data, computational results and scripts
3.6.6 Rationales for using the code in SR-Can
3.7
Ecolego3.7.1 Introduction
3.7.2 Suitability of the code
3.7.3 Usage of the code
3.7.4 Development process and verification
3.7.5 Handling of input data, computational results and scripts
3.7.6 Rationales for using Ecolego in SR-Site
3.8
ERICA Tool
3.8.1
Introduction
3.8.2 Suitability of the code
3.8.3 Usage of the code
2.8.4 Development process and verification
3.8.5 Handling of input data, computational results and scripts
3.8.6 Rationales for using the code in SR-Site
3.9
FARF31
3.9.1 Introduction
3.9.2 Suitability of the code
3.9.3 Usage of the code
3.9.4 Development process and verification
3.9.5 Handling of input data, computational results and scripts
3.9.6 Rationales for using the code in SR-Site
3.10 MARFA
3.10.1 Introduction
3.10.2 Suitability of the code
3.10.3 Usage of the code
3.10.4 Development process and verification
3.10.5 Handling of input data, computational results and scripts
3.10.6 Rationales for using the code in SR-Site
3.11 MATLAB
3.11.1 Introduction
3.11.2 Suitability of the code
3.11.3 Usage of the code
3.11.4 Development process and verification
3.11.5 Handling of input data, computational results and scripts
3.11.6 Rationales for using the code in SR-Site
3.12 MATLAB – COMP23
3.12.1 Introduction
3.12.2 Suitability of the code
3.12.3 Usage of the code
3.12.4 Development process and verification
3.12.5 Handling of input data, computational results and scripts
3.12.6 Rationales for using the code in SR-Site
3.13 MATLAB – FPI
3.13.1 Introduction
3.13.2 Suitability of the code
3.13.3 Usage of the code
3.13.4 Development process and verification
3.13.5 Handling of input data, computational results and scripts
3.13.6 Rationales for using the code in SR-Site
3.14 MATLAB – Pandora
3.14.1 Introduction
3.14.2 Suitability of the code
3.14.3 Usage of the code

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3.14.4 Development process and verification
3.14.5 Handling of input data, computational results and scripts
3.14.6 Rationales for using the code in SR-Site
3.15 MIKE SHE
3.15.1 Introduction
3.15.2 Suitability of the code
3.15.3 Usage of the code
3.15.4 Development process and verification
3.15.5 Handling of input data, computational results and scripts
3.15.6 Rationales for using the code in SR-Site
3.16 Numerical GIA model
3.16.1 Introduction
3.16.2 Suitability of the code
3.16.3 Usage of the code
3.16.4 Development process and verification
3.16.5 Handling of input data, computational results and scripts
3.16.6 Rationales for using the code in SR-Site
3.17 Numerical permafrost model
3.17.1 Introduction
3.17.2 Suitability of the code
3.17.3 Usage of the code
3.17.4 Development process and verification
3.17.5 Handling of input data, computational results and scripts
3.17.6 Rationales for using the code in SR-Site
3.18 PHAST
3.18.1 Introduction
3.18.2 Suitability of the code
3.18.3 Usage of the code
3.18.4 Development process and verification
3.18.5 Handling of input data, computational results and scripts
3.18.6 Rationales for using the code in SR-Site
3.19 PHREEQC
3.19.1 Introduction
3.19.2 Suitability of the code
3.19.3 Usage of the code
3.19.4 Development process and verification
3.19.5 Handling of input data, computational results and scripts
3.19.6 Rationales for using the code in SR-Site
3.20 Solubility model (Simple Functions)3.20.1 Introduction
3.20.2 Suitability of the code
3.20.3 Usage of the code
3.20.4 Development process and verification
3.20.5 Handling of input data, computational results and scripts
3.20.6 Rationales for using the code in SR-Site
3.21 TOUGHREACT
3.21.1 Introduction
3.21.2 Suitability of the code
3.21.3 Usage of the code
3.21.4 Development process and verification
3.21.5 Handling of input data, computational results and scripts
3.21.6 Rationales for using the code in SR-Site
3.22 UMISM
3.22.1 Introduction
3.22.2 Suitability of the code
3.22.3 Usage of the code
3.22.4 Development process and verification
3.22.5 Handling of input data, computational results and scripts
3.22.6 Rationales for using the code in SR-Site

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References

TR-10-517

1

Introduction

In the current chapter, the SR-Site safety assessment and the current document is initially introduced,
followed by a brief presentation of other documents within the SR-Site series of reports and an outline
for current report.

1.1

Objectives and scope of the SR-Site assessment

The role of the safety report SR-Site in SKB’s licence application is to demonstrate that the repository
SKB intends to build at the Forsmark site is safe in the long term. If safety is demonstrated, the SR-Sitereport can serve its intended purpose in the licence application.
The main purposes of the safety assessment project SR-Site are:•

To assess the safety, as defined in applicable Swedish regulations, of the proposed KBS-3V
repository at Forsmark;•To provide feedback to design development, to SKB’s R&D programme, to detailed site investigations and to future safety assessment projects.

The SR-Site report supports the licence application. The objective of the SR-Site report is to investigate
whether the KBS-3V method has the potential of fulfilling regulatory safety criteria at the Forsmark
site, with the host rock conditions emerging from the surface based site investigations. The assessment
is based on a reference design of the engineered parts of the repository, including reference methods
to achieve the specified design, taking into account methods of controlling that the specifications of
the reference design have been achieved. Another important purpose is to give feedback for further
developments to that specification, in particular by giving input to the development of updated designpremises.

1.2

Objectives and scope of the current report

The purpose of this report is to give an overview of the modelling tasks and computer codes used in
the safety assessment SR-Site and the quality assurance procedures and documents relating to the codes.
More specifically, the report contains.
•

Assessment model flow charts (AMF’s) that describe the modelling tasks in SR-Site and how thedifferent modelling tasks are associated.

•

The principles behind the QA measures regarding the codes and the calculations.

•

A brief presentation of each code used for modelling tasks identified in the AMF, with references
to other documents that describe the mathematical model (the equations solved), verification measures, QA routines for input data handling and storage of results, QA routines for code development,
version control, etc.

The aim is, however, not to give rationales for including a certain process in the modelling or to support
the selected input data. This is done in the three Process reports and the Data report, respectively.

1.3

Key reports in the assessment

Several of the steps carried out in the SR-Site safety assessment result in specific reports that areof central importance for the conclusions and analyses in the SR-Site Main report. These specificreports, referred to as main references, are 16 in number. Besides the main references there are about
80 additional references, treating more narrow issues, supporting the main report and/or one or moreof the main references. The SR-Site report hierarchy is illustrated in Figure 1-1.

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SR-Site
Main report

Main references
FEP report

ClimatereportFuel andcanisterprocess report

Six Production
reports
Biosphere
synthesis
reportModelsummaryreportDatareportBuffer, backfill
and closure
process report
FHA
reportGeosphere
process
reportRadionuclidetransport
reportAdditional references

Figure 1-1. The hierarchy of the Main report, main and additional references to the SR-Site project. The
six production reports include for example the Spent fuel report and the Underground openings construction
report (reproduced from Figure 2-3 of the SR-Site Main report).

In addition to the dedicated SR-Site reports, references are made to a variety of documents, articles
and publications, either from SKB or from other organisations, or as part of the open literature.
In this report, the Main report and main references of the SR-Site project are referenced by using
abbreviations. The abbreviations of the discussed reports, as well as their full references, are given
in Table 1-1.

1.4

Outline of the report

In the current chapter, the purpose of the report and of the SR-Site project in general is presented.
In Chapter 2, the basic ideas for this report and requirements on codes used for assessment calculations are presented. The different modelling tasks and flow of information can be identified in theAssessment Model Flow charts (AMF’s).
While some of the modelling tasks identified in the AMF’s are simple scoping calculations otherrequire complex computer codes. As it would be impractical to include all kinds of modelling tasks
performed within the framework of the safety assessment and to apply the same QA requirementson all computer codes used for modelling, the codes are subdivided into categories on which therequirements are formulated differently. The methods used for distinguishing between the different
categories of codes are presented in Chapter 2. The QA requirements on codes used for the calculation tasks are also described in Chapter 2 together with a template used when describing each code.
Finally, in Chapter 3, the different codes used for the assessment calculations are presented following the outline presented in Chapter 2. Modelling data used in the safety assessment are archived at
SKB, see Table 1-2.

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Table 1-1. Abbreviations and full references of SKB reports, used in SR-Site.
Abbreviation used whenreferenced in SR-Site

Full reference, as given in the reference list

Main report

Main report, SKB 2011. Long-term safety for the final repository for spent nuclear fuel at
Forsmark. Main report of the SR-Site project.TR-11-01, Svensk Kärnbränslehantering AB.

FEP report

FEP report, SKB 2010. FEP report for the safety assessment SR-Site. SKB TR-10-45,
Svensk Kärnbränslehantering AB.

Spent fuel report

Spent fuel report, SKB 2010. Spent nuclear fuel for disposal in the KBS-3 repository.
SKB TR-10-13, Svensk Kärnbränslehantering AB.

Canister production
reportCanister production report, SKB 2010. Design, production and initial state of the canister.
SKB TR-10-14, Svensk Kärnbränslehantering AB.

Buffer production report

Buffer production report, SKB 2010. Design, production and initial state of the buffer.
SKB TR-10-15, Svensk Kärnbränslehantering AB.

Backfill production report Backfill production report, SKB 2010. Design, production and initial state of the backfill andplug in deposition tunnels. SKB TR-10-16, Svensk Kärnbränslehantering AB.
Closure production report Closure production report, SKB 2010. Design, production and initial state of the closure.
SKB TR-10-17, Svensk Kärnbränslehantering AB.
Data report

Data report, SKB 2010. Data report for the safety assessment SR-Site. SKB TR-10-52,
Svensk Kärnbränslehantering AB.

Underground openings
construction report

Underground openings construction report, SKB 2010. Design, construction and initialstate of the underground openings. SKB TR-10-18, Svensk Kärnbränslehantering AB.

Fuel and canister
process report

Fuel and canister process report, SKB 2010. Fuel and canister process report for thesafety assessment SR-Site. SKB TR-10-46, Svensk Kärnbränslehantering AB.

Buffer, backfill andclosure process report

Buffer, backfill and closure process report, SKB 2010. Buffer, backfill and closure processreport for the safety assessment SR-Site. SKB TR-10-47, Svensk Kärnbränslehantering AB.

Geosphere processreportGeosphere process report, SKB 2010. Geosphere process report for the safetyassessment SR-Site. SKB TR-10-48, Svensk Kärnbränslehantering AB.

Climate report

Climate report, SKB 2010. Climate and climate related issues for the safety assessment
SR-Site. SKB TR-10-49, Svensk Kärnbränslehantering AB.

Radionuclidetransport report

Radionuclide transport report, SKB 2010. Radionuclide transport report for the safetyassessment SR-Site. SKB TR-10-50, Svensk Kärnbränslehantering AB.

Model summary report

Model summary report, SKB 2010. Model summary report for the safety assessment
SR-Site. SKB TR-10-51, Svensk Kärnbränslehantering AB.

FHA report

FHA report, SKB 2010. Handling of future human actions in the safety assessment SR-Site.
SKB TR-10-53, Svensk Kärnbränslehantering AB.

Biosphere synthesis
reportBiosphere synthesis report, SKB 2010. Biosphere analyses for the safety assessment
SR-Site – synthesis and summary of results. SKB TR-10-09, Svensk Kärnbränsle­hantering AB.

Table 1-2. List of SR-Site modelling data archived at SKB.
SKBdoc, id, version

Title

Issuer, year

1256019 ver 1.0
1258988 ver 1.0
1260295 ver 1.0
1260297 ver 1.0

Hydrogeological model data and results – Forsmark
Canister and buffer shear – App 10 I TR-10-34
Results from radionuclide transport calculations with COMP23 and FARF31
Scripts and input data used for the radionuclide transport calculations with
COMP23 and FARF31
Hydrogeochemistry: SR-Site and comparative analysis
Data used in SR-Site Biosphere
Scripts and input data used in 3DEC modelling reported in TR-10-23
Scripts and input data used in 3DEC modelling reported in TR-08-11
Matlab scripts used in EFPC Development and Benchmarks (FPI chapter in MSR)
Matlab scripts used in EFPC/FPI modelling in SR-SITE (FPI chapter in MSR)
General Matlab codes used in EFPC/FPI modelling (FPI chapter in MSR)
CODE_BRIGHT Input files to the models used in SR-Site
Scripts and data used for Abaqus modelling of buffer in SR-Site
Scripts and data used for Analytical erosion corrosion calculations
Data used in the SR-Site Climate program
Simple Functions calculations and data used in SR-Site
Scripts and data used for TOUGHREACT modelling in SR-Site
Oxygen ingress at Forsmark
PHAST data used for water saturated bentonite in SR-Site (TR-10-59)
Radionuclide transport calculations with MARFASKB, 2010
SKB, 2010
SKB, 2010
SKB, 2010

1262945 ver 1.0
1263189 ver 1.0
1264505 ver 1.0
1264508 ver 1.0
1264530 ver 1.0
1264531 ver 1.0
1264532 ver 1.0
1265606 ver 1.0
1265608 ver 1.0
1265612 ver 1.0
1265613 ver 1.0
1265616 ver 1.0
1265618 ver 1.0
1265689 ver 1.0
1265807 ver 1.0
1266150 ver 1.0

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SKB, 2010
SKB, 2010
SKB, 2010
SKB, 2010
SKB, 2010
SKB, 2010
SKB, 2010
SKB, 2010
SKB, 2010
SKB, 2010
SKB, 2010
SKB, 2010
SKB, 2010
SKB, 2010
SKB, 2010
SKB, 201011

2

Principles for quality assurance ofcomputer codes

In this chapter, principles relating to quality assurance of computer codes used in the safety assessment
SR-Site are described. To provide an overview of the modelling activities and the flow of information
between them, assessment model flow charts, AMF’s, are used. The majority of the modelling activities
identified in the AMF’s are associated with different computer codes. For the different codes, QA
requirements are identified and a template for documenting how these apply for the different codesis presented.

2.1

Assessment model flow chart

To illustrate how major modelling tasks in the assessment are related, two Assessment Model Flow
charts (AMF’s), have been constructed for SR-Site assessment. The first illustrates modelling of the
excavation and operation phase and the initial temperate period, Figure 2-1, while the second illustrates
modelling of permafrost and glacial conditions, Figure 2-2. In the AMF’s, modelling activities, input
and output to and from the activities and assessments based on model output are identified for different
parts of the repository system.
In addition to the models presented in the flow chart, minor calculations are performed, for instancewhen post processing results or when preparing input data. These are not included in the present
document as described in subsequent sections.

2.2

Computer codes and AMF activities

While the AMF’s show the different modelling activities performed within the framework of the safetyassessment, Table 2-1 and Table 2-2 show computer codes used for each modelling task. In the tables,
the section in the present report where the code is reported is listed together with the reference to thereport in which the results of the calculations are presented.

2.3

Types of codes used in the assessment

In the AMF’s, a large number of modelling activities can be identified. Table 2-1 and Table 2-2 showthese together with the different codes that are used for the modelling activities. The complexity of thecomputer codes ranges from simple routines written in scripts languages in commercially available
codes like MATLAB or Microsoft Excel to large programs (thousands of lines) written in programming
languages like C++ and Fortran. Also the origin of the codes differs substantially. While some arecommercial, have a large world-wide user base and can be regarded as well tested, others are written
exclusively for the safety assessment at hand.
For codes developed within the framework of the SKB safety assessments, the source codes are
generally available for review as opposed to commercially available codes where the quality assurance
procedures of the developer have to be accepted. A differentiated approach to quality assurance, withadaptations to the types of codes used in the assessment, is thus required.

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The following categories of computer codes have been identified:
1. Commercial system software such as operating systems, compilers and data base software.
Although necessary for the assessment, these codes are not regarded as assessment codes andare hence not included in the AMF or in the model documentation.
2. Software used to solve problems that can be verified by simple hand calculations. This category
also includes codes used for unit conversion and pre- and post-processing of data. This category
is not included in this document.
3. Wide-spread commercial or open source codes. These have a large user base and are therefore
considered to be sufficiently well tested. Therefore, the need for verification tests within SR-Site islimited. These codes are not written exclusively for the safety assessment and the user of the code
may in many cases be an expert on using the code in general. The documentation for these codesis generally extensive but may not be written with any particular application in mind. Source codes
for the commercial codes are generally not available for review and the development process has
been carried out independent of the SR-Site project. Using these codes for assessment calculations
implies that the QA procedures used by the developer of the codes are accepted.
4a. Modified commercial codes. Some commercially available codes allow the user to add functionality to the original code through standardised methods with the extension working as an integrated
part of the original code. Since functionality is added, the need for verification studies is larger thanfor codes in the previous category. Verification studies within SR-Site are however only required
for the added functionality and not for the original code. Using these codes for assessment calculations implies that the QA procedures used by the developer of the codes are accepted, but alsothat good developing practices are followed for the part of the code developed within the safetyassessment.
4b. Calculations performed with codes developed within the safety assessment, frequently written inlanguages like C++ and Fortran. These codes are in general written with the safety assessment
application in mind and have a considerably smaller user base than codes in category 3. The needfor verification is thus larger for these codes.
There may be cases where it is not evident whether a code should be in category 4a or in category 4b.
Codes developed within the project may for instance contain routines from mathematical libraries (likeODE solvers etc) which are well tested and have a large user base. However, the basic requirement(showing QA compliance for the parts that is not part of the original code) is the same for 4a and 4b.
Based on these categories, the quality assurance procedures for each type of code are presented in
the following section.

2.4

Requirements on assessment codes

Four basic requirements regarding quality assurance of codes and calculation results apply:
1. It must be demonstrated that the code is suitable for its purpose. This is required for all categories
defined above.
2. It must be demonstrated that the code has been properly used. This is required for all categories
defined above.
3. It must be demonstrated that the code development process has followed appropriate procedures
and that the code produces accurate results. This requirement applies to codes in category 4 sincethese have been developed by the implementer. For codes in categories 1 to 3, the procedures ofthe developer are accepted.
4. It must be described how data are transferred between the different computational tasks. Notethat this does not include a description on how data are handled internally by the model (coveredin point 1 and 2 above and in documents where the calculations are presented), instead this section
addresses data transfer between modelling activities. Due to the large number of modelling activities,
it is possible that data is passed between activities in many different ways.

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The requirements are further described below and a template to be used when writing the code presentation for the model summary report is given in Section 2.5. Of the six headings in the template,four relate directly to the basic requirements stated above.

2.5

Template used for reporting the codes in Chapter 3

2.5.1 Introduction
The code is briefly introduced and the categorisation according to the definition in Section 2.4 is given.
This section should contain the following:•

A brief description of the problem solved by the code in the SR-Site assessment.

•

The usage of the code in previous performance assessments (at SKB or elsewhere) and, if relevant,which previously used code it supersedes and the reason for this.

•

The version of the code and the platform used in the assessment calculations.

•

The category chosen for the code, based on the definition in Section 2.3, and a description of how
the code has been developed.

This part may be written either by the SR-Site team or by subcontractors using the code.

2.5.2 Suitability of the code
It needs to be shown that the code is suitable for solving the problem at hand. One indication of suitability included in this description concerns the used input parameter ranges. The parameter ranges
should be within those for which the computer code gives acceptable results. This section should
contain the following information:•

A description (or references to supporting documents) of mathematical models (the equations tobe solved) and a description of the methods by which the solution is obtained.

This part may be written either by the SR-Site team or by subcontractors using the code.

2.5.3 Usage of the code
It needs to be shown that sufficient information on the usage of the code is available. This section
should contain the following:•

A description of how the code is documented. Clearly, the format of the documentation may differ
considerably between different codes and is hence not specified in this template. In some cases,
for instance spreadsheet codes in Microsoft Excel, the documentation may be included in the
spreadsheet/code itself and no additional documentation is required. For commercial codes, theexisting documentation is in most cases sufficient.

This part may be written either by the SR-Site team or by subcontractors using the code.

2.5.4 Development process and verification
For codes that have been developed for the SR-Site project (category 4) it needs to be shown that thedevelopment process has been carried out in an appropriate manner. This section should contain thefollowing:•

The measures that have been taken to ensure that the code produces the correct solution to themathematical problem. This can e.g. be achieved by comparison to solutions obtained with othercodes or to analytic solutions for special cases, if available.

•

A description of how consistency of results between different versions of the code is demonstrated.
This may be done using a test batch with examples that proves the functionality of the code.

This part may be written either by the SR-Site team or by subcontractors using the code.

TR-10-51

15

2.5.5 Handling of input data, computational results and scripts
In this section it is described how data are passed between the model at hand and other models in the
AMF. In this section it is also described how results and scripts used in the calculations are archived.
It is also recommended to describe how the working process is controlled, for example if the version
management system Subversion SVN /Küng and Onken 2009/ is used to keep track of changes. Thispart may be written either by the SR-Site team or by subcontractors using the code.
2.5.6 Rationales for using the code in the assessment
Under this heading, the formal decision to use the code in the assessment is provided together witha brief motivation (this text is written by the SR-Site team).

16

TR-10-51

Figure 2-1. The assessment model flow chart for the excavation/operation period and the initial temperate period
after closure. In the AMF, modelling activities covered in the present report can be seen as yellow rounded rectangles.
Input data and results (input data to other models) presented in the Data report (DR) appears as blue rectangles(with reference to the section in the Data report). Data in other reports are presented as rectangles.

