Contractor Report to United Kingdom Nirex Limited

Options for Monitoring During the Phased Development of a Repository for Radioactive Waste

Define objectives for General methodology for the identification of Define objectives for monitoring options monitoringmonitoring

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June 2002 SS A A M M - ii - SAM-J078-R1 SAM-J078-R1

Options for Monitoring During the Phased Development of a Repository for Radioactive Waste

SAM / NNC / Nagra / CSEC

June 2002

This report has been prepared for UK Nirex Ltd. by Safety Assessment Management Ltd. in co-operation with NNC Ltd., the National Cooperative for the Disposal of Radioactive Waste, Switzerland and the Centre for the Study of Environmental Change (CSEC), Lancaster University under the terms of Nirex contract SC2803/009.

Safety Assessment Management Ltd. Beech Tree House Hardwick Road Whitchurch-on-Thames READING RG8 7HW United Kingdom

Tel: 0118-984-4410 Fax: 0118-984-1440 SS A A M M

- ii - SAM-J078-R1 Preface

This report is part of an ongoing programme of research conducted by United Kingdom Nirex Limited (Nirex) and its contractors. It is a component of the research into the concept of phased disposal in a geological repository, which is the one of a number of options for the long-term management of radioactive waste in the UK.

An important aspect of the phased disposal concept is that monitoring would be carried out at all stages of the repository development in order to provide assurance of the current and possible future safety, and to provide input to the technical and societal decision making related to the repository development. Nirex has developed substantial expertise in some types of monitoring that will be necessary during the development of a repository, e.g. in relation to waste characterisation and site investigation. The aim of the current study is to identify monitoring options taking a broad view of the possible information requirements. This is the first step in the development of an overall strategy for monitoring within a phased disposal concept.

The present report outlines a methodology for the identification of monitoring options and discusses monitoring under several broad objectives associated with the phased development of a geological repository. The report is a compilation of work by several contractors and tackles monitoring under each of the objectives in somewhat different styles and at different levels of detail. This provides an information base that Nirex may now consider, together with experience from other studies, in the development of a more coherent strategy for monitoring.

The report has been reviewed by Nirex, but the views expressed and the conclusions reached are those of the authors and do no necessarily represent those of Nirex. The report has been prepared, verified and approved for publication by Safety Assessment Management Ltd. The work was carried out in accordance with quality assurance arrangements established by the contractors and Nirex, which are consistent with ISO 9001.

Feedback

Readers are invited to provide feedback to Nirex on the contents, clarity and presentation of this report and on the means of improving the range of Nirex reports published. Feedback should be addressed to:

The Helpline Administrator United Kingdom Nirex Limited Curie Avenue Harwell, Didcot Oxfordshire OX11 0RH United Kingdom or by e-mail to [email protected]

Safety Assessment Management Report SAM-J078-R1

SAM-J078-R1 - i - June 2002

- ii - SAM-J078-R1 Contents

Preface...... i Contents...... ii

1 INTRODUCTION...... 1 1.1 Background...... 1 1.2 Objective and scope of this report...... 2 1.3 What is monitoring?...... 3 1.4 References...... 4

2 METHODOLOGY FOR ANALYSING MONITORING OPTIONS...... 5 2.1 General approach...... 5 2.2 The objectives for monitoring...... 7 2.3 Temporal aspects of a monitoring programme...... 10

3 WASTE MANAGEMENT AND REPOSITORY STRATEGIC DECISIONS...... 13

4 REPOSITORY DESIGN AND CONSTRUCTION...... 16 4.1 Scope of this chapter...... 16 4.2 Approach to identifying information requirements...... 16 4.3 Assessment of host rock and site suitability (related to repository design and construction)...... 18 4.4 Assessment of access and infrastructure feasibility...... 20 4.5 Assessment of construction feasibility...... 20 4.6 Assessment of operation feasibility...... 22 4.7 Assessment of backfilling and sealing feasibility...... 24 4.8 Assessment of environmental impact...... 26 4.9 References...... 27

5. THE LONG-TERM SAFETY CASE...... 45 5.1 Scope of this chapter...... 45 5.2 Approach to identifying information requirements...... 45 5.3 Assessment of site suitability (related to long-term safety)...... 47 5.4 Assessment of groundwater pathways...... 48 5.5 Assessment of gas pathways...... 49 5.6 Assessment of human intrusion pathways...... 51 5.7 Assessment of toxic hazard...... 52 5.8 Post-closure criticality...... 52 5.9 References...... 53

SAM-J078-R1 - iii - 6 THE OPERATIONAL SAFETY CASE...... 73 6.1 Approach to identifying information requirements...... 73 6.2 Radiological safety...... 75 6.2.1 External exposure of the operating staff...... 75 6.2.2 External exposure of members of the public...... 78 6.2.3 Internal exposure of the operating staff...... 78 6.2.4 Internal exposure of members of the public...... 88 6.3 Conventional safety...... 89 6.3.1 General...... 89 6.3.2 Monitoring seismic activity...... 89 6.4 References...... 91

7 RETRIEVABILITY...... 98 7.1 Approach to identifying information requirements...... 98 7.2 Integrity of underground excavations...... 100 7.3 Waste matrix characteristics...... 102 7.4 Corrosion...... 108 7.4.1 Waste containers...... 108 7.4.2 Other equipment in the vault...... 113 7.4.3 Monitoring options for corrosion...... 114 7.5 References...... 115

8 ENVIRONMENTAL ASSESSMENT...... 119 8.1 Approach to identifying information requirements...... 119 8.2 Activity in environmental media...... 120 8.3 Parameters affecting long-term performance...... 121 8.4 Conventional environmental requirements of major construction projects...... 123 8.5 References...... 123

9 THE POLICY, LEGAL AND REGULATORY FRAMEWORK...... 129 9.1 The current policy, legal and regulatory framework...... 129 9.2 Monitoring and response to changes...... 130 9.3 References...... 131

10 PUBLIC ACCEPTABILITY AND WIDER CONFIDENCE ISSUES...... 132 10.1 Scope of this chapter...... 132 10.2 The nature of social engagement with monitoring...... 132 10.3 Some characteristics of current public requirements for monitoring...... 134 10.4 Monitoring the public acceptability of the monitoring strategy and the repository development...... 137 10.5 Opportunities and needs for dialogue...... 141 10.6 Different audiences and different requirements...... 145

- iv - SAM-J078-R1 10.7 Monitoring institutional capability and social stability...... 149 10.8 The social aspects of monitoring - conclusions...... 153

11 CONCLUSIONS...... 155

Acknowledgement...... 156 Document Issue Record...... 157

SAM-J078-R1 - v - 1 INTRODUCTION

1.1 Background

United Kingdom Nirex Limited (Nirex) is examining options for the long-term management of radioactive waste in the UK and currently has responsibility to investigate options for the long-term management of intermediate-level waste and certain low-level waste that may not be suitable for disposal in existing near-surface disposal facilities. In considering options, Nirex has set three ‘strategic imperatives’ that must be satisfied:

 A coherent concept (i.e. one that design studies and safety assessments show can work),

 Acceptance (i.e. meeting regulatory requirements and safety guidelines and, also, achieving broad acceptance by stakeholders),

 Resources (sufficient to be able to develop and implement the concept).

To date, most work has been done on the deep geological disposal option, which is in line with previous Government policy (HM Government 1995). This has resulted in the development of the concept of phased disposal in a deep geological repository. This is the concept on which Nirex currently base packaging advice to waste producers.

The phased geological disposal concept

In the Nirex phased geological disposal concept, waste would be conditioned and packaged at waste producers’ sites and transferred for interim storage in engineered surface stores. As a first step towards disposal, the waste would be transferred to a deep underground repository for a period of underground storage. The underground storage environment would be carefully controlled to ensure continued integrity of the packages. During the underground storage period access would be maintained to allow monitoring of the waste and of the surrounding rock, and to facilitate retrieval of the waste packages if required.

When a sufficient level of technical and societal confidence in the system has been established, the decision to move from underground storage to disposal could be taken. This step would involve backfilling the waste emplacement vaults and, after a further period, sealing and closure of the repository access ways. At each stage in the process, options would be available to: – reverse the process and return to an earlier stage, – remain at the current stage, or – proceed to the next stage in the process.

SAM-J078-R1 - 1 - Retrievability of the waste and monitoring are key requirements in such a staged, reversible concept. The retrievability of the waste in this concept has already been examined in some detail (Nirex, 2001a; SAM/NNC/Nagra, 2001). The work described in this report builds on the earlier work and considers the role of, and options for, monitoring within a phased geological disposal concept. The work also takes account of input from two workshops organised by Nirex (UK CEED, 2000 & 2001; Nirex, 2001b) at which issues related to retrievability and monitoring were identified and discussed.

1.2 Objective and scope of this report

The objective of this report is:

To establish, for the Nirex phased disposal concept, potential requirements for monitoring and the options available for such monitoring.

The report covers potential requirements for monitoring during all stages of the development of the disposal system. It considers a broad range of potential monitoring including: – the establishment of baseline conditions, – system performance at the time of monitoring, – the provision of data to be used in repository design and the prediction of long- term performance, and – monitoring in the broader sense including non-technical assurance and monitoring of regulatory and social developments that may impact on the repository project.

Results from monitoring could be key factors in providing the confidence needed to progress from one stage to the next in a repository development programme. Thus, the justification for monitoring needs to consider the contribution to public acceptability as well as purely technical requirements, and public views may influence the design of some aspects of the monitoring programmes.

The aim of the report is to identify the potential options available for such monitoring. The report considers – why the monitoring may be required, – what parameters may require monitoring and – how these parameters can be monitored.

In this report, Chapter 2 sets out a methodology for identifying and analysing monitoring options, based on the three questions stated above. With regard to the first question – why monitoring may be required – the chapter identifies eight high-level objectives under which monitoring can be considered. Subsequent chapters then explore what parameters might be monitored and how monitoring might be done, to satisfy each of the broad objectives.

- 2 - SAM-J078-R1 1.3 What is monitoring?

The term monitoring has been defined by the IAEA (IAEA, 2001) and also discussed with reference to repository development by several national waste management agencies, e.g. SKB (Olsson et al., 2001), Andra (Mouroux, 2001) and Nagra (Hugi et al., 2001). The IAEA defined monitoring as:

Continuous or periodic observations and measurements of engineering, environmental or radiological parameters to help evaluate the behaviour of the repository system or the impacts of the repository and its operation on the environment.

In all of the above references, the term monitoring refers to the continuous or periodic observation and measurement of parameters. The emphasis is on providing information which will aid in the step-wise implementation of a repository development programme, considering retrievability of the waste, reversibility of steps towards disposal, and the long- term safety of the repository. In some waste disposal programmes, however, monitoring includes less obvious aspects, such as monitoring the progress in science and technology, including experience with other repository programmes (Hugi et al., 2001). In the majority of cases, it is assumed that monitoring would be designed and implemented so as not to compromise the long-term safety of the repository. It is also widely accepted that the long- term safety of geological disposal should not rely on a continued capability to monitor a repository after it has been sealed and closed, e.g. (IAEA, 2001; EA/SEPA/DoE NI 1997; Hugi et al., 2001). On the other hand, monitoring may continue after closure and may be required for legal reasons and for public acceptability reasons.

This study takes a broad view of the term monitoring, to include activities related to waste and site characterisation, operational and long-term safety, system stability and reliability, quality checking and other issues. The latter includes monitoring of scientific and technical developments, trends in the production of waste and its management and socio-political factors, including the organisational capability to maintain and close the repository. While some monitoring is essential for technical and safety reasons, Nirex’s phased disposal approach provides opportunities for additional monitoring that may provide information necessary to promote the wider scientific and public confidence that may be vital to the successful implementation of a repository development programme.

In this report, monitoring is taken to mean:

measurements of parameters and observations that may have implications for the design and management of the disposal system, its performance assessment and development of confidence in the disposal system performance or its assessment.

This is based on a definition discussed during the currently ongoing European Commission Thematic Network Study on monitoring in the phased development of geological repositories. Single or “one-of” measurements are not considered as monitoring unless the measurement is for the purpose of establishing a baseline for future measurements. Measurements of parameters or characteristics that will not change over the timescale of potential investigation, e.g. lithological characteristics, are not monitoring.

SAM-J078-R1 - 3 - 1.4 References

HM Government 1995. Review of Radioactive Waste Management Policy - Final Conclusions. Cm 2919, HMSO, London. Hugi, M, Zuidema, P, Fritschi, M and Nold, A L 2001. Surveillance of a deep geological repository for radioactive waste. Proceedings of WM’01 Conference, Tucson, Arizona. IAEA 2001. Monitoring of geological repositories for high level radioactive waste. IAEA- TECDOC-1208. International Atomic Energy Agency, Vienna. Mouroux, B 2001. Research program related to retrievability, reversibility and monitoring of geological disposal in France. Proceedings of WM’01 Conference, Tucson, Arizona. Nirex 2001a. The Nirex Phased Disposal Concept. Nirex Report N/025. Nirex 2001b. Generic repository studies: Responses to feedback on monitoring and retrievability. Nirex Report N/033. Olsson, O, Svemar, C, Papp, T, Hedin, T 2001. The potential for retrievability and application of monitoring within the KBS-3 concept for final disposal of spent nuclear fuel. Proceedings of WM’01 Conference, Tucson, Arizona. SAM/NNC/Nagra 2001. Technical implications of retrievability on the Nirex phased disposal concept. Contractor report to UK Nirex, SAM Report SAM-J064-R1. UK CEED 2000. Workshop on the Monitoring and Retrievability of Radioactive Waste, December 2000. UK CEED 2001. Workshop on the Monitoring and Retrievability of Radioactive Waste, 12 February 2001. EA/SEPA/DoE NI 1997. Disposal Facilities on Land for Low- and Intermediate Level Radioactive Waste: Guidance on requirements for Authorisation. Environment Agency.

- 4 - SAM-J078-R1 2 METHODOLOGY FOR ANALYSING MONITORING OPTIONS

2.1 General approach

A methodology is required to demonstrate that a comprehensive identification and analysis of options has been made within the wide range of possible types of monitoring and, also, to focus the effort of identifying options towards those that will be most useful in the development of the repository.

In this report, the identification and analysis of monitoring options is carried out according to the three questions introduced in Section 1.2, i.e. Why ? What ? How ? Figure 2.1 illustrates the general methodology, which is also outlined below.

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WHAT? HOW? IdentifyIdentify monitoringmonitoring IdentifyIdentify informationinformation IdentifyIdentify parametersparameters methodsmethods,, i.e.i.e. requirementsrequirements underunder relatedrelated toto eacheach measurementmeasurement eacheach objectiveobjective informationinformation requirementrequirement techniques,techniques, schemes,schemes, instrumentsinstruments etcetc

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Figure 2.1: General methodology for the identification of monitoring options.

Why is monitoring required?

The broad answer to this question is that monitoring is required to help develop, design and implement the disposal system, to evaluate the behaviour of the disposal system and the impacts of the repository and its operation on the environment, and to assure that these impacts are acceptable.

SAM-J078-R1 - 5 - More specifically, in this project, the question is broken down to consider why monitoring might be required in support of several objectives that will need to be met in order to develop an acceptable disposal system. For example, a rigorous long-term safety case is a necessary component of an acceptable disposal system; thus, the development of this safety case is an objective that must be met. The first step of the method is, therefore, to identify an overarching set of objectives.

Monitoring supplies the information required to satisfy an objective or, more generally, to assess the extent to which an objective is or can be achieved. Thus, a second step is to identify the information requirements to allow an assessment of each objective. This may mean breaking down an objective to its component parts. For example, in order to develop a long-term safety case it is necessary to gain information related to the overall site suitability from a long-term safety perspective and to gain information related to the potential for radionuclide release by various pathways.

What should be monitored?

Having identified the information requirements related to each objective, it is next possible to identify the parameters which should be monitored in order to satisfy the information requirements. In some cases a parameter required may be measured or obtained directly, whereas in other cases several measurements and/or some analysis or interpretation may be necessary to derive the required parameter.

The rationale for monitoring of each parameter or group of parameters can then be considered in more detail, for example in terms of when and where a parameter should be measured in order to contribute to the assessment of the objective. This consideration will later guide the definition of monitoring options.

How should monitoring be done?

Finally, the monitoring methods to obtain given parameters can be considered. This includes the measurement techniques, instruments and schemes necessary to obtain values of the required parameters. The uncertainty associated with a method should be considered, especially where this might lead to an uncertainty on parameter value that must be considered in its use in assessment of each objective.

Knowledge of the practical capabilities of monitoring methods together with an understanding of the rationale for monitoring of each parameter or group of parameters should enable practical and useful monitoring options to be defined.

The above description and Figure 2.1 indicate a general methodology which may be adapted to apply to the various objectives analysed in the following chapters of this report. The common stage of the methodology, i.e. the identification of objectives, is discussed in the following subsection.

- 6 - SAM-J078-R1 2.2 The objectives for monitoring

The objectives to be met in developing a phased geological disposal concept could be expressed in various ways. Any set of objectives that is devised may include some overlaps and is not expected to represent a unique set. Provided, however, that the set is reasonably comprehensive then it provides a useful basis for considering the requirements for monitoring. The following eight headings are suggested as a sufficient set for the current study.

Waste management and repository strategic decisions

A repository is required with suitable capacity, at an appropriate time and location, with due regard to UK nuclear energy and radioactive waste management policies, the types and volumes of waste arising, scientific and technological developments, and social acceptability. The phased disposal (or any alternative management solution) needs to be implemented with regard to the above factors (external to the project) and, also, technical and specific findings from the ongoing site and repository investigations (within the project).

Repository design and construction

The repository must be constructed at a suitable location, according to an appropriate technical design, and utilising appropriate construction methods. For example, the host rock and geological environment should be suitable for repository construction, and the design should be adapted to the wastes and the geological environment.

Long-term safety case

A long-term safety case must be provided that, initially, shows reasonable prospects of meeting long-term safety requirements and, eventually, that long-term safety can be reasonably assured. For example, that the potential radionuclide release pathways can be adequately assessed, estimated releases are acceptable and that any outstanding long-term safety issues can be resolved by further study or engineering adaptations. The long-term safety case must provide technical evidence of safety (e.g. compliance with regulatory requirements) and, also, may also be expected to provide less technical arguments concerning safety.

Operational safety case

An operational safety case must be provided before commencing operation of the repository and, thereafter, the conditions must be monitored to assure the terms of the safety case and authorisations are respected. This will include the requirement that the potential exposure of the operating staff and members of the public to radiation are ALARP, and that non- radiological safety is assured.

Reversibility and retrievability

The repository should be designed and operated such that that is possible to reverse a given step in implementation including, if necessary, the step of waste emplacement. This requires

SAM-J078-R1 - 7 - flexibility of design to respond to new information, constraints and opportunities, e.g. new waste management technologies, changed policy, regulatory or social requirements. In particular, the repository environment and structure may have to be controlled rather closely to ensure that all necessary systems for waste retrieval can be safely maintained and operated.

Environmental assessment

The repository must be designed and operated such that all environmental impacts are acceptable, e.g. non-radiological and conventional impacts can be controlled and assessed, and are acceptable. This includes environmental impacts of construction as well as operational and post-closure impacts.

Policy, legal and regulatory framework

The repository must be implemented such that all policy, legal and regulatory requirements are met, e.g. international, national and local requirements under conventional and special legislation. This will include, for example, specific regulations related to waste management, local planning requirements, EC environmental legislation and international nuclear safeguards requirements.

Public acceptability and wider confidence issues

The repository must be implemented such that public acceptability and wider confidence issues are satisfied, e.g. the social equity of the decision process, social acceptability at a given site, , reassurance of safety.

Table 2.1 sets out the objectives listed above and, under each heading, examples of more specific aims within each objective, referred to as information requirements. Monitoring should supply the information needed to show that these objectives are met. Similar information requirements could, in principle, appear under several objectives. To reduce duplication, however, requirements are placed under the heading to which they most directly relevant. Chapters 3 to 10 of this report discuss the options for monitoring under each of the objectives given in the Table.

- 8 - SAM-J078-R1 Table 2.1: Objectives and examples of information requirements to allow their assessment.

Objectives 1. 2. 3. 4. 5. 6. 7. 8. Waste Repository design Long-term safety Operational safety Reversibility and Environmental Policy, legal and Public management and and construction (LTS) case (OpS) case retrievability assessment regulatory acceptability and repository framework wider confidence strategic decisions issues Examples of information requirements for assessment of these objectives. Assessment of Assessment of Assessment of Assessment and Assessment and Assessment and Acceptability Acceptability Types and Suitability of the Site suitability for control of control of control of under under volumes of waste site from the point long-term safety Worker Pre-backfill: Traffic, noise, Government Need for to be disposed of view of Radiological radiological safety Waste package visual amenity, policy, e.g. repository, see 1. Required capacity construction of: pathways: Worker integrity disturbance of consultation Equity and natural habitants requirements and timing of - vaults in host - Groundwater conventional Vault stability management of repository rock, safety etc. International and the process, see 7. - access and infra- - Gas pathway In-vault Potential EC requirements, Waste Public equipment Safety of the management structure within - Human intrusion radiological safety pollutants, e.g. safeguards, facility the geological Vault contaminants etc. EIS developments Develop Public - LTS, see 3. environment confidence in environment (rad & non-rad) Local planning Scientific and conventional - OpS, see 4. technical - surface access long-term safety safety Groundwater Social and requirements developments and infra- Chemo-toxic management economic impacts Long-term safety Environmental structure During mining impact of the Conditions during hazard assessment and construction, Monitoring and Liabilities requirements, see Design facility, see 6 repository life- Post-closure waste maintenance 3 determining cycle, see 4, 5 and criticality emplacement and Post-backfill: Operational safety Confidence parameters, e.g. of 6. C&M period requirements, see monitoring underground Vault backfilling 4 Scientific and Regulatory and layout and vault Pre-closure & sealing technical peers social design criticality Repository access Terms of developments, see backfilling & authorisation 7 and 8. sealing

SAM-J078-R1 - 9 - 2.3 Temporal aspects of a monitoring programme

Monitoring will be required before and during the development of a repository, and also after its closure, for scientific, technical, management, safety, regulatory, legal and public acceptability reasons. Another approach to identifying the information requirements and monitoring options could be to consider these against the phases of repository development.

The what, why and how of monitoring could be considered at each of the following phases.

 Before site selection – including waste characterisation, QA of packages and grout, monitoring of conditions in surface stores, and definition of the process by which the concerns of stakeholder groups will be taken into account in developing and implementing the monitoring programme.

 Site characterisation from the surface – including surface and underground characterisation for safety assessments and preliminary design studies, definition of site models and baseline environmental assurance and liability monitoring.

 Underground access and exploration (RCF phase) – including characterisation for repository design and more detailed long-term safety assessment, testing of hydrogeological and geotechnical response to excavation and improved scientific understanding including model validation.

 Repository design and construction – including detailed examination of rock conditions in the vault locations, testing of vault stability and equipment, large-scale underground safety issues, ventilation and drainage tests and baseline operational safety monitoring.

 Waste receipt and emplacement (which will begin in parallel with construction) – including checking of inventory and condition of waste received at the repository, package placement, vault stability, package conditions, vault environment, equipment function and maintenance, operational safety monitoring (for public and workers) and compliance with nuclear safeguards requirements.

 Monitored underground storage (Care & Maintenance phase) – including continuation of monitoring of vault stability, package conditions, vault environment, equipment function and operational safety, nuclear safeguards, assurance of retrievability, plus longer term confirmation of models and observation of vault-host rock interactions.

 Backfilling and post vault backfilling – including monitoring of backfill quality and placement, geological responses, evolution of backfill conditions and maintenance and safety of the remaining underground openings.

 Closure and post-closure – including monitoring of seal quality and installation, confirmation of geological stability, monitoring of physiochemical evolution of the repository environment and continuation of environmental and hydrogeological monitoring for reassurance purposes.

- 10 - SAM-J078-R1 A systematic analysis of information requirements and monitoring options against the phases of development has not been attempted in this project. Figure 2.2 provides an overview of the different types of monitoring that may be required over the course of a repository development programme.

This approach could be developed in future work by Nirex. It would, however, require the definition of more precise goals and information needs that monitoring would be expected to provide at each stage. This is closely connected to the approach that would be taken in advancing the phased development, e.g. the degree of caution or pragmatism that will be exercised in advancing the development, addressing the question of how much information is enough at each step and how can an adequate level of confidence can be defined. This is a matter for Nirex to consider.

SAM-J078-R1 - 11 - Figure 2.2: Possible monitoring activities against the stages of repository development

Abbreviations: EIA = Environmental Impact Assessment; PPSA = Preliminary Postclosure Safety Assessment; DPSA = Detailed Postclosure Safety Assessment.

 Candidate site selection  Repository site confirmation? Key points  Begin RCF  Begin repository construction  Begin emplacement  Backfill vaults  Complete emplacement  Closure Stages Before site Site Underground Repository design Waste receipt and Monitored Post vault backfill Post closure (overlapping in selection characterisation access and & construction emplacement underground (underground (institutional some cases) exploration (RCF) storage access) control) Waste and Waste characterisation & checking ...... Check at receipt Confirm continued retrievability packages QA of packages and grout etc. Monitor condition in stores (inc. corrosion) Monitor condition in underground (inc. corrosion) Nuclear safeguards (active) ...... Passive safeguards Surface Establish baseline for EIA Reassurance and liability monitoring against baseline ...... environment (incl. Characterise for operational safety assessments Operational safety monitoring (public) . . . . near-surface hydrology) Characterise for post-closure safety assessments Postclosure safety public assurance Deep geology and Establish baseline for EIA Reassurance and liability monitoring against baseline ...... hydrogeology Characterise for PPSA Characterise for DPSA (inc. responses) Ongoing confirmation of understanding (inc. effects of EBS on geology) Characterise for RCF design Characterise for repository design (inc. responses) Characterise for sealing Confirm sealing Underground Characterise for RCF design Characterise for repository design (inc. responses) structures and Excavation and support installation tests Vault structure monitoring & maintenance geotechnical Monitor opening and support stability (mine safety and understanding) Underground Mine safety monitoring Ventilation control tests environment Baseline radiological (radon etc.) Operational safety monitoring (workers) (atmosphere, surfaces & Vault environment monitoring (cleanliness, temperature, humidity, radiological) drainage) Drainage control and monitoring Vault drainage control and monitoring Underground Equipment installation and testing Continued operability/retrievability equipment Equipment maintenance assurance and safety...... Backfilling and Backfill and seal tests Backfill and seal installation and QA sealing Confirm early backfill evolution

- 12 - SAM-J078-R1 3 WASTE MANAGEMENT AND REPOSITORY STRATEGIC DECISIONS

Project decision making – internal and external factors

Monitoring is seen as activity to provide information to ensure the safety and good management of a project – in this case the phased development of a geological repository. Within the phased, reversible development of a geological repository, monitoring is required at each stage of the development:

– to record or confirm the system description and provide baselines against which any changes can be assessed;

– to assure satisfactory technical conditions for the safe and reversible continuation of the current phase or to alert the operator (or other responsible authority) concerning changes in conditions that require actions to be initiated;

– to give the necessary information to provide the technical confidence to take the next step (i.e. move to the next phase) or possibly uncover reasons to step back;

– to provide non-technical assurance of safety at each phase and confidence to take the next step.

Within the project, the focus is mainly on the monitoring of technical factors related to the physical system and its impact on the environment – which could be termed internal factors. Taking a more strategic view, however, the overall management of the project needs to take account of factors such as in government policy, the types, volume and timing of waste arising, major scientific and technical developments and public attitudes, all of which bear on the overall need for, timing and acceptability of the project.

This section considers the monitoring of these external factors which bear on overall waste management and repository strategic decision making.

Preliminary identification of factors – why and what?

Table 3.1 makes a preliminary identification of strategic aspects and notes reasons why monitoring of each aspect may be relevant. Information requirements related to each aspect are also indicated, i.e. what in general terms needs to be monitored. This material can only be very general in nature, since the policy regarding waste management solutions, and framework for their development, are currently under review in the UK.

SAM-J078-R1 - 13 - Table 3.1: Monitoring of external factors bearing on waste management and repository strategic decisions

Aspect – why Information requirements – what Comment on monitoring or rationale

Waste arising Types, volumes and general characteristics of conditioned UK Radioactive Inventory compiled and periodically waste allocated to deep disposal. Amounts currently in updated by the DEFRA and Nirex. To assess the need for repository, timing store and estimated future arisings. and required disposal volume. Waste management development New waste management, conditioning and packaging Scientific and technical literature monitored as part of developments liable to lead to significant changes in future Nirex current waste packaging research programme. To assess consequent modifications of arisings or providing options for a re-packaging of existing the need for repository, timing and wastes. required disposal volume. Availability of new disposal options or significant changes in geological disposal concept. Future nuclear power and Government policy and industry intentions with regard to “Expected” scenarios should be represented in the UK reprocessing scenarios nuclear power use and reprocessing determine future Radioactive Waste Inventory but possibility for changes scenarios. leading to very different waste arising outcomes should To assess the disposal needs associated be borne in mind. with such scenarios. Economic aspects Costs of waste conditioning and packaging for storage The balance of costs between storage and disposal may and/or final disposal. determine economic arguments for the timing of To assess the costs of repository repository development and closure. development and operation and Costs of storage. associated waste management costs. Costs of repository development including closure and/or extended underground storage. Scientific, environmental and Developments that might (ultimately) impact on the need General awareness of scientific and environmental technical developments for and timing of the repository or its economics, which developments should be sufficient, as impacts are liable could include: to take effect only over several tens of years. To assess whether such developments might impact on the feasibility, safety – developments in power generation, e.g. more efficient Specific studies should be made to maintain awareness and/or cost of repository development. nuclear or non-nuclear power technologies which of technical developments related to geological sciences, impact on future power scenarios; underground construction, waste handling, storage

- 14 - SAM-J078-R1 – recognition of previously unrecognised environmental conditions, instrumentation etc. or human health benefits or detriments; – more efficient underground investigation or construction techniques; – new modelling and assessment techniques that impact on assessment calculations and safety arguments. Legal and regulatory developments Changes and possible changes of national regulatory Nirex keeps such developments under review and requirements and international guidance. incorporates requirements into company safety To assess whether such developments standards. Further discussed under Objective 7 (Chapter might impact on the feasibility, safety Changes in planning and environmental law. 9). standards and/or cost of repository development. Social developments and acceptability Local and national public views on nuclear matters and Should be kept under review and may be taken into conditions for acceptability of a radioactive waste account in siting and project development. Further To assess factors bearing on social repository. discuss under Objective 8 (Chapter 10). acceptability of development. Repository and waste conditions Overall conditions in the underground and of the stored Technical monitoring discussed under Objectives 2, 4 waste may lead to re-evaluation of economics of and 5 (Chapters 4, 6 and 7). Here the concern is the To assess continued operability and underground storage and desirability or not of early closure. impact on the overall economics and feasibility. maintenance or refurbishment requirements. Assessed current and long-term The assessed current or long-term safety may impact on Technical monitoring discussed under Objectives 3, 4 safety overall acceptability of the solution, e.g. the solution is and 6 (Chapters 5, 6 and 8). Here the concern is any shown to be much safer than forecast or subject to risk impact on overall acceptability. To assess continued operational safety previously unrecognised risks. and eventual long-term safety and any need for changes in management or design to maintain such.

SAM-J078-R1 - 15 - 4 REPOSITORY DESIGN AND CONSTRUCTION

4.1 Scope of this chapter

This chapter addresses monitoring with regard to the design and construction of the underground waste repository. The time frame of interest comprises all stages of the development process, i.e. before site selection, site characterisation from the surface, underground access and exploration, the actual phase of repository design and construction, waste receipt and emplacement, monitored underground storage, and finally the post-vault backfill pre-closure phase.

The information requirements which meet the monitoring objectives related to repository design and construction follow from considerations related to a robust design (for the reason of long-term safety), feasible construction, safe operation and compatibility of the underground disposal system with its natural environment. In particular, the requirements of the Nirex Phased Disposal Concept (Nirex 2001) are taken into account, e.g. an extended period of open disposal vaults.

The information requirements for repository design and construction are associated with the assessment of rock and site suitability (in relation to repository design and construction - as opposed to the long-term safety case, see Chapter 5), the feasibility of access to the underground and to build the necessary repository infrastructure. Furthermore, the chapter addresses the aspects of construction and operation feasibility, and the backfilling and sealing of the repository. Finally, the information requirements for assessing the potential impact on the environment caused by repository construction are addressed.

4.2 Approach to identifying information requirements

For the purpose of site characterisation, a large number of different parameters will be measured, which eventually are used to develop a comprehensive geological, hydrogeological, geo-mechanical and geo-chemical model of the repository site. Such geoscientific models, including detailed site description and associated database, are essential inputs not only to repository design and construction, but also to the site-specific assessment of long-term safety. Selected measurements for site characterisation will be taken either once only, randomly or periodically depending on the information required and in line with the relevant stages of the repository development. The measurements will be performed from the surface or below ground, at appropriate locations of the disposal system or even at off-site laboratories. During the surface-based investigations specific locations will be selected for monitoring during the site characterisation and design/construction phase of the repository. These measurements will provide the input to establish base-line conditions, characterisation of the site and the impact of repository construction on the environment. The initial

- 16 - SAM-J078-R1 monitoring points from surface boreholes may be successively replaced or supplemented with monitoring points from underground boreholes. The site characterisation programme, therefore, will provide a starting point for a monitoring programme that possibly will continue even into the post-closure period.

Figure 4.1, below, shows the framework on which information requirements related to repository design and construction have been identified. This is based on six main aspects that must be assessed during design and construction activities, and information requirements to support these assessments. More detailed information requirements, assessment parameters and measurement methods available under each heading are then developed comprehensively in Table 4.1, at the end of this chapter.

Volume of low K rock body Rock/site Site stability suitability Identification of Explorability and predictability information requirements related Access/ Surface facilities infrastructure Repository area/ emplacement panels to repository design feasibility and construction Rock mechanics Construction Hydrogeology Repository feasibility Geochemical environment Design and Structural material

Construction Temperature requires assessment of: Groundwater inflow Operation Drainage system feasibility Atmospheric conditions Natural and other gases Rock fall

Host rock Backfilling/sealing Backfill material feasibility Mechanical stability & anchoring of seals Sealing material

Environmental Surface environment impact Sub-surface environment

Figure 4.1: Identification of information requirements related to repository design and construction

According to the International Atomic Energy Agency (IAEA 2001) monitoring of a geological disposal facility for radioactive waste is defined as ... continuous or periodic observations and measurements of engineering, environmental or radiological parameters, to help evaluate the behaviour of components of the repository system, or the impact of the repository and its operation on the environment.

SAM-J078-R1 - 17 - In the present work, however, monitoring is considered from a broader view, see Section 1.3. This includes measurements which are part of the site characterisation process and are aimed to develop the comprehensive database used for repository design and construction, and for predictive modelling in order to demonstrate the long-term safety of the repository system. This leads to the comprehensive identification of information requirements, assessment parameters and measurement methods recorded in Table 4.1.

Monitoring is aimed to meet the specific requirements of a well-defined objective (why?). Activities will take place during a certain time period (when?), which is related to the stages of repository development at a location within the repository system itself or its environment (where?). The measurements will be performed according to a defined schedule and there will be good reasons for their realisation (purpose). A scheme against which the monitoring requirements identified in Table 4.1 are classified is given at the foot of the table.

In the following text, discussion focuses on the key aspects of monitoring in the original sense of IAEA’s definition. The following sections discuss the rationale for monitoring against each of six information requirements related to repository design and construction identified in Figure 4.1:

A. Assessment of host rock and site suitability related to repository design and construction (Section 4.3).

B. Assessment of access and infrastructure feasibility (Section 4.4).

C. Assessment of construction feasibility (Section 4.5).

D. Assessment of operation feasibility (Section 4.6)

E. Assessment of backfilling and sealing feasibility (Section 4.7)

F. Assessment of environmental impact (Section 4.8).

4.3 Assessment of host rock and site suitability (related to repository design and construction)

This section addresses the monitoring requirements related to the assessment of the host rock and the site suitability from the viewpoint of repository design and construction. The specific aspects concern the required volume of low permeable host rock, site stability, explorability and predictability.

The rationale for these monitoring activities is to confirm that an adequate implementation of the underground facilities in a suitable host rock formation will be possible. Measurements will be done primarily in the context of site characterisation. The information will be used mostly for design purposes and as input for predictive modelling, but also to establish baseline conditions and system performance at the time of monitoring, and for technical confidence building (i.e. confirmation of earlier input data and assumptions for predictive modelling).

- 18 - SAM-J078-R1 Specific monitoring activities (in the sense of the IAEA definition) concern the following issues:

Layout-determining features – continuous observations of groundwater pressure in exploration boreholes from the surface (all development phases after selection of the site) and from underground facilities (i.e. rock characterisation facility (RCF), test vault, main disposal facility - as long as accessible); – monitoring of inflow in tunnels and underground boreholes (as long as underground facilities accessible); – periodic analysis of water samples from layout-determining features (time evolution of chemical composition - as long as underground facilities are accessible).

Surface subsidence and deformation of rock mass

During all repository development phases starting with underground access and exploration to the post-closure phase (institutional control) the following continuous observations will provide information on surface subsidence and deformation of rock mass: – precision leveling at the surface; – tilt measurements in observation boreholes drilled from the surface; – satellite based geodetic measurements; – precision leveling in underground facilites (as long as accessible); – time dependant geophysical measurements (4D-seismics, electromagnetic, geoelectric and seismic differential tomography) performed in underground boreholes and tunnels (as long as accessible).

Seismicity – event-triggered seismic measurements at the surface and by underground stations (geophones, accelerometers) before site selection, during site characterisation from the surface and during the whole period of underground access, respectively.

Heterogeneity of potential host rock – continuous observation of pore pressure or hydraulic heads in surface boreholes during construction of access tunnels, RCF and test vault and main disposal facility.

These measurements will together provide valuable information on the hydraulic properties of the host rock in general and the layout-determining features in particular, and on the rock mechanical stability of the site. The applied measuring techniques are standard hydrogeological and geotechnical practise and the corresponding instrumentation can be maintained operational over reasonably long observation periods.

SAM-J078-R1 - 19 - Other monitoring aspects under the issue of host rock and site suitability are related to site characterisation (cf. Section A of Table 4.1).

4.4 Assessment of access and infrastructure feasibility

This section deals with the monitoring in relation to the feasibility of having access to the repository site and the possibility to build the necessary infrastructure above and below ground. The rationale behind such activities is the confirmation that the site fulfils the necessary requirement in terms of local development plans and the local geological setting, which would allow the development and implementation of a waste repository. The information will be used for design purposes and as input for predictive modelling, some also to establish baseline conditions and to demonstrate compliance with regulatory requirements.

The information requirements under the issue of access feasibility and feasibility to construct the necessary repository infrastructure concern the access to the surface facilities and the underground (disposal) facilities. Most of these requirements must be addressed already before site selection or will be investigated as part of the site characterisation process. Therefore, they are not considered as monitoring activities in the sense of the IAEA definition. However, in order to eventually construct any shafts, ramps or other form of access tunnels a comprehensive characterisation of the overlying and bounding geological formation will be necessary, including the acquisition of information on mechanical stability, regional hydrology (i.e. groundwater flow path) and the presence of major fracture zones.

For the investigation of the local groundwater flow-fields a specially dedicated

– continuous groundwater monitoring programme, consisting of ground water pressure measurements in boreholes from the surface will be established before construction begins. The corresponding data acquisition and interpretation techniques are well known and the instrumentation is very reliable.

Other aspects under the issue of feasibility of access and infrastructure are mostly one-time measurements related to site characterisation. They are outlined in section B of Table 4.1.

4.5 Assessment of construction feasibility

Monitoring activities associated with the feasibility to construct an underground disposal facility with access shafts/ramps or tunnels, RCF, test vault and main disposal facility are the topic of the discussion in the present section. The particular aspects to be addressed in this context are rock mechanics, hydrogeological and geochemical conditions and the characterisation of structural material to be used in underground workings.