TR-10-51

17

Solubility data
(DR 3.4)

Fission Gas
ReleaseSpent fuel report Inventory

Backfill andBuffer production
reports

GW

Solubilities(TR-10-50)

GW

Fuel conversion(DR 3.3)

IRF and CRF(DR 3.2)

Inventory for RN
transport(DR 3.1)

Selection ofradionuclides(TR-10-50)

Remaining oxygen

Consumption of initiallyentrapped oxygen (buffer
and backf.) (R-06-106)

Cation andsulphideconcentration

Migration data of buffer
and backfill(DR 5.3)

Initial copper coverage(DR 4.1)

Canister production
reportExpansion of
buffer into tunnel(TR-10-11)

GW

Early
chemicalalteration
effects

Geometries

GW

Failure due to mechanical load

Migration data of buffer
and backfill(DR 5.3)

Density and porosity of
buffer and backfill(DR 5.1)

Flow related migration
parameters(DR 6.7)

Spalling and EDZ(DR 6.5)

FPI calculations(TR-10-21)

GEO-DFN(DR 6.3)

Bentonite
colloids

Uneven bentonite
swelling pressure(DR 4.1)

Earthquakesummary report(TR-08-11)

Resistance toshear movement(DR 4.1)Rockmechanics(DR 6.4)

Near fieldreleaseColloid
concentration

Buffer initialstate atpermafrost/
glacialRadionuclide
Transport, near-field(TR-10-50)

GW

Bentonite
colloids

Canister production
reportNon-flow related
migration properties(DR 6.8)

Grout degradation(TR-10-25)

SDM-Site(TR-08-05)

Buffer and PW chemicalcomposition

Buffer chemistry
and migration in buffer(TR-10-59)

Density
distribution

Chemical alterations
during saturation(TR-10-59)

Near-field rocktemperature

Underground openings
construction report
including layout

Peak buffertemperature
Backfill production report
Buffer production report
Closure production report

Canisterproduction report

Underground openings,
canister, Backfill andBuffer production reports
Time for large
defect(DR 4.2)

Canister
failureFlow related migration
parameters(DR 6.7)

Loss of mass
(TR-10-11)

Mechanicalerosion

Piping/erosion(TR-10-11)

Long-term chemical alterations effects

Earlychemicalalteration
effects

GW flow and salinity
during saturation(R-09-19)

Acceptablebuffer mass loss
for maintaining
diffusive
conditions

Corrosion calculations(incl. buffer erosion)(TR-10-66)
Failure due to corrosion

Swelling(TR-10-11)

Saturation times
and implication forrepository function

THM saturation(TR-10-11)

Buffer and rocktemperature(TR-10-23)

Bedrock thermal data
DR 6.2

Flow in fracture
FPC/EFPCTHM Data report(TR-10-44)

Decay heat

Flow related migration
parameters(DR 6.7)

Hydraulic properties(DR 6.6)

Spalling and EDZ(DR 6.5)

Backfill and Buffer
production reports

Strategy for thermal
dimensioning(R-09-04)

Radionuclidetransport, far-field(TR-10-50)

Flow related
migration properties(DR 6.7)

Repository scalehydro model

Site scalehydro model

Far-field release

LegendLDF(DR 7.2)

Activity
concentrations

Biosphere landscapemodel(TR-10-06)

Landscapedevelopment(TR-10-05)

Climatecase

Ecosystem reports(TR-10-01,TR-10-02 and TR-10-03)

National andinternationalguidelines

Groundwater composition
over glacial cycle(TR-10-58)

Element reports(TR-10-07)

Discharge
pointsSDM-Site(TR-08-05)

Calculation

Input to/output fromother partsof the AMF

SR-Site report

Hydraulic properties ofengineered barriers(DR 5.1, 5.2)
Spalling and
EDZ(DR 6.5)

Shore-line
displacement(DR 7.1)

Spalling and EDZ(DR 6.5)

Earlymechanicalalterations/effects

Regional scale
Hydro model

Hydraulicproperties(DR 6.6)

Hydro temperatedomain(R-09-20, R-09-22)

SDM-Site(TR-08-05)

Fracturing(TR-10-23)

Reactivation(TR-10-23)

Near-field stresses(TR-10-23)

Doses(TR-11-01)

Radiological effects
on non-human biota(TR-10-08)

Biosphere synthesis
report(TR-10-09)

GW

Groundwatercomposition(DR 6.1)

Sulphideconcentration(TR-10-39)

SDM-Site(TR-08-05)

Assessment/
assumption

Input to/output fromother AMF

External
reportFigure 2-2. The assessment model flow chart for permafrost and glacial conditions. In the AMF, modelling
activities covered in the present report can be seen as yellow rounded rectangles. Input data and results (input
data to other models) presented in the Data report (DR) appears as blue rectangles (with reference to thesection in the Data report). Data in other reports are presented as rectangles.

18

TR-10-51

Solubility data
(DR 3.4)

Fission Gas
ReleaseSpent fuel report Inventory

Canister production
reportAcceptablebuffer mass loss
for maintaining
diffusive
conditions

Buffer initial stateat permafrost/
glacialCanister production
reportFlow related migration
parameters(DR 6.7)

Hydraulic properties(DR 6.6)

Spalling and EDZ(DR 6.5)

Bedrock thermal data
DR 6.2SDM-Site(TR-08-05)

Ice sheetmodelling(TR-09-19)

GW

Climatecase

Solubilities(TR-10-50)

GW

Fuel conversion(DR 3.3)

IRF and CRF(DR 3.2)

Inventory for RN
transport(DR 3.1)

Selection ofradionuclides(TR-10-50)

Bentonite
colloids

Isostaticload

Geometries

GW

Migration data of buffer
and backfill(DR 5.3)

Density and porosity of
buffer and backfill(DR 5.1)

Flow related migration
parameters(DR 6.7)

Spalling and EDZ(DR 6.5)

Failure due to mechanical load

FPI calculations(TR-10-21)

GW

Radionuclidetransport,near-field(TR-10-50)

Spalling and EDZ(DR 6.5)

Layout D2

Hydraulic properties(DR 6.6)

Shore-line
displacement(DR 7.1)

Near-fieldreleaseColloid
concentration

Bentonite
colloids

Hydraulic properties ofengineered barriers(DR 5.1, 5.2)

Non-flow related
migration properties(DR 6.8)

Uneven bentonite
swelling pressure(DR 4.1)

Canisterproduction report

Earthquakesummary report(TR-08-11)

Resistance toshear movement(DR 4.1)
GEO-DFN(DR 6.3)

Stress evolution
during glacial
cycle (TR-09-15)

Effect of stressevolution on canister

Reactivation (postglacial faulting)(TR-10-23)

Fracturing(TR-10-23)

Near-field stresses(geosphere)(TR-10-23)

SDM-Site(TR-08-05)

Modelling of stressevolution during
glaciation

Rock mechanics(DR 6.4)

Ice thickness(DR 7.1)

GlacialCanisterproduction report

Buffer and backfill
freezing cases(TR-10-40)

Permafrost
depth(DR 7.1)

Periglacial

Underground openings,
Canister, Backfill andBuffer production reports

Time for large
defect (DR 4.2)

Canister
failureFailure due to corrosion

Failure due isostatic load

Isostatic failure(DR 4.1)

Isostaticload

Long-termchemical alterations
effects

Concentrationof cations andcorrodants
Corrosion calculations(incl. buffer erosion)(TR-10-66)

Buffer and PW chemicalcomposition

THC behaviour(TR-10-59)

Buffer initialstate atpermafrost/
glacialClimate reference
evolution(TR-09-19)

GW

Initial copper
coverage (DR 4.1)

Migration data ofbuffer and backfill(DR 5.3)

Flow in fracture
FPC/EFPCPermafrost modelling(TR-09-17)

GIA modelling; (Global
Isostatic Adjustment)(TR-06-23)

SDM-Site(TR-08-05)

Regional scale
Hydro model

Radionuclide
Transport, far-field(TR-10-50)

Flow related
migration properties(DR 6.7)

Hydro, ice location II(R-09-20)

Repository scalehydro model

LDF(DR 7.2)

External
reportDoses(TR-11-01)

Radiological effects
on non-human biota(TR-10-08)

Biosphere synthesis
report(TR-10-09)

GW

Groundwatercomposition(DR 6.1)

Oxygen penetration
during glacial period(TR-10-57)

Assessment/
assumption

Input to/output fromother AMF

Activity
concentrations

Biosphere landscapemodel (TR-10-06)

Landscapedevelopment(TR-10-05)

Climatecase

Ecosystem reports(TR-10-01,TR-10-02 and TR-10-03)

National andinternationalguidelines

Groundwater composition
over glacial cycle(TR-10-58)

Far-field release

Element reports(TR-10-07)

Discharge
pointsSite scalehydro model

Hydro glacial domain(R-09-21, R-09-22)

Calculation

Input to/output fromother partsof the AMF

SR-Site report

LegendTR-10-51

Table 2-1. Links between modelling activities in the AMF for excavation/operation and temperate periods (Figure 2-1) and thecomputer codes used. The modelling activities in the left column correspond to yellow objects in Figure 2-1.
Modelling activity in AMF

Code used

Presented in
sectionModelling report
Reference

In AMF

Buffer and rock temperature

3DEC

3.1

Hökmark et al. 2010

TR-10-23

THM saturation (buffer and backfill)

Abaqus3.2Åkesson et al. 2010

TR-10-11

Near-field stresses (geosphere)

3DEC

3.1

Hökmark et al. 2010

TR-10-23

Reactivation

3DEC

3.1

Hökmark et al. 2010

TR-10-23

Fracturing (spalling)

3DEC

3.1

Hökmark et al. 2010

TR-10-23

FPI calculations: calculation of the occurrence of Full
Perimeter Intersecting fractures in deposition tunnels

FPI script in MATLAB

3.11, 3.13

Munier 2010

TR-10-21

Chemical alterations during saturation (geosphere)

PHAST

3.18

Sena et al. 2010

TR-10-59

Grout degradation

CODE_BRIGHT

3.4

Grandia et al. 2010

TR-10-25

Groundwater flow and salinity during saturation

DarcyTools

3.6

Svensson and Follin 2010

R-09-19

Swelling

Abaqus3.2Åkesson et al. 2010

TR-10-11

CODE_BRIGHT

3.4

Åkesson et al. 2010

TR-10-11

Buffer chemistry and migration in buffer

PHAST, TOUGHREACT

3.18, 3.21

Sena et al. 2010

TR-10-59

Consumption of initially entrapped oxygen (buffer
and backfill)

PHAST

3.18

Grandia et al. 2006

TR-06-106

Corrosion calculations (including buffer erosion
calculations)

Analytical expressions (Excel)

3.3

SKB 2010

TR-10-66

Hydro temperate domain

ConnectFlow

3.5

Joyce et al. 2010
Selroos and Follin 2010

R-09-20
R-09-22

Groundwater composition over glacial cycle

PHREEQC

3.19

Salas et al. 2010

TR-10-58

Solubilities

Simple Functions

3.20

Radionuclide transport report

TR-10-50

Radionuclide transport, near-field

COMP23

3.12

Radionuclide transport report

TR-10-50

Radionuclide transport, far-field

FARF31

3.9

Radionuclide transport report

TR-10-50

MARFA

3.10

Radionuclide transport report

TR-10-50

Ecolego

3.7

Avila et al. 2010

TR-10-06

MIKE_SHE

3.15

Avila et al. 2010

TR-10-06

Pandora3.14

Avila et al. 2010

TR-10-06

Erica

3.8

Avila et al. 2010

TR-10-06

Biosphere landscape model

19

20

Table 2-2. Links between modelling activities in the AMF for permafrost and glacial periods (Figure 2-2) and the computer codesused. The modelling activities in the left column correspond to yellow objects in Figure 2-2.
Modelling activity in AMF

Code

Code presented
in section

Modelling report
Reference

Permafrost modelling

Numerical permafrost model

3.17

Climate report, details in
Hartikainen et al. 2010

TR-09-17

Ice sheet modelling

UMISM

3.22

Climate report

TR-09-19

GIA modelling (Global Isostatic Adjustment)

Numerical GIA model

3.16

Climate report, details in SKB 2006a

TR-06-23

FPI calculations; calculation of the occurrence of Full
Perimeter Intersecting fractures in deposition tunnels

FPI script in MATLAB

3.11, 3.13

Munier 2010

TR-10-21

Near-field stresses (geosphere)

3DEC

3.1

Hökmark et al. 2010

TR-10-23

Reactivation

3DEC

3.1

Hökmark et al. 2010

TR-10-23

Fracturing

3DEC

3.1

Hökmark et al. 2010

TR-10-23

Groundwater composition over glacial cycle

PHREEQC

3.19

Salas et al. 2010

TR-10-58

Hydro, glacial domain

DarcyTools

3.6

Vidstrand et al. 2010
Selroos and Follin 2010

R-09-21R-09-22

Hydro, ice location II

DarcyTools

3.6

Joyce et al. 2010

R-09-20

Oxygen penetration during glacial period

PHREEQC, PHAST

3.19, 3.18

Sidborn et al. 2010

TR-10-57

THC behaviour

PHAST

3.18

Sena et al. 1020

TR-10-59

Corrosion calculations (including buffer erosion
calculations)

Analytical expressions (Excel)

3.3

SKB 2010

TR-10-66

Solubilities

Simple functions

3.20

Radionuclide transport report

TR-10-50

Radionuclide transport near-field

COMP23

3.12

Radionuclide transport report

TR-10-50

Radionuclide transport far-field

FARF31

3.9

Radionuclide transport report

TR-10-50

MARFA

3.10

Radionuclide transport report

TR-10-50

Ecolego

3.7

Avila et al. 2010

TR-10-06

MIKE_SHE

3.15

Avila et al. 2010

TR-10-06

Pandora3.14

Avila et al. 2010

TR-10-06

Erica

3.8

Avila et al. 2010

TR-10-06

Biosphere landscape model

In AMF

TR-10-51

3

Description of the codes

This chapter provides a description of the codes used in the SR-Site safety assessment based on themodels identified in the assessment model flowcharts. Each modelling activity and its associated code arepresented in Table 2-1 and Table 2-2. The text for each code follows the outline presented in Section 2.5.

3.1

3DEC

3.1.1 Introduction
3DEC simulates the mechanical and thermo-mechanical response of discontinuous media subjected
to either static or dynamic loading. 3DEC is a three-dimensional numerical program based on the
distinct element method for discontinuum modelling /Itasca 2003, 2007/. The program is based on
the extensively tested formulation used by the two-dimensional version UDEC /Itasca 2005/.
3DEC was originally developed for stability analyses of rock slopes. It has been used for studies
related to mining engineering and for studies related to deep disposal of nuclear wastes. Both static anddynamic analyses for deep underground openings have been performed, see for instance /Stephansson
et al. 1991, Sjöberg 1992, Senseny 1993/. 3DEC has been used by SKB in earlier studies regarding
thermo-mechanical effects on the bedrock around a deep repository /Hakami et al. 1998/. Much of therock mechanics analyses referred to in SR 97 were conducted using 3DEC. In SR-Can, 3DEC was used
for static analyses of mechanical effects on rock and rock fractures within and around the repository/Fälth and Hökmark 2007/, and for dynamic analyses of fracture shear displacements induced by postglacial fault movements /Fälth and Hökmark 2006/.
In SR-Site 3DEC is used for similar analyses as those carried out in SR-Can:•

Static analyses of mechanical effects on rock and rock fractures within and around the repository.
Effects caused by excavation of the repository openings, by pore pressures, by heat generation andglacial loads are considered. Effects of particular interest are creation of stress concentrations aroundthe repository openings and fracture displacements that may change the hydraulic conditions. Bothnear-field and large-scale models are analysed /Hökmark et al. 2010/. For these analyses, version 4.1
of 3DEC is used /Itasca 2007/.

•

Dynamic earthquake simulations are carried out in order to make estimates of the possible effects
that post-glacial seismic events in pre-existing deformation zones may have on nearby fractures interms of induced shear displacements /Fälth et al. 2010/. For these analyses, version 3.0 of 3DEC isused /Itasca 2003/.

The SR-Site 3DEC analyses are run on Windows-based PC-systems. Since 3DEC is a wide-spreadcommercial code which allows the user to add functionality by use of the built-in programming
language FISH, and since specifically developed FISH routines are integral parts of the SR-Siteapplication calculations, 3DEC is regarded as a category 4a code.

3.1.2 Suitability of the code
3DEC is specially designed for mechanical analysis of jointed rock masses. The discontinuous medium
is represented by an assemblage of discrete blocks and the discontinuities are treated as boundary
conditions between the blocks. Large displacements along discontinuities and large rotations of blocks
are allowed. The blocks may be either rigid or deformable. Deformable blocks are subdivided into amesh of finite difference elements, which respond according to either linear or non-linear stress-strain
laws /Itasca 2003/. The relative displacements along the discontinuities are also governed by linear or
non-linear force-displacement laws, both in the normal- and shear directions. 3DEC also has a thermal
logic implemented, which is specially oriented for solving design problems related to nuclear waste
disposal. The temperatures at all node locations are calculated for specified “snapshots” in time byuse of analytical point- and line source solutions. The temperatures (and temperature increments) are

TR-10-51

21

then used by the mechanical logic in 3DEC for the calculation of thermal stresses. The thermal logic isbased on linear thermal conduction and superposition of temperature contributions from different heatsources. The material is assumed to be thermally homogenous and isotropic with constant properties.
In the assessment work, the rock continuum, i.e. the intact rock between the discontinuities, ismodelled as a linear elastic material. For the mechanical response of the discontinuities (fractures),an elastic and ideal-plastic law is applied assuming linear behaviour in the elastic range combinedwith the Mohr-Coulomb failure criterion.
The embedded programming language FISH is used for a number of tasks:•

The coordinates for each heat source are imported into 3DEC using FISH.

•

It is used to reduce computer run time when analyzing thermo-mechanical static near-field models.
3DEC temperatures are calculated once for each set of models and then imported into different
model versions using a specifically developed FISH routine.

•

FISH is used for the development of a technique for defining circular-shaped fractures by assigning
specific fracture material properties to selected parts of the discontinuities. This functionality isused in both the static analyses and in the dynamic earthquake simulations.

•

In order to suppress irrelevant fracture shear movements in static thermo-mechanical models,a FISH routine is used to control fracture shear strength after each step-wise change of thermal
stresses. It is also used to set pore pressures in the fractures.

•

FISH is used to control boundary movements in the thermo-mechanical static near-field models.

In the earthquake simulations, FISH is used to control the initiation and propagation of fault rupture.
Parameter values used in the SR-Site applications, i.e. values of rock mass and intact rock elastic
parameters, values of fracture strength and fracture stiffness as well as values of rock thermal properties,
are well within ranges covered by verified examples of analyses found in the extensive 3DEC
literature, see e.g. /Last and Harper 1990, Kulatilake et al. 1992, Cappa et al. 2006/.

3.1.3 Usage of the code
The documentation of 3DEC /Itasca 2003, 2007/ is provided by Itasca Consulting Group Inc. The
documentation contains a complete description of the code and of the constitutive models that are
implemented. A specific part of the documentation contains a description of the FISH language.
Text files containing all model data (geometries, material data, initial- and boundary conditions,solution strategies) are used as input to the code. In the input files, specific results to be monitored andrecorded during the analysis can be specified. These results can be plotted or exported as text files.
The FISH scripts are also written as text files. The scripts are activated by data calls in the input files.
3DEC has a plotting tool, which can be used for control of the model (geometry, application ofboundary conditions etc) during model building. The plotting tool also have a wide range of possibilities for producing vector- and contour plots used during post processing of calculation results.

3.1.4 Development process and verification
The formulation and development of the distinct element method, which is the core in 3DEC, begun
in 1971 with the initial presentation /Cundall 1971/ and the development has been in progress sincethen. The 3DEC documentation includes a suite of systematic comparisons between 3DEC results
and corresponding analytical solutions. Models with different types of geometry, different types ofmaterial behaviour and different types of boundary conditions are included. At present time, the codeis subject for progressive development.
The specific FISH routines developed for use in the safety assessment calculations were rigorously
tested and verified in small test models before implementation into the assessment models. Information
regarding some specific FISH routines can be found in /Fälth et al. 2010/.

22

TR-10-51

3.1.5 Handling of input data, computational results and scripts
The results from the static models analysed by /Hökmark et al. 2010/ were documented and evaluatedwithin that study. They were used to make estimates of the potential for thermally induced spallingaround the repository openings and of transmissivity changes in fractures and fracture zones. The text
files containing all model input data and the corresponding FISH scripts are stored at Clay Technology’s
data server (administrativa dokument\Projekt\3DEC SR-Site\data) as well as at the record management
system at SKB (SKBdoc 1264505, see Table 1-2).
The results from the dynamic earthquake models analysed by /Fälth et al. 2010/ were documented
and evaluated within that study where they were used for the development of schematic deposition
rules. The text files containing all model input data and the corresponding FISH scripts are stored at
Clay Technology’s data server (administrativa dokument\Projekt\3DEC dynamik\data\Input files(TR-08-11)) as well as at the record management system at SKB (SKBdoc 1264508, see Table 1-2).

3.1.6 Rationales for using the code in SR-Site
The code 3DEC has been thoroughly tested within the framework of SR-Can and shown to be adequate
for the intended purpose. Models and scripts have been successively developed and backward traceability is thereby warranted. The SR-Site team still considers 3DEC being the code that best fulfil the
purpose of the modelling and has therefore chosen to continue using 3DEC as the main tool both forstatic analyses and dynamic earthquake analyses.

3.2

Abaqus

3.2.1 Introduction
Abaqus is a suite of powerful engineering simulation programs, based on the finite element method,that can solve problems ranging from relatively simple linear analyses to the most challenging nonlinear
simulations. Abaqus contains an extensive library of elements that can model virtually any geometry.
It has an equally extensive list of material models that can simulate the behaviour of most typicalengineering materials including metals, rubber, polymers, composites, reinforced concrete, crushable
and resilient foams, and geotechnical materials such as soils and rock. Designed as a general-purpose
simulation tool, Abaqus can be used to study more than just structural (stress/displacement) problems.
It can simulate problems in such diverse areas as heat transfer, mass diffusion, thermal managementof electrical components (coupled thermal-electrical analyses), acoustics, soil mechanics (coupledpore fluid-stress analyses), piezoelectric analysis, and fluid dynamics.
Abaqus offers a wide range of capabilities for simulation of linear and nonlinear applications. Problems
with multiple components are modelled by associating the geometry defining each component withthe appropriate material models and specifying component interactions. In a nonlinear analysis Abaqus
automatically chooses appropriate load increments and convergence tolerances and continually adjusts
them during the analysis to ensure that an accurate solution is obtained efficiently.
Interaction

Manufacturing processes, bolted assemblies, snap-fits, and impact events all involve interaction between
contacting bodies. Understanding the behaviour of components when they come into contact is criticalto designing better products. The Abaqus Unified FEA product suite provides comprehensive contact
modelling capabilities such as the ability to model interactions between deformable bodies, rigid bodies,and self-contact.
The general contact capability in Abaqus automatically detects contact between different bodies
with little need for user intervention. Solution accuracy is improved by eliminating the possibility of
missed contact definitions. This powerful capability dramatically reduces the time needed to define
contact for complex assemblies such as those found in automobiles, aircraft, consumer products,
and portable electronics.

TR-10-51

23

Abaqus/Standard

Abaqus/Standard is a general-purpose analysis product that can solve a wide range of linear andnonlinear problems involving the static, dynamic, thermal, and electrical response of components.
Abaqus/Standard solves a system of equations implicitly at each solution “increment.” In contrast,
Abaqus/Explicit marches a solution forward through time in small time increments without solving
a coupled system of equations at each increment (or even forming a global stiffness matrix).
Abaqus/Explicit

Abaqus/Explicit is a special-purpose analysis product that uses an explicit dynamic finite element
formulation. It is suitable for modelling brief, transient dynamic events, such as impact and blast
problems, and is also very efficient for highly nonlinear problems involving changing contact conditions, such as forming simulations.
Abaqus/CFD

Abaqus/CFD is a computational fluid dynamics analysis product. It can solve a broad class of
incompressible flow problems including laminar and turbulent flow, thermal convective flow, anddeforming mesh problems.
Abaqus/CAE

Abaqus/CAE (Complete Abaqus Environment) is an interactive, graphical environment for Abaqus. It
allows models to be created quickly and easily by producing or importing the geometry of the structure
to be analyzed and decomposing the geometry into meshable regions. Physical and material properties
can be assigned to the geometry, together with loads and boundary conditions. Abaqus/CAE contains
very powerful options to mesh the geometry and to verify the resulting analysis model. Once the model
is complete, Abaqus/CAE can submit, monitor, and control the analysis jobs. The Visualization module
can then be used to interpret the results.
Abaqus/Aqua

Abaqus/Aqua is a set of optional capabilities that can be added to Abaqus/Standard. It is intended forthe simulation of offshore structures, such as oil platforms. Some of the optional capabilities include
the effects of wave and wind loading and buoyancy.
Abaqus/Design

Abaqus/Design is a set of optional capabilities that can be added to Abaqus/Standard to perform design
sensitivity calculations.
Geometry translators

Abaqus provides the following translators for converting geometry from third-party CAD systems toparts and assemblies for Abaqus/CAE:•The CATIA V5 Associative Interface creates a link between CATIA V5 and Abaqus/CAE thatallows you to transfer model data and propagate design changes from CATIA V5 to Abaqus/CAE.

•The SolidWorks Associative Interface creates a link between SolidWorks and Abaqus/CAE thatallows you to transfer model data and propagate design changes from SolidWorks to Abaqus/CAE.

•The Pro/ENGINEER Associative Interface creates a link between Pro/ENGINEER and Abaqus/CAE
that allows you to transfer model data and propagate design changes between Pro/ENGINEER and
Abaqus/CAE.

•The Geometry Translator for CATIA V4 allows you to import the geometry of CATIA V4-format
parts and assemblies directly into Abaqus/CAE.

•The Geometry Translator for I-DEAS converts parts and assemblies in I-DEAS to geometry files
that can be imported by Abaqus/CAE.

•The Geometry Translator for Parasolid allows you to import the geometry of Parasolid-format
parts and assemblies directly into Abaqus/CAE.

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In addition, the NX Associative Interface creates a link between NX and Abaqus/CAE that allows
you to transfer model data and propagate design changes between NX and Abaqus/CAE. The NX
Associative Interface be purchased and downloaded from the Elysium web site.
Translator utilities

Abaqus provides the following translators for converting entities from third-party preprocessors to
input for Abaqus analyses or for converting output from Abaqus analyses to entities for third-party
postprocessors:
•
•
•
•
•
•
•

abaqus fromansys translates an ANSYS input file to an Abaqus input file.
abaqus fromnastran translates a Nastran bulk data file to an Abaqus input file.
abaqus frompamcrash translates a PAM-CRASH input file into an Abaqus input file.
abaqus fromradioss translates a RADIOSS input file into an Abaqus input file.
abaqus tonastran translates an Abaqus input file to Nastran bulk data file format.
abaqus toOutput2 translates an Abaqus output database file to theNastranOutput2 file format.
abaqus tozaero enables the exchange of aeroelastic data between Abaqus and ZAERO.

Abaqus is a widely spread commercial Finite element code developed and supported by Dassault
Systèmes that has been available on the market for more than 40 years.
In the SR-Site assessment, Abaqus has been used for a large range of applications, e.g. analyzing
coupled thermo-hydro-mechanical (THM) problems or when simulating the response of the canisterand buffer due to earthquake induced shear load. For the earthquake simulation, glacial load has
also been included. These modelling activities have been presented in the following supporting
documents to the assessment:•••

Buffer homogenization /Åkesson et al. 2010a/.
Canister sinking /Åkesson et al. 2010a/.
Modelling and analysis of canister and buffer for earthquake induced rock shear and glacial load
/Hernelind 2010/.

The buffer homogenisation modelling activities are part of the Canister Retrieval Test (CRT) within
the Task Force for Engineered Barrier Systems (TF-EBS). The test was, in this context, used to study
material models for unsaturated bentonite blocks and calculation techniques. Very similar results werereached with the Abaqus and the CODE_BRIGHT model, see Section 3.4 /Åkesson et al. 2010a/ wherea more detailed description of the modelling activity is given. Abaqus has been used for solving THM
problems since SR97 /Börgesson and Hernelind 1999/.
For modelling of canister sinking, Abaqus was used to simulate the vertical movement of a canister
emplaced in a deposition hole due to creep. The equations to be solved and the material models used
is presented in the modelling report /Åkesson et al. 2010a/, corresponding problems were solved using
Abaqus in SR-Can /Börgesson and Hernelind 2006a/. In SR-Can, Abaqus was used to simulate Rockshear through a deposition hole /Börgesson et al. 2003, Börgesson and Hernelind 2006b/. Abaqus isregarded to belong to category 3 and category 4a when user defined subroutines are used to extend
the functionality.
Different versions of Abaqus (e.g 6.6-PR3, 6.7-5 and 6.8-1) has been used, mainly due to whichlatest version is available when the analyses are performed.

3.2.2 Suitability of the code
Abaqus is used for a number of tasks in SR-Site, the equation solved are further described in eachmodelling report /Åkesson et al. 2010a, Hernelind 2010/. The code is especially well suited for large,
non-linear models including general interaction between different components involving several
different fields such as displacement, temperature and pore pressure.

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3.2.3 Usage of the code
Due to the large, world-wide user base there exists numerous user guides for the code, produced by
the developer of the code and also by independent companies. The code is commonly used for different kind of mechanical modelling and there are common to find consultants specialised in using
the code itself. Training classes are available at different levels both at universities and at privatecompanies besides Dassault Systèmes.
3.2.4 Development process and validation
No dedicated verification or validation tests of the Abaqus code have been performed within the
SR-Site project (the code has however been used to study material models in the Canister retrieval
test with good results). A description of the QA procedures of the manufacturer of the code is available
on their webpage as listed below.
The formal Quality Assurance Management System is the foundation of their efforts to deliver highquality products and services at an acceptable cost.
There are two principal reasons they impose strict quality assurance: customer satisfaction and productreputation. The approach to quality assurance meets the ISO 9001:2008 standard. The processes intheir Quality Management System are designed to meet the requirements set forth by the International
Organization for Standardization as defined within the ISO 9001:2008 Standard and also to facilitatecustomer compliance with US Nuclear Regulatory Commission’s quality assurance requirements forsoftware used for calculations associated with the design of nuclear power facilities in the USA.
Their Quality Management System is founded on a collection of well-documented processes thatincorporate multiple checks and balances. The development process, for example, ensures that development is performed as a collaborative effort with proposal, design, code, and test review performed
by a team representing developers, technical writers, the Quality Assurance group, management,
and customers. Similarly, the bug management process calls for each bug to be reviewed by the Bug
Manager, Quality Assurance Manager, and development group manager. Throughout the products’
lifecycles, documented plans, formal signoffs, and dashboard-like status tracking facilitate establishing,communicating, and achieving clearly defined quality objectives.
There is no question that these efforts are resource intensive. Equally, there is no question that they
are firmly committed to these processes, because the quality of their products and services is central
to the long-term health of their relationships with their customers.
When user defined subroutines are used these have been verified by using simple test examples withknown solutions (if possible) or by careful inspection of the obtained results.

3.2.5

Handling of input data, computational results and scripts

Buffer homogenisation and canister sinking

Input-files are stored on disk-systems at 5T Engineering and are archived at SKB’s record management system (SKBdoc 1265608, see Table 1-2).
Modelling and analysis of canister and buffer for earthquake induced rock shear andglacial load

Scripts and input-files used for the analyses presented in /Hernelind 2010/ have been archived in
SKB’s record management system (SKBdoc 1258988, see Table 1-2).

3.2.6 Rationales for using the code in SR-Can
The SR-Site team and the contractors involved in the modelling task consider Abaqus to be a suitablecode for the applications, the code is regarded to be one of the dominating softwares in its field andis widely spread and commonly used by the subcontractors.

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3.3

Analytical model for quantification of buffer erosion andcanister corrosion

3.3.1 Introduction
This model uses simple analytical expressions, derived and qualified elsewhere in the SR-Sitedocumentation, for calculations of the extent of buffer erosion and canister corrosion /SKB 2010/.
The calculations are performed in Microsoft Excel.
The code is developed specifically for SKB and is classified as category 4b. A first version of thecode was used in the safety assessment SR-Can /SKB 2006b/. The final calculations in SR-Site weredone with versions 0.7 and 0.8. The final SR-Site version 1.0 differs from v 0.8 only with respect tothe comments in the Excel sheet.

3.3.2 Suitability of the code
The SR-Site mathematical models for buffer erosion and canister corrosion are simple analyticalexpressions, described in /SKB 2010/, that are readily implemented in this spreadsheet code. This
code is thus suitable for calculations of the two processes in the safety assessment SR-Site.
3.3.3 Usage of the code
The code is implemented as a Microsoft Excel-file (SKBdoc 1265612, see Table 1-2). Simple user
instructions are provided in the file.
3.3.4 Development process and verification
A first version of the code was developed for the safety assessment SR-Can /SKB 2006/. The SR-Siteversion of the code has been developed in several steps as documented in a history sheet in the Excel-file(SKBdoc 1265612, see Table 1-2). The mathematical expressions for erosion and corrosion arepresented in /SKB 2010/. It has been verified that the code yields identical results as example
calculations referred to in /SKB 2010/.
3.3.5 Handling of input data, computational results and scripts
Most input data are entered manually in the Excel-file and have default values that are write-locked
in a specific version of the code. Hydrogeological input data (SKBdoc 1260297, 1256019, see
Table 1-2) are provided in separate Excel files that are linked to the calculation file.
Key results of the extent of erosion and corrosion are obtained in a few output cells in the Excel file.
Results to be used as input to radionuclide transport calculations are automatically generated in a
dedicated sheet, on a format suitable for that purpose. These data are stored in SKBdoc 1265612 (seeTable 1-2).
The code is basically run in a single realisation mode. An Excel script (macro) is available to automatically run a number of realisations of a particular hydrogeological model. The Excel add-in @Risk isthen used in combination with the script.

3.3.6 Rationales for using the code in the assessment
The code is tailor made for the needs in the SR-Site assessment. It has been developed and is used bymembers of the SR-Site project.

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3.4

CODE_BRIGHT

3.4.1 Introduction
In the SR-Site safety assessment, CODE_BRIGHT (COupled DEformation BRIne, Gas and Heat
Transport) is utilized for solving coupled thermo-hydro-mechanical (THM) problems in geologicalmedia. A large part of the TH, HM and THM simulations presented in /Åkesson et al. 2010a/ hasbeen produced using CODE_BRIGHT. Some examples from /Åkesson et al. 2010a/ where CODE_
BRIGHT is used are: Backfill saturation (H), Buffer saturation (TH), Buffer homogenization (THM),
Backfill homogenization (HM) and Tunnel plug saturation (H). In addition, CODE_BRIGHT has
been used in model calulations of grout degradation /Grandia et al. 2010/.
In the SR-Can safety assessment, CODE_BRIGHT was used for investigating the influence of trapped
air in the backfill /Börgesson et al. 2006/. For references to other work concerning radioactive waste
disposal where CODE_BRIGHT has been used, see /CODE_BRIGHT v3 Validation document 2009/.
CODE_BRIGHT has been extensively verified and validated in international benchmark exercises,
documented in /CODE_BRIGHT v3 Validation document 2009/, and has been applied to the analysis
of different geoenvironmental schemes, waste disposal designs and geotechnical problems involving
saturated/unsaturated soil behaviour.
CODE_BRIGHT is a Fortran code. Four different versions of the code, running on Windows platforms,
have been used in the work with SR-Site assessment:••••

Version 2.2 (category 3).
Version 3beta (category 3).
Version 3beta with modification 1 (category 4a).
Version 3beta with modifications 1 and 2 (category 4a).

The unmodified code versions belong to category 3, whereas the modified code versions belong
to category 4a. The modifications concern one of the mechanical constitutive laws, based on theBarcelona Basic Model (BBM).
In modification 1 the swelling modulus κs of BBM is made dependent on the void ratio by using
experimental swelling pressure curves, see /Åkesson et al. 2010a, Appendix C/. Modification 2
consists of incorporation of a varying critical state line slope parameter M that is governed by anexperimentally motivated deviatoric failure stress curve, see /Åkesson et al. 2010a, Appendix D/.
Research and development of the code is supported by the UPC (Technical University of Catalonia)
and CIMNE (International Center for Numerical Methods in Engineering at UPC). A consortium ofinternational companies contributes financially to these developments and checks the efficiency andquality of the resulting software. The consortium also provides a valuable link with geoenvironmental and geotechnical engineering practice.

3.4.2 Suitability of the code
CODE_BRIGHT is a tool designed to handle coupled THM problems in geological media. The code
is able to solve non-saturated multiphase flow under non-isothermal conditions. The equations thatgovern the THM problem are categorized into four main groups, namely, balance equations, constitutive equations, equilibrium restrictions and definition constraints. Equations for mass balance were
established following the compositional approach /Olivella et al. 1994/. That is, mass balance isperformed for water, air and mineral species instead of using solid, liquid and gas phases. Equation
for balance of energy is established for the medium as a whole. The equation of momentum balance
for the porous medium is reduced to that of stress equilibrium /Olivella et al. 1996/.
The constitutive equations establish the link between the independent variables (or unknowns) andthe dependent variables. There are several categories of dependent variables depending on the complexity with which they are related to the unknowns. Basic constitutive laws are divided in thermal,
hydraulic and mechanical. The governing equations are finally written in terms of the unknowns
when the constitutive equations are substituted into the balance equations. The unknowns are
obtained by solving the system of PDE’s (Partial Differential Equations) numerically in a coupledway. From state variables, dependent variables are calculated using the constitutive equations or
the equilibrium restrictions.

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For the numerical treatment of the different terms of the balance equations, the first step is theapproximation of the material derivate with respect to the solid as an eulerian derivate, owing to theassumption of small strain rate. Details related to the discretisation of the problem and the numerical
technique used can be found in /CODE_BRIGHT User’s Guide 2009/. In summary, it can be
mentioned that the numerical approach can be viewed as divided into two parts: spatial and temporal
discretisation.
Regarding the boundary conditions of the mechanical problem, forces and displacement rate can be
enforced in any spatial direction and at any node. In the hydraulic problem, mass flow rate of waterand dry gas can be prescribed at any node, and liquid/gas pressure can be also enforced at any node.
Finally, regarding the thermal problem, heat flow and temperature can be prescribed at any node of
the mesh /CODE_BRIGHT User’s Guide 2009/.
For modelling the mechanics of buffer and backfill material, which consist of expansive bentonite clay,
a thermo-elastoplastic law, based on BBM /Alonso et al. 1990/ which was developed to describe thehydro-mechanical behaviour of partially saturated soils, is used. In the safety assessment SR-Can/SKB 2006b/, the relevance of the thermo-elastoplastic model for highly expansive clays was identified as a subject for developments. The modifications made on this constitutive law, as described in/Åkesson et al. 2010a, Appendix C and Appendix D/, are results of the investigations made on this topic.
The parameter setting is discussed in detail in the SR-Site THM Data Report /Åkesson et al. 2010b/.

3.4.3 Usage of the code
The documentation of CODE_BRIGHT is provided by /CODE_BRIGHT User’s Guide 2009/. The
documentation contains a description of the code and the models that are implemented.
CODE_BRIGHT uses GiD system for preprocessing and post-processing. GiD is an interactive graphical user interface that is used for the definition, preparation and visualisation of all the data related tonumerical simulations. This data includes the definition of the geometry, materials, conditions, solution
information and other parameters. The program can also generate the finite element mesh and write
the information for a numerical simulation in its adequate format for CODE_BRIGHT. It is possible
to run the numerical simulation directly from the GiD system and to visualise the results withouttransfer of files. Detailed information will be found in /CODE_BRIGHT User’s Guide 2009, chapters
CODE_BRIGHT Preprocess and Postprocess/.

3.4.4 Development process and verification
CODE_BRIGHT was developed at the UPC in the beginning of the 1990s /Olivella et al. 1994,
1996, Olivella 1995/. The code has been verified and validated through comparisons with analyticalsolutions for a number of problems, see /Olivella 1995, CODE_BRIGHT v3 Verification document
2009/. In /CODE_BRIGHT v3 Validation document 2009/ numerous references are given where
CODE_BRIGHT has been used.
The implemented modifications of the BBM-based mechanical constitutive law in the code are only
active when mechanical problems are solved using this specific mechanical law. The code modification is contained within the part of the code describing the constitutive law. Thus, the foundation of
the code has not been altered by the implementation of the modification. The implementations havebeen tested and validated for special cases where the solution is known. Where isotropic problems havebeen solved, the CODE_BRIGHT solutions have been compared to solutions obtained by MathCad
implementations. The modifications of the swelling modulus κs and critical state line slope parameter
M are described in /Åkesson et al. 2010a, Appendix C and Appendix D, respectively/.

3.4.5 Handling of input data, computational results and scripts
The results from the CODE_BRIGHT models used for THM analyses by /Åkesson et al. 2010a/
were documented and evaluated within that study. They were used to analyse the saturation time, thehomogenisation process and maximum temperatures for different system components. All input files
to the CODE_BRIGHT models are stored at Clay Technology’s data server (Administrativa dokument\
Projekt\THM SR-Site modellering\data\) and archived at SKB (SKBdoc 1265606, see Table 1-2).
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In the data archive the different tasks sorted in specific folders. These folders are divided in two
folders, one for all CODE_BRIGHT models and one for all additional documentation (\Task n(description)\FE-models, \Task n (description)\Other documents).

3.4.6 Rationales for using the code in the assessment
CODE_BRIGHT is regarded as a suitable code for solving the problem at hand. The contractor
performing the calculations has a long experience in using the code.

3.5

ConnectFlow

3.5.1 Introduction
ConnectFlow is the suite of Serco’s groundwater modelling software /Serco 2008a/ that includes the
NAMMU /Serco 2008b/ continuous porous medium (CPM) module and the NAPSAC /Serco 2008c/
discrete fracture network (DFN) module. ConnectFlow is also the name given to the concept of nesting
CPM and DFN sub-models into a combined CPM/DFN model. A further module, GeoVisage, is a dedicated 3D visualisation application for interpreting the results from ConnectFlow. Hence, ConnectFlow
is a very flexible tool for modelling groundwater flow and transport in both fractured and porous media
on a variety of scales. NAMMU was originally developed as part of UK Nirex programme. NAPSAC
was initially developed as part of the international Stripa project /Herbert et al. 1991, Herbert and
Lanyon 1992/. Integration of the DFN and CPM concepts started as part of UK Nirex programme/Jackson et al. 1997/ and the Äspö Task Force /Holton and Milický 1997/. ConnectFlow is now
maintained and developed through the international iCONNECT club /Holton et al. 2003/ (including
SKB, Posiva, NAGRA and Obayashi) and by other commercial users.
ConnectFlow has a long track-record of being used in the SKB programme since SR 97 /Boghammar
et al. 1997, Hartley et al. 1998/. Bespoke developments have been made to suit the needs of sitemodelling and safety assessment calculations /Marsic et al. 2001, Marsic et al. 2002/. The role of thesoftware in the safety assessment was proposed in /SKB 2003/ and illustrated in the SR-Can interim
assessment /Hartley et al. 2004, SKB 2004/. The use of ConnectFlow within SR-Site is a natural
progression from its application in the site-descriptive modelling /Follin 2008/. Connectflow version
9.6 is used in SR-Site.
The simulations for SR-Site have been run on a Linux cluster at Serco, Harwell, UK. Due to therelatively large user base, the software is of category 3 within SR-Site.

3.5.2 Suitability of the code
The fractured nature of the rocks in the Östhammar and Oskarshamn areas requires the consideration ofboth DFN and equivalent CPM models, both to interpret the hydraulic properties of the rocks and toconstruct realistic models of flow and transport. ConnectFlow is unique in offering both these capabilities in the same package and allowing both approaches to be combined. In addition, ConnectFlow
allows the modelling of a wide range of physical processes of relevance to SR-Site such as: transientgroundwater flow; saturated and unsaturated groundwater flow; coupled groundwater flow and salt
transport; transport of reference waters with rock matrix diffusion; coupled groundwater flow andheat transport; variable-density flow and transport in fracture networks; and radionuclide transport.
3.5.3 Usage of the code
The capabilities of ConnectFlow are described in the Technical Summary Document /Serco 2008a/.
Input data is supplied to the code as text files and results are output as binary files and as an ASCII
log-file which can be checked for errors, warnings and issues such as convergence. The syntax of the
input data and the input language is documented in the HTML Command Reference Manual. The
code can also be run using a Graphical User Interface (GUI) which is documented by an on-line User
Manual. Checking of input files is recorded by the originator and then cross-checked by a second user.

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3.5.4 Development process and verification
ConnectFlow is maintained and developed under an appropriate QA programme /Serco 2008g/ by the
Waste Management and Environment Department within Serco. The QA Programme conforms to theinternational standard BS EN ISO 9001 (2000) and to the TickIT Guidelines. The Concurrent Versions
System (CVS) version management system is used to store all source code and test data for ConnectFlow.
This automatically logs the author and date of each change to the system, and enables previous versionsof the code to be accessed and recreated if necessary. All changes are thoroughly tested, and must be
approved by the Software Manager before they are accepted. Through the ConnectFlow QA programme,
Serco Assurance seeks to continually improve the quality and reliability of the program.
NAMMU has been verified within several international project including HYDROCOIN and
INTRACOIN /SKI 1984, SKI 1986, NEA/SKI 1988/. NAPSAC has been verified within the STRIPA
project /Herbert et al. 1991, Herbert and Lanyon 1992/. A full description of the verification of
NAMMU and NAPSAC are given in /Serco 2008d, e/. Testing of combined models is reported in theConnectFlow Verification Manual /Serco 2008f/. Each release of ConnectFlow is verified by runninga full test set for all modules of the software with over 200 test cases.

3.5.5 Handling of input data, computational results and scripts
ConnectFlow runs are carried out using data sets written in ConnectFlow’s command language.
The input files for each run are specified in the header of the data set. Each input file is stored under
the project directory on Serco’s Linux cluster at Harwell, UK and is either generated by a previous
ConnectFlow run or is downloaded from SKB’s Trac system (svn/SR-SiteDataStorage). Some input
files are processed by Java programs to produce input suitable for ConnectFlow, e.g. the IFZ files forthe hydraulic conductor domains (HCD) and the grids for the repository layout. All Java programs
and Perl scripts are kept under the project directory on Serco’s Linux cluster at Harwell, UK.
Output files are also stored under the project directory on Serco’s Linux cluster at Harwell, UK.
Some of these are processed by Perl scripts to produce output suitable for delivery to other teams.
The final output for delivery is uploaded to SKB’s Trac system (svn/SR-SiteDataStorage).
The ConnectFlow input and output data used in SR-Site are archived at SKB (SKBdoc 1256019, see
Table 1-2).

3.5.6 Rationales for using the code in SR-Site
ConnectFlow is used in SR-Site for saturated groundwater flow calculations to provide groundwaterflow and transport inputs to safety assessment calculations. Since the code allows alternative conceptualmodels, such as a DFN, it has some advantages over a purely porous medium approach. There areseveral experienced users familiar with the SKB programme available to work on SR-Site.

3.6

DarcyTools

3.6.1 Introduction
DarcyTools is a computer code for simulation of flow and transport in porous and/or fractured media. The
fractured media in mind is a fractured rock and the porous media the soil cover on the top of the rock.
DarcyTools is a general code for this class of problems, but the analysis of a repository for nuclear
waste is the main intended application.
A number of novel features are introduced in DarcyTools. The most fundamental is perhaps the method
to generate grid properties (DarcyTools is a continuum porous-media code); a fracture network, withproperties given to each fracture, is represented “directly” in the computational grid. This method isbelieved to result in very accurate anisotropy and connectivity properties. Another key feature is thegrid system; an unstructured Cartesian grid which accurately represents objects, read into the code as
CAD-files, is used in DarcyTools v3.4.

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DarcyTools is developed through collaborative effort by SKB, CFE AB (Computer-aided Fluid
Engineering AB) and MFRDC (Michel Ferry Research&Development Consulting) with SKB as theowner of the code. DarcyTools builds upon earlier development of groundwater models, carried out by
CFE AB during the last twenty years. One such early development is represented by /Svensson 1991/,
where predictions of inflows to the Äspö HRL, prior to its construction, are reported. At this time thegeneral purpose equation solver PHOENICS /Spalding 1981/ was used. DarcyTools is based on thesolver MIGAL /Ferry 2002/ and the development work on DarcyTools was initiated early 2001. The
first well documented version of DarcyTools is v2.1, which was released in 2004. Version 3.4 is theversion presently in use and the updated documentation of this version is scheduled for the end of 2010.
Both Windows and Red Hat Linux versions are available. The code is regarded as a category 4b code
as the user base is small and limited to SKB projects. The SR-Site application of the code is describedin recent publications /Svensson et al. 2010, Svensson 2010, Svensson and Ferry 2010/.