The rationale for such monitoring activities lies in the evaluation of rock mechanical, hydrogeological and geochemical conditions in order to check for compliance with the requirements to construct the underground facilities. The measurements are mostly done for

- 20 - SAM-J078-R1 multiple purposes, i.e. to establish baseline conditions, to be used for design data, to assess system performance at the time of monitoring, to provide input data for predictive modelling and to build-up technical confidence. The time periods for such monitoring activities are naturally these when access to the underground facilities is possible.

Specific monitoring activities are

Deformation of underground workings – periodic or continuous measurement of cross-sections of underground workings (convergence measurement, load cells between rock and liner, instrumented anchor, multi-point extensometer); – continuous observations with inclinometer and micrometer (fixed or sliding) at walls of underground workings; – continuous measurements of local strain (e.g. applying CSIRO HI cells); – continuous underground observations using installation of micro–seismic array ; – periodic triangulation check and tilt meter measurement .

All the measurements listed above are performed in the RCF, test vault, main disposal facility vault and corresponding access tunnels as long as underground access is feasible. The instrumentation corresponds to standard geomechanical techniques.

Local stress field – continuous monitoring of stress changes in rock (relative stress changes during excavation to investigate load path) using flat jacks and strain cells during underground access and exploration and repository construction in RCF and test vault; – continuous monitoring of stresses in engineered structures using load cells and strain cells during the development periods when access of the underground facilities is possible.

Rock desaturation and other aspects – continuous and direct measurement of rock desaturation (i.e. suction pressure, water content, pore pressure) in short radial boreholes; – (periodic) indirect measurement of rock desaturation (by geoelectrical profiles - radial and along underground workings); – continuous observation of stress development behind the liners; – periodic evaluation of change of seismic velocity in short radial boreholes (interval velocities, cross-hole scans, tomography); – continuous leveling.

The specified monitoring activities are all performed in the RCF and test vault during the development periods with access to the underground facilities.

Hydrogeology of fracture zones

SAM-J078-R1 - 21 - – continuous water sampling with plastic sheets and periodic measurements with flowmeter or scale in all underground facilities (as long as the underground areas are accessible).

Groundwater composition and natural gases – periodic analysis of water samples; – continuous in-situ gas detection (balance, composition, concentration); – periodic laboratory analysis of gas samples.

All groundwater and gas samples would be collected either in boreholes from the surface (site characterisation from the surface) or in one the underground facilities (RCF, test vault, main disposal facility) as long as underground access is possible.

Deformation and ageing of structural material – periodic or continuous measurement of underground deformation (convergence measurement using instrumented anchor); – periodic geometry control of drainage (leveling) - only after repository construction; – periodic in-situ control of system components regarding degradation/corrosion (lining, rock anchors, waste handling equipment etc. (done by X-ray and visual inspection); – periodic analysis of cement core sample (e.g. uniaxial strength, elastic parameters, tensile strength, mineralogical composition, corrosion of reinforcement).

These activities are performed in the RCF, test vault and main disposal facility to check the system performance at the time of monitoring as long as underground access is conceivable. Standard instrumental techniques can be applied for such measurements which can be controlled and regularly maintained over the necessary time periods.

The aspect of the ambient temperature that is equally important for the construction feasibility is addressed in the following section on operation feasibility (see Section 4.6).

Other monitoring aspects under the issue of construction feasibility are related to site characterisation and further discussed in section C of Table 4.1.

4.6 Assessment of operation feasibility

This section addresses monitoring activities related to the operation feasibility of the underground facilities. Specific aspects deal with the ambient atmospheric conditions (with potential impacts on workers and waste packages), groundwater inflow and drainage, gas hazards and the mechanical stability of the underground facility.

- 22 - SAM-J078-R1 The rationale for such monitoring is that the operation of the disposal facility is safe for the operating personal, the general public and the environment, i. e. that prescribed regulatory requirements are respected. The purpose of the measurements is to establish baseline conditions, to be used for systems design, as input in predicting modelling, for technical confidence building, but mostly to evaluate the system performance at the time of monitoring.

The majority of the proposed monitoring activities correspond to monitoring in the sense of the IAEA definition. They are related to the following issues:

Ambient temperature and atmospheric conditions – temperature probes in long-term pore pressure monitoring intervals (below ground in exploration boreholes from the surface, during all development phases of the repository); – exploration boreholes from underground (conventional temperature probes, optical fibre sensors - in RCF and test vault); – monitoring of air temperature in tunnels and vaults; – anemometer; – humidity (hygrometer); – environmental parameters (hygrometer, air pressure transducer and air temperature probe) at intake of ventilation and at different points in repository; – analysis of air samples; – optical sensor to investigate air quality.

Inflow rates and chemical composition of groundwater – cover of plastic sheets and flow measurement with flowmeter or scale (local and integral measurements); – water sampling and geochemical analysis; – continuous measurement of physical / chemical parameters of ground water (e.g. electrical conductivity).

With a few exceptions, all measurements related to the temperature, atmospheric conditions, and rates and quality of inflowing groundwater (see both items listed above) could presumably be done either periodically or continuously in all underground facilities (i.e. RCF, test vault, main disposal facility incl. access tunnels) as long as these are accessible.

Functionality of drainage system – continuous balance of waters (water intake and waste water outflow with flowmeters); – periodic visual inspection by TV camera; – periodic waste water sampling and geochemical analysis.

SAM-J078-R1 - 23 - Periodic and continuous analyses and inspections shall guarantee compliance with waste water quality standards and ensure a proper functioning of the water drainage system as long as underground facilities (RCF, test vault, main facility) are operational and accessible.

Natural and other gases – continuous measurement of explosive gas concentrations with detectors in accordance with specific regulations (applying electrochemical, infrared (IR), or ultraviolet (UV) sensor technology); – continuous toxicity measurement with gas detectors in accordance with specific regulations (applying electrochemical, infrared IR, or ultraviolet UV sensor technology); – continuous radon emanation according to governmental regulations.

These measurements are aimed to prevent any hazard potentially caused by the occurrence of natural gases or by gases generated by the emplaced waste. Such measurements should take place in all underground workings (RCF, test vault, main disposal facility vaults, access tunnels) starting from the development phase of underground access and exploration until the repository will be sealed.

Rock fall / stability of rock support – periodic (or continuous) measurements of rock movement and extent of underground deformation (extensometers, inclinometers, micrometers); – periodic measurement of seismic interval velocities in short radial boreholes; – continuous stress path monitoring (using flat jacks, strain cells); – periodic evaluation of borehole cores from liner (uni-axial strength, elastic parameters, tensile strength, minerological composition, corrosion of reinforcement); – continuous measurement of load on tunnel support (instrumented anchors, load cells); – liner inspection (optical methods, markers).

These monitoring activities will ensure safe working conditions for the operating personal and guarantee the continued operability of mechanical and other installations (e.g. hoisting devices, electrical installations). Measurements will either be done in the RCF and test vault (first three items), or in addition also in the main disposal facility faults plus access tunnels (next three items) as long as access of the underground facilities must be maintained.

Other monitoring aspects under the issue of operation feasibility are related to site characterisation (cf. section D of Table 4.1).

- 24 - SAM-J078-R1 4.7 Assessment of backfilling and sealing feasibility

The present section deals with monitoring activities related to the backfilling disposal vaults and the sealing of the repository. The specific aspects concern the properties of the excavation damage zone around underground workings, the properties of the backfill materials and the mechanical stability of sealing plugs for tunnels, caverns and shafts.

The rationale for these monitoring activities lies in the confirmation of the conditions that: after the waste has been received and emplaced, the disposal vaults can be adequately backfilled; and that, after the last phase of repository development, the underground facilities can altogether be properly sealed. The information is required for design purposes, to evaluate system performance at the time of monitoring, as input for predictive modelling and for technical confidence building.

Specific monitoring activities concern the following issues:

Extent and hydraulic properties of excavation damage zone – continuous (or periodic) deformation measurements (using extensometers, inclinometers, micrometers) in underground workings (also necessary to establish baseline conditions); – seismic methods for time evolution of excavation damage zone (reflection or refraction tomography, interval velocity, downhole velocity - also for baseline conditions); – continuous acoustic emission measurements (micro-seismic array); – measurement of transmissivity and heads before, during and after tunnel construction ("mine-by-test"); – continuous (or periodic) measurement of transmissivity and heads with specialised packer systems after tunnel construction (e.g. MMPS or SEPPI probe); – continuous inflow measurements at discrete points; – continuous water content measurements (e.g. TDR time domain reflectometry); – continuous water potential measurements (e.g. thermocouple psychrometer).

Properties of backfill material – in-situ demonstration test for continuous (or periodic) evaluation of water content, hydraulic conductivity.

Long-term stability of plugs – continuous in-situ demonstration test for mechanical and hydraulical loading, geodetic measurements, acoustic emission measurements; – in-situ demonstration test with continuous (or periodic) evaluation of emplacement density, water content, hydraulic conductivity, gas permeability, swelling pressure.

SAM-J078-R1 - 25 - All monitoring activities listed above may take place in the RCF and the test vault during all repository development phases when underground access is feasible (i.e. underground access and exploration, repository construction, waste receipt and emplacement, monitored underground storage).

The measurements are based in part on some advanced, non-standard underground investigation technology. The reliability of instrumentation is ensured as long as proper maintenance is possible whenever needed.

The monitoring aspects under the issue of backfilling and sealing feasibility are further discussed in section E of Table 4.1.

4.8 Assessment of environmental impact

The present section addresses the monitoring which is related to the potential impacts of the underground disposal facility on the surface and sub-surface environment. The specific information requirements concern topographical deformations, airborne discharges and the conditions for groundwater usage at the site.

The rationale for such monitoring is a) to establish baseline conditions of the natural environment (for reasons of liability) before any important work is done at the site and b) to assess the potential and actual impact of underground access and exploration, repository construction, waste receipt and emplacement, (monitored) underground storage and repository closure. All activities identified under the issue of environmental impact are classifiable as monitoring in the sense of the IAEA definition.

Topographical deformations – continuous precision leveling at the surface; – continuous tilt measurements in observation boreholes drilled from the surface; – continuous satellite-based geodetic measurements.

These monitoring activities start with (or before - to establish baseline conditions) the underground access and include the post-closure phase.

Airborne discharge – continuous operation of meteorological station at the site surface, starting at the time of site characterisation from the surface and including the post-closure phase of the repository; – continuous analysis of waste air (radon emanation, gas detectors) at the point of discharge as long as the underground facilities are ventilated.

Groundwater usage – continuous piezometer measurements in boreholes from the surface;

- 26 - SAM-J078-R1 – continuous flowmeter tests at the site surface environment to evaluate the evolution of production rates (springs, wells); – hydrological monitoring: stream and river discharge/recharge locations and flow rates; – periodic analysis of water samples in (off-site) laboratories to evaluate the chemical and isotopic composition of the groundwater.

The above are required throughout the development phases of site characterisation from the surface to the post-closure phase (institutional control). All monitoring activities listed under the separate information requirements above provide in parallel baseline information, data for system performance at the time of monitoring, data to be used in predictive modelling and contribute to the build-up technical re-assurance.

The monitoring aspects under the issue of environmental impacts are further discussed in section F of Table 4.1.

4.9 References

IAEA 2001. Monitoring of geological repositories for high level radioactive waste. IAEA- TECDOC-1208. International Atomic Energy Agency, Vienna. Nirex 2001. The Nirex Phased Disposal Concept. Nirex Report N/025.

SAM-J078-R1 - 27 - Table 4.1: Development of information requirements, assessment parameters and measurement methods related to repository design and construction

Note: Measurement methods are classified according to the scheme given in the key given at the foot of this table.

Repository Design and Construction Aspect Information Assessment parameters Measurement methods requirement A. Assessment of rock / site suitability ( - related to repository design and construction) Volume of low Formation size and Horizontal and vertical dimensions of potential Literature search (1; A; c, II, IV) permeability rock homegeneity host rock formation at practicable depths Remote sensing (1; satellite and airborne; a, II, body IV) Geological mapping (1; C; a; II,IV) Geophysical surface investigations [2D and 3D seismics, geoelectric measurements] (1-2; C; a; II, IV) Exploration boreholes from surface (1-2; D; a; II, IV)

Volume of low Layout determining Nature, orientation and frequency of potential Exploration boreholes from surface with different permeability rock features layout determining features – major faults, dips and dip directions [core logging, structural body (contd.) discontinuities and/or inclusions other rock types logging, fluid logging, packer tests (multiple- scale), borehole seismics, crosshole Minimum distance to nearest fault zone (or any investigations] (1-2; D; a; II, IV) water-conducting discontinuity) Geophysical surface investigations [seismics, electromagnetics, very low frequency VLF] (1-2; C; a, II, IV) Exploration boreholes from underground vaults [core logging, structural logging, fluid logging, packer tests, borehole seismics, crosshole

- 28 - SAM-J078-R1 investigations] (3-4; E-G; a; II, IV) Tunnel mapping [geological and hydrogeological] (3-4; E-G; a; II, IV) Monitoring of groundwater pressure in exploration boreholes from surface (2-8; D; e; II- V) Monitoring of groundwater pressure in exploration boreholes from underground vaults (3-6; E-H; e; II-V) Monitoring of inflow in tunnels and underground boreholes (3-6; E-G; c; II-V) Evolution of groundwater composition in layout- Analysis of water samples (2-6; D-H; c; I-V) determining features (age of water) Site stability Important geological Occurrence and characteristics of major faults Exploration boreholes from surface [see above] features (1-2; D; a; II, IV) Exploration boreholes from vaults [see above] (3- 4; E-G; a; II, IV) Vault, shaft, ramp and tunnel mapping [geological and hydrogeological] (3-4; E-G; a; II, IV) Monitoring of pore pressure in exploration boreholes from surface (2-8; D; e; II-V) Monitoring of pore pressure in exploration boreholes from underground vaults (3-6; E-H; e; II-V) Monitoring of inflow in tunnels and underground boreholes (3-6; E-G; c; II-V) Surface subsidence Large scale deformations (subsidence and tilting) Precision leveling at surface (3-8; C; c; I, III-V) /deformation of rock mass - as a consequence Tilt measurements in observation boreholes (3-8;

SAM-J078-R1 - 29 - of repository C; c;I, III-V) construction and operation Satellite based geodetic measurements (3-8; satellite; c; I, III-V) Precision leveling in underground facilites (3-6 Rock desaturation - above the repository zone - (4); E-H; c; III-V) from the surface and underground Time dependant geophysical methods [4D- seismics, electromagnetic, geoelectric and seismic differential tomography] from underground boreholes and tunnels (3-6; E; c; III-V) Site stability (contd.) Seismicity (with respect to incidents during repository Event-triggered seismic stations at surface construction and operation (rockburst, effects on [geophones, accelerometers] (1-6; C; e; II-VI) underground workings, waste handling equipment etc.): Event-triggered seismic underground stations [geophones, accelerometers] (3-6; E-F; e; II-VI) Earthquake observations (strength, frequency) incl. deduction of Stress measurement [hydraulic fracturing, under / overcoring, flat jacks, borehole slotter, - parameters of design earthquake observation of borehole instabilities] (2-4, D-E; a; II-III) - probability of its occurrence Rock mechanical testing [triaxial lab test, direct shear testing, in situ load plate test, in situ shear test, pull test on reinforced support etc.] (2-4; B, E; a-b, II) Explorability and Accessibility of potential Possibility of access from the surface (deep Investigation of topographic conditions (1-2; A,C; predictability host rock for boreholes, geophysical/seismic investigations) a; II) exploration purposes and/or from underground (investigations in Infrastructure [roads, farm land, forest, lakes, exploratory drift, RCF) power lines] (1-2; A,C; a; II) Permitting [private land owners, local government, forestry] (1-2; C; a; II) Explorability and Homogeneity/ Assessment parameters to be defined in context Exploration boreholes from surface [core logging, predictability heterogeneity of with the specific site fluid logging, hydraulic testing, water sampling, (contd.) potential host rock structural logging] (2; D; a; II)

- 30 - SAM-J078-R1 - hydrogeological classification of rock type Exploration boreholes from underground [as (porous / fractured medium, soft / hard rock) above and hydraulic crosshole test] (3-6; E-H; a,c; II-V) - assessment parameters for fractured rock: fracture classification, fracture statistcs Monitoring of pore pressure changes or hydraulic (orientation, frequency, size, width...), heads during construction of RCF and repository hydraulic properties (transmissivity, spatial (3-8; D; e; I-V) variability, anisotropy Geological mapping in tunnels and vaults [tunnel - assesment parameters for porous scanner, conventional mapping, stereo (sedimentary) rock: spatial extent of facies, photography] (3-4; E-H; a; II, IV) textural characteristics (sacles of interlayering), K-tensor, spatial variability of Hydrogeological mapping in tunnel and vaults K, scale depedance of K (laboratory against [WFS, inflow points, wet areas, channeling] (3-4; field) E-H; a; II, IV) Long-term geochemical sampling in tunnels and vaults [inflow points, boreholes] (3-6; E-H; c; III- V) (Feasibility of) spatial Assessment parameters to be defined in context Investigation of heterogenity with geophysical interpolation/ with the specific site methods [e.g. tomography] (2-4; C-H; a; II,IV) extrapolation of hydrogeological, - inventory of relevant features Validation of experiments on different scales against observations [boreholes, tunnels etc.] (3-4; geochemical and rock - definition of scales of interest mechanical conditions E-F; a; IV-V) - definition of processes of interest Hydrogeological incl. hydodynamical modelling on different scales Geochemical sampling of formation waters and member analysis (3-6; E-H; c; III-V)

SAM-J078-R1 - 31 - Repository Design and Construction Aspect Information Assessment parameters Measurement methods requirement B. Assessment of access / infrastructure feasibility Surface facilities Access to Major topographical features: Location, altitude, Study of local and regional infrastructure, main/auxiliary slope, available land area, ... measurements according to government buildings, unloading regulations station and repository entrance Availability/feasibility to Layout of regional road system and/or rail system Study of local and regional infrastructure, construct access routes measurements according to government regulations Other repository Availability of electric power, heat, water (incl. Study of local and regional infrastructure, infrastructure waste water treatment) measurements according to government regulations Repository area/ Feasibility of Characteristics of overlaying/bounding geological Literature search [tunneling experience under emplacement panels construction of shaft, formations: similar conditions, case histories, resources] (1-2; ramp or other form of A; a; II) access tunnel - mechanical stability (...) Investigation of land use and groundwater use and - regional hydrogeology/identification of present potential aquifers ] (1-2; A; a; II) groundwater flow paths (hydraulic conductivities, gradients) Groundwater monitoring (1-8; D; e; I, III-V) - major fracture zones, incl. xenolithes Tracer tests in groundwater and deep aquifers (1- (mechanical strength, water flow, natural gas 2; D; a (b); I, III-V) flow) Exploration borehole from surface [stress - underground usage (groundwater, other measurements, core logging, core samples, resources) logging, hydraulic testing, water samples, gas monitoring during drilling and testing] (1-2; D; a; I, II, IV) Geomechanical laboratory tests on samples

- 32 - SAM-J078-R1 [uniaxial tests, triaxial tests, direct shear tests, direct and indirect tensional tests, creep tests, slake durability tests, swelling tests] (1-6; B; a; II) Structural information from seismics (1-2, C; a; II, IV)

SAM-J078-R1 - 33 - Repository Design and Construction Aspect Information Assessment parameters Measurement methods requirement C. Assessment of construction feasibility Rock mechanics Deformation of Evolution of cavern cross-section, geotechnical Measurement cross sections [convergence, load underground workings response to excavation (as a function of time) cells between rock and liner, instrumented anchor, (surrounding rock and multi-point extensometer) (3-6; E-H; c, e ; I-V) structures) Acoustic emissions Inclinometer, micrometer (fixed or sliding) (3-6; Geodetic survey (precision levelling), tilt E-H; c; I-V) measurements Local strain measurements (CSIRO HI cells) (3-6; E-H; e; I-V) Micro-seismic array (3-6; E-H; e; I-V) Triangulation, tilt meter (3-6; E-H; c; I-V) Excavation damage zone (see below: backfill/sealing feasibility) Local stress field Stress tensor within surrounding rock and Exploration boreholes from surface [hydraulic engineered structures fracturing] (1-2; D; a; II-V) Stress measurement from underground [ hydraulic fracturing, over- / undercoring technique, borehole slotter] (3-5; E-H; a; II-V) Monitoring of stress changes in rock [flat jacks, strain cells (relative stress changes during excavation to investigate load path)] (3-4; E-F; e; II-V) Monitoring of stress in engineered structures [load cells, strain cells] (3-6; E-H; e; II-VI) Rock mechanics Rock mass quality Rock mechanical strength Standard laboratory tests on samples [uniaxial tests, triaxial tests, direct shear tests, direct and