3.6.2 Suitability of the code
Due to the collaborative (SKB and CFE AB/MFRDC) development of DarcyTools, it was from start
decided that DarcyTools should be “the tailor-made SKB code”. It is hence not surprising that the key
features of the code match the requested capabilities in for example site investigation or glaciation
studies. It is beyond the scope of the present text to describe these features (see Svensson et al. 2010)
but one may anyway mention: DFN-generation, free surface algorithm, multirate diffusion modeland coupled groundwater flow and salt transport. In addition to useful features, a code needs to beefficient. The earlier mentioned unstructured grid in combination with the equation solver MIGAL(an unstructured multigrid solver) ensures that DarcyTools v3.4 is a state of the art code with respect
to efficiency.
These features make DarcyTools v3.4 a suitable code for a wide range of problems that needs to beconsidered by SKB.

3.6.3 Usage of the code
Three main documents /Svensson et al. 2010, Svensson 2010, Svensson and Ferry 2010/ describe thecode and its use in detail. Recent real world applications, for example /Follin et al. 2005, Svensson
and Follin 2010, Svensson and Rhén 2010, Vidstrand et al. 2010a, b/ provide other valuable sourcesof information.
One of the documents is a User’s Guide, which describe all input parameters. These input parameters
make up the so called CIF (Compact Input File), which is written in XML format. DarcyTools also
includes a Fortran input file, where more advanced features (transient boundary conditions, newsource/sink terms, etc) can be introduced. Tecplot has been selected as the standard tool for postprocessing. Input files for Tecplot are readily generated.
An important part in the usage of the code is the monitoring of the simulation on the computer screen.
Convergence parameters, development of variables in control points or profiles are plotted on the screen
during the simulation. In v3.4 it is even possible to plot the distribution of variables in specified planes.

3.6.4 Development process and verification
One of the three documents mentioned above, /Svensson 2010/, deals with verification, validation anddemonstration. About thirty simple test cases, most with an analytical solution, are used to ensure thatthe equations are solved correctly. When a new major version of the code is released, all test cases
are updated and checked to ensure both consistency with the old version and to make sure that the
new version is correct. Validation is considered to be the process by which the code is shown to agreewith measured data (“the right equations are solved”). A number of comparisons with field data are
included in the above mentioned report. So far, no attempt to show that DarcyTools conforms to any
international QA standard has been made.

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3.6.5 Handling of input data, computational results and scripts
Input files are downloaded from svn/SR-SiteDataStorage and stored on the working directory. In thisdirectory, which is backed-up regularly, also output files and scripts for running various parts of thecode are stored. DarcyTools results used by other models and analyses within SR-Site are stored in
svn/SR-SiteDataStorage.
The DarcyTools input and output data used in SR-Site are archived at SKB (SKBdoc 1256019, see
Table 1-2).

3.6.6 Rationales for using the code in SR-Can
DarcyTools has been developed by CFE AB and MFRDC in cooperation with SKB especially forsolving the problem at hand. The calculations have been performed by several consultants withassistance by the main developer of the code.

3.7

Ecolego3.7.1 Introduction
Ecolego is a flexible software tool for modelling of dynamic systems and performing deterministic
or probabilistic simulations. Ecolego is used in SR-Site for probabilistic and supporting simulations
for generating Landscape Dose Factors (LDF’s) /Avila et al. 2010/. Thus, Ecolego is used as acomplement to Pandora (see Section 3.15).
Ecolego has been developed by Facilia AB and was originally sponsored by the Swedish Radiation
Safety Authority (SSM) and the Norwegian Radiation Protection Authority (NRPA). Ecolego is now
commercial software and is being used by companies and institutions all over the world. The version
used within the SR-Site project is Ecolego 4.0.
Since Ecolego is a commercial code with a large user-base it belongs to category 3.

3.7.2 Suitability of the code
Ecolego has been designed to maximize transparency and flexibility, while at the same time offer
powerful numerical solvers. Large models with many compartments, expressions, parameters andspecies are easily managed with the user interface. Ecolego also has many features for quality assurance,such as:•••••An integrated radionuclide database.
An integrated parameter database, as well as the possibility to set up an external (shared)
parameter database.
Sub-system library.
Unit checking.
Sub-version support.

Ecolego supports both deterministic and probabilistic simulations. Sensitivity analysis can be performed on probabilistic results. The mathemathical model is described in detail in /Andersson 2010/.

3.7.3 Usage of the code
Ecolego has a thorough web-based user guide (www.ecolego.facilia.se) which is continuously updated
using the Wiki-concept. The user guide provides sufficient guidance for the use of the code, withstep by step tutorials for the novice user and also full description of all implemented methods andfeatures. At the same web site, there is also access to other resources such as a forum for support,
ideas, answers and community talk as well as an issue tracker to report eventual bugs and request
improvements.

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The correct usage of the code is assured since Ecolego is used, in the SR-Site project, in close collaboration with the developer of the code (see /Avila et al. 2010/ for a description of the version usedin SR-Site).

3.7.4 Development process and verification
Ecolego has been developed since 2002 and has been verified and validated through several comparisonswith both analytical solutions as with benchmarks of other software such as Amber and Simulink/Maul et al. 2004/. The SR-Site models have been implemented in both Pandora (Simulink, see
Section 3.15) and Ecolego to validate the simulation results. The Ecolego software is continuously
tested using standard unit testing algorithms.
3.7.5 Handling of input data, computational results and scripts
After a simulation, an Ecolego model is saved together with its input data and the results as an
assessment file. Each simulation performed for SR-Site has been stored as an assessment at SKB’s
subversion server.
Input data used for simulations are stored within the assessment file and originally extracted fromthe version handled Pandas assessments files representing the base cases at SKB subversion serverusing Java-scripts. The scripts used to perform batch simulations are archived at Facilia’s internal
concurrent versioning system (CVS).
The Ecolego input and output data used in SR-Site are archived at SKB (SKBdoc 1263189, see
Table 1-2).

3.7.6 Rationales for using Ecolego in SR-Site
Ecolego is used in SR-Site since the code is suitable for risk assessments of complex dynamic systems
evolving over time with any number of species. Ecolego has databases and other add-ons especiallydesigned for the field of radiological risk assessment.
The models used for biosphere modelling in SR-Site involve large number of parameters and complex
relationships between the inputs and the outputs. In addition, Ecolego enables quick modifications
and simulation of large number of assessments.

3.8

ERICA Tool

3.8.1
Introduction
The ERICA Tool is used in SR-Site as a tool for estimation of dose rates to non-human biota /Torudd
2010/. It was developed to support the ERICA Integrated Approach in the ERICA EURATOM projectin the area of radiological environmental protection (www.erica-project.org). The ERICA Integrated
Approach can be applied in planned and existing exposure situations. The use of the ERICA Integrated
Approach is facilitated by the ERICA Tool, which is a software programme that guides the user throughthe various steps, keeps records and communicates with a number of purpose-built databases /Beresford
et al. 2007/.
The ERICA Tool is being maintained by a consortium comprising the Norwegian Radiation Protection
Authority, Environment Agency (England and Wales), Centre for Ecology & Hydrology (UK), IRSN
(France) the Swedish Radiation Safety Authority and CIEMAT (Spain).
The ERICA Tool is freely available (http://www.project.facilia.se/erica/download.html) and has alarge international user base. Since it not written exclusively for the SKB safety assessment, the codeis regarded as a category 3 code.

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3.8.2 Suitability of the code
The ERICA Tool is a software programme that guides the user through the environmental impact
assessment process, keeps records and performs the necessary calculations to estimate dose rates toselected biota. The implementation of the code in SR-Site is described by /Torudd 2010/.
The Tool interacts with a number of databases and other functions that help the assessor to estimate
environmental media activity concentrations, activity concentrations in biota, and dose rates to biota.
The databases consider the majority of the radionuclides included in Publication 38 of the International
Commission on Radiological Protection (ICRP) /ICRP 1983/. The ERICA Tool also interfaces with
the FREDERICA radiation effects database (www.frederica-online.org), which is a compilation of thescientific literature on radiation effect experiments and field studies, organised around different wildlife
groups and, for most data, broadly categorized according to four effect umbrella endpoints: morbidity,
mortality, reproduction, and mutation.
The databases of the ERICA Tool are built up around a number of reference organisms. Each reference
organism has its own specified geometry and is representative of either terrestrial, freshwater or marine
ecosystems. The approach is compatible with that used by ICRP; some of the geometries proposed forthe ICRP ‘reference animals and plants’ are used as defaults in the ERICA Tool.

3.8.3 Usage of the code
A thorough web-based user guide, found at www.erica-project.org, is continuously updated. The user
guide provides sufficient guidance for the use of the code, with step by step tutorials and also fulldescription of all implemented methods and features. The detailed help assists the user in making
appropriate choices and inputs, as well as interpret the outputs. At the same web site, there is also
access to other resources such as a forum for support, ideas and answers as well as an issue tracker
to report eventual bugs and request improvements.
2.8.4 Development process and verification
This is a freely available code used in several international projects, developed and maintained by aninternational consortium and the developer grant for the development process and verification of the code.
3.8.5 Handling of input data, computational results and scripts
After a simulation, an ERICA model is saved together with its input data and the results as an assessment file. Each simulation performed for SR-Site has been stored and is found in SKB doc 1263189(see Table 1-2).
3.8.6 Rationales for using the code in SR-Site
The ERICA Tool is used in SR-Site since it is a well documented and internationally used and reviewed
tool for estimation of dose rates to non-human biota.

3.9

FARF31

3.9.1 Introduction
FARF31 /Lindgren et al. 2002/ is a code used for radionuclide migration calculations in the far-field,
i.e. the geosphere. It is based on a model with a one-dimensional advection-dispersion equation alonga, possibly curved, stream tube coupled to a pure diffusion equation in the direction perpendicular
to the centroid of the stream tube, for a number of radionuclides. Chain decay and ingrowth areincluded in the model. The concept of a stream tube can be compared to the combined effect of alarge number of individual fractures all sharing the same inlet and outlet. The transversal dimensionof the stream tube, the penetration depth, must be chosen by the user.

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FARF31 has been used by SKB in the SR 95 /SKB 1995/, the SR 97 /SKB 1999/ the SR-Can Interim/SKB 2004/ and SR-Can /SKB 2006b/ safety assessments of a final repository of the KBS-3 type.
In addition, the code has been used by Andra /Andra 2005/ and the European Commission’s Joint
Research Centre /Prváková 2005/.
The code was initially developed by SKB in the early 1990’s as a submodel of the SKB safety assessment framework Proper. This framework is a collection of codes used for migration and consequencecalculations through the near-field, the far-field and the biosphere, and uses standardised methods totransfer data and results between the different submodels. FARF31 has been continuously developed
by SKB and subcontractors from its conception until the present version 1.2.1. FARF31 is a Fortran 77
code. In SR-Site a stand-alone version of the code, called from MATLAB scripts, is used.
Since the code has been developed by SKB, the code is belonging to category 4b.

3.9.2 Suitability of the code
The governing equations are solved in the Laplace domain using the groundwater travel time inthe longitudinal direction as the independent variable to obtain a unit response function, which issubsequently convoluted with the input function to obtain the output function. A detailed descriptionof the solution method can be found in /Norman and Kjellbert 1990/.
The FARF31 code has been developed by SKB to be a reasonably accurate, simplified model of the
fully three-dimensional far-field transport problem, which still is fast enough to allow for probabilistic
calculations. The solution method, based on Laplace transformation of the governing equations andnumerical inversion, limits its applicability to cases with constant transport properties, but this poses
no problem at the present level of knowledge. However, a different solution method must be used
to include colloid facilitated transport in the model. This is possible to handled in a version of thecode called FARF33, where the governing equations are discretised in space using a first order finite
volume scheme in both the longitudinal and the transversal direction /Vahlund and Hermansson 2006b/.
However, in SR-Site the MARFA code is used for colloid facilitated transport (see Section 3.10).
In a dedicated test batch (Appendix B in the FARF31 User’s Guide /Lindgren et al. 2002/) and in previous assessments, the capability of solving problems for the expected input data ranges has been shown.

3.9.3 Usage of the code
In the FARF31 User’s Guide /Lindgren et al. 2002/ the program and its implementation and usage
details are explained. Text files are used to pass input data to the code and results from the code.
During each run log files are produced, which makes it possible to ensure the right parameter values
have been used after the simulation has finished.
3.9.4 Development process and verification
In the validity document /Elert et al. 2004/ it is shown that the results are equal to analytical solutions
and results from other numerical codes.
In order to ensure the functionality of the code on new machines, batch scripts are used to check out
the desired version from the version control system SCCS /Boghammar 1999/ and to set up the build
environment. After every major code change resulting in a new version, the problems of the FARF31
test batch /Lindgren et al. 2002/ are used in regression tests of the code to ensure that its accuracy
and reliability is intact.

3.9.5 Handling of input data, computational results and scripts
In SR-Site, FARF31 runs are handled with MATLAB scripts. The release from the near-field calculated with COMP23, see Section 3.12, is transferred to FARF31 in the MATLAB scripts. Resultsfrom the hydrogeological calculations with ConnectFlow given as ASCII-files (ptb-files) (SKBdoc
1256019, see Table 1-2) are simply converted to MATLAB input-data.
Input data, results and scripts are stored in Subversion. The used input data and scripts are documentedin SKBdoc 1260297 (Table 1-2). The main results are available in SKBdoc 1260295 (Table 1-2).
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3.9.6 Rationales for using the code in SR-Site
The SR-Site team has selected the FARF31 code for the SR-Site safety assessment since it has been
designed to solve the radionuclide transport problem at hand and since the knowledge of the codeis good.

3.10

MARFA

3.10.1 Introduction
MARFA 3.2.2 /Painter and Mancillas 2009/ is a Fortran 95 code used for radionuclide migration
calculations in the geosphere. It represents transport along one-dimensional flowpaths extracted froma ConnectFlow or similar flow model. The solution method is a particle-based Monte Carlo approach/Painter et al. 2008/. Advection, longitudinal dispersion, limited or unlimited diffusion in rock matrix
adjacent to the flow path, equilibrium sorption, and decay/ingrowth are represented. Colloid-facilitatedtransport may be represented in MARFA by appropriate manipulation of input parameters. Fullheterogeneity is supported. That is, the code allows an arbitrary (user input) number of flowpaths andeach flowpath may be divided into an arbitrary number of segments with different flow and transport
properties within each segment. Different segments may have different retention models (e.g. matrix
diffusion in some segments and equilibrium sorption in others). MARFA 3.2.2 also supports temporalvariability in flowpath properties. Specifically, different flow velocities and non-flow related transportparameters may be entered for different time periods. However, the three-dimensional flowpath
trajectories themselves are assumed fixed in MARFA 3.2.2.
MARFA is a category 4b code.

3.10.2 Suitability of the code
MARFA 3.2.2 accurately represents processes that are expected to be dominant transport processes
in the Forsmark geosphere, similar to the FARF31 code (Section 3.9). MARFA was developed torepresent certain features, events and processes that are not represented in the FARF31 code. Specifically,
the solution method in MARFA does not require the flowpath to be homogenised into an effective
constant-property pathway. Theoretical justification for such homogenisation has been demonstrated
for single nuclides, but not for radionuclides linked through decay chains. In addition, MARFA also
allows for different retention models in different parts of the flowpath, thus making it possible torepresent sorption in backfilled tunnels or near-surface soils. MARFA also allows flow velocities
and retention parameters to change with time.
3.10.3 Usage of the code
Data input to MARFA is through a series of input files, as described in the MARFA User’s Manual/Painter and Mancillas 2009/.
3.10.4 Development process and verification
MARFA was developed at the Geosciences and Engineering Division (GED) of Southwest ResearchInstitute (SwRI) in Texas, USA. The GED conducts all quality affecting activities in compliancewith applicable requirements of Title 10 of the US Code of Federal Regulations Part 50, Appendix B(10 CFR Part 50, Appendix B; Domestic Licensing of Production and Utilization Facilities, Quality
Assurance Requirements for Nuclear Power Plants and Fuel Reprocessing Plants). More specifically,
quality affecting research and development activities related to geological disposal of high-level
radioactive waste and spent nuclear fuel comply with the requirements of 10 CFR Part 63, Subpart G(Disposal of High-Level Radioactive Wastes in a Geologic Repository at Yucca Mountain, Nevada,Quality Assurance). The industry implementing standard for 10 CFR Part 50, Appendix B is American
Society of Mechanical Engineers (ASME) NQA-1, Quality Assurance Requirements for Nuclear
Facilities Applications (1986).

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Software is developed, controlled, and modified using GED Technical Operating Procedure (TOP)018, Development and Control of Scientific and Engineering Software. This procedure invokes the
US Nuclear Regulatory Commission (NRC) regulatory guidance documents NUREG/BR-0167,
Software Quality Assurance Programs and Guidelines, and NUREG-0856, Final Technical Position
on Documentation of Computer Codes for High-Level Waste Management. Furthermore, TOP-018
identifies appropriate processes and documentation to control appropriate elements of the softwaredevelopment process. These measures include but are not limited to preparation of a software requirements description, software development plan, software validation plan, software release notices,
software change notices, and similar documentation, as appropriate taking into consideration the size,
complexity, and importance of the software being developed or modified. TOP-018 also provides
guidance on preparation of a user guide.
Software validation tests are summarized in the MARFA user’s manual /Painter and Mancillas 2009/.

3.10.5 Handling of input data, computational results and scripts
MARFA requires flowpath definitions, radionuclide mass release rates from the near field, and retention parameters for the far field. MARFA is designed to directly accept ConnectFlow (see Section 3.5)
ptv-files to define flowpaths. However, some modelling cases required the ConnectFlow-generated
ptv-files to be modified to remove certain segments of the calculated flowpaths or to remap rocktype numbering. Non-flow related transport parameters are input through the definition of certain
parameters of the retention model. These are input through an ASCII file as described in the MARFA
users manual /Painter and Mancillas 2009/. Non-flow related transport parameters sampled with the@RISK code (add-in to Microsoft Excel) were reformatted in the MARFA input format. Similarly,
radionuclide release rates from COMP23, Section 3.12, were reformatted to the required MARFA input
format. MARFA generates results in units of Bq/yr for each radionuclide. These results are saved in
ASCII files and were also converted to units of Sv/yr for display purposes using SR-Site landscapedose factors (LDF’s) for the temperate period. A complete input/output set for each MARFA calculation
completed in support of SR-Site is archived in the QA system of the Geosciences and Engineering
Division of Southwest Research Institute (for growing pinhole cases) and in SKB’s record management
system (SKBdoc 1256019, 1266150, see Table 1-2).
3.10.6 Rationales for using the code in SR-Site
The SR-Site team has selected MARFA for the SR-Site safety assessment since it was specificallydesigned to integrate with the safety assessment workflow used by SKB. In contrast to FARF31
the MARFA code supports full spatial variability for all pathway properties as well as colloidalfacilitated transport. The results produced by MARFA have been shown to be in good agreementwith results from other codes, for example FARF31.

3.11

MATLAB

3.11.1 Introduction
MATLAB /MathWorks 2010a/ is an interactive environment and computing language for numericcomputation, analysis and visual presentation. MATLAB has been developed since the late 1970’s
and is globally widespread. MATLAB (versions R2008a, R2008b and R2010a) has been used fora variety of tasks in SR-Site for instance, migration calculations in all parts of the repository system(COMP23, Section 3.12), landscape models (Pandora, Section 3.14) and FPI-calculations (Section 3.13),
and also for pre- and post-processing of data and their visualisation.
Simulink /MathWorks 2010b/, an extension integrated with MATLAB, is an environment for
multidomain simulation and model-based design for dynamic and embedded systems. It provides aninteractive graphical interface to MATLAB and implements MATLAB with a customisable set ofblock libraries.
While MATLAB and Simulink on their own are regarded as a category 3 code, the advanced applications using MATLAB are regarded as category 4 codes.

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3.11.2 Suitability of the code
As MATLAB and Simulink only provide the platform for different codes, the suitability is shown foreach separate calculation task.
3.11.3 Usage of the code
MATLAB and Simulink are both well documented codes and courses in using the codes are available.
3.11.4 Development process and verification
This is a commercial code and the developer grant for the development process and verification of
the code. The large number of users worldwide warrants swift reactions on programming errors.
3.11.5 Handling of input data, computational results and scripts
In the SR-Site assessment, MATLAB is not used as a separate code, instead MATLAB provides
mathematical solving capability and, together with Simulink, graphical environment for the codesdeveloped or tuned for SR-Site.
3.11.6 Rationales for using the code in SR-Site
When performing numerical analysis tasks, MATLAB and Simulink are one of few available codes
and are well suited for their tasks.

3.12

MATLAB – COMP23

3.12.1 Introduction
In SR-Site an implementation of the COMP23 model written in MATLAB/Simulink, is used for thenear-field migration calculations. This implementation of the COMP23 is also called Compulink/Vahlund and Hermansson 2006a/.
COMP23 has been used by SKB in the SR 95 /SKB 1995/, the SR 97 /Lindgren and Lindström
1999, SKB 1999/, the SR-Can Interim /SKB 2004/ and SR-Can /SKB 2006b/ safety assessments ofa final repository of the KBS-3 type. A closely related code, NUCTRAN/NUCFLOW, (which origins
from the same source but allows for multiple sources as opposed to COMP23 which only handles
single sources) was used in the safety assessment SAFE of the SFR repository for operational waste/Lindgren et al. 2001/. In addition, the code has been used by Andra /Andra 2005/ and the European
Commission’s Joint Research Centre /Prváková 2005/ and, to some extent, by the Lithuanian Energy
Insitute (LEI) /Neerdael and Finsterle 2010/.
COMP23 /Cliffe and Kelly 2006/ is originally a Fortran77 code used for radionuclide migration
calculations in the near-field (the canister and the engineered systems) and includes models for fueldissolution, handling of element specific solubility, and migration through advection and dispersion in
the different parts of the engineered system. The code was initially developed as NUCTRAN /Romero
1995/ and was subsequently incorporated into the SKB safety assessment calculation framework
Proper as the submodel COMP23. Proper is a collection of codes used for migration and consequencecalculations through the near-field, the far-field and the biosphere and uses standardised methods totransfer data and results between the different submodels. COMP23 has been continuously developed
by SKB and subcontractors until the present version 1.2.2.
The code is considered a category 4b code.

3.12.2 Suitability of the code
COMP23 has been developed by SKB with the main objective to solve the problem at hand andincludes all essential models needed when modelling radionuclide migration through the engineered
system. Some of the models have been used temporarily in the development process of the KBS-3
repository and can be regarded as being obsolete based on the present level of knowledge. The code
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contains for instance several models of different complexity used to calculate the dissolution rate forthe fuel matrix. However, for SR-Site a linear model is used, which corresponds best to the present
level of knowledge of the actual processes suggested in the Data report and the Fuel and canister
process report. For the solubility limits inside the canister which is a mechanism limiting the concentration inside the canister, a shared solubility model is used where the solubility limit for an element is shared proportionally between the different isotopes of the same element. For radionuclides
embedded in the metal parts of the fuel assemblies the releases are determined by constant corrosion
rates. Sorption coefficient, diffusivity and porosity are given for each nuclide which allows cations
and anions to be treated differently. The validity of the different models used in the code is discussed
in the Fuel and canister process report and the Buffer, backfill and closure process report.
The spatial discretisation used in the modelling of the KBS-3 system (the sub-division of the near-field
into compartments) is described in appendix in the Radionuclide transport report. The discretisation is manly based on an earlier study /Lindgren and Widén 1998/ where different discretisation
techniques have been tested in order to find a discretisation that is coarse enough to allow for the
problem to be solved using probabilistic calculations, but yet fine enough allowing for the problem
to be solved with acceptable accuracy. In order to be able to have a relative coarse spatial discretisation, analytical expressions are possible to use at the mouth of the canister defect and at the fracture
bentonite interface /Neretnieks 1986, Romero 1995, Kelly and Cliffe 2005/.
In a dedicated test batch /Lindgren et al. 2008/, in the validity document, /Kelly and Cliffe 2006/ andin previous assessments, the capability in solving problems for the expected input data ranges has
been shown. Compulink uses a subset of the COMP23 test batch /Vahlund and Hermansson 2006a/.

3.12.3 Usage of the code
In the COMP23 user’s manual /Romero et al. 1999, Cliffe and Kelly 2006/ the program and themodels implemented are explained in detail. For the MATLAB-version used in SR-Site /Vahlund andHermansson 2006a/ provides additional documentation on the usage. MATLAB scripts are used tohandle input and output.
3.12.4 Development process and verification
In a validity document /Kelly and Cliffe 2006/, the features of the code are presented and some ofthese are benchmarked against analytical solutions and in some cases to other codes. In addition to
the validity document, a test batch /Lindgren et al. 2008, Vahlund and Hermansson 2006a/ has been
prepared in which the features of the code are demonstrated both for simple test cases which can beverified with analytical solutions or other codes and also for realistic KBS-3 cases using realistic data.
Using the test batch the accuracy between different versions may be verified to ensure that code
modifications does not change the capability of the code to solve the problem at hand.
The Matlab/Simulink version of COMP23 uses Subversion for version handling. The Fortran versionof the COMP23 uses the version control system SCCS /Boghammar 1999/ and batch scripts are used
to set up the computational environment.

3.12.5 Handling of input data, computational results and scripts
In this section it is described how data are passed between COMP23 and other models identified in theAMF, see Figure 2-1 and Figure 2-2. Table 3-1 summarises the data and how it is passed to COMP23
and if other model activities are performed to obtain the input data. The used input data and scripts
are version controlled in Subversion and documented in SKBdoc 1260297 (Table 1-2). The results are
stored in Subversion and the main results are available in SKBdoc 1260295 (Table 1-2).
3.12.6 Rationales for using the code in SR-Site
The SR-Site team has selected the MATLAB/Simulink version of COMP23 code for the SR-Sitesafety assessment since it has been designed to solve the radionuclide transport problem at hand andsince the knowledge of the code is good.

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Table 3-1. Input data passed to COMP23.
Data

Other model activity

Data passing

Inventory for RN transport (DR 3.1)

Subversion, Data report Section 3.1

IRF, CRF and Corrosion time for metalparts (DR 3.2)

Subversion, Data report Section 3.2
Subversion, Data report Section 3.3

Fuel conversion (DR 3.3)
Solubility data (DR 3.4)

Solubilities, Section 3.20

Subversion

Time for large defect (DR 4.3)

Corrosion calculations (incl. buffer
erosion), Section 3.3

Subversion, Data report Section 4.3,
(SKBdoc 1265612)

Geometries
Flow related migration parameters(DR 6.7)

Underground openings production report,
Canister production report, Buffer production report, Data report Section 4.1
Hydro, Section 3.5 (Connectflow)

Subversion (ptb-files), Data report Section 6.7 (SKBdoc 1256019)

Density and porosity of buffer andbackfill (DR 5.1)

Subversion, Data report Section 5.1

Migration data of buffer and backfill

Subversion, Data report Section 5.3

3.13

MATLAB – FPI

3.13.1 Introduction
The full perimeter intersection criteria (FPI) were used in the safety assessment SR-Can /SKB 2006b/
as a proxy for large fractures. This enabled a quantitative estimate of the number of canisters thatmight fail due to earthquakes.
Using site descriptive models as input, the codes compute the probability of intersection between
fractures, idealised as infinitely thin, circular discs, and either canisters, deposition holes or tunnelsof various shapes and orientations /Munier 2010/. The critical fracture radii, i.e. radii sufficiently
large to host slip exceeding the canister failure criterion, are dependent on the distance to deformation
zones and the dip of the fracture, as demonstrated in /Fälth et al. 2010/. Combined with estimates ofearthquake frequencies /e.g. Bödvarsson et al. 2006/ it is possible to compute an average number ofpotentially damaged canister for various time frames.
The codes are implemented as MATLAB /MathWorks 2010a/ scripts (see also Section 3.11), using
the parallel processing toolbox /MathWorks 2010c/ for computation speed. A few subroutines werecompiled in C++ for additional speed, using the compiler Visual Studio /Microsoft 2008/. The versionof the code used in SR-Site is “version SR-Site”.
FPI is considered as a category 4b code.

3.13.2 Suitability of the code
The codes were tailor-made for the sole purpose of computing fracture/canister intersection probabilities.
The method is described in /Munier 2010/.
3.13.3 Usage of the code
The codes require MATLAB (see also Section 3.11) and the parallel processing toolbox. The compilation of certain subroutines to C++ was targeted to a 64 bit platform and would need to be recompiled
to run on a 32 bit platform. The code is documented in /Munier 2010/.
3.13.4 Development process and verification
The notion of using full perimeter intersections as proxies for large fractures was originally introduced
in /Munier 2006/ in which the terminology, geometrical framework and first versions of the codes
were presented. In /Munier 2007/ a sensitivity analysis was published together with some fundamental
benchmark cases /Hedin 2008/. The number of cases to consider, and their output, forced a radical
rewriting of the codes and a need to compile some slow routines into native C++. These early reports

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were complemented in /Munier 2010/ with a large number of analytical and semi-analytical benchmarks
e.g. /Hedin 2010/, more sensitivity analyses and an application to both the Forsmark and Laxemar
sites. The codes, presented in /Munier 2010/, were radically rewritten to enable parallel processing,in particular with regards to simulation logic. The version of the codes in /Munier 2010/ are thoseused in SR-Site though the simulation output has been complemented with additional realisations
to stabilise results further.

3.13.5 Handling of input data, computational results and scripts
There are several sources of input to the simulations. The most important ones are the DFN models
for each site. All DFN models of the site description reside in SKB’s model database as Microsoft
Excel sheets, described in detail in the Data Report. However, the FPI codes require ASCII input
files with a special formatting. These ASCII-versions of the DFN models are stored together with
the MATLAB scripts.
The output also consists of ASCII-files of various formats. These are concatenated into Workbooks
in Statistica /Statsoft Inc. 2009/ in which they are analysed. Statistica also provides the graphicaloutput in terms of tables, diagrams and charts.
All files, which includes compiled subroutines, MATLAB scripts, input, output and Statistica workbooks are handled in Subversion, and are archived at SKB (SKBdoc 1264530, 1264531, 1264532,
see Table 1-2).

3.13.6 Rationales for using the code in SR-Site
The FPI codes were thoroughly tested within the framework of SR-Can and shown to be adequate
for the intended purpose. Models and scripts have been successively developed and backwards
traceability is thereby warranted. The SR-Site team still considers the FPI codes adequate to fulfil
the purpose of the simulations and has therefore chosen to continue using the FPI codes as the main
tool for analyses of canister/fracture intersection probabilities.

3.14

MATLAB – Pandora

3.14.1 Introduction
The software package Pandora is used in SR-Site for deterministic simulations for derivation of theLandscape Dose Factors (LDF’s) for SR-Site /Åstrand et al. 2005, Avila et al. 2010, Ekström 2011/.
Pandora is an extension of the well-known codes MATLAB and Simulink /Mathworks 2010a, b/.
Pandora simplifies the development of compartment models consisting of large systems of ordinary
differential equations and the handling of radionuclide decay chains. The Pandora tool comprises alibrary of Simulink blocks that facilitates the creation of compartment models, a Manager as an aid in
the model building phase and a standalone assessment tool called Pandas for the model simulation
phase. Pandora has been developed by Facilia AB and financed by SKB and Posiva OY. Pandas andthe Manager have been financed by SKB alone. Pandora is also used for biosphere modelling by
Posiva OY. In SR-Site, Pandora svn revision number 5172 is used.
Pandora is considered as a category 4b code.

3.14.2 Suitability of the code
Pandora was developed for the specific needs of the biosphere modeling required for the safetyassessments of high level nuclear waste repositories. It has all required functionalities, including:
•
•
•
•
•
•
•
42

handling of large sets of parameters,
handling of time evolving parameters,
representation of discrete transitions between states,
handling of large number of radionuclides and decay chains,consideration of time evolving and spatially distributed discharges,
version handling of parameters, models and assessments,
capability to perform probabilistic simulations and sensitivity analysis.
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Pandora extends the Simulink graphical user interface as to allow the user to easily inspect and modify
the conceptual and mathematical models implemented. The equations on which the model is built aredescribed in /Andersson 2010/.

3.14.3 Usage of the code
The Pandora code has an internal user guide with step by step tutorials as to build models as well
as a general description report /Ekström 2011/, which provides sufficient guidance for the additional
functionalities that have been incorporated to the commercial codes MATLAB and Simulink.
MATLAB and Simulink are well documented and has good support and updating is provided by
the developers /Mathworks 2010a, b/.
The path to build a landscape model starts by creating a library of ecosystem models in Pandora,
which facilitates handling several instances of the ecosystem models in the landscape model. For eachlandscape object, a Simulink subsystem is created, which includes models of all ecosystem types that
may exist in the object during the whole simulation period. An eventual discrete transition between
ecosystem models is implemented using switches available in Simulink. The decay and ingrowth ofradionuclides in decay chains are handled with the help of the Pandora Radionuclide block.
For integrating the model, the user can choose from a large list of solvers available in Simulink,including solvers that are appropriate for stiff systems of equations with discrete events. In SR-Sitethe solver ode15s was used, this due to the high stiffness of the implemented models. The activity
concentrations and doses were calculated from the amounts of activity in different compartments
predicted with the Pandora model by using a post-processing routine created in MATLAB andincorporated with Pandas assessment. Since Pandora is integrated with the assessment tool Pandas,
it also allows for performing sensitivity and uncertainty analyses of the implemented models.

3.14.4 Development process and verification
Pandora has been benchmarked, tested and compared with other similar tools /Åstrand et al. 2005,
Ekström 2011/. The solutions with the predecessor of Pandora (Tensit) were compared with analyticalresults, as well as with numerical results obtained with other simulation tools /Jones et al. 2004, 2005/.
These comparisons have shown that Pandora provides reliable solutions.
3.14.5 Handling of input data, computational results and scripts
In SR-Site, Pandora runs are handled with Matlab scripts. Input data (universal constants, time
specific-, site specific- or generic parameter values) are transferred from Excel tables to Pandora
in the Matlab scripts.
Input data, results and scripts are stored at SKB’s subversion server. These files are archived in the
SKB record management system (SKBdoc 1263189, see Table 1-2).

3.14.6 Rationales for using the code in SR-Site
Pandora was developed by SKB and Posiva OY for their specific needs in biosphere modelling. BothSKB and Posiva have been active in the development of the code, as to assure that the code satisfies
all requirements, including quality assurance requirements. The decision to develop Pandora was taken
after it was concluded that other available commercial tools did not have all required functionalities.

3.15

MIKE SHE

3.15.1 Introduction
In SR-Site, MIKE SHE (Système Hydrologique Europeen) is used for hydrology and near surfacehydrogeology calculations. MIKE SHE makes it possible to model the integration between surface
water, groundwater and evaporation processes and makes it possible to describe and understand thecomplexity of the water flows in the surface system. The MIKE SHE model provides the dose-modelwith data on water fluxes in and between different compartments of the dose-model.
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MIKE SHE is developed by the Danish Hydraulic Institute (DHI). The code describes the mainprocesses in the land phase of the hydrological cycle, from rainfall to river flow /Graham and Butts
2005/. The model consists of five different compartments; saturated zone, unsaturated zone, overland
flow, evapotranspiration and channel flow, Figure 3-1, in which the water flow is calculated separately.
In addition to the different compartments there is a frame component that takes care of the coupling
and water exchange between the different compartments which runs simultaneously with the othercomponents of the model. Transport calculations, particle tracking and advection-dispersion calculations, can also be performed within the MIKE SHE modelling tool.
MIKE SHE Version 2009 /DHI 2009/ is used within the SR-Site modelling. The system is certified
for Windows 2000 Professional and Windows XP Professional X64 Edition. MIKE SHE was also
used in SR-Can but the code has been developed since then. The coupling between the river flow
model and the groundwater flow model in the present version has been updated, so that the water
can be transported from the aquifer to the river either via the bottom sediment or over the river bank,as well as allowing water to flood from the river to the ground surface and then infiltrate. Also theevapotranspiration module has been developed. In the MIKE SHE version 2009 it is possible forplants to extract water from the saturated zone which better describes the water turnover in wetlands/Vikström and Gustafsson 2006/. It is possible to define a water tolerance for each vegetation type,if the water tolerance is high the plant can extract all its water from the groundwater zone.
MIKE SHE is used in the hydrological and near surface hydrological modelling within SR-Site.
The SDM MIKE SHE model /Bosson et al. 2008/ has been the basis for the models developed within
the framework of SR-Site where both models describing present and future conditions have beendeveloped. Different climate cases and the effect on the hydrology of the shore line displacement anddevelopment of the landscape have been analysed. The MIKE SHE modelling is reported in /Bosson
et al. 2010, Lindborg 2010/.
The code is commercial and is regarded as a category 3 code.

Figure 3-1. The MIKE SHE model /Abbott et al. 1986/.

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3.15.2 Suitability of the code
MIKE SHE is an advanced integrated hydrological system capable to simulate both surface andgroundwater with the same precision as models focused on either groundwater or surface waters.
The model is able to simulate the interaction between the surface water and the groundwater which
is important when studying potential flow paths from the repository, i.e the water flow from thegeosphere to the biosphere.
The precipitation can either be intercepted by leaves or fall to the ground. The water on the groundsurface can infiltrate, evaporate or form overland flow. Once the water has infiltrated the soil, it enters
the unsaturated zone. In the unsaturated zone, it can either be extracted by roots, and leave the system
as transpiration, or it can percolate down to the saturated zone, see Figure 3-1. MIKE SHE is fully
integrated with a channel-flow program, MIKE 11. When using the MIKE 11 code together with
MIKE SHE, the two programs run simultaneously allowing for water exchange between the twocodes during the whole simulation. The water exchange between M11 and MIKE SHE is further
described in /Gustafsson et al. 2009/.
Based on the calculated flow field, particle tracking calculations (in the saturated zone) andadvection-dispersion calculations can be performed. Within the SR-Site application both particle
tracking and advection-dispersion calculations have been performed. The solute transport in theadvection-dispersion module can be calculated for all the components (river, overland, unsaturated
zone, groundwater).
The following processes are included in the MIKE SHE advection-dispersion module:••••

Water and solute transport in macro pores.
Sorption of solutes described by either equilibrium sorption isotherms or kinetic sorption isotherms.
Attenuation of solutes described by exponential decay.
Plant uptake of solutes.

There is a direct coupling between MIKE SHE and the GIS program ArcMap which is part of the
ArcGIS framework. This is a large advantage since most of the input data to the present modelling
can be obtained in GIS format. It is possible to use both shape-files and ESRI-grid files as input.
Both pre- and post processing can be made in the ArcGIS program. The program has been developed
to calculate the integrated ground- and surface-water system (flow and transport in porous medium,the unsaturated zone and flow and transport of surface water). Hence, the parameter ranges used
when simulating are within the ranges for which the program is valid.

3.15.3 Usage of the code
The MIKE SHE user manual /DHI 2009/ consists of two documents;•

The MIKE SHE user guide:The document describes how to set up a model and how to process input and output data.

•

The MIKE SHE reference guide:The document describes in detail the individual tools and dialogs the user is encountered to whenworking in the MIKE SHE user interface. The document also includes detailed descriptions of
the numeric engines and governing equations used in the MIKE SHE modelling system.

The MIKE SHE user manual follows as a pfd-file with the installation media. The manuals are notavailable in a printed version.

3.15.4 Development process and verification
The MIKE SHE model has its origin in the SHE model, Systèm Hydrologique Européen, whichbecame operational 1982. The model was developed by three organisations; the British institute ofHydrology, the French consulting company SOGREAH and the Danish hydraulic institute, DHI.
Today DHI markets the MIKE SHE code. The code is developed as new modelling ideas and needs
are identified by the users. The latest version of the model is MIKE SHE version 2010.

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The coupling between MIKE SHE and ArcGIS leads to a close integration with SKB’s GIS-database.
This ensures a good quality as well as high level of traceability for the input data to the model.
Many organisations have reviewed and evaluated the MIKE SHE code. MIKE SHE has been selected
as the best modelling tool for integrated groundwater/surface water modelling in many independent
reviews, /e.g. CDM 2001/. Each review has had different objectives and has used different criteria
in the review process. A number of references are available at DHI website (www.dhigroup.com).

3.15.5 Handling of input data, computational results and scripts
Input data is supplied to the code as text files, shape-files or ESRI-grid files. Result files are timeseries files, *.dfs0 or grid-files, *.dfs2 and *.dfs3. Both dfs0-files, dfs2-files and dfs3-files are easily
converted to text files. The dfs2-files can also directly be converted to GIS-format, shape-files or
ESRI-grid files. An ASCII log-file is produced for each simulation, this file can be used to checkfor errors, warnings and issues such as convergence. The MIKE SHE model can also be run using
a Graphical User Interface (GUI) which is documented by an on-line user manual.
Several modelling activities have provided the various external input data and models required for
the SR Site hydrological and near surface hydrogeological numerical modelling. The MIKE SHE
SDM model is the starting point for all model cases simulated within the SR-Site MIKE SHE modelling. The input data used in the SR-Site MIKE SHE modelling is described in /Bosson et al. 2010/.
All time series data from the site investigations, used as input data to the MIKE SHE model, arestored in the SKB Sicada database. Spatial distributed input data to the MIKE SHE models are stored
in the SKB GIS database. Models and data from other scientific disciplines in the SR-Site projectthat are used in the MIKE SHE SR-Site modelling are stored at SKB’s subversion server.
The MIKE SHE model generates numerous result data files. For practical reasons the model result
files cannot be uploaded on svn. A separate server at SKB has therefore been in use for storing the
MIKE SHE results files (G:\skb\modellering\mikeshe). The scripts used in MIKE SHE for SR-Site
are archived at SKB (SKBdoc 1263189, Table 1-2).
Details about all input data to the MIKE SHE SR-Site model and references to specific data extractions
from each database mentioned above are found in /Bosson et al. 2010/.

3.15.6 Rationales for using the code in SR-Site
MIKE SHE is regarded as a suitable code for solving the problem at hand, since it is a well documented
and internationally used and reviewed tool for calculating waterflows in the surface system.

3.16

Numerical GIA model

3.16.1 Introduction
The GIA (Glacial Isostatic Adjustment) code is used to calculate the isostatic adjustment of the solid
earth due to loading by ice and water during a glacial cycle. The gravitationally-consistent redistributionof water within the oceans is a central component of the algorithm, allowing accurate relative sea-leveland shoreline migration to be calculated.
In SR-Site the GIA code is used to reconstruct relative sea-level and shoreline positions in the regionof interest. It is also used to carry out sensitivity tests regarding e.g. the influence of earth and ice
model parameters on the output, see the Climate report.
The GIA code has been used in an extensive range of research projects. These include constraining
mantle viscosities /Milne et al. 2001, 2004/, constraining former ice sheet volumes /Milne et al. 2002/,
understanding Holocene sea-level change and modelling GIA effects around the world /Mitrovica and46

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Milne 2002, Gehrels et al. 2004, Milne et al. 2005, 2006/, testing global melt scenarios /Clark et al.
2002, Bassett et al. 2005/, investigating the effect of 3D earth structure on GIA predictions /Whitehouse
et al. 2006/, and identifying present-day melt sources and constraining the recent mass balance ofpolar ice sheets /Mitrovica et al. 2001, Tamisiea et al. 2001, 2003/. The GIA code was also used for
the SR-Can safety assessment /SKB 2006a/.
The GIA code is a category 4b code, written in Fortran, and has been developed by Dr. G.A. Milneover a number of years in collaboration with Prof. J.X. Mitrovica at the University of Toronto /Milne
1998, Milne and Mitrovica 1998, Milne et al. 1999/. The complete version of the code, which
includes all of the advances described below, is used by a small user base of postgraduate students
and postdoctoral researchers working in either Milne’s or Mitrovica’s research groups. The versionof the code used for SR-Site is the one described in /Mitrovica and Milne 2003/.

3.16.2 Suitability of the code
The GIA code solves the sea-level equation /Farrell and Clark 1976/ via the pseudospectral approachdeveloped by /Mitrovica and Peltier 1991/. The code has been significantly extended since this timeto account for several different processes and thus improve the accuracy of the computation. Firstly,
time-dependent shoreline positions are taken into account when calculating the ocean-loading function.
Secondly, the water influx to regions vacated by retreating, marine-based ice is carefully accounted forin the distribution of the load /Milne et al. 1999/. Thirdly, changes to the rotational state of the Earth
as a result of both surface and internal mass redistributions are considered /Mitrovica et al. 2005/. And
fourthly, the impact of lateral variations in Earth structure is taken into account when calculating thesolid Earth response to loading. The theory that the most recent version of the code is based on, andthe algorithm employed to solve the governing equations, are described in /Mitrovica and Milne 2003/
and /Kendall et al. 2005/, the extension of the code to include lateral structure is described in /Latychev
et al. 2005/. These publications define the state-of-the-art in computing sea-level changes associatedwith glaciation.
The code has a number of built-in analytical checks to ensure that the output is correct.

3.16.3 Usage of the code
Due to the nature of the development of the GIA code, and the intended user base, there is no formal
documentation available. The correct usage of the code is assured since the numerical GIA model isused, in the SR-Site project, by scientists working in close collaboration with the developer of the code.
The version used in SR-Site is described in /Mitrovica and Milne 2003/.
The input data and parameters required by the GIA model are: 4D (spatial and temporal) global ice
history for the duration of the model run; various radial Earth properties including the viscous properties of the Earth’s mantle, the thickness of the Earth’s lithosphere, elastic structure, density structure,and gravitational acceleration, as well as data relating to the shape of the Earth and its rotation (flattening
coefficient and spin rate); and a global topography data set. The model was run over a range of time
periods when carrying out the sensitivity tests, and time steps varied between 500 and 7,000 years,
depending on the level of resolution required. Details of model setups and input data for individual
SR-Site simulations are found in the Climate report.
At each time step, output data relating to relative sea-level, the height of the equilibrium sea surface,and solid earth deformation are calculated at each grid node. The computations are performed in thespherical harmonic domain at a truncation suitable for the region of study. For Fennoscandia, a truncation of 256 degree and order enables accurate predictions of relative sea-level and solid Earth deformation (vertical and horizontal). The model output is stored as an array of spherical harmonic coefficientsand so predictions can be generated for any point on the surface of the Earth at each time step.

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3.16.4 Development process and verification
In developing the code, a number of comparisons were made to analytical solutions wherever possible
to test the accuracy of the numerical schemes employed.
A small number of research groups have developed their own sea-level code based on the resultspresented in the papers referenced above. However, not all versions include the latest developments
discussed in the most recent papers (e.g. /Mitrovica and Milne 2003/). The solid earth response to
GIA-loading has recently been successfully benchmarked between several groups (http://www.fis.
uniurb.it/spada/GIA_benchmark_results.html ), but a systematic benchmark of the full sea-level
equation is still in progress.
For the SR-Site work it was necessary to determine shoreline positions within the Gulf of Bothnia
during periods when the Gulf was cut off from the oceans, and a lake formed above sea level. The
code was adapted to meet this specific requirement.

3.16.5 Handling of input data, computational results and scripts
Data were transferred between the ice sheet (UMISM, see Section 3.22), GIA, and permafrost
simulations (see Section 3.17) by text or Excel-files. Figure 3-2 shows the input and output data
shared between the three models. Data are archived in SKBdoc 1265613 (Table 1-2).
3.16.6 Rationales for using the code in SR-Site
The GIA code was used in SR-Site for simulating isostatic changes during the last glacial cycle for
input to safety assessment calculations. The code was selected for the SR-Site safety assessment
since it is one of the world-leading in its field.