- 34 - SAM-J078-R1 (contd.) indirect tensional tests, creep tests, slake durability tests, swelling tests] (1-4; B; a; II, IV- V) In situ tests [load plate, direct shear, dilatometer] Q-value (or other rock mass rating) (coupled to (3-4; E-F; a; II, IV-V) cavern geometry and repository depth) Borehole core investigations for Q-value detection [uniaxial compressive strength, drill core quality (RQD), spacing of discontinuities, conditions of discontinuities, groundwater inflow conditions, in situ stress conditions, orientation of discontinities with respect to tunnel] (1-4; B; a; II) Other aspects Desaturation profile (rock and tunnel walls, Direct measurement of desaturation [suction temperature, pore pressure, ... pressure, water content, pore pressure] in short radial boreholes (3-6; E-F; e, I-V) Indirect measurement of desaturation: [geoelectrical profiles - radial and along tunnel] (3-6; E-F; c; I-V)

Swelling properties Laboratory swelling tests (1-4; B; a; II-V) Dissolution phenomena (porosity change, etc.) Development of stresses behind liner (3-6; E-F; e; II-V) Other rock mechanical parameters: ...? Change of seismic velocity in short radial boreholes [interval velocities, crosshole scans, tomography] (3-6; E-F; c; II-V) Leveling (3-6, E-F; c; II-V)

SAM-J078-R1 - 35 - Hydrogeology Fracture zones Location of inflow points and evolution of inflow Hydrogeological and geological tunnel mapping rate (3-4; E-H; a; II-V) Water sampling with plastic sheets and measurement with flowmeter or scale (3-6; E-H; c; 1-V) Hydraulic testing in boreholes intersecting the feature (3-4; E-H; a; II-V)

Geochemical Rock mineralogy (a) Concentration of constituents with unfavourable Mineralogical analysis of rock samples [e.g. x-ray environment impact on engineered underground workings diffractometry] ( 2-4; D-H; a; II-IV) (a) from cores (all sulphite containing minerals, e.g. pyrite, etc.) Groundwater Analysis of water samples (2-6; D-H; c; I-V) composition (b) (b) from water from water-conducting features (salinity, CO2, H2S, etc. )

Concentration of natural gases (methane, CO2, H2S, etc.) Natural gases In situ gas detection [balance, composition, concentration] (2-6; D-H; e; I-V) Laboratory analysis of gas samples (2-6; D-H, c; I-V) Structural material Deformation Deformation of cavern lining, rock anchors, waste Tunnel deformation [convergence measurement, handling equipment, ventilation system, waste instrumented anchor] (3-6; E-F partly G-H; c, e; water system, electrical equipment, etc. II-V) Geometry control of drainage [leveling] (4-6; E- H; c; III)

- 36 - SAM-J078-R1 Structural material Ageing Degradation/corrosion rates of ... (same as above) In situ control [X-ray, visual inspection] (3-6; E- (contd.) H; c; III) Survey of material discontinuities (fissure rates) Cement core sample [uniaxial strength, elastic parameters, tensile strength, minerological composition, corrosion of reinforcement] (3-6; E- H; c; III)

Repository Design and Construction Aspect Information Assessment parameters Measurement methods requirement D. Assessment of operation feasibility Temperature Ambient temperature Ambient temperature in underground workings Exploration boreholes from surface [temperature less than design upper logs, temperature probes in long-term pore limit Rock temperature pressure monitoring intervals] (1-8; D; e; I-V) Heat generation potential (waste packages) Exploration boreholes from underground Cement hydration heat [conventional temperature probe, optic fiber sensor] (3-6; E-F; e; I-V) Heat from machinery (repository operation) Monitoring of air temperature in tunnels and Ventilation rate vaults (3-6; E-H; e; I-V) Anemometer (3-6; E-H; e; II) Humidity [hygrometer] (3-6; E-H; e; II)

SAM-J078-R1 - 37 - Groundwater inflow Inflow rate (into Evolution of inflow rates (at particular inflow Cover of plastic sheets and flow measurement underground workings) points) with flowmeter or scale [point and integral] (3-6; E-H; e; I-V)

Chemical composition Evolution of chemical composition of inflowing Water sampling and geochemical analysis (3-6; E- groundwater H; c; I-V) Continuous measurement of physical / chemical parameters of ground water [electrical conductivity] (3-6; E-H; e; I-V) Drainage system Functionality Obstruction/clogging of drainage system (periodic Balance of waters [water intake and waste water functionality check) outflow with flowmeters] (3-6; E-H; e; I-V) TV-camera inspection (3-6; E-H; c; III) Waste water sampling and geochemical analysis (3-6; E-H; c; III) Bioactivity (biofilm generation rate) Discharge conditions Chemical composition of waste water, see above temperature Atmospheric Ambient air quality Water content of ambient air Environmental parameter [hygrometer, air conditions" pressure transducer and air temperature probe] at - humidity of fresh air intake of ventilation and at different points in - humidity of discharge air repository (3-6; E-H; c; III) Concentration of sodium and chloride ("salinity"), Analysis of air samples (3-6; E-H; c; III) ... Dust concentration/other constituents in ambient Optical sensor to investigate air quality (3-6; E-H; air c; III) Electro-magnetic impact Observation of impacts of lightning strokes on Statistical analysis (3-6; E-H; c; III) (lightning) operating equipment/electrical installations

- 38 - SAM-J078-R1 Natural and other Explosion hazard Evolution of concentration of flammable/ Ex-measurement with gas detectors in accordance gases explosive gases: methane, hydrogen, ... with specific regulations [electrochemical, infrared IR, or ultra-violet UV sensor technology] (3-6; E-H; e; III) Chemotoxicity Evolution of concentration of chemotoxical gases: Tox-measurement with gas detectors in natural gases (methane, hydrogen, CO2), from the accordance with specific regulations waste (methane, hydrogen, CO2), from repository [electrochemical, infra-red IR, or ultra-violet UV operation (CO2) sensor technology] (3-6; E-H; e; III) Radiotoxicity Evolution of concentration of radioactive gases: Radon emanation according to governmental natural (Radon-222), from waste (tritium, regulations (3-6; E-H; e; I-V) methane, CO2, ...) Rock fall Mechanical properties Rock mechanical strength Laboratory measurements on rock samples [3-4; of excavation damage E-F; a; II, IV) zone (EDZ) Deformation measurements [load plate tests, extensometers, inclinometers micrometers] (3-6; E-F; a, c, e; I-V) Seismic interval velocities in short radial borholes (3-6; E-F; c; I-V) Stress measurements [overcoring or borehole Stress tensor (around underground workings) slotter at different distances from tunnel] (3-4; E- F; a; II, IV) Stress path monitoring [flat jacks, strain cells] (3- 4; E-F; e; II, IV) Stability of rock support Evolution of Borehole cores from liner [uniaxial strength, system elastic parameters, tensile strength, minerological - mechanical properties of tunnel/cavern lining composition, corrosion of reinforcement] (3-6; E- - load on rock anchors H; c; III) Degradation/corrosion rate of elements of rock Load on tunnel support [Instrumented anchor, support system (lining, rock anchors, ...) load cells] (3-6; E-H; e; II-VI) Observation of material discontinuities (fissure Liner inspection [optical, marker] (3-6; E-H; c;

SAM-J078-R1 - 39 - rate) III)

- 40 - SAM-J078-R1 Repository Design and Construction Aspect Information Assessment parameters Measurement methods requirement E. Assessment of backfilling/sealing feasibility Host rock Excavation damage zone Extent of EDZ around underground workings Deformation measurements during mine-by- (EDZ) (tunnels, caverns) experiment [load plate tests, extensometers, inclinometers micrometers] (3-6; E-F; a, c, e; I-V) Seismic methods [refraction tomography, interval velocity, downhole velocity] (3-6; E-F; a, c, e; I- V) Acoustic emissions [micro seismic array] (3-6; E- F; e; II-V) Short radial boreholes [core logging, structural Evolution of hydraulic properties logging] (3-4; E-F; a; II-IV) Measurement of transmissivity and heads before, during and after tunnel construction [mine-by-test] (3-6; E-F; c, e; II-V) Measurement of transmissivity and heads with specialised packer systems after tunnel construction [e.g. MMPS or SEPPI probe] (3-6; E- F; c, e; II-V) Inflow measurements at discrete points (3-6; E-F; e, II-V) Desaturation/ Evolution of saturation profile of rock mass Water content measurements [e.g. TDR] (3-6; E- resaturation around underground workings (incl. EDZ) F; e, II-V) Water potential measurements [e.g. thermocouple psychrometer] (3-6; E-F; e, II-V) Ventilation or mini ventilation test (3-6; E-F; a, II-

SAM-J078-R1 - 41 - V) Backfill material Mechanical properties Evolution of mechanical strength, ... Laboratory tests (3-6; B; a; II) Demonstration in situ test [density, push-out test etc.] (3-6; E-F; a; II-V) Hydraulic properties Evolution of Laboratory tests [oedometer] (3-6; B; a; II) - backfill saturation profile Demonstration in situ test [water content, hydraulic conductivity] (3-6; E-F; e, c; II-V) - conductivity (for water and gas) Mechanical stability Mechanical properties Evolution of mechanical strength, ... Laboratory tests (3-6; B; a; II) of plugs for tunnel/cavern/shaft Demonstration in situ test (3-6; E-F; a; II-V) seals Long-term stability of Evolution of mechanical properties (strength) Laboratory tests [mechanical strength, chemical mechanical plug alteration, micro cracks] (3-6; B; c; II) Movement of mechanical plug and surrounding rock mass Demonstration in situ test [mechanical and hydraulical loading, geodetic measurements, acoustic emissions] (3-6; E-F; ca; II-V) Sealing material Hydraulic properties Evolution of Laboratory tests [oedometer, conductivity as function of emplacement density and saturation] - saturation profile (across repository seals) (3-6; B; c; II) - conductivity (for water and gas) Demonstration in situ test [emplacement density, water content, hydraulic conductivity, gas permeability, swelling pressure] (3-6; E-F; e, c; II- V) Long-term stability of Evolution of hydraulic properties (permeability see above sealing materials for water and gas)

- 42 - SAM-J078-R1 Repository Design and Construction Aspect Information Assessment parameters Measurement methods requirement F. Assessment of environmental impact Surface environment Topographical subsidence at surface - above repository zone Precision leveling at surface (3-8; C; c; I, III-V) deformations Tilt measurements in observation boreholes (3-8; C; c;I, III-V) Satellite based geodetic measurements (3-8; satellite; c;I, III-V) Arial discharge Composition of waste air (flammable gases, toxic Meteo station at surface (2-8; C; e; I, III-V) gases, radiotoxic gases) Waste air investigation [radon emanation, gas detectors] (3-7; C; e; I, III-V) Sub-surface Use of groundwater Evolution of production rates (springs, wells) Piezometer measurements (2-8, D; e, I, III-V) environment Flowmeter (2-8, C; e, I, III-V) Chemical and isotopic composition Analysis of water samples (2-8, B, c; I, III-V)

SAM-J078-R1 - 43 - Key to Tables 4.1 and 5.1: Scheme to classify monitoring requirements

HEADING When? Where? Periodicity Purpose Basis Stage of development Location

Reference Time period Place/Area Periodicity Purpose 1. Before site selection A. Literature (inc. regulations a. Once only measurement I. Establishment of baseline etc.) conditions Classification 2. Site characterisation from b. Random check the surface B. Laboratory II. Data for design 3. Underground access and c. Periodic exploration C. Site surface environment III. System performance at the d. Routine and frequent time of monitoring 4. Repository construction D. Below ground from the e. Continuous 5. Waste receipt and surface IV. Data to be used in modelling/ predictions emplacement E. In RCF 6. Monitored underground V. Technical confidence storage (C&M period) F. In test vault building (inc. validation) 7. Post-vault backfill pre- G. Main disposal facility VI. Re-assurance monitoring closure vaults 8. Post-closure (continued H. Main disposal facility ex- institutional control) vault I. At analogue site

The above scheme is used to abbreviate the text that might otherwise have to be written in Tables 4.1 and 5.1 explaining the timing, location, periodicity and purpose of each measurement. A method of classifying the monitoring measurements could also be helpful to assist in selecting subsets of parameters or monitoring measurements that are relevant to a particular time period, region of the repository or purpose.

- 44 - SAM-J078-R1 5. THE LONG-TERM SAFETY CASE

This chapter addresses the requirements for monitoring with regard to the long-term safety of the repository. The requirement is considered over all stages of the repository development programme, i.e. from the phase before site selection to the post-closure phase with continued institutional control.

The monitoring requirements to verify/confirm the presumed long-term evolution of the disposal system are deduced from the Post-closure Performance Assessment conducted in the framework of the Nirex Phased Disposal Concept (Nirex, 2001).

The corresponding monitoring options are associated with site suitability in relation to long- term safety and the potential release of radioactivity from the engineered barrier system, with subsequent transport through the geosphere by groundwater and/or gas, including the dispersion of radionuclides in the biosphere. The possible monitoring requirements related to human intrusion are also identified. Finally, the section deals with the long-term requirements of monitoring the toxic hazards associated with the deep geological disposal of low- and intermediate-level waste and of monitoring related to post-closure criticality.

The long-term safety of the repository will be achieved by the selection of a suitable site, the provision of a robust design and the proper functioning for the engineered barrier system. The following principles for monitoring the long-term safety of a deep geological repository apply: a) long-term safety must not depend on any monitoring activities performed after the repository has been closed; b) long-term safety may not be impaired by monitoring actions or complementary measures (e.g. to facilitate retrieval of the waste); c) monitoring should be continued as long as it is thought to be beneficial to society.

The aim of monitoring in relation to the long-term safety case is, therefore, to provide confirmation of the suitability of the disposal site and verification of an adequate evolution of the disposal system; this would also include confirmation of some of the conceptual and numerical models developed to describe system behaviour. Measurements need to be taken

SAM-J078-R1 - 45 - either once only, randomly, periodically or even continuously throughout the various stages of repository development at appropriate locations within the disposal system.

Unacceptable deviations from the expected evolution of the repository may call for corrective actions, i.e. if any regulatory requirements or safety objectives are violated (either at present or with reasonable likelihood in the future), the deviations cause a threat to the public, and if there is a clear indication that the observed deviations are linked to the presence of the repository.

Figure 5.1, below, shows the framework on which information requirements related to the long-term safety case have been identified. This is based on six main aspects that must be assessed during the development of a long-term safety case, and information requirements to support these assessments. More detailed information requirements, assessment parameters and measurement methods available under each heading are then developed comprehensively in Table 5.1, at the end of this chapter.

Sufficient volume of low K host rock

Site suitability Site predictability and stability Identification of information Depth / erosion rate > 1Ma requirements related Source term to the long-term safety case Groundwater Release from EBS pathway Release from geosphere

Biosphere paths

Long-term Gas source term Safety Case Gas pathway Gas migration requires assessment of: Gas exposure paths

Intrusion modes

Human intrusion Intrusion probabilities

Intrusion consequences

Toxic source term

Toxic hazard Toxic release / migration

Toxic exposure paths

Post-closure Distribution of fissile material criticality Factors affecting redistribution & moderation

Figure 5.1: Identification of information requirements related to the long-term safety case

As in Chapter 4, a broad view of monitoring (broader than the IAEA definition, see Chapter 4) has been taken to making a comprehensive identification of information requirements,

- 46 - SAM-J078-R1 assessment parameters and measurement methods. This is recorded in Table 5.1. The measurements are classified according to the same scheme as used in Table 4.1.

The following discussion is more limited, however, and focuses on the key aspects of monitoring - regarding the development of the long-term safety case - in the original sense of IAEA's definition (IAEA 2001). The following sections discuss the rationale for monitoring against each of six information requirements related to long-term safety.

A. Assessment of site suitability related to long-term safety (Section 5.3)

B. Assessment of groundwater pathways (section 5.4

C. Assessment of gas pathways (Section 5.5)

D. Assessment of human intrusion pathways (Section 5.6)

E. Assessment of toxic hazard (Section 5.7)

F. Assessment of post-closure criticality (Section 5.8)

5.3 Assessment of site suitability (related to long-term safety)

This section addresses monitoring activities related to the suitability of the site from the point of view of long-term safety. The specific monitoring aspects deal with the requirement of a low permeability host rock and selected issues related to the geological long-term evolution of the site (i.e. site predictability and stability, including assessment of terrain uplift and erosion).

The rationale behind these monitoring activities is a) to supplement the site characterisation process with long-term observations, and b) to assure that the chosen repository site fulfils the requirements as demanded by long-term safety. The data will be used for repository design and predictive modelling, especially also for confirmation of earlier input data and model assumptions (technical confidence building).

Specific monitoring activities concern the following issues:

Groundwater flow – Continuous measurement of groundwater pressure in exploration boreholes from the surface and from underground workings (through all stages of repository development); – Continuous measurements of water inflow into underground workings and underground boreholes (as long as underground access is possible).

Groundwater chemistry – Periodic chemical and isotopic analysis of groundwater composition and its evolution(as an indicator of potentially fast groundwater pathways).

SAM-J078-R1 - 47 - All of the above to be done with the aim to characterise the hydraulic properties of the host rock and of any water-conducting features, and to identify possible fast groundwater flow paths.

Site stability

Continuous geodetic leveling and seismic wave detection done before site selection and during site characterisation from the surface will be used to assess the tectonic stability of the site. Geodetic leveling can also be applied to provide information on uplift and erosion; the evolution of sedimentary deposits downstream of the repository site is also monitored for the same purpose.

These monitoring techniques (i.e. piezometric measurement, collection of inflowing groundwater, geodetic leveling and seismic wave detection) are well established and the corresponding instrumentation has proven to be reliable even over long observation times.

Other monitoring aspects under the issue of site suitability are primarily related to site characterisation (cf. Section A of Table 5.1).

5.4 Assessment of groundwater pathways

This section deals with the monitoring requirements related to the groundwater pathways within the long-term safety case. Specific topics concern the waste (i.e. activity source term), the release of radionuclides from the engineered barrier system, the transport through the geosphere, and finally the biosphere transport and exposure paths.

The rationale behind these monitoring activities is to collect information on the waste (i.e. activity source term), to supplement the geological/ hydrogeological database of the site (originating from site characterisation) and to supplement the database for the engineered barrier system and the host rock (including the data on interactions of radionuclides with engineered and natural barriers), that allows for a comprehensive evaluation of repository safety in relation to the groundwater release path. The data will be used mostly for repository design and as input for predictive modelling, some of it also to assess system performance at the time of monitoring and for technical confidence building.

Specific monitoring activities address the following issues.

Activity source term – Emplacement/balancing scheme for radionuclide inventory and material masses of emplaced waste (operated during the repository stage of waste receipt and emplacement).

Engineered barriers – In-situ testing of engineered barriers (vault liner, backfill material) for the evaluation of the time development of hydraulic properties.

Host rock

- 48 - SAM-J078-R1 – Large-scale inflow and ventilation test for the continuous assessment of the large- scale hydraulic properties of the host rock, its heterogeneities and of the excavation damaged zone (EDZ - test to be performed in RCF); – Long-term head monitoring in single boreholes/crossholes with the aim of determining local hydraulic gradients.

Most of the above activities will take place during the stage of underground access and exploration in the RCF and test vault.

Further monitoring activities may be related to the information requirement on the backfill material, such as – Emplacement/balancing scheme for backfill material: mass balance and composition; – Chemical analysis of porewater in backfill material with regard to alkalinity (pH) at emplacement and its evolution in time (in surface laboratory before site selection and during underground access and exploration using RCF and test vault, respectively).