Input:Air temperature

Air temperature
Ice sheet:- thickness- extent

Ice sheet:- thickness- basal temperature
Relative sea level

Ice sheet model

Output: Ice sheet:- thickness- extent- basal temperature

GIA model

Permafrost model

Relative sea level

Permafrost
Frozen groundFigure 3-2. Data transferred between the ice sheet (UMISM), GIA, and permafrost simulations.

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3.17

Numerical permafrost model

3.17.1 Introduction
The numerical permafrost model code, written in Fortran, is used to calculate the developmentof permafrost and perennially frozen ground. Originally, the code was developed at the Helsinki
University of Technology for soil freezing problems /Hartikainen 1994/ being built on a general
finite element solver code for non-linear non-stationary problems /Freund and Lempinen 1994/.
The first version of the numerical permafrost model code was written for the international project
DECOVALEX III in order to investigate thermo-hydro-mechanical impacts of processes associatedwith freezing and thawing of subsurface during periods of glaciation/deglaciation on the long-term
performance of a hypothetical post-closure repository /Hartikainen 2004, Chan et al. 2005/.
Thereafter, the code has been used in SR-Can /SKB 2006a/ to make a 1D reconstruction of thedevelopment of permafrost and perennially frozen ground at Forsmark during the last glaciation
cycle and to perform sensitivity analyses on the important factors and parameters affecting thedevelopment of permafrost and frozen ground.
For SR-Site the code was updated to deal with spatially varying surface conditions and salt transport
as well as to solve large systems of equations. The second version of the code was then used toinvestigate and demonstrate effects of multidimensional features of surface and subsurface conditions on the occurrence, development and distribution of permafrost and perennially frozen groundin a 2D vertical cross-section at Forsmark /Hartikainen et al. 2010/. The study included features suchas varying climate conditions, water bodies and topography, lateral variations in physical properties
and heat generation from the spent fuel as well as effects of the phase change of saline water,
groundwater flow and salt transport. The code is classified as a category 4b code.

3.17.2 Suitability of the code
The second version of the code solves the equations of energy balance and mass balance of groundwater, ice and salts together with the generalized Clausius-Clapeyron equation of the phase change
between water and ice, the Darcy equation of groundwater flow and the equation of non-Fickian salt
diffusion /Hartikainen et al. 2010/. The model, considering the ground as saline water saturated
porous medium, includes a description of the following physical processes:••••

heat and mass transfer in freezing and thawing ground,phase change of groundwater being affected by groundwater pressure and salt concentration,
exclusion of salt during freezing,density dependent groundwater flow in unfrozen and partially frozen ground.

Anisotropies of material properties such as permeability and thermal conductivity are allowed.
Information on surface conditions including air temperature, ice-sheet thickness, basal temperature,
shoreline migration, and vegetation are given as time varying boundary conditions.
The code is based on the finite element method and implicit time integration schemes, and solves theabove-mentioned coupled nonlinear partial differential equations using a consistent regularisation
technique for discontinuities due to phase changes and the Newton-Raphson method for the nonlinear
problem /Mikkola and Hartikainen 2002/, and the preconditioned stabilized bi-conjugate gradientalgorithm /van der Vorst 1992/ for the system of linearized equations.
Prior to the SR-Site project, the code has been used in several research projects including soil freezing
problems /Hartikainen and Mikkola 1997, 2006, Mikkola and Hartikainen 2001, 2002/, and developmentof permafrost and perennially frozen ground /Hartikainen 2004, 2006, Chan et al. 2005, SKB 2006a/.

3.17.3 Usage of the code
Description of the first version of the code is given in /Freund and Lempinen 1994, Hartikainen 1994,
2004/, while the model settings for the second version of the code, as well as SR-Site input and output
data to the model, are described in /Hartikainen et al. 2010/.

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3.17.4 Development process and verification
The model development and verification for the second version of the code as well as the consistencyof results between the second and first version of the code can be found in /Hartikainen et al. 2010/.
3.17.5 Handling of input data, computational results and scripts
In the code, both input and output data as well as the runtime information of solution convergenceand progress are dealt with in ASCII format, how data is transferred between the ice sheet (UMISM),
GIA, and permafrost simulations is shown in Figure 3-2. MATLAB and COMSOL are used to pre- andpost-process the data. Data are archived in SKBdoc 1265613 (Table 1-2).
3.17.6 Rationales for using the code in SR-Site
The code was selected for the SR-Site safety assessment since it is one of the world-leading in its field.
The code was used in SR-Site for simulations of freezing of saturated bedrock for a reconstructing
last glacial cycle conditions and for a number of sensitivity tests.

3.18

PHAST

3.18.1 Introduction
PHAST v.1 /Parkhurst et al. 2004/ simulates multi-component, reactive transport in 3D saturated
groundwater flow systems. PHAST is a versatile groundwater flow and solute transport simulator
with capabilities to model a wide range of equilibrium and kinetic geochemical reactions. The flow
and the transport calculations are based on a modified version of HST3D /Kipp 1987, 1997/ that is
restricted to constant fluid density and constant temperature. The geochemical reactions are simulatedwith the geochemical code PHREEQC /Parkhurst and Appelo 1999/, which is imbedded in PHAST.
PHAST has been used in the SR-Site assessment for modelling oxygen transport (melt water
enriched in oxygen) during episodes of a glaciation cycle.
PHAST has also been used for the assessment of the interaction of the fully water-saturated bentonite withgroundwater through a series of tree-dimensional (3D) numerical models /Sena et al. 2010a /.
PHAST has been also used as numerical tool in previous performance assessment studies at SKB/Arcos et al. 2006, Grandia et al. 2006, Luna et al. 2006, Domènech et al. 2006, Grandia et al. 2007,
Sena et al. 2008/.
The version of the code is regurarly updated. The code and revision history is available at(http://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phast/index.html). The latest version is PHAST
v.2.0.2. Due to the frequent release of new revisions of the code, different versions of the code has
been used, but most of the work performed in the SR-Site has been carried out using the version
v.1.5.1.
Since the code is an open source code, of a large user base and not written exclusively for the SR-Siteproject, the code is regarded as a category 3 code.

3.18.2 Suitability of the code
PHAST is a robust geochemical code able to model the different geochemical processes of interest in
the SR-Site assessment.
The PHAST simulator is a general computer code with the capability to model various reaction
chemistry formulations (homogeneous equilibria using an ion-association thermodynamic model,
heterogeneous equilibria between the aqueous solution and minerals, gases, surface complexation sites,
ion exchange sites, solid solutions, and kinetic reactions). It can handle various equation-discretisation,
types of boundary conditions (specified-head, flux and leaky conditions), source-sink, and equationsolver options. Four types of flow and reactive transport simulations can be performed with PHAST:50

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steady-state simulation of groundwater flow, transient simulation of groundwater flow, steady-state
simulation of flow followed by reactive transport and transient simulation of flow with reactive
transport. PHAST is applicable to the study of natural and contaminated groundwater systems at avariety of scales ranging from laboratory experiments to local and regional field scales /Parkhurst et al.
2004/. However, PHAST is not suitable for some types of reactive transport modelling, in particular forunsaturated zone flow, and simulating transport of gas phases and non-aqueous liquid phases. On theother hand, PHAST is restricted to constant temperature and density.
PHAST solves a set of partial differential equations for flow and transport and a set of nonlinear algebraic and ordinary differential equations for chemistry. The equations that are solved numerically are
the saturated groundwater flow equation for conservation of total fluid mass, a set of solute-transport
equations for conservation of mass of each solute component of a chemical-reaction system, and aset of chemical-reaction equations comprising mass balance equations, mass-action equations andkinetic-rate equations. The groundwater flow and solute-transport equations are coupled through thedependence of advective transport on the interstitial fluid-velocity field. The solute-transport equations
and the chemical equations are coupled through the chemical concentrations terms. The chemical
equations are fully coupled through the concentration terms and must be solved simultaneously.
By using a sequential solution approach for flow, transport and reaction calculations, numericalsolutions are obtained for each of the dependent variables. Operator splitting is used to separate thesolute-transport calculations from the chemical reactions calculations. Finite differences techniques
are used for the spatial and temporal discretisation of the flow and transport equations.
The aqueous model for PHAST is an ion-association model that is applicable to ionic strengths to
1 molal. Thus, PHAST is not an appropriate simulator for many systems and processes, includingtransport of volatile organic compounds in a soil zone, hydrothermal systems, most high ionic-strengthbrines, or heat storage and recovery in aquifers. More detailed information on the geochemical andtransport equations that can be solved using this code can be obtained from the PHAST user’s manual/Parkhurst et al. 2004/.

3.18.3 Usage of the code
In the PHAST user’s manual /Parkhurst et al. 2004/ the program is explained in detail anda lot of examples are provided. In addition to this document the web page of the authors(http://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phast/index.html) also contains a lot of
information and well documented examples as well as an active and interactive section of FAQ.
Reactive-transport simulations with PHAST require three input files: a flow and transport data file,a chemistry data file, and a thermodynamic data file. All data files are built with modular keyword
data blocks. Each data block defines a specific kind of information (e.g. grid locations, boundaryconditions information, or initial chemical composition). All spatial data are defined by zones, which
are rectangular volumes. All this information is easily introduced by means of .dat files.
Simulations results can be saved in a variety of file formats (ASCII or binary HDF). Results can bethus, easily post-processed by using the program PHASTHDF to extract subsets of the data stored in
the HDF file and the program MODEL VIEWER (only for Windows) to produce 3D visualizationsof the problem definition and of the simulation results. Both programs are distributed together with
PHAST.

3.18.4 Development process and verification
This is an open source computer code developed by the United States Geological Survey. The codeis widely used and its algorithm has been checked through several scientific publications and throughthe example files distributed with the computer program.
3.18.5 Handling of input data, computational results and scripts
All input and output files to PHAST are ASCII text files. Three types of input files are needed: athermodynamic data base, described in the Data Report, and two input files. One of them describes

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the initial composition of the aqueous solutions in each volume (for each material), and the mineral
precipitation/dissolution reactions to be modelled. The other input file describes the grid, the transportparameters, including the time discretisation, and the boundary conditions.
For the modelling of oxygen intrusion along a fracture and into the rock matrix, the input files werecreated with a text editor. The output file, which consists of lines of text with column data, may bedirectly imported into other programs, such as Microsoft’s Excel, for plotting.
The data used for modelling of oxygen ingress in SR-Site are archived at SKB (SKBdoc 1265689,
see Table 1-2). The data used for modelling of bentonite – groundwater interaction are archived in
SKBdoc 1265807 (Table 1-2).

3.18.6 Rationales for using the code in SR-Site
The SR-Site team has selected the PHAST code since it is useful to solve 3D fluid flow and reactive
transport problems (advection, diffusion and dispersion) under water saturated conditions. The levelof knowledge of this program is high and well-supported.

3.19

PHREEQC

3.19.1 Introduction
PHREEQC v.2 /Parkhurst and Appelo 1999/ is a computer program written in the C programming
language that is designed to perform a wide variety of low-temperature aqueous geochemical
calculations.
It has been used in the near-field (canister and the engineered systems) in several ways. In somecases it has been directly used to perform simple 1D transport modelling but in most cases has
been used as a pre-conditioning tool for large scale 2D simulations performed with other codes. In
SR-Site, it has been used for simulations of the evolution of the groundwater composition within thecandidate repository site of the Forsmark and Laxemar areas assuming different climate conditions
and hydrological situations. The hydrochemical calculations have been performed by simulating
mixing of five end-member waters and mineral equilibrium reactions.
PHREEQC has been also used as numerical tool in previous performance assessment studies at SKB
and elsewhere /Duro et al. 2006, Grivé et al. 2010a, Guimerà et al. 2006/.
The version of the code is regularly updated. The code and revision history is available at(http://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/index.html). The latest version of thecode is PHREEQC 2.17 (SIT “Specific Interaction Theory”). Due to the frequent release of newrevisions of the code, different versions of the code has been used. However, most of the work
performed has been carried out using PHREEQC v.2.10.
Since the code is an open source code, of a large user base and not written exclusively for the
SR-Site project, the code is regarded as a category 3 code.

3.19.2 Suitability of the code
For the modelling of chemical behaviour at the candidate repository sites (Forsmark and Laxemar),under different climatic periods and hydrological assumptions, PHREEQC is a suitable tool. It
can be used as a speciation program to calculate saturation indices as well as spatial and temporal
distribution of aqueous species by mixing of solutions and considering equilibrium with mineralphases (including redox elements).
PHREEQC is based on equilibrium chemistry of aqueous solutions interacting with minerals, gases,
solid solutions, exchangers and sorption surfaces, but also includes the capability to model kinetic
reactions with rate equations specified in the form of Basic statements. It also includes a 1D transport

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algorithm that comprises dispersion, diffusion and various options for dual porosity media. Moredetailed information on the geochemical and transport equations that can be solved using this code
can be obtained from the PHREEQC v.2 user’s manual /Parkhurst and Appelo 1999/.
Several limitations need to be considered. PHREEQC uses ion-association and Debye-Hückel expressions to account for the non-ideality of aqueous solutions /Parkhurst and Appelo 1999/. This type ofaqueous model is adequate at low ionic strength, but may break down at higher ionic strengths (in therange of seawater). Other limitation of the aqueous model is lack of internal consistency in the datain the databases. On the other hand, in reference to surface complexation calculations, PHREEQC
incorporates the generalized two-layer model, a two-layer model that explicitly calculates diffuse-layercompositions, and a non-electrostatic surface-complexation model. Other model have not been
implemented. With respect to solid solution simulations, ternary non-ideal solid solutions are not also
implemented.

3.19.3 Usage of the code
In the PHREEQC v.2 user’s manual /Parkhurst and Appelo 1999/ the program is explained in detailand a lot of examples are provided. In addition to this document, the web pages of both authors(http://www.xs4all.nl/~appt/a&p/ and http://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/)
also contain a lot of information and well documented examples as well as an active and interactive
section of FAQ.
Input data is easily introduced by means of the edit tool provided by the same program. Selected
output data can be obtained in ASCII-text formatted files that can be read and modified with
Microsoft Excel program or similar.

3.19.4 Development process and verification
This is an open source computer code developed by the United States Geological Survey. The code is
widely used and its algorithm has been checked through several scientific publications and throughthe example files distributed with the computer program.
3.19.5 Handling of input data, computational results and scripts
All input and output files to PHREEQC are ASCII text files. Two types of input files are needed: athermodynamic data base, described in the Data Report, and an input file describing the mineral
precipitation/dissolution reactions to be modelled (either equilibrium or kinetically controlled), andmixing if included in the model. Diffusion processes can also be specified in this input file.
For the modelling of the geochemical evolution of the groundwaters at Forsmark during a glacial
cycle, simple computer programs were devised to create input files and to read and extract data fromthe output files. These programs and the procedure is described in detail in the Appendix of /Salas
et al. 2010/. The output from the hydrogeological models, in terms of spatial coordinates, salinitities
and, if available, mixing proportions of reference waters, together with the composition of thesereference waters, was used to construct the input files to PHREEQC /Salas et al. 2010/.
For the modelling of oxygen intrusion into the rock matrix, the format of an output file from PHREEQC(“selected output”) is controlled through the input file. The selected output file, which consists of linesof text with column data, may be directly imported into other programs, such as Microsoft’s Excel, forplotting.
The data used for SR-Site are archived at SKB (SKBdoc 1262945 and SKBdoc 1265689, see Table 1-2).

3.19.6 Rationales for using the code in SR-Site
The SR-Site team has selected the PHREEQC code because it is useful to characterize mixturesof solutions in equilibrium with mineral phases, considering simplistic 1D transport calculations,and for a high number of simulated points characterised by different mixing fractions. The level ofknowledge of this program is high and well-supported.

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3.20

Solubility model (Simple Functions)3.20.1 Introduction
The Simple Functions spreadsheet is a tool to determine the solubility limits of radionuclides especiallydesigned for Performance Assessment exercises. This tool has been developed in an Excel spreadsheet,
and as such, it belongs to category 4b.
The development of this tool was promoted by the necessity of having a confident and easy-to-handle
tool to calculate solubility limits in an agile and relatively fast manner. It was originally built up
by Amphos 21 in the frame of the SR-Can project as a request by SKB. Later, it was improvedby adding uncertainty calculation. The most recent update /Grivé et al. 2010b/ incorporates recent
thermodynamic data changes and provides two versions, which differ in the conditions under which
the solubility assessment is done:•

VERSION A is designed to calculate radionuclide solubility limits in representative groundwatercompositions supplied by the user.

•

VERSION B is designed to calculate radionuclide solubility limits in a groundwater that has
interacted with Fe-corrosion products.

3.20.2 Suitability of the code
This tool is an Excel spreadsheet that contains the simple algorithms needed to determine the solid
phase that may exert the solubility control under the conditions of interest for a given radionuclide
and its solubility.
The aim of the Simple Functions spreadsheet is to facilitate the calculation of the solubility limits.
Current geochemical codes calculate the speciation of many different elements in solution, and use
an associated thermodynamic database containing the stoichiometry and stability of every aqueousand solid species. Most of these thermodynamic databases are exhaustive, in an attempt to cover awide range of water compositions and they contain information on aqueous species that only appear
under very specific water compositions which have been judged to be of no interest for the current
solubility assessment.
The Simple Functions spreadsheet is tailored for the conditions of interest and contains only those species accounting for at least 10% of the total element in solution under the following range of conditions:
•
•
•
•
•
•
•

T = 25ºC.
I ≤ 0.2m (ionic strength (I) in molality units (m)).
6 < pH < 11.
–8 < pe < 14.
5·10–5 < [SO4] < 5·10–2 (range of interest for SR-Site).
10–4 < [CO3] < 5·10–3 (range of interest for SR-Site).
In VERSION A, [Fe]aq range given by the user; in VERSION B [Fe]aq is given by the equilibrium
magnetite/goethite at the pH of interest.

The elements included in the Simple Functions spreadsheet are Sr, Ra, Ni, Sn, Se, Ag, U, Zr, Nb,
Pa, Np, Pu, Am, Cm, Tc, Pd, Sm, Ho, Th and Pb. Moreover the aqueous speciation of the following
major elements is also considered: HCO3–, SO42–, Cl–, Ca2+, Na+ and Fe2+.

3.20.3 Usage of the code
The capabilities of Simple Functions spreadsheet are described in the Simple Functions Spreadsheet
tool presentation report /Grivé et al. 2010/. Input data are directly supplied into the Excel spreadsheet
where the user can also find the output results.
This tool can be used together with the @RISK application (add-in to Microsoft Excel, see
http://www.palisade.com/risk/) to perform probabilistic calculations.

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3.20.4 Development process and verification
The Simple Functions spreadsheet has been developed as an easy-handling tool to calculate ranges
and distributions of solubility limits to be used in the radionuclide transport calculations. Because of
its simplicity, calculations are less complete than those used in other geochemical codes.
Simple Functions Spreadsheet tool presentation report /Grivé et al. 2010/ includes results of a benchmarking exercise in which the solubilities calculated with Simple Functions spreadsheet have been
compared with the solubilities calculated with the code PHREEQC /Parkhurst and Appelo 2001/ andin some cases calculated with the code HYDRA-MEDUSA /Puigdomènech 2002/.
The validity of the activity correction approach used in the Simple Functions spreadsheet to calculate
solubility values at high ionic strengths and the uncertainty associated with the Simple Functions
spreadsheet calculations in the case of groundwater temperatures different from 25ºC (in the range
0 to 100ºC) have also been tested and reported in /Grivé et al. 2010/.
The influence of temperature appears to be more important than that of the ionic strength, but inview of the results of the validation process, the Simple Functions spreadsheet can be considered
a good tool for an easy and fast calculation of the solubility of radionuclides under the different
groundwater compositions and temperatures of interest for SR-Site, always used with caution andkeeping in mind its limitations.

3.20.5 Handling of input data, computational results and scripts
The Simple Functions spreadsheet code is an Excel file. It is a user-friendly tool that requires the
input of a groundwater composition and provides the concentration of radionuclides in equilibriumwith their respective solubility limiting phases under the conditions of the groundwater composition.
Therefore, any groundwater composition (calculated or measured) can be introduced in the tool.
Calculated radionuclide concentrations can be directly used in other codes.
In SR-Site, groundwater data is supplied to the tool, which contains the uncertainties in thermodynamic
data for the relevant reactions. The output produced is the solubility limit for the radioelements. Together
with the @RISK tool, Simple Functions is used to calculate distributions of solubility to be used in
the radionuclide transport calculations in SR-Site.
The data used for SR-Site are archived at SKB (SKBdoc 1265616, see Table 1-2).

3.20.6 Rationales for using the code in SR-Site
The SR-Site team has selected the Simple Functions Spreadsheet for the SR-Site safety assessment
since it is a tailor-made tool for the production of probabilistic distributions of radioelement solubilities.
The results produced by the tool are in good agreement with those from conventional geochemical
codes (e.g. PHREEQC).

3.21

TOUGHREACT

3.21.1 Introduction
TOUGHREACT is used in SR-Site for simulations of reactive transport in the buffer /Sena et al. 2010a/.
TOUGHREACT v.1.2 /Xu et al. 2008/ results from coupling the calculation of geochemical reactions
to the THOUGH2 code /Pruess et al. 1999/, which solves multiphase, non-isothermal fluid flow, heatflow and multi-component transport. Aqueous complexation, gas dissolution/ex-solution and cationexchange are modelled under local equilibrium. Mineral precipitation/dissolution may be modelledeither under equilibrium or kinetics assumptions. Additionally, changes in porosity, permeability andcapillary pressure may be computed /Pruess et al. 1999/.
TOUGHREACT has been used by SKB in the “SKB-NF-2009” /Sena et al. 2010a/ and “LOT-A2
experiment”/Sena et al. 2010b/ projects. In the project “LOT-A2 experiment”, a 1D axis-symmetricmodel was developed to simulate the thermo-hydraulic, transport and geochemical processes that
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have been observed during the LOT A2 test. In the SKB-NF-2009 project, the effect of the thermal
period and the water saturation are analysed. These simulations are based on the outcomes of theprevious numerical model built for the simulation of the LOT-A2 experiment.
Since the code is not written exclusively for the SKB projects, the code is regarded as a category 3 code.

3.21.2 Suitability of the code
The first version of the code was developed by introducing reactive geochemistry into the frameworkof the existing multi-phase fluid and heat flow code TOUGH2 /Pruess 1991/. The present version of
TOUGHREACT provides the following equation-of-state modules: EOS1, with typical applications
to hydrothermal problems, EOS2 for multiphase mixtures of water and CO2 with typical applications
to hydrothermal problems, EOS3 for multiphase mixtures of water and air with typical applications
to nuclear waste disposal problems, EOS4 with the same capabilities as EOS3 but with vapour pressure
lowering effects due to capillary pressure, EOS9 with typical applications to ambient temperature andpressure reactive geochemical problems, and ECO2N for multiphase mixtures of water, CO2 and NaClwith typical applications to CO2 disposal in deep brine aquifers.
More detailed information on the geochemical and fluid flow and transport equations solved can beobtained from the TOUGHREACT User’s Guide /Xu et al. 2008/ and the TOUGH2 User’s Guide,
version 2.0 /Pruess et al. 1999/.

3.21.3 Usage of the code
In the TOUGHREACT User’s Guide /Xu et al. 2008/ different examples have been included as test
problems (geothermal systems, diagenetic and weathering processes, subsurface waste disposal, acidmine drainage remediation, contaminant transport and groundwater quality). The major processes
for fluid and heat flow are: (1) fluid flow in both liquid and gas phases under pressure, viscous andgravity forces, (2) interactions between flowing phases represented by characteristic curves (relative
permeability and capillary pressure), (3) heat flow by conduction and convection, and (4) diffusionof vapor and air /Pruess et al. 1999/. Aqueous complexation, acid-base, redox, gas dissolution/ex-solution,and cation exchange are considered under local equilibrium. Mineral dissolution and precipitation canproceed either subject to local equilibrium or kinetic conditions /Xu et al. 2008/. Linear adsorption
and decay can be included.
3.21.4 Development process and verification
The code was developed by the Earth Sciences Division of the Lawrence Berkeley National Laboratory(University of California) as a comprehensive non-isothermal multi-component reactive fluid flow
and geochemical transport simulator to be applied to many geologic systems and environmental
problems. The code is widely used and its algorithm has been checked through several scientificpublications and through the example files distributed with the computer program.
3.21.5 Handling of input data, computational results and scripts
Input data and output results are easily treated by means text editors. Output data can be also easily
selected and obtained in .txt or .dat files that can be read and modified with Microsoft Excel program
or similar.
Three input files are required: (1) flow.inp, including rock properties, time-stepping, grid, initial andboundary conditions and data related to a multi-phase fluid and heat transport simulations /Pruess
et al. 1999/; (2) solute.inp, containing flags and input parameters for reactive transport calculations(diffusion coefficients, tolerances, e.g.); and (3) chemical.inp, defining the geochemical system,
initial water compositions, material zones, and kinetic data for minerals. In addition, the program
requires a thermodynamic database file.
The data used for SR-Site are archived at SKB (SKBdoc 1265618, see Table 1-2).

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3.21.6 Rationales for using the code in SR-Site
The SR-Site team has selected the TOUGHREACT code because it is useful to solve non-isothermal
and multicomponent reactive fluid flow and geochemical transport calculations. The level of knowledgeof this program is high and well-supported.

3.22

UMISM

3.22.1 Introduction
UMISM (University of Maine Ice Sheet Model) is a dynamic ice-sheet model capable of simulating
realistic ice sheets that are typically not in balance with climate (advances and retreats given changes
in external forcing).
UMISM is used in SR-Site for reconstructing the ice sheet for the last glacial for the constructionof the reference glacial cycle, and for input to simulations of other phenomena such as permafrost,
isostatic changes, crustal stress, and ground water flow. The UMISM code was also used for sensitivity
tests regarding e.g. maximum ice sheet thickness, see the SR-Site Climate report.
The UMISM has previously been used for simulations of Fennoscandian ice sheets for various purposes,
cf /Fastook and Holmlund 1994, Holmlund and Fastook 1995, Näslund et al. 2003/ and in SKB safetyassessments /SKB 2006a, 2008/.
The UMISM finite-element code (Fortran) has been developed by Prof. J. Fastook, at the Computer
Science Department at University of Maine, U.S.A., e.g. /Fastook and Chapman 1989, Fastook 1990,
1994, Fastook and Holmlund 1994, Fastook and Prentice 1994, Johnson 1994/. In SR-Site, the versionof UMISM as of October 2004/April 2005 was used. The code is classified as a category 4b code.

3.22.2 Suitability of the code
The climate input, forcing the ice sheet evolution, is the mean annual air temperature at sea level,
and its variation over time. The mass balance is determined from an empirical relationship constituting a simple parameterisation of the ice sheet’s effect on local climate /Fastook and Prentice 1994/.
Distributed air temperatures over the model domain are determined from height over sea level anddistance from the pole. The UMISM model includes a mathematical description of precipitation froma number of other parameters; distance from the pole, saturation vapour pressure (function of altitude
and laps-rate), and surface slope. This is an empirical relationship developed from the Antarctic ice
sheet /Fastook and Prentice 1994/. Over a certain model domain, with a topography described froma Digital Elevation Model (DEM), this climate description gives a spatial pattern of air temperaturesat ground level and a pattern of precipitation. Given a suitable climate forcing, the model develops athermo-dynamic ice sheet over the DEM. Derived ice temperatures, together with density variations
with depth, control ice hardness and ice flow. The thermodynamic calculation accounts for vertical
diffusion, vertical advection, and heating caused by internal shear.
The UMISM ice sheet model includes a simplified isostatic description for the deformation of thecrust due to the weight of the modelled ice sheet configuration. The UMISM code also includes ahigh-resolution modelling option by nesting.

3.22.3 Usage of the code
In the SR-Site ice sheet reconstruction simulations, inputs parameters to the model are: landscape
topography, geothermal heat flux, global sea-level variations, thermo-mechanical properties of theice, isostatic properties of the Earth’s crust, and annual air temperature at sea level. In these runs, theprogram simulates the ice sheet for 120,000 years with 5 year time steps. For each time step, output
data calculated for each grid cell and grid node are, for example,: ice thickness, englacial and basal
ice temperatures, ice velocity, direction of ice movement, isostatic depression of crust, and amountof basal melting or freeze-on of water.
Output data from UMISM can be saved in, e.g., txt format or NetCDF (Network Common Data
Form) format.
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Descriptions of model setups, as well as input data to the model, for SR-Site simulations are found in
the Climate report. The close collaboration with the developer of the code assures the correct usageof the code in SR-Site.

3.22.4 Development process and verification
UMISM was part of the EISMINT (European Ice Sheet Modelling Initiative) model intercomparison
experiment and yielded output in agreement with many other major ice sheet models /Huybrechts
et al. 1996, Payne et al. 2000/.
3.22.5 Handling of input data, computational results and scripts
The code was adapted to meet specific requirements during the modelling work, for instance to produce certain type of output data related to the production of glacial melt water. Specific output data
formats were also produced for data export to other SR-Site activities, such as the permafrost modelling /Hartikainen et al. 2010 and Climate report, Section 3.4/, Global Isostatic Adjustment (GIA)
modelling conducted at University of Durham by P. Whitehouse /Climate report, Section 3.3/, andfor modelling of crustal stresses performed at university of Uppsala performed by B. Lund /Lund
et al. 2009/. How data is transferred between the ice sheet (UMISM), GIA, and permafrost simulations is shown in Figure 3-2.
Data were transferred from the UMISM model to other SR-Site activities in Excel spread sheets.
Data are archived in SKBdoc 1265613 (Table 1-2).

3.22.6 Rationales for using the code in SR-Site
The UMISM code was selected for the SR-Site safety assessment since a very large number ofsimulations of the Fennoscandian ice sheet have been done with the UMISM model over the years.
This has resulted in considerable experience and understanding of how to do model calibrations
against geological observations in order to obtain more realistic ice sheet configurations, which ishighly relevant for the SR-Site safety assessment. An additional reason for choosing this model is therecognized ability and interest of the model developer to engage in validating and assessing model
results against real-world observations and phenomena related to the ice sheet system that is being
modelled. This is important in phases of model calibration as well as when adopting and developing
the model to specific needs of the project.

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4

References

SKB’s (Svensk Kärnbränslehantering AB) publications can be found at www.skb.se/publications.

References with abbreviated names

Buffer, backfill and closure process report, SKB 2010. Buffer, backfill and closure process reportfor the safety assessment SR-Site. SKB TR-10-47, Svensk Kärnbränslehantering AB.
Climate report, SKB 2010. Climate and climate-related issues for the safety assessment SR-Site.
SKB TR-10-49, Svensk Kärnbränslehantering AB.
Data report, SKB 2010. Data report for the safety assessment SR-Site. SKB TR-10-52, Svensk
Kärnbränslehantering AB.
Fuel and canister process report, SKB 2010. Fuel and canister process report for the safety assessment
SR-Site. SKB TR-10-46, Svensk Kärnbränslehantering AB.
Geosphere process report, SKB 2010. Geosphere process report for the safety assessment SR-Site.
SKB TR-10-48, Svensk Kärnbränslehantering AB.
Main report, SKB 2011. Long-term safety for the final repository for spent nuclear fuel at
Forsmark. Main report of the SR-Site project. SKB TR-11-01, Svensk Kärnbränslehantering AB.
Radionuclide transport report, SKB 2010. Radionuclide transport report for the safety assessment
SR-Site. SKB TR-10-50, Svensk Kärnbränslehantering AB.
Spent fuel report, SKB 2010. Spent nuclear fuel for disposal in the KBS-3 repository. SKB TR-10-13,
Svensk Kärnbränslehantering AB.
Underground openings construction report, SKB 2010. Design, construction and initial state of
the underground openings. SKB TR-10-18, Svensk Kärnbränslehantering AB.
Other public references

Abbott M B, Bathurst J C, Cunge J A, O’Connell P E, Rasmussen J, 1986. An introduction to
the European Hydrological System – Systeme Hydrologique Europeen, “SHE”, 2: Structure of aphysically-based, distributed modelling system. Journal of Hydrology, 87, pp 61–77.
Alonso E E, Gens A, Josa A, 1990. A constitutive model for partially saturated soils. Géotechnique,
40, No. 3, pp 405–430.
Andersson E (ed), 2010. The limnic ecosystems at Forsmark and Laxemar-Simpevarp. SR-Site
Biosphere. SKB TR-10-02, Svensk Kärnbränslehantering AB.
Andra, 2005. Dossier 2005 Granite – safety analysis of a geological repository. Châtenay-Malabry:
Agence nationale pour la gestion des déchets radioactifs (ANDRA).
Arcos D, Grandia F, Domènech C, 2006. Geochemical evolution of the near field of a KBS-3
repository. SKB TR-06-16, Svensk Kärnbränslehantering AB.
Avila R, Ekström P-A, Åstrand P-G, 2010. Landscape dose conversion factors used in the safetyassessment SR-Site. SKB TR-10-06, Svensk Kärnbränslehantering AB.
Bassett S E, Milne G A, Mitrovica J X, Clark P U, 2005. Ice sheet and solid Earth influences on
far-field sea-level histories. Science, 309, pp 925–928.
Beresford N, Brown J, Copplestone D, Garnier-Laplace J, Howard B, Larsson C-M, Oughton D,
Pröhl G, Zinger I (eds), 2007. D-ERICA: an INTEGRATED APPROACH to the assessment andmanagement of environmental risks from ionising radiation. Description of purpose, methodology
and application. ERICA Project, contract number FI6R-CT-2004-508847, European Commission.
Boghammar A, Grundfelt B, Hartley L, 1997. Investigation of the large scale regional hydrogeological situation at Ceberg. SKB TR 97-21, Svensk Kärnbränslehantering AB.
Boghammar A, 1999. Säkerhet och Vetenskap. Implementation and version control for softwaredeveloped by SKB. User’s Guide rev 2. SKB Arbetsrapport TS-99-13, Svensk Kärnbränslehantering AB.
TR-10-51

59

Bosson E, Gustafsson L-G, Sassner M, 2008. Numerical modelling of surface hydrology and nearsurface hydrogeology at Forsmark. Site descriptive modelling, SDM-Site Forsmark. SKB R-08-09,
Svensk Kärnbränslehantering AB.
Bosson E, Sassner M, Sabel U, Gustafsson L-G, 2010. Modelling of present and future hydrology
and solute transport at Forsmark. SR-Site Biosphere. SKB R-10-02, Svensk Kärnbränslehantering AB.
Bödvarsson R, Lund B, Roberts R, Slunga R, 2006. Earthquake activity in Sweden. Study in connection with a proposed nuclear waste repository in Forsmark or Oskarshamn. SKB R-06-67, Svensk
Kärnbränslehantering AB.
Börgesson L, Hernelind J, 1999. Coupled thermo-hydro-mechanical calculations of the water
saturation phase of a KBS-3 deposition hole. Influence of hydraulic rock properties on the water
saturation phase. SKB TR-99-41, Svensk Kärnbränslehantering AB.
Börgesson L, Hernelind J, 2006a. Canister displacement in KBS-3V. A theoretical study.
SKB TR-06-04, Svensk Kärnbränslehantering AB.
Börgesson L, Hernelind J, 2006b. Earthquake induced rock shear through a deposition hole.
Influence of shear plane inclination and location as well as buffer properties on the damage caused
to the canister. SKB TR-06-43, Svensk Kärnbränslehantering AB.
Börgesson L, Johannesson L-E, Hernelind J, 2003. Earthquake induced rock shear through adeposition hole. Effect of the canister and the buffer. SKB TR-04-02, Svensk Kärnbränslehantering AB.
Börgesson L, Fälth B, Hernelind J, 2006. Water saturation phase of the buffer and backfill in theKBS-3V concept. Special emphasis given to the influence of the backfill on the wetting of the buffer.
SKB TR-06-14, Svensk Kärnbränslehantering AB.
Cappa F, Guglielmi Y, Rutqvist J, Tsang C-F, Thoraval A, 2006. Hydromechanical modelling ofpulse tests that measure fluid pressure and fracture normal displacement at the Coaraze Laboratory
site, France. International Journal of Rock Mechanics and Mining Sciences, 43, pp 1062–1082.
CDM, 2001. Evaluation of integrated surface water and groundwater modelling tools. Camp Dresser
and McKee, Cambridge MA.
Chan T, Christiansson R, Boulton G S, Ericsson L O, Hartikainen J, Jensen M R, Mas Ivars D,
Stanchell F W, Vistrand P, Wallroth T, 2005. DECOVALEX III BMT3/BENCHPAR WP4: The
thermo-hydro-mechanical responses to a glacial cycle and their potential implications for deep geologicaldisposal of nuclear fuel waste in a fractured crystalline rock mass. International Journal of RockMechanics and Mining Sciences, 42, pp 805–827.
Clark P U, Mitrovica J X, Milne G A, Tamisiea M E, 2002. Sea-level fingerprinting as a direct test
for the source of global meltwater pulse IA. Science, 295, pp 2438–2441.
Cliffe K A, Kelly M, 2006. COMP23 version 1.2.2 user’s manual. SKB R-04-64, Svensk Kärn­
bränslehantering AB.
CODE_BRIGHT User’s Guide, 2009. Geotechnical Engineering Department, Technical Universityof Catalunya, Spain.
CODE_BRIGHT v3 Validation document, 2009. Geotechnical Engineering Department, Technical
University of Catalunya, Spain.
CODE_BRIGHT v3 Verification document, 2009. Geotechnical Engineering Department,
Technical University of Catalunya, Spain.
Cundall P A, 1971. A computer model for simulating progressive, large scale movements in blocky
rock systems. In: Rock Fractures: Proceedings of the International Symposium on Rock Mechanics,
Nancy, France, October 1971, paper II-8.
DHI, 2009. MIKE SHE – User Manual. DHI Water & Environment, Hørsholm, Denmark.
Domènech C, Arcos D, Duro L, Grandia F, 2006. Effect of the mineral precipitation-dissolution
at tunnel walls during the operational and post-operational phases. SKB R-06-108, Svensk Kärn­
bränslehantering AB.
Duro L, Grivé M, Cera E, Gaona X, Domènech C, Bruno J, 2006. Determination and assessmentof the concentration limits to be used in SR-Can. SKB TR-06-32, Svensk Kärnbränslehantering AB.
60

TR-10-51

Ekström P-A, 2011. Pandora – a simulation tool for safety assessments. Technical description anduser’s guide. SR-Site Biosphere. SKB R-11-01, Svensk Kärnbränslehantering AB.
Elert M, Gylling B, Lindgren, M, 2004. Assessment model validity document FARF31.
SKB R-04-51, Svensk Kärnbränslehantering AB.
Farrell W E, Clark J A, 1976. On postglacial sea level. Geophysical Journal of the Royal
Astronomical Society, 46, pp 647–667.
Fastook J L, 1990. A map-plane finite-element program for ice sheet reconstruction: a steady-state
calibration with Antarctica and a reconstruction of the Laurentide ice sheet for 18,000 BP. In: Brown
H U (ed). Computer assisted analysis and modeling on the IBM 3090. White Plains, N.Y.: IBM
Scientific and Technical Computing Department.
Fastook J L, 1994. Modeling the ice age: the finite-element method in glaciology. Computational
Science & Engineering, 1, pp 55–67.
Fastook J L, Chapman J E, 1989. A map plane finite-element model: three modeling experiments.
Journal of Glaciology, 35, pp 48–52.
Fastook J L, Holmlund P, 1994. A glaciological model of the Younger Dryas event in Scandinavia.
Journal of Glaciology, 40, pp 125–131.
Fastook J L, Prentice M, 1994. A finite-element model of Antarctica: sensitivity test for meteorological mass-balance relationship. Journal of Glaciology, 40, pp 167–175.
Ferry M, 2002. MIGAL. www.mfrdc.com
Follin S, 2008. Bedrock hydrogeology Forsmark. Site descriptive modelling, SDM-Site Forsmark.
SKB R-08-95, Svensk Kärnbränslehantering AB.
Follin S, Stigsson M, Svensson U, 2005. Variable-density groundwater flow simulations andparticle tracking – Numerical modelling using DarcyTools, Preliminary site description Simpevarp
subarea – version 1.2. SKB R-05-11, Svensk Kärnbränslehantering AB.
Freund J, Lempinen A, 1994. A general purpose finite element solver. Report 40, Institute ofComputational Dynamics, Helsinki University of Technology.
Fälth B, Hökmark H, 2006. Seismically induced slip on rock fractures. Results from dynamic
discrete fracture modeling. SKB R-06-48, Svensk Kärnbränslehantering AB.
Fälth B, Hökmark H, 2007. Mechanical and thermo-mechanical discrete fracture near-field
analyses based on preliminary data from the Forsmark, Simpevarp and Laxemar sites. SKB R-06-89,
Svensk Kärnbränslehantering AB.
Fälth B, Hökmark H, Munier R, 2010. Effects of large earthquakes on a KBS-3 repository.
Evaluation of modelling results and their implications for layout and design. SKB TR-08-11, Svensk
Kärnbränslehantering AB.
Gehrels W R, Milne G A, Kirby J R, Patterson R T, Belknap D F, 2004. Late Holocene sea-levelchanges and isostatic crustal movements in Atlantic Canada. Quaternary International, 120, pp 79–89.
Graham D N, Butts M B, 2005. Flexible, integrated watershed modelling with MIKE SHE. In:
Singh V P, Frevert D K (eds). Watershed Models. Boca Raton: CRC Press, pp 245–272.
Grandia F, Domènech C, Arcos D, Duro L, 2006. Assessment of the oxygen consumption in
the backfill. Geochemical modelling in a saturated backfill. SKB R-06-106, Svensk Kärn­
bränslehantering AB.
Grandia F, Sena C, Arcos D, Molinero J, Duro L, Bruno J, 2007. Quantitative assessment ofradionuclide retention in the near-surface system at Forsmark. Development of a reactive transportmodel using Forsmark 1.2 data. SKB R-07-64, Svensk Kärnbränslehantering.
Grandia F, Galindez J-M, Arcos D, Molinero J, 2010. Quantitative modelling of the degradation
processes of cement grout. Project CEMMOD. SKB TR-10-25, Svensk Kärnbränslehantering AB.
Grivé M, Domènech C, Montoya V, Garcia D, Duro L, 2010a. Determination and assessmentof the concentration limits to be used in SR-Can. Supplement to TR-06-32. SKB R-10-50, Svensk
Kärnbränslehantering AB.

TR-10-51

61

Grivé M, Domènech C, Montoya V, García D, Duro L, 2010b. Simple Functions Spreadsheet tool
presentation. SKB TR-10-61, Svensk Kärnbränslehantering AB.
Guimerà J, Duro L, Delos A, 2006. Changes in groundwater composition as a consequenceof deglaciation. Implications for performance assessment. SKB R-06-105, Svensk Kärn­
bränslehantering AB.
Gustafsson L-G, Gustafsson A-M, Aneljung M, Sabel U, 2009. Effects on surface hydrology andnear surface hydrogeology of an open repository in Forsmark. Results of modelling with MIKE
SHE. SKB R-08-121, Svensk Kärnbränslehantering AB.
Hakami E, Olofsson S-O, Hakami H, Israelsson J, 1998. Global thermo-mechanical effects from aKBS-3 type repository. Summary report. SKB TR 98-01, Svensk Kärnbränslehantering AB.
Hartikainen J, 1994. Maan routimisen termomekaaninen malli ja sen laskelmat (Thermomechanicalmodel for freezing soil and its computer implementation) (in Finnish). Master’s thesis. Department
of Civil Engineering and Surveying, Helsinki University of Technology.
Hartikainen J, 2004. Permafrost modelling in DECOVALEX III for BMT3. In: Eloranta E (ed).
DECOVALEX III, 1999–2003. An international project for the modelling of coupled Thermo-HydroMechanical processes for spent fuel disposal. Finnish national contributions. Helsinki: Radiation and
Nuclear Safety Authority. (STUK-YTO-TR 209), Appendix IV.
Hartikainen J, 2006. Numerical simulation of permafrost depth at Olkiluoto. Working Report 2006-52.
Posiva Oy, Finland.
Hartikainen J, Mikkola M, 1997. General thermomechanical model of freezing soil with numericalapplication. In: Knutsson S (ed). Ground freezing 97: frost action in soils: proceedings of theInternational Symposium on Ground Freezing and Frost Action in Soils, Luleå, Sweden, 15–17 April
1997. Rotterdam: Balkema, pp 101–105.
Hartikainen J, Mikkola M, 2006. Thermomechanical modelling for freezing of solute saturated
soil. In: Gladwell G M L, Huyghe J M, Raats P A C, Cowin S C (eds). IUTAM symposium on
physicochemical and electromechanical interactions in porous media. Dordrecht: Springer. (Solid
Mechanics and its Applications 125), pp 335–341.
Hartikainen J, Kouhia R, Wallroth T, 2010. Permafrost simulations at Forsmark using a numerical
2D thermo-hydro-chemical model. SKB TR-09-17, Svensk Kärnbränslehantering AB.
Hartley L, Boghammar A, Grundfelt B, 1998. Investigation of the large scale regional hydrogeological situation at Beberg. SKB TR-98-24, Svensk Kärnbränslehantering AB.
Hartley L, Cox I, Holton D, Hunter F, Joyce S, Gylling B, Lindgren M, 2004. Groundwater flow
and radionuclide transport modelling using CONNECTFLOW in support of the SR Can assessment.
SKB R-04-61, Svensk Kärnbränslehantering AB.
Hedin A, 2008. Semi-Analytic Stereological Analysis of Waste Package/Fracture Intersections in a
Granitic Rock Nuclear Waste Repository. Mathematical Geosciences, 40, 619–637.
Hedin A, 2011. Stereological Method for Reducing Probability of Earthquake-Induced Damage in a
Nuclear Waste Repository. Mathematical Geosciences 43, 1–21.
Herbert A, Gale J, Lanyon G, MacLeod R, 1991. Modelling for the Stripa site characterizationand validation drift inflow: Prediction of flow through fractured rock. Stripa Project Technical
Report 91-35, Svensk Kärnbränslehantering AB.
Herbert A W, Lanyon G W, 1992. Modelling tracer transport in fractured rock at Stripa. Stripa
Project Technical Report 92-01, Svensk Kärnbränslehantering AB.
Hernelind J, 2010. Modelling and analysis of canister and buffer for earthquake induced rock shearand glacial load. SKB TR-10-34, Svensk Kärnbränslehantering AB.
Holmlund P, Fastook J, 1995. A time dependent glaciological model of the Weichselian ice sheet.
Quaternary International, 27, pp 53–58.
Holton D, Milický M, 1997. Simulating the LPT2 and Tunnel Drawdown Experiment at Äspö using
a coupled continuum-fracture network approach. SKB HRL International Cooperation Report ICR
97-05, Svensk Kärnbränslehantering AB.
62