With regard to the release of radionuclides from the geosphere the following measurements (done before site selection and during site characterisation, below ground from the surface) will provide the necessary database for predictive geosphere transport modelling. – Long-term piezometric head investigations with the aim of determining regional hydraulic gradients; – Periodic monitoring of hydraulic properties of relevant aquifers within the geosphere with single borehole and cross-hole tests.

For the assessment of the role of the biosphere within the long-term safety case (groundwater release path) the following monitoring activities might be useful. – Continuous record of observations leading to a sound characterisation of biosphere model compartments and fluxes: e.g. location and nature of discharge zones, soil (and surficial sediments) characteristics, key data on water body and mass fluxes, local/regional climate and ecology; – Continuous evaluation of groundwater usage; – Continuous evaluation of human habits.

This last group of monitoring activities can all be done at the site surface environment through all stages of repository development. The required monitoring parameters will depend strongly on the adopted approach for the biosphere modelling. Instrumental methods (where applicable) will be closely linked to those for conventional environmental monitoring and are not discussed any further in this section.

Other items under the issue of the groundwater pathways are for instance related to waste specification, site characterisation and to the information requirements on specific processes (cf. Section B of Table 5.1).

SAM-J078-R1 - 49 - 5.5 Assessment of gas pathways

This section addresses monitoring activities related to the gas pathways within the long-term safety case. The specific monitoring aspects deal with the gas source terms, gas migration within the engineered barrier system and the geosphere and potential exposure paths.

The rationale behind these monitoring activities is to acquire data related to the gas production mechanism, to supplement the geological/ hydrogeological database (originating from site characterisation) with particular emphasis on two-phase flow, and to collect information on the behaviour of the repository system under two-phase conditions, that allows for a comprehensive evaluation of repository safety in relation to the gas release path. The data will be used primarily for repository design, predictive modelling and for reassurance monitoring.

Specific monitoring activities concern primarily the gas source term and host rock.

Gas source term – Emplacement/balancing scheme for metallic and organic mass fraction and for potentially volatile gases in the waste (during waste receipt and emplacement in test vault and main disposal facility vaults); – Corrosion experiment using gas detection technique/equipment under aerobic and anaerobic conditions; – Degradation experiment using gas detection technique/equipment under aerobic and anaerobic conditions – Continuous observation of atmospheric conditions in disposal vault; – Periodic assessment of microbial activity.

These measurements for the evaluation of gas production from the waste will be done in the course of the corresponding experiments mostly during the stages of underground access and exploration, the period of monitored underground storage until the post-vault backfill/pre- closure phase, either in the RCF or the test vault (or both). If required, the experiments may be supplemented by specific laboratory experiments and literature studies starting even before site selection.

Host rock

For the assessment of the natural gas sources within the geological environment the following monitoring activities taking place at the site surface environment, below ground from the surface and the RCF, respectively, may be envisaged: – Periodic natural gas measurements at surface; – Periodic borehole gas tests; – Continuous gas detection in underground workings.

These measurements will be done (more or less in a sequence) before site selection, site characterisation from the surface and during underground access and exploration. The last of

- 50 - SAM-J078-R1 these three monitoring items together with the periodic control and maintenance (C&M) of the gas management system are important constituents of the operational safety scheme for the underground facility.

Finally, the following monitoring activities may be used to fulfil the information requirements for the gas exposure paths: – periodic gas detection at surface and at the end of potential migration paths (e.g. major faults): flammable, radioactive and toxic gases – periodic radon measurements in buildings

Such measurements will be performed at the site surface environment and may be foreseen during all stages of the repository development.

Other aspects under the issue of the gas pathways which are not considered to be monitoring in a narrow sense are for instance related to waste specification, site characterisation and to the information requirements on specific processes such as escape of gas from the engineered barrier system and gas migration in the geosphere (cf. section C of Table 5.1).

5.6 Assessment of human intrusion pathways

This section addresses monitoring activities related to the assessment of human intrusion pathways. This includes monitoring related to the modes, probabilities and consequences of intrusion.

The rationale for these monitoring activities is to gather information that will allow for a periodic update on the assessment of the radiological consequences of intrusive actions. The data will be used in the first place for predictive modelling and re-assurance of sociologic and technical conditions; however, the (once-only) assessment of potential underground resources can provide valuable information for repository layout and design.

There is only a limited number of activities which can be identified as monitoring in the narrow sense of the IAEA definition, namely – Routine and frequent post-closure surveillance of physical and administrative controls in the context of post-closure site administration and marking; – Periodic assessment of analogue (industrial or historic) sites with regard to the retention and dissemination of information concerning the location and nature of the analogue sites; – Periodic evaluation of changes in motivation and technical capability to intrude.

Surveillance of physical and administrational controls will clearly concentrate on the post- closure period where there is continued institutional control; other socio-economical aspects will be periodically evaluated through all stages of repository development.

SAM-J078-R1 - 51 - Other monitoring items under the issue of human intrusion are related to the assessment of the site with regard to potential underground resources, and the type and frequency of intrusive actions (cf. section D of Table 5.1).

5.7 Assessment of toxic hazard

Monitoring activities associated with the assessment of the (chemo-) toxic hazard from a geological repository for radioactive waste are the topic of the following discussion. The specific aspects of monitoring are related to the registration of the toxic materials emplaced with the waste including possible reaction products, the release and migration of these substances, and the evaluation of exposure routes and toxicological consequences for individuals living at the repository site.

The rational for chemo-toxical monitoring is the protection of human individuals and the natural environment from any potential negative impact of chemo-toxic materials associated with the disposal of radioactive waste. The primary use of the acquired data is for an optimised design of the engineered barrier system and for the assessment of (hypothetical) releases and exposures using predictive modelling.

Monitoring activities in the sense of the IAEA definition are primarily associated with the operation of emplacement/balancing scheme for toxic materials during waste reception and emplacement at the underground disposal facility. Other activities are associated with the release of toxic substances from the engineered barrier system, their migration through host rock and geosphere, and possible exposure routes in the biosphere; these activities are closely linked with the corresponding monitoring activities for the assessment of the groundwater and gas pathways (see corresponding items in section 5.4 and 5.5). Most of these activities will take place during the stage of underground access and exploration in the RCF and test vault.

Other items not considered as monitoring in a narrow sense concern the information requirements on material properties, the possibilities of chemical processes within the repository system which generate toxic products, interactions between chemical compounds and the engineered barriers and the host rock, respectively, and the development of the necessary toxicological data base (cf. section E in Table 5.1).

5.8 Post-closure criticality

The rationale for these monitoring activities related to post-closure criticality is the limitation of any critical configuration of fissile materials from the waste after loss of integrity of one or more waste containers. Except for the “book-keeping” on fissile material emplaced with the waste (performed during the repository stage of waste receipt and emplacement) there are no activities that can be identified as monitoring in the narrow sense of the IAEA definition. Data will be used for predictive modelling in the framework of some stylised calculations for a selection of potentially critical configurations of fissile material inside and outside of the waste containers.

- 52 - SAM-J078-R1 Hypothetical post-closure scenarios consider the criticality of a leaking waste container or one or more collapsed waste containers in contact with groundwater. For the criticality scenarios related to the near-field and the far-field, critical re-configurations of fissile material (U-235, Pu-239 and other fissile U/Pu isotopes) would require a selective migration process in combination with high water saturation of pore spaces in the engineered barrier or the geological environment. The time frame for a potential re-distribution of fissile material outside the waste packages (i.e. in backfill or geosphere) is presumably very long and will not happen until many hundreds of years after the emplacement of the waste. This makes it difficult to propose any meaningful post-closure monitoring which could detect any critical configuration. Therefore, the most direct criticality control is to limit the fissile mass in each waste package, although other controls may be imposed on the waste form, waste container properties, disposal geometry, and backfill materials (Hicks and Green 1999).

5.9 References

IAEA 2001. Monitoring of geological repositories for high level radioactive waste, IAEA- TECDOC-1208, International Atomic Energy Agency, Vienna (Austria), April 2001. Nirex 2001. Generic phased disposal system documentation - The Nirex phased disposal concept. Nirex Report N/025, March 2001. Hicks and Green 1999. A Review of the treatment of criticality in post-closure safety assessment of radioactive waste disposal, Environment Agency R&D Technical Report P222, ISBN: 1 85705 005 3, 1999.

SAM-J078-R1 - 53 - Table 5.1: Development of information requirements, assessment parameters and measurement methods related to the the long-term safety case .

Note: Measurement methods are classified according to the scheme given in the key given at the foot of Table 4.1.

Long-term Safety Case Aspect Information Assessment parameters Measurement methods requirement A. Assessment of site suitability ( - related to long-term safety) Low permeability Layout-determining Geometry: Nature, orientation and frequency of Geophysical surface investigations: seismics, host rock features potential layout determining features – major electromagnetics, "Very Low Frequency VLF" faults, and/or changes in rock type investigation (1-2; C; a, II, IV) Hydraulic properties: average hydraulic Exploration boreholes from surface with different conductivity of host rock, transmissivity, dips and dip directions: core logging, structural logging, mineralogical analysis, fluid logging, hydraulic gradient packer tests, borehole seismics, crosshole Mineralogy: mineralogical composition (fracture, investigations (1-2; D; a; II, IV) rock matrix), porosites etc. Tunnel mapping: geological and hydrogeological (3-4; E-G; a; II, IV) Exploration boreholes from underground vaults: core logging, structural logging, mineralogical analysis, fluid logging, packer tests, borehole seismics, crosshole investigations (3-4; E-G; a; II, IV) - site investigation/characterisation - design data, data for predictive modelling - not monitoring Low permeability Layout-determining Monitoring of pore pressure in exploration

- 54 - SAM-J078-R1 host rock (contd.) features (contd.) boreholes from surface (2-8; D; e; II-V) Monitoring of pore pressure in exploration boreholes from underground vaults (3-6; E-H; e; II-V) Monitoring of groundwater inflow in tunnels (and underground boreholes): inflow rates, analysis of chemical and isotopic composition (3-6; E-G; c; II-V) Site predictability Regional hydrogeology Identification of groundwater flow paths: Geological and hydrogeological characterisation and stability of regional aquifers and aquitards (1-2; A, C-D; a hydraulic conductivities of aquifers/aquitads, head (e); I-II, IV) distribution, infiltration/exfiltration area - literature search, supplemented with borehole investigations (where necessary): Piezometric borehole investigations: hydraulic head observations (2; D; e; I-II, IV) Geological history & Sufficient understanding of geological evolution – Assessment of geological genesis (1; A; a; II, IV- future evolution gives necessary confidence in prediction of future V) evolution - design data, data used for predictive modelling See also: uplift and erosiom and technical confidence building - not monitoring Hydrogeological and Sufficient understanding of past changes and Hydrochemical analysis of groundwater samples: hydrochemical history demonstration of slowly evolving rock-water chemical/isotopic composition, age (1-2, (A) D; a; and evolution system – gives necessary confidence in prediction II, IV-V) -palaeohydrogeology of future evolution (see above) - design data, data used for predictive modelling and technical confidence building - not monitoring

SAM-J078-R1 - 55 - Site predictability Neotectonics Level of tectonic activity (i.e. demonstration of Geodetic leveling and stability (contd.) acceptability) Observation of seismeic activity (earthquake) (1-2; C; e; II, VI) Uplift and erosion Repository depth / Uplift and erosion rates Dating of periglacial gravel deposits (1; C; a; II, erosion rate > 1Ma IV, VI) - not monitoring Geodetic leveling (1-2; C; c; II, IV, VI) Evolution of sedimentary deposits (1; C; c; II, IV, VI) - design data/data used for predictive modelling

- 56 - SAM-J078-R1 Long-term safety Case Aspect Information Assessment parameters Measurement methods requirement B. Assessment of groundwater pathways Source term Radionuclide (RN) Inventory of RNs with half-life > 5 years Characterisation of RN inventory - as part of the inventory waste characterisation procedure (1; production - total and by vault site; e; II, IV) - not monitoring Emplacement/ balancing scheme for RN inventory of emplaced wastes: waste stream, RN-specific activity, time, location (5; F-G; e; IV) - continuous acquisition of information during waste emplacement operations - in main disposal facility vaults (and test vault) Disposition / Physical/chemical waste form (conditioning, Characterisation of waste form - as part of the concentrations waste matrix) waste characterisation procedure (1; production site; e; II, IV) Concentration by waste unit and vault, maximum and typical Emplacement/ balancing scheme for mass inventories of emplaced wastes: waste stream, Location and disposition of special waste streams, material, mass, location (5; F-G; e; IV) e.g. with organics, colloid potential - continuous acquisition of information during waste emplacement operations - in main disposal facility vaults (and test vault) Release from EBS Flow through EBS hydraulic permeabilities Laboratory experiments on material samples (1; engineered barrier B; a; II, IV) - heterogeneity (if significant)

SAM-J078-R1 - 57 - system (EBS) - estimated time development - not monitoring In-situ hydraulic (borehole) testing (3; E; c; II, IV) - design data/data used for predictiv modelling Host rock hydraulic conductivity, for Large-scale inflow and ventilation tests (3; E (-G); e; II-IV) - intact rock and excavation damaged zone (EDZ) Single borehole hydraulic tests: pulsed/pressurised - heterogeneity (if significant) slug tests, constant flow/constant head tests, - estimated time development of hydraulic combined flow/recovery tests, long-term head conductivity monitoring (3-4; E-F; c; II-IV) Local hydraulic gradient Crosshole hydraulic tests: constant flow, periodic flow, long-term head monitoring, directional - estimated time development of hydraulic permeability (3-4; E-F; c; II-IV) gradient - periodically (time development!) during underground access, exploration (if necessary complemented during repository construction) - in RCF and test vault Retention in Package integrity at closure and effective (not discussed) packages/matrix 1 retention life Waste matrix degradation rate Leach rate from matrix Complexant and colloid generation capacity Release from EBS Retention in backfill Backfill volume per vault Emplacement/ balancing scheme for backfill (contd.) material: mass, composition (incl. cement paste), 3 Specific mass of cement paste per m of vault backfilling location (during backfilling; G; e; IV) Cement composition, average and heterogenities

1 Not part of the current Nirex safety case but could be invoked in future.

- 58 - SAM-J078-R1 Backfill porosity, average and heterogenities Laboratory analysis of backfill samples (during backfilling; G; e; IV) - part of quality management procedure - not monitoring Sorption properties, e.g. Kds, as fn. of pH, Batch sorption experiments: literature searches (1; temperature, concentration of colloids and A; c; II, IV) and experiments (2; B; a; II, IV) complexants Tracer tests (3; E; a; II, IV) - input data for predictive modelling - not monitoring Cement leaching/degradation parameters Leaching experiments: literature searches (1; A; c; II, IV) and experiments (2; B; a; II, IV) - input data for predictive modelling - not monitoring High alkalinity (pH) at emplacement and Chemical analysis of porewater in backfill evolution material: pH measurement (1, 3; B, E-F; c; II, IV) - before site selection, during underground access and exploration - at surface laboratory, RCF and test vault Release from Groundwater flux Bulk permeability for host rock and other units in Single borehole hydraulic tests: pulsed/pressurised geosphere flow path slug tests, constant flow/constant head tests, combined flow/recovery tests, long-term head Hydraulic gradient for host rock and other units in monitoring (2-3; D-E; 1; II, IV) flow path Crosshole hydraulic tests: constant flow, periodic flow, long-term head monitoring, directional permeability (2-3; D-E; 1; II, IV) - during site characterisation from the surface,

SAM-J078-R1 - 59 - during underground access and exploration - below ground from the surface, and in RCF Groundwater inflow measurement (3-6; E-G; e; II, IV-VI) - as long as underground access possible - in all underground workings Release from Groundwater and solute Effective porosity and tortuosity, related to bulk Geological/hydrogeological mapping of water- geosphere (contd.) travel times or fracture properties, for host rock and other units conducting features incl. rock matrices: geometry in flow path (incl. micro-scale), mineralogy, porosity, etc. (2-4; D-G; e; II, IV) Matrix diffusion capacity (if relevant) Development of conceptual transport model plus Fracture or bulk rock mineralisation (dominant subsequent transport modelling (2-4; D-G, e; II, phases) IV) - during site characterisation from the surface, underground access and exploration, and during repository construction - below ground from the surface, in RCF, test vault and main disposal facility vaults - input data for modelling - not monitoring Migration experiments/tracer tests (3; E; a; IV-V) - during underground access and exploration, in RCF - input data for modelling - not monitoring Release from Groundwater and solute Fracture or bulk rock sorption properties, e.g. Kd Batch sorption experiments: literature searches (1; geosphere (contd.) travel times (contd.) A; c; II, IV) and laboratory work (2; B; a; II, IV) Colloid filtration capacity, etc. In-situ sorption experiments: radionuclides,

- 60 - SAM-J078-R1 colloids (3; E; a; II, IV) - especially for colloid filtration - before site selection (1), during site characterisation from the surface (2), during underground access and exploration (3 - by tracer tests) - by literature search (A), laboratory work (B) and in RCF (E) - input data for modelling - not monitoring Groundwater mixing Groundwater fluxes in aquifers (if relevant) or Assessment of geological genesis (1; A; a; II, IV- flux surficial sediments V) incl. future prediction Assessment of hydraulic properties of aquifers (1- 2; A, D; c: II, IV) Biosphere paths Surface characteristics Location, nature and area of potential discharge Characterisation of 'model biosphere': definition zones and phys./chem. specification of model compartments, mass fluxes (water, solid phases) Soil and surficial sediments characteristics, incl. deposition/erosion and sorption characteristics Characterisation of hydraulic regime Water body characteristics, incl. Assessment of climatic changes deposition/erosion and sorption characteristics (1-2; A, C; e; IV) Climate and ecological characterisation, present day and future - continuous procedure before site selection and during site characterisation (surface environment) - continuous evaluation, by literature search and at site surface environment - data used for biosphere modelling Human habits Critical exposure group Evaluation of groundwater usage (and water from other sources): location, rates, quality, usage (1-8;

SAM-J078-R1 - 61 - Water sources, quality and potential uses C; e; I, IV) Other potential pathways, land use, agriculture Evaluation of human habits: potential exposure and fisheries potential and practices pathways related to work, leisure, local food production, diet, etc. (1-8; C, e; IV) Diet – locally derived and total - evaluation and observation/interrogation at site Special habits, e.g. local practices and concerns surface environment/local population - continuous evaluation during all stages of repository development - input data for modelling Biosphere paths Dosimetry Dose per unit intake factors, ingestion, inhalation Compilation of radio-ecological data (incl. (contd.) (adults and children) updated values, 1-8; A; c; II, IV) Dose per unit source factors, external exposure, - from literature immersion (adults and children) - during all stages of repository development - input data for modelling - not monitoring

Long-term Safety Case Aspect Information Assessment parameters Measurement methods requirement C. Assessment of gas pathways

- 62 - SAM-J078-R1 Gas source term Hydrogen production Mass and surface area of steel and other metals, Characterisation of metallic mass fraction and e.g. aluminium, magnox specific surfaces - as part of the waste characterisation procedure (1; production site; e; II, IV) - input data for modelling - not monitoring Gas source term Hydrogen production Corrosion rates in pre and post-backfill phases Emplacement/ balancing scheme for metallic mass (contd.) (contd.) fraction of the waste: type, amount, location (5; F- Gas production G; e; II, IV) - continuously during waste receipt and emplacement in main disposal facility vaults Corrosion experiments under aerobic and anaerobic conditions (1, 3, 6-7; A-B, E-F; e; II, IV) - continuously before site selection, during underground access, C&M period and post-vault backfill/pre-closure phase - literature search and laboratory work, in RCF and test vault Time to anaerobic conditions in the vaults Time-dependency of atmospheric conditions in disposal vault: oxygen concentration (7; E-F; e; II-V) - during post-vault backfill/pre-closure phase - in RCF and test vault Carbon dioxide and Mass and disposition/location of cellulose in Characterisation of organic mass fraction - as part methane production wastes of the waste characterisation procedure (1; production site; e; II, IV)

SAM-J078-R1 - 63 - - input data for modelling - not monitoring Gas source term Carbon dioxide and Microbial population Evaluation of microbial activity: biomass, type, (contd.) methane production location etc. (1, 3, 6-7; A-B, E-F; c; II, IV) (contd.) Reaction rates - continuously before site selection, during Gas production underground access, C&M period and post-vault backfill/pre-closure phase - literature search and laboratory work, in RCF and test vault Emplacement/ balancing scheme for organic mass fraction of the waste: type, amount, location (5; F- G; e; II, IV) - continuously during waste receipt and emplacement in main disposal facility vaults Degradation experiment under aerobic and anaerobic conditions (1, 3, 6-7; A-B, E-F; e; II, IV) - continuously before site selection, during underground access, C&M period and post-vault backfill/pre-closure phase - literature search and laboratory work, in RCF and test vault Potentially gaseous and Inventory and disposition/location of H-3, C-14, Emplacement/ balancing scheme for potentially volatile radionuclides Ra-226/Rn-222 volatile gases in the waste: type, amount, location (5; F-G; e; II, IV) - continuously during waste receipt and emplacement in main disposal facility vaults

- 64 - SAM-J078-R1 Toxic gas potential Potential for generation of toxic gases ? Desk study (supplemented by selected experiments) based on waste composition (1; A- B; c; IV) - not monitoring Gas source term Natural gas sources Sources of natural gas Gas measurements at surface (1-2; C; c; I-II, IV) (contd.) Potential infiltration into the repository zone Borehole gas testing (2; D; c; I-II, IV) Gas measurements in underground workings (3; E; e; II, IV, VI) - operational safety measure

Gas migration Escape from EBS CO2 immobilisation reactions in backfill Carbonation experiment (1; B; a; II, IV) Gas permeability and nature of liner Laboratory and in-situ gas migration experiment (1, 3; B, E; a; II, IV) Condition of any gas management system C&M of gas management system (6-7; F; c; III) Migration in geosphere Gas permeability of host rock and other units in Gas flow/two-phase flow tests (1-3; B, D-E; a; II, migration path, preferential pathways incl. gas IV) transit time - design data/data used in predicting modelling

Release of natural Rn by the passage of H2 and - not monitoring CH4 Effective porosity and tortuosity, related to bulk Geological/ mineralogical analysis of core or fracture properties, for host rock and other units samples (2-3; D-E; a; II, IV) in flow path - design data/data used in predicting modelling - not monitoring Gas exposure paths Gas exit routes Potential for Gas measurement at surface: flammable gases, radioactive gases, toxic gases (1-8; C; c; I, III, VI) - groundwater abstraction (de-gassing) Radon measurements in buildings (1-8; C; c; I, III, - accumulation in cellars, buildings etc. VI) Impacts Flammability ? (can be ruled out?) Gas measurements at the end of potential

SAM-J078-R1 - 65 - Radiological dosimetry, e.g. Rn daughters migration path (e.g. major faults): flammable gases, radioactive gases, toxic gases (1-8; C; c; I, Toxic gases, e.g. H2S ? (can be ruled out?) III, VI)

- 66 - SAM-J078-R1 Long-term Safety Case Aspect Information Assessment parameters Measurement methods requirement D. Assessment of human intrusion pathways Intrusion modes Local and regional Nature and location of underground resources that Assessment of potential underground resources at resources might attract investigation, including past use repository site (1; A; a; II, VI) Evaluation of former exploration activities and underground/resource usage (1; A; a; II, VI) Exploration: seismic survey, borehole investigations and underground access (1-3; C-E; a; II, VI) - for re-assurance Definition of intrusion Type of intrusive events Survey of potential intrusive events based on modes local, regional and historic practice (1; A, C; a; IV) - input for predictive modelling - not monitoring Intrusion Historic event Number of intrusive events Survey of events at the site, in the region and in probabilities frequencies similar geologic environments (1; A, C; a; IV) - input for predictive modelling - not monitoring Post-closure site Post-closure surveillance of physical and administration and administrative controls (8; C; d; VI) marking Intrusion Sociologic and technical Retention / dissemination of location and nature Analog studies of former industrial and historical probabilities (contd.) conditions

SAM-J078-R1 - 67 - of facility sites (1-8; A, I; c; VI) Changes in motivation to intrude and technical Evaluation of human behaviour and technical capability capabilities (1-8; A, C; c; VI) Intrusion Stylised events based on - monitoring not possible consequences present day and past technology - irrelevant

Long-term Safety Case Aspect Information Assessment parameters Measurement methods requirement E. Assessment of toxic hazard Toxic source term Inventory of toxic Inventory of toxic materials in waste, packaging Characterisation of toxic materials in waste/waste materials and EBS package - as part of the waste characterisation procedure: substance, mass (1; production site; e; Identification of key toxins II, IV) Characterisation of toxic materials in EBS: substance, mass (1; A-B; a; IV) Emplacement/balancing scheme for toxic materials: waste and backfill/EBS (?) (5; F-G; e; II, IV) - input data for predictive modelling - not monitoring Toxic source term Potential for creation of Survey of possible reactions and compounds Literature search (1; A; c; IV) (contd.) toxic compounds within supplemented by laboratory experiments (1; B; a;

- 68 - SAM-J078-R1 the repository IV) - input data for predictive modelling - not monitoring Toxic release / Escape from EBS Reactions leading to immobilisation in the waste Laboratory experiment based on expected toxic migration or backfill gas releases (1; B; a; II, IV) (hydraulic and gas release parameters - see section - not monitoring B and C) Migration in geosphere Hydraulic and gas release parameters - as in B and (see section B and C) C Immobilisation mechanisms for specific toxins – In-situ investigation (3; E; a; IV) sorption, precipitation etc - input data for modelling Mobilisation mechanisms for specific toxins – colloid transport, complexation etc. - not monitoring Toxic exposure paths Exposure routes As for groundwater and gas pathways in B and C Toxicology Survey of toxicity for key potential repository Literature search (1; A; c; IV) derived toxins - input data for modelling - not monitoring

SAM-J078-R1 - 69 - Long-term Safety Case Aspect Information Assessment parameters Measurement methods requirement F. Post-closure criticality Distribution of fissile Fissile material in waste Mass of Pu-239, U-235 (Pu-241, U-233, ...) Characterisation of fissile material in waste - as and non-fissile streams part of the waste characterisation procedure: material isotope, mass (1; production site; e; II, IV) - by non-destructive techniques: gamma scanning, passive neutron counting, neutron interrogation - by destructive sampling/analysis methodologies: sampling - dissolution - analysis (-spectroscopy, -spectroscopy, liquid scintillation counting, mass spectroscopy, ...) Emplacement/balancing scheme for fissile RN mass emplaced with waste in the repository (5; G- H; e; II, IV) - continuous acquisition of information during waste emplacement operations - in main disposal facility vaults (and test vault) Properties of initial Package geometry Waste package specification (1; production site; e; waste package II, IV) Material composition, especially porosity and water saturation - at production site - input data for predictive modelling - not monitoring Distribution of fissile Neutron moderation, Mineralogical composition of EBS and host rock Design values/ literature search (1; A, a; II, IV) and non-fissile reflection, absorption in

- 70 - SAM-J078-R1 material (contd.) EBS and host rock Properties - input data for predictive modelling - not monitoring

Note: “not monitoring” indicates that the measurement is not considered as a monitoring activity in the sense of the IAEA definition.

SAM-J078-R1 - 71 - 6 THE OPERATIONAL SAFETY CASE

This chapter considers the information required to ensure the operational safety of a geological repository and the monitoring options that are available to obtain that information. In the context of a phased disposal of the waste in the repository, this section addresses the period from the time that the site receives its nuclear site licence, i.e. is licensed to receive nuclear waste, to the time that the decision is taken to backfill the vaults. Thus, it covers the operational and care and maintenance phases of the life of the repository.

The chapter addresses all the operations associated with the reception and emplacement of the waste and maintaining the repository in a safe state during the above two phases. Much of the information that is required to ensure operational safety is also important of retrievability of the waste. Some information, e.g. information on the integrity of the waste and the vaults over long periods of time, is most relevant to retrievability and the main discussion of this information is found in Chapter 7.

The Operational Safety Assessment which is part of the Generic Safety Case (Nirex 2001a), identifies the hazards that have been addressed in the Generic design of the repository to ensure that it can be operated safely. These are shown in Table 6.1.

Operational safety in the repository would be achieved by the selection of a suitable site, the provision of a robust design, the safety systems and by monitoring. Monitoring would have an important role in enhancing the safety features and systems by: a) detecting departures from normal (safe) operating conditions b) detecting fault conditions that may lead to the development of unsafe conditions (at each stage of a fault sequence) c) providing relevant information to enable actions to be taken to prevent unsafe conditions developing d) providing, in the case of an incident with implications for safety, valuable information to enable the management of the situation in a way that would minimise the risk of injury or death, and achieve the return to normal (safe) operating conditions.

Monitoring, therefore, serves a two-fold role by either detecting a hazard, such as radiation or a fire, or by monitoring processes occurring in the repository that could cause a hazard to develop, e.g. the presence of flammable gases produced by the wastes. To meet operational safety requirements, it must be demonstrated that safe conditions occur in all areas of the repository at each stage of its development.

- 72 - SAM-J078-R1 Table 6.1: Operational safety requirements.

Safety of Operating Radiological Safety External radiation Staff Internal radiation Conventional Safety Impact Entrapment Fire Explosion Flooding Electrocution Asphyxiation Exposure to Irritant/ Toxic Gasses Exposure to Irritant/ Toxic Fluids Working Conditions Public Safety Radiological Safety Ingestion Inhalation External radiation Conventional Safety Exposure to Toxic Gasses Trespass Subsidence (very unlikely)

Notes to Table 6.1: ‘Working Conditions’ covers factors such as temperature, humidity in air; noise and light, ease of access, safety rails etc. which must be ensured under the Health and Safety at Work Act.

Partial departures from normal conditions, e.g. increased CO2, levels may increase risk of human error. ‘Toxic’ is taken to refer to all adverse medical indications resulting from a substance. Certain substances in use would be subject to control under COSHH regulations. Use of explosives is also subject to regulatory control.

To identify the information that is required, there is a need to address each of the potential hazards that are listed in Table 6.1, the conditions that may lead to a fault and the faults that could occur. A list of potential faults that may occur in each area is addressed by the Fault Schedule in the Appendix to the Operational Safety Assessment (Nirex, 2001a).

The way in which a hazard (e.g. exposure to radiation) can develop in the repository can be developed from the Fault Schedule in the form of a fault tree. This is illustrated in a simplified form in Figure 6.1 for the case of the external exposure of the operating staff. In this example, the requirement for information is broken down into the various ways that the staff could be exposed to external radiation and, for each one, the parameters that need to be

SAM-J078-R1 - 73 - monitored to ensure that the dose remains within the constraints of the safety case are identified. A complete set of fault trees such as shown in Figure 6.1 have been developed for each of the hazards identified in Table 6.1, and these were the basis for the comprehensive identification of information requirements and associated parameters given in Table 6.2.

The requirements for information that have been identified from the fault trees have been compiled as tables that list the requirements for information, the areas where this required, the parameters that could be monitored and the potential monitoring devices. In the case of operational safety, this information is presented in Table 6.2 (at the end of this chapter). Under the current arrangements for nuclear sites, it is the responsibility of the licensee, who would also be the operator of the repository, to ensure that the monitoring, which is required to support the operational safety case, is carried out and that any significant safety issues are reported to the regulator.

6.2 Radiological safety

6.2.1 External exposure of the operating staff i) Normal operation

The majority of the requirements for information and the associated techniques for monitoring, to ensure that the external exposure of the repository staff and members of the public is both within statutory limits and is reduced to ALARP, are the same as for any nuclear facility in the UK. These requirements are included here for completeness, but are not discussed in detail.

As indicated in Table 6.2, it is anticipated that the radiation dose experienced by the operating staff would be monitored using a legal dosimeter and the standard instruments for measuring doses for specific tasks where this is required.

The waste packages that have been produced to date, and those that will be produced in the future, are designed to meet the current UK transport regulations for radioactive packages, and the generic design of the repository ensures that these packages can be handled and emplaced safely. It is the responsibility of the waste producers to ensure that the radiation levels associated with each package meet these requirements and to be able to provide the operator of the repository with the necessary documentation that confirms that these requirements have been met.

On receipt of the waste packages at the repository, the operator has the option of relying on the information provided by the waste producers to be correct, to carry out limited checks, as indicated in Table 6.2, or monitoring each waste package on arrival to ensure that the stated radiation levels are correct and that no damage has occurred during transit. Either manual or remote techniques could be used and both are currently employed at repositories abroad (Nirex 2001b). Thereafter, radiation levels from the waste packages would only increase after the shielded transport containers are removed in the Inlet Cell, in the case of some ILW packages, or as a result of an accident.

- 74 - SAM-J078-R1 Parameters to be monitored Legal requirement to monitor doses of all personnel in Individual worker doses Radiologically Controlled Areas

Surface dose rate High radiation from package on arrival Area dose rates along waste route

Area dose rate with alarm Lid or overpack Loss of shielding removed External due to drop accidentally exposure of Issues related to prevention of workers dropped loads

Loss of ILW shielding Interlock failure Interlock failure with alarm

Failure rectified None remotely Failure of transfer equipment Man access Area dose rate in ILW route required

Criticality on Change in gamma radiation emplacement

Figure 6.1:Derivation of parameters related to radiological safety for workers – example of fault tree methodology

SAM-J078-R1 - 75 - In nuclear facilities, it is common practice for the radiation levels in key areas, such as the waste route and the general access areas within the repository, to be monitored by area gamma-ray monitors. Before waste is handled at the repository, these would measure the natural radiation levels. ii) Accidents.

- General

The accidents that could lead to a loss of shielding or the need to enter a high radiation area are identified in Figure 6.1. Where there is the potential for an accident to lead to an unplanned increase in the radiation level, alarms associated with the area monitors could alert the operating staff and, where there may be a need to enter a high radiation area after an accident, area monitors could provide an initial indication of the conditions in the affected area.

In the generic design, interlocks would prevent access to areas where unshielded ILW is handled when waste is present. The integrity of these interlocks could be monitored and an alarm could warn the operators in the case of failure.

Where unshielded ILW is handled remotely, operations could be visible through shielding windows, in the case of the Inlet Cell, or using CCTV, so that normal operations could be observed and, following an accident, recovery operations could be planned and managed from outside the high radiation area.

It is standard practice for the breakdown of equipment in the active areas, which may lead to the requirement to enter them, to be minimised by implementing a Monitoring, Inspection and Testing System (MITS).

MITS are widely used in the nuclear industry to ensure that plant operates satisfactorily between maintenance periods. For safety related equipment, the requirements would be a formal part of the safety case and the most important of these are identified below. It is normal practice for the requirement to implement MITS to be incorporated in the site licence. They could be integrated into the management procedures of the facility and included in the operating rules and technical specifications.

- Criticality

The risk to both the operating staff and members of the public from criticality is addressed in the Generic Operational Criticality Safety Assessment (Nirex 2001c), which supports the Generic Operational Safety Assessment. This shows that the only potential for a criticality accident during the operational and care and maintenance phases of the repository would be due to the undetected failure of the waste producers to control the fissile inventories of the waste packages.

To control fissile inventories, Nirex specify a Safe Fissile Mass (SFM) for each waste package and require that the waste producers complete Criticality Compliance Documentation for every packaged waste stream, which must demonstrate that the SFM is

- 76 - SAM-J078-R1 not exceeded. Independent QA checks on selected waste packages could provide assurance that the stated fissile content is not exceeded

Confirmation that criticality has not occurred could be provided by permanent gamma radiation rate detectors in each ILW vault or by a detector attached to the crane.

6.2.2 External exposure of members of the public.

The only potential for members of the public to be directly exposed to radiation from sources on the site of the repository is from waste packages that are stored in the railway sidings or lorry park waiting to be unloaded. As noted above, these packages are required too be designed so that the external dose rate meets the current UK transport regulations and they could be monitored on arrival to confirm that their surface dose rate meets Nirex’s requirements. The design of the surface facilities would ensure that the off-site dose rate is below regulatory requirements.

6.2.3 Internal exposure of the operating staff. i) Normal operation.

- Contamination monitoring

As in the case of external exposure, many of the requirements for information and the associated techniques for monitoring, to ensure that the internal exposure of operating staff and members of the public is within statutory limits and is reduced to ALARP, are the same as for any nuclear facility in the UK, although measures to control contamination and isolate contamination areas may need to be adapted to the underground environment.

At civil nuclear facilities in the UK, the approach to controlling the exposure of the operators to radiation from ingestion or inhalation is to control the level of surface and airborne contamination throughout the facility. In the case of the repository, this could start by monitoring the level of contamination on each waste package as it arrives, although this would also be done before they are dispatched from the waste producer. Thereafter, the only potential for contamination is from contamination on the surfaces of waste packages that arrive in shielded overpacks, as a result of an accident or as a result of the degradation of the waste packages.

The general access areas within the Radiologically Controlled Area (RCA) could be monitored using beta-in-air monitors or static air samplers, and alarms could warn the operators of airborne contamination levels that are above preset values. These monitors could establish the baseline level of natural airborne activity, such as radon, before any waste is handled, and monitor this activity throughout the life of the repository.

Contamination levels along the ILW waste route from the Inlet Cell could be measured by health physics staff prior to maintenance periods. The same staff could also periodically monitor surface contamination in the general access areas of the repository to ensure that it remains clean.

SAM-J078-R1 - 77 - - Active ventilation system

In the generic design, all areas where there is the potential for airborne contamination, including the vaults, would be served by an active ventilation system that would collect and filter the air before it is discharged to the environment. The working parts of this system, such as the fans, could be continuously monitored for signs of mal-operation, such as loss of pressure drop or power input, to ensure that they operate correctly.

It is also necessary to know that the air flows into and out of the facility are within the design parameters. It is standard practice to use flow gauges for this purpose. These would normally be situated in the main header ducts and would therefore be close to the filter room for the extract system and to the air handling unit for the supply system. A low flow alarm, associated with the instrumentation in the extract header duct, could be interlocked to stop the supply fans and prevent over-pressurisation of the filters. The flow gauges on the extract system could also be used to control the speed of the extract fan, via a control system known as an inverter drive, which would compensate for the increasing pressure drop across the extract filters as they accumulated material.

It is standard practice for the ventilation system to supply air to the uncontaminated areas of a nuclear facility and withdraw air from the potentially more contaminated areas such as the vaults. Airborne activity is prevented from being carried to less contaminated areas by ensuring that the flow rate from one area to the other meets the requirements of the relevant code of practice, which is currently AECP 1054 –1998. It is standard practice for the air flows to be measured during decommissioning using techniques such as vane anemometers, hot wires and smoke tubes. The periodic checking of these air flows over the operating life of the facility would be specified in the pre-operational safety report and incorporated into the operating procedures.

Thus, the design could ensure that pressure differentials would exist between the ambient pressure in the facility and the potentially contaminated areas such as the Inlet Cell, and between the Inlet Cell and the UILW vaults. These pressure differentials could be monitored by differential pressure switches that would provide a warning if the specified pressure differentials were not maintained.

In the Generic design, plant, such as filters, are employed to ensure that, in the event of a fault that resulted in a backflow of gas from a contaminated area to a less contaminated area, the less contaminated area was not contaminated. Such failures are normally tested regularly at a frequency that is specified in the pre-operational safety report.

All the above requirements for information and the associated techniques are standard for any nuclear facility. An example of a modern facility where all these techniques are employed is the plant to remove and treat liquid sodium from the Prototype Fast Reactor at Dounreay. ii) Integrity of the waste packages.

- General

The main incentive to maintain and monitor the condition of the waste packages is to ensure that they can be retrieved and, thus, this topic is discussed in Section 7, which addresses

- 78 - SAM-J078-R1 retrievability. However, monitoring the integrity of the waste packages is also essential in the content of operational safety, as it is necessary to ensure that the release of radioactive material from the waste is ALARP and does not exceed the values used in the safety case. As at any store, it is a regulatory requirement to monitor the condition of the waste to ensure that any signs of degradation are identified at an early stage and to ensure that conditions are maintained that would minimise any degradation (HSE 2001, EA 2001).

Some degradation of the waste packages is inevitable and, the waste packages contain filtered vents, which allow gasses that are produced within the waste to vent to the atmosphere of the vaults. As described above, the Generic design contains an active ventilation system that would collect and process any gasses or particulates that may be released from the waste.