TR-10-51

Holton D, Hartley L J, Hautojärvi A, Marschall P, Selroos J-O, 2003. iCONNECT Club:
Integrated Continuum and Network Approach to Groundwater flow and Contaminant Transport.
MRS 2003. Scientific basis for nuclear waste management XXVII, Kalmar, Sweden.
Huybrechts P, Payne T, EISMINT Intercomparison Group, 1996. The EISMINT benchmarks fortesting ice-sheet models. Annals of Glaciology, 23, pp 1–12.
Hökmark H, Lönnqvist M, Fälth B, 2010. THM-issues in repository rock. Thermal, mechanical,
thermo-mechanical and hydro-mechanical evolution of the rock at the Forsmark and Laxemar sites.
SKB TR-10-23, Svensk Kärnbränslehantering AB.
ICRP, 1983. Radionuclide transformations : energy and intensity of emissions: report of a task groupof committee 2 of the International commission on radiological protection on data used in ICRP
publication 30. Oxford: Pergamon. (ICRP Publication 38; Annals of the ICRP 11-13).
Itasca, 2003. 3DEC – 3-Dimensional Distinct Element Code, User’s guide, Version: 3. Itasca
Consulting Group Inc. Minneapolis, USA.
Itasca, 2005. UDEC, Universal Distinct Element Code, Version: 4. Itasca Consulting Group Inc.
Minneapolis, USA.
Itasca, 2007. 3DEC – 3-Dimensional Distinct Element Code, User’s guide, Version: 4.1. Itasca
Consulting Group Inc. Mineapolis, USA.
Jackson C P, Watson S P, et al. 1997. Nirex 97. An assessment of the post-closure performanceof a deep waste repository at Sellafield.Volume 2: Hydrogeological model development – Effective
parameters and calibration. UK Nirex Report no S/97/012 [Volume 2], UK Nirex Limited.
Johnson J, 1994. A basal water model for ice sheets. Ph. D. thesis. University of Minnesota.
Jones J, Vahlund F, Kautsky U, 2004. Tensit – a novel probabilistic simulation tool for safetyassessments. Tests and verifications using biosphere models. SKB TR-04-07, Svensk Kärnbränsle­
hantering AB.
Jones J, Kautsky U, Vahlund F, 2005. Tensit – a simulation tool for nuclide transport, risk and dose
calculations. Radioprotection, 40, Suppl. 1, pp S933–S938.
Joyce S, Applegate D, Hartley L, Hoek J, Swan D, Marsic N, Follin S, 2010. Groundwaterflow modelling of periods with temperate climate conditions – Forsmark. SKB R-09-20, Svensk
Kärnbränslehantering AB.
Kelly M, Cliffe K A, 2006. Validity document for COMP23. SKB R-06-76, Svensk
Kärnbränslehantering AB.
Kendall R A, Mitrovica J X, Milne G A, 2005. On post-glacial sea level – II. Numerical formulationand comparative results on spherically symmetric models. Geophysical Journal International, 161,
pp 679–706.
Kipp K L, 1987. HST3D – a computer code for simulation of heat and solute transport in three
dimensional ground-water flow systems. Denver, Co: U.S. Geological Survey. (Water-resources
investigations report 86-4095).
Kipp K L, 1997. Guide to the revised heat and solute transport simulator HST3D – Version 2.
Denver, Co: U.S. Geological Survey. (Water-resources investigations report 97–4157).
Kulatilake P H S W, Ucpirti H, Wang S, Radberg G, Stephansson O, 1992. Use of the distinct
element method to perform stress analysis in rock with non-persistent joints and to study the effectof joint geometry parameters on the strength and deformability of rock masses. Rock Mechanics andRock Engineering, 25, pp 253–274.
Küng S, Onken L, 2009. TourtoiseSVN. Version: 1.6.10, Build 19898 – 32 Bit, 2010/07/16
15:46:08. Tigris.org. http://subversion.tigris.org/
Last N C, Harper T R, 1990. Response of fractured rock subject to fluid injection part I.
Development of a numerical model. Tectonophysics, 172, pp 1–31.
Latychev K, Mitrovica J X, Tamisiea M E, Tromp J, Moucha R, 2005. Influence of lithosphericthickness variations on 3-D crustal velocities due to glacial isostatic adjustment. GeophysicalResearch Letters, 32, L01304, doi:10.1029/2004GL021454.
TR-10-51

63

Lindborg (ed), 2010. Landscape Forsmark – data, methodology and results for SR-Site.
SKB TR-10-05. Svensk Kärnbränslehantering AB.
Lindgren M, Lindström F, 1999. SR 97 – Radionuclide transport calculations. SKB TR-99-23,
Svensk Kärnbränslehantering AB.
Lindgren M, Widén H, 1998. Discretization in COMP23 for SR97. SKB R-98-03, Svensk Kärn­
bränslehantering AB.
Lindgren M, Gylling B, Elert M, 2002. FARF31 Version 1.2 – User’s guide. SKB TS-02-03,
Svensk Kärnbränslehantering AB.
Lindgren M, Pettersson M, Cliffe A, Kelly M, 2008. COMP23 Test batch. SKB R-06-112, Svensk
Kärnbränslehantering AB.
Lindgren M, Pettersson M, Karlsson S, Moreno L, 2001. Project SAFE. Radionuclide release anddose from the SFR repository. SKB R-01-18, Svensk Kärnbränslehantering AB.
Luna M, Arcos D, Duro L, 2006. Effects of grouting, shotcreting and concrete leachates on backfill
geochemistry. SKB R-06-107, Svensk Kärnbränslehantering AB.
Lund B, Schmidt P, Hieronymus C, 2009. Stress evolution and fault stability during the Weichselian
glacial cycle. SKB TR-09-15, Svensk Kärnbränslehantering AB.
Marsic N, Hartley L, Jackson P, Poole M, Morvik A, 2001. Development of hydrogeologicalmodelling tools based on NAMMU. SKB R-01-49, Svensk Kärnbränslehantering AB.
Marsic N, Hartley L, Sanchez-Friera P, Morvik A, 2002. Embedded regional/local-scale model ofnatural transients in saline groundwater flow: Illustrated using the Beberg site. SKB R‑02‑22, Svensk
Kärnbränslehantering AB.
Maul P, Robinson P, Broed R, Avila R, 2010. Further AMBER and Ecolego intercomparisons.
SKI Report 2004:05, Statens kärnkraftinspektion (Swedish Nuclear Power Inspectorate), SSI Report
2004:01, Statens strålskyddsinstitut (Swedish Radiation Protection Authority).
MathWorks, 2010a. MatLab 7. Natick, MA: MathWorks Inc.
MathWorks, 2010b. Simulink. Natick, MA: MathWorks Inc.
MathWorks, 2010c. Parallel processing toolbox. Version: V5.0 (R2010b). Natick, MA: MathWorks Inc.
Microsoft, 2008. Visual C++ 2008. Version: 2008 Express edition. Bellevue, WA: Microsoft Corp.
Mikkola M, Hartikainen J, 2001. Mathematical model of soil freezing and its numerical implementation. International Journal for Numerical Methods in Engineering, 52, pp 543–557.
Mikkola M, Hartikainen J, 2002. Computational aspects of soil freezing problem. In: Mang H A,
Rammerstorfer F G, Eberhardsteiner J (eds). Proceedings of the Fifth World Congress on Computational
Mechanics, Vienna, 7–12 July 2002.
Milne G A, 1998. Refining models of the glacial isostatic adjustment process. Ph. D. thesis.
University of Toronto.
Milne G A, Mitrovica J X, 1998. Postglacial sea-level change on a rotating Earth. GeophysicalJournal International, 133, pp 1–19.
Milne G A, Mitrovica J X, Davis J L, 1999. Near-field hydro-isostasy: the implementation ofa revised sea-level equation. Geophysical Journal International, 139, pp 464–482.
Milne G A, Davis J L, Mitrovica J X, Scherneck H-G, Johansson J M, Vermeer M, Koivula H,
2001. Space-geodetic constraints on glacial isostatic adjustment in Fennoscandia. Science, 291, pp
2381–2385.
Milne G A, Mitrovica J X, Schrag D P, 2002. Estimating past continental ice volume from sealevel data. Quaternary Science Reviews, 21, pp 361–376.
Milne G A, Mitrovica J X, Scherneck H G, Davis J L, Johansson J M, Koivula H, Vermeer M,
2004. Continuous GPS measurements of postglacial adjustment in Fennoscandia: 2. Modeling
results. Journal of Geophysical Research, 109, B02412, doi:10.1029/2003JB002619.

64

TR-10-51

Milne G A, Long A J, Bassett S E, 2005. Modelling Holocene relative sea-level observations fromthe Caribbean and South America. Quaternary Science Reviews, 24, pp 1183–1202.
Milne G A, Shennan I, Youngs B A R, Waugh A I, Teferle F N, Bingley R M, Bassett S E,
Cuthbert-Brown C, Bradley S L, 2006. Modelling the glacial isostatic adjustment of the UK
region. Philosophical Transactions of the Royal Society A – Mathematical, Physical & Engineering
Sciences, 364, pp 931–948.
Mitrovica J X, Milne G A, 2002. On the origin of late Holocene sea-level highstands within equatorial
ocean basins. Quaternary Science Reviews, 21, pp 2179–2190.
Mitrovica J X, Milne G A, 2003. On post-glacial sea level: I. General theory. Geophysical JournalInternational, 154, pp 253–267.
Mitrovica J X, Peltier W R, 1991. On post-glacial geoid subsidence over the equatorial oceans.
Journal of Geophysical Research, 96, pp 20053–20071.
Mitrovica J X, Tamisiea M E, Davis J L, Milne G A, 2001. Recent mass balance of polar ice
sheets inferred from patterns of global sea-level change. Nature, 409, pp 1026–1029.
Mitrovica J X, Wahr J, Matsuyama I, Paulson A, 2005. The rotational stability of an ice-age
earth. Geophysical Journal International, 161, pp 491–506.
Munier R, 2006. Using observations in deposition tunnels to avoid intersections with critical
fractures in deposition holes. SKB R-06-54, Svensk Kärnbränslehantering AB.
Munier R, 2007. Demonstrating the efficiency of the EFPC criterion by means of Sensitivity
analyses. SKB R-06-115, Svensk Kärnbränslehantering AB.
Munier R, 2010. Full perimeter intersection criteria. Definitions and implementations in SR-Site.
SKB TR-10-21, Svensk Kärnbränslehantering AB.
NEA/SKI, 1988. The international HYDROCOIN project. Groundwater hydrology modelling
strategies for performance assessment of nuclear waste disposal. Level 1: Code verification. Oecd/
Nea; SKI.
Neerdael B, Finsterle S, 2010. The use of numerical models in support of site characterization andperformance assessment studies for geological repositories. Nuclear Engineering and Technology,
42, pp 145–150.
Neretnieks I, 1986. Stationary transport of dissolved species in the backfill surrounding a waste
canister in fissured rock: some simple analytical solutions. Nuclear Technology, 72, pp 194–200.
Norman S, Kjellbert N, 1990. FARF31 – A far field radionuclide migration code for use with the
PROPER package. SKB TR 90-01, Svensk Kärnbränslehantering AB.
Näslund J O, Rodhe L, Fastook J L, Holmlund P, 2003. New ways of studying ice sheet flow
directions and glacial erosion by computer modelling – examples from Fennoscandia. Quaternary
Science Reviews, 22, pp 245–258.
Olivella S, 1995. Nonisothermal multiphase flow of brine and gas through saline media. Ph. D.
thesis. Geotechnical Engineering Department, Technical University of Catalunya, Spain.
Olivella S, Carrera J, Gens A, Alonso E E, 1994. Non-isothermal multiphase flow of brine and gas
through saline media. Transport in Porous Media, 15, pp 271–293.
Olivella S, Gens A, Carrera J, Alonso E E, 1996. Numerical formulation for a simulator (CODE_
BRIGHT) for the coupled analysis of saline media. Engineering Computations, 13, pp. 87–112.
Painter S, Mancillas J, 2009. MARFA version 3.2.2 user’s manual: migration analyses of radio­
nuclides in the far-field. SKB R-09-56, Svensk Kärnbränslehantering AB.
Painter S, Cvetkovic V, Mancillas J, Pensado O, 2008. Time domain particle tracking methods for
simulating transport with retention and first-order transformation. Water Resources Research, 44,
W01406, doi:10.1029/2007WR005944.
Parkhurst D L, Appelo C A J, 1999. User’s guide to PHREEQC (version 2): a computer programfor speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations.
Denver, Co: U.S. Geological Survey. (Water-resources investigations report 99-4259).

TR-10-51

65

Parkhurst D L, Appelo C A J, 2001. User’s guide to PHREEQC (Version 2.4.6). A computer programfor speciation, batch reaction, one dimensional transport and inverse geochemical calculations.
Denver, Co: U.S. Geological Survey.
Parkhurst D L, Kipp K L, Engesgaard P, Charlton S R, 2004. PHAST: a program for simulating
ground-water flor, solute transport, and multicomponent geochemical reactions. U.S. Geological
Survey Techniques and Methods 6-A8. Denver, Co: U.S. Geological Survey.
Payne A J, Huybrechts P, Abe-Ouchi A, Calov R, Fastook J L, Greve R, Marshall S J, Marsiat I,
Ritz C, Tarasov L, Thomassen M P A, 2000. Results from the EISMINT model intercomparison:
the effects of thermomechanical coupling. Journal of Glaciology, 46, pp 227–238.
Pruess K, 1991. TOUGH2 – A general purpose numerical simulator for multiphase fluid and heat
flow. Report LBL-29400, Lawrence Berkeley Laboratory.
Pruess K, Oldenburg C, Moridis G, 1999. TOUGH2 User’s Guide, Version 2.0. Report LBNL43134, Lawrence Berkeley National Laboratory, University of California.
Prváková S, 2005. Deep geological disposal and its long-term safety. EUR 22100, European
Commision.
Puigdomènech I, 2002. MEDUSA (Make Equilibrium Diagrams Using Sophisticated Algorithms)
Windows interface to the MS-DOS versions of INPUT, SED and PREDOM (FORTRAN programs
drawing chemical equilibrium diagrams) Vers. 31 July. 2002. Royal Institute of Technology (KTH),
Stockholm.
Romero A L, 1995. The near-field transport in a repository for high-level nuclear waste. Ph. D.
thesis. Department of Chemical Engineering and Technology, Royal Institute of Technology,
Stockholm, Sweden.
Romero L, Thompson A, Moreno L, Neretnieks I, Widén H, Boghammar A, 1999. Comp23/
Nuctran user´s guide – Proper version 1.1.6. SKB R-99-64, Svensk Kärnbränslehantering AB.
Salas J, Gimeno M J, Auqué L F, Molinero J, Gómez J, Juárez I, 2010. SR-Site – hydrogeochemical evolution of the Forsmark site. SKB TR-10-58, Svensk Kärnbränslehantering AB.
Selroos J-O, Follin S, 2010. Groundwater flow modelling methodology, setup and results – SR-Site
Forsmark. SKB R-09-22, Svensk Kärnbränslehantering AB.
Sena C, Grandia F, Arcos D, Molinero J, Duro L, 2008. Complementary modelling of radio­
nuclide retention in the near-surface system at Forsmark. Development of a reactive transport modelusing Forsmark 1.2 data. SKB R-08-107, Svensk Kärnbränslehantering AB.
Sena C, Salas J, Arcos D, 2010a. Aspects of geochemical evolution of the SKB near field in the frameof SR-Site. SKB TR-10-59, Svensk Kärnbränslehantering AB.
Sena C, Salas J, Arcos D, 2010b. Themo-hydro-geochemical modelling of the bentonite buffer,
LOT A2 experiment. SKB TR-10-65, Svensk Kärnbränslehantering AB.
Senseny P E, 1993. Stress wave loading of a tunnel: a benchmark study. In: Hossain Q A (ed).
Dynamic analysis and design considerations for high-level nuclear waste repositories: proceedingsof the symposium held in San Francisco, 19–20 August 1992. New York: American Society of Civil
Engineers, pp 311–338.
Serco, 2008a. ConnectFlow Release 9.6 Technical Summary Document. SA/ENV/CONNECTFLOW/15, Serco Assurance, UK.
Serco, 2008b. NAMMU Release 9.6 Technical Summary Document. SA/ENV/CONNECTFLOW/8,
Serco Assurance, UK.
Serco, 2008c. NAPSAC Release 9.6 Technical Summary Document. SA/ENV/CONNECTFLOW/12, Serco Assurance, UK.
Serco, 2008d. NAMMU Release 9.6 Verificiation Document. SA/ENV/CONNECTFLOW/9, Serco
Assurance, UK.
Serco, 2008e. NAPSAC Release 9.6 Verificiation Document. SA/ENV/CONNECTFLOW/13, Serco
Assurance, UK.

66

TR-10-51

Serco, 2008f. ConnectFlow Release 9.6 Verificiation Document. SA/ENV/CONNECTFLOW/16,
Serco Assurance, UK.
Serco, 2008g. ConnectFlow Quality Plan. SA/ENV/CONNECTFLOW/1, Serco Assurance, UK.
Sidborn M, Sandström B, Tullborg E-L, Delos A, Molinero J, Hallbeck L, Pedersen K, 2010.
SR-Site: Oxygen ingress in the rock at Forsmark during a glacial cycle. SKB TR-10-57, Svensk
Kärnbränslehantering AB.
Sjöberg J, 1992. Failure modes and pillar behavior in the zinkgruvan mine. In: Tillerson J A,
Wawersik W R (eds). Proceedings of 33rd U.S. Rock Mechanics Symposium, Sante Fe, June 1992.
Rotterdam: Balkema, pp 491–500.
SKB, 1996. SR 95. Template for safety reports with descriptive example. SKB TR 96-05, Svensk
Kärnbränslehantering AB.
SKB, 1999. Deep repository for spent nuclear fuel. SR 97 – Post-closure safety. Main report.
SKB TR-99-06 Vol. I, Vol. II and Summary, Svensk Kärnbränslehantering AB.
SKB, 2003. Planning report for the safety assessment SR-Can. SKB TR-03-08, Svensk
Kärnbränslehantering AB.
SKB, 2004. Interim main report of the safety assessment SR-Can. SKB TR-04-11, Svensk Kärn­
bränslehantering AB.
SKB, 2006a. Climate and climate-related issues for the safety assessment SR-Can. SKB TR-06-23,
Svensk Kärnbränslehantering AB.
SKB, 2006b. Long-term safety for KBS-3 repositories at Forsmark and Laxemar – a first evaluation.
Main report of the SR-Can project. SKB TR-06-09, Svensk Kärnbränslehantering AB.
SKB, 2008. Safety analysis SFR 1. Long-term safety. SKB R-08-130, Svensk Kärnbränslehantering AB.
SKB, 2010. Corrosion calculations report for the safety assessment SR-Site. SKB TR-10-66, Svensk
Kärnbränslehantering AB.
SKI, 1984. INTRACOIN. International Nuclide Transport Code Intercomparison study. Final reportlevel 1. Code verification. SKI 84 3, Intracoin/Ski.
SKI, 1986. INTRACOIN. International Nuclide Transport Code Intercomparison study. Final reportlevels 2 and 3. Model validation and uncertainty analysis. SKI 86 2, Intracoin/Ski.
Spalding D B, 1981. A General Purpose Computer Program for Multi-Dimensional One- and TwoPhase Flow. Mathematics and Computers in Simulation XXIII: pp 267–276.
Statsoft Inc., 2009. Statistica 9.1. Version: 9.1.210.0. Statsoft Inc. 2300 East 14:th st. Tulsa OK,
74104, USA http://www.statsoft.com /Stephansson O, Shen B, Lemos J, 1991. Modelling of excavation, thermal loading and bentonite
swelling pressure for a waste repository. In: High-level waste management: proceedings of theSecond Annual International Conference, Las Vegas, Nevada, 28 April–3 May 1991. New York:
American Society of Civil Engineers, pp 1375–1381.
Svensson U, 1991. Groundwater flow at Äspö and changes due to the excavation of the laboratory.
SKB HRL Progress report 25-91-03, Svensk Kärnbränslehantering AB.
Svensson U, 2010. DarcyTools, Version 3.4. Verification, validation and demonstration. SKB R-10-71,
Svensk Kärnbränslehantering AB.
Svensson U, Ferry M, 2010. DarcyTools, Version 3.4. User’s guide. SKB R-10-72, Svensk Kärn­
bränslehantering AB.
Svensson U, Follin S, 2010. Groundwater flow modelling of the excavation and operation phases– SR-Site Forsmark. SKB R-09-19, Svensk Kärnbränslehantering AB.
Svensson U, Rhén I, 2010. Groundwater flow modelling of the excavation and operation phases– Laxemar. SKB R-09-23, Svensk Kärnbränslehantering AB.
Svensson U, Ferry M, Kuylenstierna H-O, 2010. DarcyTools, Version 3.4. Concepts, methods andequations. SKB R-07-38, Svensk Kärnbränslehantering AB.

TR-10-51

67

Tamisiea M E, Mitrovica J X, Milne G A, Davis J L, 2001. Global geoid and sea level changes
due to present-day ice mass fluctuations. Journal of Geophysical Research, 106, pp 30849–30863.
Tamisiea M E, Mitrovica J X, Davis J L, Milne G A, 2003. Long wavelength sea level and solid
surface perturbations driven by polar ice mass variations: fingerprinting Greenland and Antarctic ice
sheet flux. Space Science Reviews, 108, pp 81–93.
Torudd J, 2010. Long term radiological effects on plants, animals of a deep geological repository.
SR-Site Biosphere. SKB TR-10-08, Svensk Kärnbränslehantering AB.
Vahlund F, Hermansson H, 2006a. Compulink. Implementing the COMP23 model in Simulink.
SKB R-06-86, Svensk Kärnbränslehantering AB.
Vahlund F, Hermansson H, 2006b. A direct numerical approach to solving the transport equations
for radionuclide transport in fractured rock. SKB R-04-50, Svensk Kärnbränslehantering AB.
van der Vorst H A, 1992. Bi-CGSTAB: a fast and smoothly converging variant of BI-CG for thesolution of nonsymmetric linear systems. SIAM Journal on Scientific and Statistical Computing, 13,
pp 631–644.
Vidstrand P, Follin S, Zugec N, 2010a. Groundwater flow modelling of periods with periglacial
and glacial conditions – SR-Site Forsmark. SKB R-09-21, Svensk Kärnbränslehantering AB.
Vidstrand P, Rhén I, Zugec N, 2010b. Groundwater flow modelling of periods with periglacial andglacial climate conditions – Laxemar. SKB R-09-25, Svensk Kärnbränslehantering AB.
Vikström M, Gustafsson L-G, 2006. Modelling transport of water and solutes in future wetlands in
Forsmark. SKB R-06-46, Svensk Kärnbränslehantering AB.
Whitehouse P, Latychev K, Milne G A, Mitrovica J X, Kendall R, 2006. Impact of 3-D
Earth structure on Fennoscandian glacial isostatic adjustment: implications for space-geodetic
estimates of present-day crustal deformations. Geophysical Research Letters, 33, L13502,
doi:10.1029/2006GL026568.
Xu T, Sonnenthal E, Spycher N, Pruess K, 2008. TOUGHREACT User’s guide: a simulation
program for non-isothermal multiphase reactive geochemical transport in variably saturated geologic
media. LBNL-55460, Lawrence Berkeley National Laboratory, University of California.
Åkesson M, Kristensson O, Börgesson L, Dueck A, 2010a. THM modelling of buffer, backfill
and other system components. Critical processes and scenarios. SKB TR-10-11, Svensk Kärn­
bränslehantering AB.
Åkesson M, Börgesson L, Kristensson O, 2010b. SR-Site Data report. THM modelling of buffer,
backfill and other system components. SKB TR-10-44, Svensk Kärnbränslehantering AB.
Åstrand P-G, Jones J, Broed R, Avila R, 2005. Pandora technical description and user guide.
Posiva Working Report 2005-64. Posiva Oy, Finland.

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