- Surface storage

Depending on the conditions at the waste producers’ stores, some degradation of the waste packages may occur during their period of surface storage. There is, therefore, an incentive for Nirex to monitor the conditions under which waste packages are stored and their state before they are sent to the repository. This would enable Nirex to make an assessment of any deterioration that may have occurred and the potential rate of degradation in the repository. It may lead to the rejection of waste packages before they are dispatched to the repository.

- Chloride contamination

Because of the importance of chloride in enhancing the degradation of waste containers, the monitoring of a sample or all waste packages for chloride contamination when they arrive at the repository is an important consideration. This contamination may have occurred at the surface store or in transit, as many of the surface stores are at coastal sites. Detection on arrival would enable chlorides to be removed from LLW and SILW packages before the waste is transported underground. For shielded ILW packages, this could be carried out in the Inlet Cell.

- Corrosion on receipt

There is also the possibility of detecting any signs of corrosion visually, either at the surface facilities or in the inlet cell. Where signs of corrosion are a concern, the package could be returned to the waste producer or repackaged.

- Vault environment

In addition to ensuring that chloride levels are low when the waste packages are emplaced, the key to minimising degradation during storage is controlling the atmospheric conditions in the vaults. Thus, monitoring parameters such as temperature, relative humidity and chloride levels within each vault is an important consideration.

The temperature of the vault extract air could be measured using standard ventilation temperature sensors. These are used in most air conditioning applications and in nuclear applications, such as at gas cooled reactors during blow-down of the coolant. Room temperature sensors could also be placed in each vault to provide confirmation that the

SAM-J078-R1 - 79 - ventilation system is operating as specified. The temperature of the supply air could also be monitored in order to ensure that the dehumidifiers that would be used to control the humidity of the air that enters the facility are operated in an optimum mode.

There are two reasons for monitoring the humidity of the air that is extracted from the vaults. As well as insuring that the humidity in the vaults is below the level that is specified to ensure that the corrosion of the waste containers is minimised, the measurements will also warn of any potential damage to the HEPA filters in the extract system due to excessive moisture. The maximum humidity of the supply air could also be specified and monitored. Humidistats would be suitable for this purpose and, although dew point sensors are more accurate, the increased accuracy (±1% compared to ±5%) is not considered to be justified for this application.

In addition to the inlet air and contamination of the waste packages, another potential source of chlorides in the vaults is groundwater if there were a fault in the groundwater management system. The chloride concentration of the extract air from the vaults could be measured using on-line continuous gaseous sensors. In a typical arrangement, these would monitor air that is withdrawn from a sampling ring that is located in the extract duct manifold of each vault. The supply air could also be monitored and treated, if necessary, to ensure that the chloride level is below a specified level.

The values of all the above parameters can be controlled within specified limits by controlling the ventilation flow.

All the above monitoring equipment is commonly used within the process and nuclear industries and some, such as gaseous sampling, is in common use within the mining industry.

- In-vault corrosion

Within the vaults themselves, monitoring of corrosion could be carried out by visual inspection using TV cameras mounted on a manipulator on the crane. A more comprehensive monitoring of waste packages could be carried out by periodically removing representative waste packages of each type from the vaults and inspecting them. Access to remove waste packages in the vaults would be easier for the UILW packages that would be emplaced using a crane, than for the packages that are emplaced using a fork lift truck. It is noted that the guidance notes to NII inspectors (HSE 2001) state that "the design (of any future storage facilities) should provide access to all waste packages and the ability to retrieve any package in the facility within a reasonable period of time". In Appendix 6 of HSE (2001), this is defined as within a period of one week.

A possible alternative or supplement to removing packages from the main vaults for inspection is to establish a monitoring vault in which representative waste packages could be stored under conditions that reasonably bound those that would exist in the main vaults. These packages could be withdrawn periodically and examined using both non-intrusive and intrusive methods.

In addition to radioactive gasses, the degradation of the waste packages will lead to some production of combustible gases. The detection of combustible gasses could be carried out

- 80 - SAM-J078-R1 using gaseous analysers in the same way as the chloride concentration could be monitored. The monitoring of these gasses would ensure that there is no potential for a fire hazard.

- Groundwater monitoring

The key to ensuring that water does not enter the waste storage areas of the vaults is the satisfactory operation of the groundwater monitoring system. The operation of the system itself could be monitored by continuously monitoring the water levels in the sumps, the satisfactory operation of the pumps and regular inspections to ensure that blockages have not occurred. The failure of the pumps would also be minimised by implementing MITS.

In the generic design, the waste storage areas of the vaults should be dry, but the monitoring of their sumps would identify any significant presence of water. Monitoring this water for radioactivity and chlorides would also provide additional information on the state of the vault and its waste. iii) Preventing the impact or crushing of waste.

In addition to natural radioactivity and the degradation of the waste, the other potential cause of radioactivity becoming airborne in the repository is from accidents that could damage one or more waste packages.

Collisions between transport vehicles, the drift train, fork lift trucks or transport bogies, which are carrying waste packages, and other objects could be prevented by conventional safety systems for transport that would be regularly maintained inspected and tested.

When the waste reaches the vault, there is a need to ensure that it is stacked securely. This could be achieved by visual inspection in the LLW and SILW vaults and by using a remote system in the unshielded ILW vaults. This is discussed in iv) below.

Thereafter, preventing crushing could be ensured by monitoring the integrity of the vaults, their retaining structures and internal structures such as the liner. The monitoring options for these are discussed in Section 7. iv) Secure stacking of the waste

- Requirement

A positioning system could be used to ensure that the waste containers are (a) placed sufficiently accurately when being stacked to ensure stack stability, and (b) placed correctly in relation to the vault structural datums.

The system would also provide a means of obtaining data on the global location of individual packages.

SAM-J078-R1 - 81 - - Possible techniques

In the case of the LLW and SILW containers, the positioning in the generic design would be carried out using a purpose-built forklift truck. The design of the packages contain features that would ensure that each container is securely located above the one below and the process could be monitored visually by the operator and the supervisor.

In the case of the UIL stillages, the packages a would be emplaced by a remotely-controlled crane. In this case, a fixed optical distance-measuring device would be the preferred solution. Optical tachometers - electro-optical theodolites, such as the Geodimeter - are self-contained instruments that are accurate to a few mm per km, and are widely used in surveying. Typically, all they require is a passive retroreflecting prism on the distant target. They could easily be interfaced to plant monitoring and control computers. The computer system could be programmed to record the location of each package. Simple laser rangefinders are less accurate than these more sophisticated instruments, which use phase comparator techniques to achieve accuracy.

The prism could be located in the bogie above the hoist and the tachometer could be placed in the crane maintenance area. In this way, both could be maintained or replaced outside the vault.

The advantages of having a fixed, non-contacting instrument are that: - cumulative position errors do not occur; - a single instrument could, in principle, measure hoist position simultaneously in the x-, y- and z-directions by measuring range, bearing and elevation (see note later); - the instrument could be located in a protected position, to reduce the possibility of damage, and to allow calibration and maintenance; - there are few mechanical parts to wear out; - ageing instruments could easily be replaced with newer devices without having to work on the crane itself.

One disadvantage is that line-of sight is usually required but, in this particular application, this is not likely to be a problem, except when measuring the height of the hoist, where a package might be obscured by other packages that are already in situ. The grab height would best be measured by other means. Depending on the design of the grab, the height might only need to be known to a relative low level of accuracy.

This technique would allow packages to be positioned within a few mm at ranges up to hundreds of metres from the measuring point.

Two possible modes of emplacing the UILW and recording the position of the package can be envisaged: - a process control system identifies a vacant position in a vault and automatically routes the crane and new package to that position, using the distance measurements as control inputs en route. The final position coordinates would then be recorded and archived.

- 82 - SAM-J078-R1 - a manual system might be used, in which a human operator remotely controls the crane to a vacant location. The crane is then aligned with the target position with other aids, such as CCTV images or machine vision systems, for example. When the package is placed in position, the position at that time is recorded and archived in the normal way.

In both case, the measurements of package position would be made continuously. However, most of the data would be discarded, with only the final package position being retained.

Such systems are in place at nuclear installations operated by BNFL and British Energy.

- Confirmatory measurements

Once the package has been left in position and the crane has withdrawn, there is no reason to suppose that any significant change in position will occur.

Periodic checks on stack alignment and position could be made if required. This could be done, for example, by traversing the crane above the array of packages and examining CCTV images using a machine vision system. It is probable that arrays of stacked containers would be periodically viewed from above anyway, to check their condition. The TV cameras could be mounted on the crane.

In addition, it is envisaged that - the monitoring equipment would be periodically calibrated in accordance with an agreed procedure; - a suitable maintenance, test and inspection regime would be in place

- Storage of data

It is anticipated that the site operator would be bound by agreed procedures to archive the data until at least the time that the repository is closed in a secure and retrievable form. Because of its potential importance if there were ever a need to retrieve any waste, the location of each container, together with data on the physical and chemical properties of the waste and its container, could be regularly backed up in diverse locations, perhaps outside the repository. This follows standard procedures that are common in industry.

More specifically, the container position data, once acquired, could be routed to at least two separate databases within the plant computer systems, one covering general historic plant engineering data and another covering the identity and position of all containers in the repository.

- Standards

There is no standard for stacking packages. However, it is expected that the process of positioning the stillages would be carried out to a specific procedure, with specific acceptance criteria based on the accuracy required for a stable column. This could be monitored locally by, for example, a machine vision system attached to the crane, and comparing the position of a stillage with the one on which it was about to be placed.

SAM-J078-R1 - 83 - v) Monitoring to ensure the security of lifts by cranes

- Requirement

Unintentionally dropping a load from a crane is clearly undesirable in any circumstances. Depending on the crane, the load, and onto what it is dropped, the consequences might include - damage to plant; - injury to personnel; - damage to waste containers with the potential for a radioactive release; - radiation dose and economic penalties due to recovery operations;

Three integrity issues need consideration. These are - lift security, in terms of the failure of equipment such as hooks and slings in normal operation; - general security in terms of a load snagging or lifts in excess of the rated equipment capacity; - security of the lift after the waste package has been stored in a vault for a considerable period and the lifting features of the container may have experienced a significant degree of corrosion. This situation applies to retrieval operations.

Risks from the first issue can be reduced by regular inspection and separate tests of those components affected; the others by monitoring loads in the lifting system.

The design of the cranes, their safety features, modes of operation and inspection and test regimes would all be defined at the earliest stage in the project.

- Possible techniques

The approach to maintaining safe operation is twofold: regular, planned inspection of all demountable items of lifting equipment, including slings, hooks, etc, coupled with the full use of installed plant features such as automatic safe load indicators and cut-out devices.

The regular inspection of demountable equipment is standard practice in industrial premises. In general, cranes are normally fitted with a number of safety devices. Those relevant here are: - safe load indicators, which are based on well-established load cell technology; and - automatic cut-out devices, (essentially switchgear developments) which halt crane motions when an overload situation is detected.

Both rely on established methods.

- 84 - SAM-J078-R1 - Frequency of measurements

There are several current national standards that address the frequency with which the inspection of lifting equipment is specified. The most important one is given below. It is standard industrial practice to inspect slings, shackles, chains and the like at intervals of 1 year. Items that are found to be faulty are normally destroyed, while those that are in a suitable condition are colour-coded with paint markings. The current 'safe' colour is displayed in the vicinity. In the repository, the most critical lifts (of waste packages) would be made with dedicated, non-demountable equipment, and defining an inspection period for such equipment is common practice.

The magnitude of the load could be implicitly measured (by the automatic safe load indicator fitted to the crane) every time a lift is made. This measurement would detect the effects of snagging.

- Standards

The relevant standards are: - BS ISO 10972-1:1998, which gives guidance on crane mechanical devices, such as load indicators, brakes, clutches, etc - BS 7121: Part 1: 1989 - "Safe use of cranes" – which discusses safe load indicators

- Precedent

The application of existing standards and techniques has ensured that repetitive, pre-planned lifting with fixed and possibly semi-automated cranes has remained a low-risk activity for many years. vi) Preventing the dropping of waste

- Requirement

Preventing waste packages from being dropped is important to

- prevent damage to the waste packages before they are emplaced and - avoid the possible radiological and economic penalties associated with retrieving the waste package.

Cranes have been in use in industry for as long as industry has existed, and there are many well-established and well-developed standards which are applicable to crane testing. A typical example that is applicable in this case is BS7121 : part 2 : 1991 - "Code of practice for safe use of cranes - Part 2 - Inspection, testing and examination. This code comprehensively covers procedures for testing and inspecting crane mechanisms and gantries, by means of full

SAM-J078-R1 - 85 - visual inspections, proof load testing, deflection of supports and effectiveness of braking systems.

The major difficulties with the application of this (or similar) standard(s) to the repository case lie not in the inspection of the crane itself, which could be carried out in a maintenance area, but of the track and/or gantries, which would be in each vault. BS 7121 requires: - an inspection of the track and joints whilst loaded, and - that the deflection of the gantries should not exceed a certain fraction of the span (1/600 for BS5950 cranes) when the crane maximum safe working load is applied. This corresponds to about 30 mm for a 20m span.

The former requirement could be satisfied with the aid of CCTV monitors mounted on the crane. The second could be checked by means of an optical alignment system, based in a fixed, safe position. It should be noted that the alignment system would be separate from the position measurement system described earlier, and would not need to be as sophisticated.

The application of non-contacting optical techniques is attractive in this context, for the following reasons: - they are inherently highly accurate; - all complex items of monitoring equipment are in fixed, safe locations; - only passive targets need be attached to plant items; - replacement in due course would not involve work on the plant items.

It is anticipated that the above standardised tests would be applied at regular intervals - perhaps every year - to show that the plant is safe and fit for purpose. However, it is assumed that at longer intervals - perhaps ten-yearly - more comprehensive tests would be carried out on the main structural components of the crane to ensure that the condition of cracks in plates and welds had not changed. This would involve a number of well-established test methods, including - x-ray inspection; - dye penetrant testing; - ultrasonic testing.

Application of these techniques to the crane itself would be straightforward, and could be done in the maintenance area with no difficulty. It would be a more a complex undertaking to apply the same tests to the gantry structures in the repository vaults, but x-ray and ultrasonic testing are amenable to a high degree of automation, to the extent that it could be carried out by simple robotic devices. This would certainly be the case for simple structures like

I-section beams. Both these techniques are non-invasive, but of the two, radiography is preferable, as no couplant residues would be left behind as a potential source of corrosion.

- 86 - SAM-J078-R1 - Frequency of measurements

BS 7121 gives the legal requirements for the incidence of monitoring activities according to various authorities. The most relevant authorities quoted are: - the construction(lifting operations) regulations 1961; - miscellaneous mines (general) regulations 1956.

These authorities specify various degrees of inspection (covered by BS7121) before the crane is used first, after being out of use, weekly, etc.

Normally, more comprehensive specialised measurements, such as X-ray or ultrasonic inspection, are carried out during manufacture, and repeated at intervals of about 10 years. The inspection and test schedule is established at the earliest stage, and forms part of the pre- operational safety case.

- Use of the data

It is common in industry for operators to work to procedures that require the test data to be stored in a secure and retrievable form for as long as the crane may be required. .

- Standards

For regular inspections, the use of an established standard, such as that cited above, is common practice. For less frequent inspections, (of welds, etc), specific assessments could be made at the time, in the light of best contemporary engineering practice. This procedure might take the form of a periodic safety review, similar to the current practice in the civil nuclear industry.

- Precedent

BS 7121 is a well-established standard. Many other standards also exist.

Dye penetrant, X-ray and ultrasonic testing of engineering structures are also well-established techniques, having been in use for many years.

6.2.4 Internal exposure of members of the public

As in the case of external exposure, many of the requirements for information and the associated techniques for monitoring in order to ensure that the internal exposure of members of the public is within statutory limits and is reduced to ALARP, are the same as for any nuclear facility in the UK.

Members of the public would be prevented from being exposed to radiation as a result of radioactivity that is discharged to the environment during the operational and care and maintenance phases of the repository, by ensuring that these discharges are within the discharge limits that would be authorised by the relevant environment agency. All potentially radioactive discharges would be monitored.

SAM-J078-R1 - 87 - It is common practice for plant that is employed to treat radioactive discharges, such as filters, be tested regularly to ensure that the specified decontamination factor is maintained. In addition, the pressure drop across each filter is monitored continuously and an alarm is initiated if the measurements are outside defined limits. In this way, any collapse or bypass of the filter or excess material on the filter is detected and the filter can be replaced. Common techniques include photohelic gauges with impulse lines connected upstream and downstream of the filter.

In addition, the absence or presence of radioactivity from the repository in the environment during the operational and care and maintenance phases could be monitored by deposition measurements around the site and the regular taking of environmental samples, e.g. from grass. These measurements could start before waste arrived at the repository and would contribute to the establishment of the baseline of natural radioactivity in the area. This is discussed in Section 8.

6.3 Conventional safety

6.3.1 General

The issues associated with protecting the operating staff from non-radiological (conventional) hazards are the same as in any major mining complex and industrial waste handling facility. Consequently, only some of the major issues are indicated here. Several of the requirements for information are the same as those that are required to achieve radiological safety. Examples are the need to demonstrate the satisfactory performance of the ventilation systems and the integrity of the underground structures, lifting and transport equipment.

Additional requirements include the need for information associated with internal and external hazards such as fire, flooding and seismic activity. As indicated in Table 6.2, this information can be provided by heat detectors, level indicators in the sumps and means of measuring seismic activity. The first two are standard in any industrial activity and are not discussed further. Seismic monitoring is discussed below

6.3.2 Monitoring seismic activity

- Requirement

Although one of the criteria for any site that is chosen for the construction of a waste repository would be a low incidence of earthquakes, the possible impact of even low level seismic events will still need to be taken into consideration. Two classes of seismic event can be considered:

 Major earthquake, giving rise to - damage to plant; - inoperability of plant;

- 88 - SAM-J078-R1 - major hazards to personnel unable to escape; - damage to waste packages

 Minor earthquake or 'routine' seismic events, giving rise to: - minor damage to plant, still operational but perhaps with faults; - minor risk to personnel safety; - small movements of stacked waste containers.

Clearly, all of these events and consequences are undesirable. Some possible consequences would be avoided by proper engineering design. Avoidance of all seismically-induced problems is not possible, but with some warning, certain other consequences can avoided. This could be achieved with the appropriate monitoring equipment, that is capable of trending the low-level vibration and earth movements, which occur regularly.

Seismometers are normally used to measure seismic or earthquake activity. These devices normally measure ground acceleration or velocity, and are supplied complete by specialist manufacturers.

As an alternative, clinometers may be used to measure very small changes in local ground deformation (local tilt). Some commercially-available devices are capable of making measurements in the sub-microradian range, and are sometimes used to monitor volcanoes, again, for impending eruptions.

It is envisaged that trend data would be produced automatically, again requiring no operator intervention. However, it is likely that some interpretation of the data produced would be required, since the repository would be an active (i.e. busy) industrial site, with moving heavy plant such as trains. Seismometers would probably respond to structure-borne vibration and clinometers to local structural deformation caused by such movements.

- Frequency of measurements

Monitoring may either be continuous or triggered by vibration above a given threshold. Where data storage facilities are limited, the latter would be the appropriate choice. However, in this application, continuous capture, storage and trending would be more useful. Given the low frequency bandwidth of the data (typically 30 Hz) and the capacity of modern computer systems, this can be achieved. Various arrangements could be put in place to mitigate any storage problems, should they arise; for example, the actual data could be stored for, say, 1 year, after which only the statistical description of the data need be stored thereafter. For a large repository structure, more than one seismic sensor unit would be installed.

The measurements could be made by an automated, permanently installed monitoring system. This could be designed, installed and commissioned by a specialist organisation at the start of the project. Thereafter, the equipment should function automatically, with no operator intervention, save for periodic calibration.

SAM-J078-R1 - 89 - It is anticipated that the operator would appoint a Safety Officer responsible for, amongst other things, the safety of plant and personnel due to seismic activity.

- Use of the data

For all nuclear site, the definition of 'significant seismic events', the actions required and the likely consequences are defined at the earliest possible stage, and before any construction activities begin. It is likely that construction and operation of a repository would be conditional upon the existence of a comprehensive understanding of the local seismic activity and of appropriate response plans for such events.

As indicated, the trends in data could be analysed to show that local seismic activity was stable and at an acceptably low level. It may be possible to interpret indicated trends to give some advance warning of major activity. The action taken on receipt of such a warning - might, for example be to suspend waste movements and/or evacuate the premises.

In the long term, data could be archived in the normal way, so that it could be used as part of an audit if required.

- Standards

There recognised standards for the design and construction of this type of equipment. The key part of the installation is the transducer system. One important standard is BS 7119: 1989 - "Shock and vibration measurements - characteristics to be specified for seismic pick- ups".

There are also appropriate standards for the installation of the remainder of the equipment mainly cabling, computer system, software, etc.

- Precedent

Seismic monitoring using seismographs, seismometers, clinometers and accelerometers has been carried out for many years. The technology is well developed. The prediction of earthquakes from seismic data is less well developed.

6.4 References

EA 2001. Development of Agency Guidance for Nuclear Industry Submissions for Conditioning Intermediate Level Waste. Environment Agency Technical Report P411. HSE 2001. Guidance for Inspections on the Management of Radioactive Materials and Radioactive Waste on Nuclear Licensed Sites, 13 March 2001. Nirex 2001a. Generic phased disposal system documentation - Operational Safety Assessment. Nirex Report N/030. Nirex 2001b. Pacey N, Dutton LMC, Nirex Generic Repository Design – Demonstration of Proven Technology. Nirex contractor report, NNC Report C6421/TR/001 Issue 3, January 2001.

- 90 - SAM-J078-R1 Nirex 2001c. Generic phased disposal system documentation - Operational Safety Assessment, Operational Criticality Safety Assessment, Nirex Report N/030.

SAM-J078-R1 - 91 - Table 6.2: Information requirements, parameters and monitoring related to operational safety

Requirement for Information Area Parameter Monitoring /Sub Requirement Device

1 Radiological Safety. 1.1 External Exposure. 1.1.1 Individual Dose All Personnel in the Radiologically Individual Dose Film Badge or Equivalent plus Electronic Controlled Area Personal Dosimeter (May be legal dosimeter)

1.1.2 Radiation from Railway Sidings and Truck Surface Doserate. Hand Held Gamma-ray Monitor Package Reception Areas Automatic Monitoring

Waste Route up to and including Area Doserate. Area Gamma-ray Monitors Vault Reception Area

General Access Areas outside Area Doserate Area Gamma-ray Monitors Shielded ILW Waste Route Areas

1.1.3 Interlock Failure Unshielded ILW Transfer Facilities Interlock Failure Alarm including the Inlet Cell and the Vault Reception Area.

1.1.4 Equipment Failure Areas of the UILW Route including Closed Circuit TV (CCTV) Requiring Recovery the Vaults. Maintenance, Inspection and Test Schedules (MITS)

1.1.5 Criticality

 Fissile content of Waste Producers See Table 8.1: Waste Packages Waste Packages

- 92 - SAM-J078-R1 Requirement for Information Area Parameter Monitoring /Sub Requirement Device On-site QA Laboratory See Table 8.1: Waste Packages

Regulatory (EA) QA Laboratory

 Detection of Criticality ILW Change in gamma flux Gamma radiation flux meter

1.2 Internal Exposure

1.2.1 Surface Surface of Waste Packages on Contamination Level Swabs and Probe Surveys Contamination Arrival and Reception Area

1.2.2 Airborne Contamination General Access Areas within the Airborne Contamination Level. Beta in Air Monitors Radiologically Controlled Area Static Air Samplers

1.2.3 Operation of Fans Pressure Drop Ventilation System Power Input

Main Header Ducts Flow Flow Gauges

Extract Header Duct Low Flow Alarm interlocked with the supply fans

Vane anemometers Boundaries between areas of Air Flow Hot wires potentiality different contamination Smoke tubes levels Differential pressure switches Potentially contaminated areas such Pressure differential as the Inlet Cell and the UILW vaults

SAM-J078-R1 - 93 - Requirement for Information Area Parameter Monitoring /Sub Requirement Device

1.2.4 Confirm Performance DOP Testing of Filters at boundaries PARTICULATE THROUGHPUT of contaminated areas Filters at boundaries of contaminated areas

Waste Producers Stores See Table 8.1: Waste Packages 1.2.5 Maintain Integrity of Waste Packages over Operational Period.

 Monitor Surface See Table 8.1: Waste Packages Storage Conditions Surface stores of waste  Monitor Chloride See Table 8.1: Waste Packages Contamination on Receipt Reception Area Inlet Cell for ILW packages with shielding removed

- 94 - SAM-J078-R1 Requirement for Information Area Parameter Monitoring /Sub Requirement Device

Reception Area  Determine Level of See Table 8.1: Waste Packages Corrosion on Arrival Inlet Cell for ILW packages with shielding removed.

Outlet duct of vault ventilation  Monitor Atmospheric See Table 8.1: Waste Packages system. Conditions in Vaults

Vaults  Monitor Corrosion in See Table 8.1: Waste Packages Vaults CCTV  Monitor Corrosion in See Table 8.1: Waste Packages Laboratory Dummy Vault

 Monitor Gaseous Outlet duct of vault ventilation Airborne Contamination Gaseous Monitors Discharge from waste system. Combustible Gasses Gaseous samples/analyses

 Groundwater Management System Sumps Water Level Level Probes Radioactive Content Scintillation counters Chloride Level. Chemical analysis

Pumps Pressure Drop Power Input

 Vault drains Vault drain sumps Moisture Moisture sensors Radioactive content Scintillation counters Chloride level Chemical analysis

1.2.6 Prevent Impact or

SAM-J078-R1 - 95 - Requirement for Information Area Parameter Monitoring /Sub Requirement Device Crushing of Waste.

 Ensure Waste is ILW Vaults Optical tachometer with retroreflecting Stacked Securely prism

CCTV from Crane

LLW Vaults Visual

 Vault Integrity Vault roof, walls and floors. See Table 71: Vault and Liner Integrity

 Liner Integrity Vaults See Table 10.1: Vault and Liner Integrity

1.2.7 Security of lifts by cranes  Weight of load Cranes Throughout Waste Route Weight of load Load gauges

1.2.8 Prevent Dropped Loads

Integrity of Plant Structures Rails and joints Distortion when loaded CCTV Optical alignment system

 Integrity of Welds Cranes Throughout Waste Route Crack Size X-ray Ultrasonic Test Dye Penetrant Tests

- 96 - SAM-J078-R1 Requirement for Information Area Parameter Monitoring /Sub Requirement Device

 Corrosion of Structures Cranes Throughout Waste Route

 Integrity of Breaking Systems Cranes Throughout Waste Route Visual  Integrity of Transport Systems

Drop Tests

Operating Tests

1.3 Exposure of Members of the Public.

1.3.1 Gaseous and Discharge Stack Isotopic Discharges. Gaseous Activity Monitor Particulate Discharge to the Environment

1.3.2 Filter Efficiency Discharge Line Particulate/Iodine Throughput Dispersed Oil Particulate (DOP) Testing and Methyl Iodide Tests Pressure drop Photohelic Gauges 1.3.3 Deposited Activity Site Boundary Deposited Activity Tacky Shades and Environmental Samples.

1.3.4 Liquid Discharge to the Environment Discharge Line Gamma Radiation Levels Liquid Activity Monitor

Monitoring Tanks Isotopic Discharges. Sampling System

SAM-J078-R1 - 97 - Requirement for Information Area Parameter Monitoring /Sub Requirement Device

All areas Electronic Tests Heat Detectors

CONVENTIONAL SAFETY Status of Suppression Systems Gas Cylinder Pressure Detection Systems 1.4 Fire

1.5 Flooding Sumps Water level Level Detectors 1.6 Seismic Activity Selected points throughout the repository Ground acceleration Seismographs Seismometers Structural movement Accelerometers

- 98 - SAM-J078-R1 7 RETRIEVABILITY

This chapter address the information that is associated with maintaining the ability to retrieve the waste throughout both the operational and care and maintenance phases, that is the ability to withdraw the waste packages from a vault and return them to the surface if necessary. The period covered by these phases could last for a few hundred years after waste emplacement.

The monitoring requirements associated with retrievability are discussed in SAM/NNC/Nagra (2001). In order to maintain the ability to readily retrieve the waste over a long period, the principal requirements for information are associated with i) the structural integrity of the vaults and the other excavated areas of the repository, ii) the structural integrity of the waste matrices and their containers, iii) the ability of the operating and safety systems to function and iv) the information that is required to develop a safety case to support the retrieval of the waste. i) Integrity of underground excavations

The requirements for information associated with the structural integrity of the vaults and the other underground facilities is addressed in Section 7.2. ii) Integrity of waste matrices and containers

There are two aspects associated with the structural integrity of the waste matrices and their containers, i.e. waste packages. Firstly, there is the behaviour of the waste and the material in which it is encapsulated, since any changes to that may occur to their physical and chemical properties may affect the ability of the package to contain the waste. There is, therefore, the associated requirements to establish a baseline of these properties against which future measurements can be compared. These aspects are addressed in Section 7.3 together with the requirements for monitoring the evolution of the waste matrices after they are emplaced.

Secondly there is a requirement for information on the extent to which the containers themselves are corroding and the extent to which this would affect their integrity and ability to contain the waste. This is addressed in Section 7.4

SAM-J078-R1 - 99 - iii) Operating and safety systems

The requirements for information to ensure that the operating and safety systems are functioning correctly are the same as those that are required to support the operational safety case and have been addressed in Section 6. However, the issues associated with the corrosion of key in-vault components, such as the crane rails and supports in the ILW vaults, the liner and the rock bolts, are addressed with the other corrosion issues in Section 7.4

In addition to monitoring the ability of the packages to contain the waste, there is also the need for information on the integrity of the lifting features and the visibility of the identifiers associated with each waste package and stillages2. Both of these would be affected by corrosion and are addressed in Section 7.4

A further requirement associated with retrievability is information on any changes that may occur in the dimensions of the waste packages to ensure that the dimensions of the packages have not increased to the extent that the emplacement operations cannot be reversed. It is unlikely that this will be a significant issue for the shielded ILW and LLW packages, since these would be removed using a fork lift truck and returned to the surface without the need to add shielding. However, the unshielded ILW would need to be returned via the Inlet Cell, where a shielding overpack would be added before the package is transported to the surface. There is, therefore, a requirement to ensure that waste can be carried on the transfer bogie to the Inlet Cell, placed in the overpack and the lid installed. This is part of the overall requirement for information on waste characteristics that is address in Section 7.3 iv) Safety case

The information that would be required to support the safety case for retrieving the waste is very similar to that which is required to support the operational safety case, which has been addressed in Section 6. However, as noted in earlier sections, the issues that are specific to the integrity of the vaults, the characteristics of the waste and the corrosion of the waste containers and the in-vault structures are addressed in Sections 7.2 to 7.4 below.

In addition to the data on the physical and chemical properties of the waste packages, the safety case for retrievability would also be supported by the records of the location of each package, the measurements that had been made over the operational and care maintenance phases, the maintenance that had been carried out and records of incidents.

A major difference between the safety cases for operational safety and retrievability is that degradation of the waste packages and their containers may mean that they could be less robust if an accident occurred during retrieval than they were during emplacement. This is an additional requirement for the information on waste characteristics and corrosion that is addressed in Sections 7.3 and 7.4. v) Compilation

The requirements for information that are addressed in this section are tabulated in Table 7.1 (at the end of this chapter).

2 It is currently envisaged that large fraction of the ILW will be contained in stainless steel drums. For ease of movement and stacking, each group of 4 drums will be retained in a metal frame termed a stillage.

- 100 - SAM-J078-R1 7.2 Integrity of underground excavations i) Requirement

Information on the integrity of the vaults and the other underground excavations is key to determining the length of time for which the repository can be operated prior to backfilling the vaults and ultimately closing the facility.

Damage to the vaults or any of the underground excavations may occur because of a number of reasons, including - geological instability, seismic activity and earthquakes; - explosion caused by plant malfunction, escaping gas, etc

The latter would be a very sudden event and would be prevented by good design, by the safety systems that would be provided to prevent explosive gasses accumulating, by the monitoring that is discussed in Section 6 and by administrative procedures. Systems that monitor the integrity of the vault structures and the other underground excavations would clearly be of no use in this situation. However, useful data may be obtained by monitoring parameters that are affected by the geological processes, because, apart from earthquakes, they operate slowly and early warnings of instability may be obtained 3. Regular monitoring may give sufficient warning to allow remedial measures to be taken to rectify structural faults, or ultimately to backfill and close the repository or to withdraw the waste if closing the repository could not be justified. ii) Possible techniques

The very long term monitoring of 'permanent' structural features, such as the vaults and the other underground excavations, could be carried out in a way that does not depend on the availability or operability of any particular device over even moderate periods. Instead, the relationships between engineered features in the structure would be monitored. This approach gives protection against obsolescence and technological changes, which will inevitably occur over the long periods for which the repository will be operational. In this application, for example, external devices might be used to monitor crack growth, rather than embedded strain gauges, which cannot be serviced or replaced.

Although not the primary monitoring device, seismometers would provide some useful data in respect of vault integrity. These have already been discussed in Section 6.3(ii). Data from such devices are relevant, and could be incorporated into a repository integrity monitoring scheme. Seismometers fulfil the general criterion outlined above, in that they are removable, replaceable devices, which are not an integral part of the structure being monitored.

Seismometers could be placed outside the vaults, where they could readily be replaced at the end of their operational life.

3 What is meant here is the slow, but inevitable development of instabilities in the vaults due a variety of natural processes, the effects of which are likely to be exacerbated by the operation of the repository, i.e. keeping it open.

SAM-J078-R1 - 101 - While seismometers effectively monitor the low-frequency dynamic components of ground movement, clinometers measure static angular variations. They are therefore useful for monitoring long-term permanent changes in the shape of structures, in the absence of any truly fixed reference. Clinometers could form an important part of a long-term structural monitoring system. Suitable devices would be relatively low in cost, and it is anticipated that, in a large repository structure, many (~100) may be used. These could be monitored by an automated, computer-based system providing, say, one result per hour for each measurement point. In practice, the clinometer outputs would possibly be monitored continuously, but the data could be averaged over longer periods to eliminate the effects of short-term local structural loadings.

Outside the vaults, the clinometers could be placed directly on the rock surface and floor, where they could be readily replaced at the end of their life. Within the vaults, the rock surface would be hidden by the groundwater membrane and the liner. However, because the latter would be rigidly mounted to the rock, clinometers mounted on the liner would provide data on any movement of the rock surface. In the UILW vaults, they could be replaced remotely using manipulators attached to the crane.

A supplementary technique is to measure the behaviour of cracks in the liner, if it is constructed of concrete. Most large cast concrete structures have cracks of some size within them. Often, they are visible at the surface, and changes in the width of the crack can indicate structural movement. Crack growth monitoring is an established method for checking the stability of structures. In this application, the best approach would be to embed features within the structure on either side of the crack, and monitor the distance between them. Provided the features were suitably designed (e.g. 20 mm diameter round pegs), and made from a stable material (e.g. a stainless steel), their separation could be monitored by any of a large number of devices. An automated system using electronic displacement transducers (typically Linear Variable Differential Transformers or LVDTs) would be suitable. The reliable lifetime of an LVDT-based system might be 10-20 years, or even more, after which replacement might be necessary. Some form of in situ calibration arrangement would also be required.

- Period of measurements

The schematic design of a suitable monitoring system is expected be undertaken at the earliest opportunity in the life of the project. The granting of a licence to operate an underground repository is likely to be conditional on the incorporation of suitable structural monitoring schemes and procedures.

Measurements would be made continuously if, as would be likely, a relatively large-scale automated installation were used. For a small number of measurements, a manual method could be used, but coverage would be limited to non-active areas.

- Use of the data

As indicated, the data would be trended to ensure that structural movements were within acceptable limits. Should the trend of the measurements indicate that the stability of the underground excavations was in doubt, it would be necessary to assess if a repair programme

- 102 - SAM-J078-R1 would be feasible and, ultimately, this programme would be assessed by the regulator. Should repairs not be feasible, the options would be to backfill the affected part of the repository or remove the waste. The optimum would depend on the level of confidence in the long term safety case at the time.

In the long term, data would be archived in the normal way.

- Standards

No particular national standards covering structural cracking and building deformation have been identified. However, it is very likely that, at the design stage, comprehensive engineering data would be provided to specify acceptable changes. These would be used to formulate a set of criteria against which the results of monitoring exercises could be evaluated.

- Precedent

Large engineered structures, such as bridges, dams and large buildings - such as nuclear power stations - are routinely monitored for structural movement. The techniques for carrying out such monitoring activities are well established. The mining industry is a source of further data in this area.

7.3 Waste matrix characteristics i) Requirement

This and the following section (7.4) review the requirements for information on the waste characteristics from the point of view of the operator of the storage and disposal facility.

Section 7.1 has identified that information on the waste characteristics is required to meet the following objectives:

 Long term safety case

 Operational safety case

 Retrievability

The information that is required to support these objectives would demonstrate compliance with regulatory requirements.

It can be condensed into two reasons for monitoring the waste packages, namely; a) To construct an inventory of the radioactivity, chemical and physical properties of the waste that has been emplaced in the repository. b) To determine any change in the physical and chemical properties of the waste packages that may occur up to the time that the vaults are backfilled, since, over

SAM-J078-R1 - 103 - the long period of time before the vaults are backfilled, these changes may affect the ability of the containers to contain the waste and the behaviour of the waste packages if an accident should occur when waste is retrieved. There is therefore a need to establish a baseline of these properties against which future measurements can be compared.

Monitoring the changes in the physical and chemical properties of the waste coupled with models of waste behaviour would provide data with which the predictions of the models can be compared and an early warning of unsatisfactory situations before they occur.

There are four key periods for obtaining information on waste characteristics namely: a) Immediately prior to and during waste conditioning. b) Prior to the dispatch of the waste to the repository, particularly if there is a significant period of storage at the waste producer’s site. c) During receipt at the Nirex facility. d) During the operational and care and maintenance periods.

ii) Monitoring of packages consigned to Drigg

As a starting point, it is instructive to consider the monitoring currently done on receipt of LLW waste packages for disposal at Drigg (Gardner & Grimwood, 1997), although the monitoring is performed before the waste is encapsulated.. At Drigg, there are three levels of monitoring to establish or check the characteristics of the waste as indicated below.

Scheme of monitoring of waste packages currently received at Drigg Level 1. Documentation validation 100% of packages Radiation Contamination Weight Level 2. [Non-destructive assay] Real time radiography 5% of packages High resolution segmented gamma-ray scanning Passive and active neutron counting Level 3. [Destructive assay] Physical, chemical and radiochemical determinations 1% of packages

The current Nirex requirements for waste packaging require a higher level of QA than is required for the LLW that is currently consigned to Drigg, however. In addition, the Environment Agency, carries out independent monitoring on the order of 150 of these

- 104 - SAM-J078-R1 consignments per year at the Waste Quality Checking Laboratory at Winfrith (Newstead et al., 2000). This monitoring allows the Environment Agency to check the declarations that have been made about the consigned waste. The Environment Agency have expressed their intention to carry out the same level of confirmatory checking of waste that will be consigned to the repository as is currently carried out for waste that is consigned to Drigg (Williams, 1998). iii) Monitoring of packages consigned to the repository. a) Extent of monitoring

In the case of LLW packages that are consigned to the repository, there is no technical difficulty in carrying out the same monitoring on receipt as is carried out at Drigg even though the waste that would be consigned to the repository would be encapsulated. Both destructive and non-destructive testing on encapsulated waste is carried out in Belgium (Iseghein et al, 1997), France (CEA Brochure), Germany (Lierse & Wimmer, 1997, Odoj et al, 1997) and Spain (Suarez, 1997). However, in the case of the repository, the timescales involved in any of the radionuclides affecting humans or the environment is much longer than for the LLW consigned to Drigg and the contribution of the LLW to any potential radiological consequence is much less than that of the ILW, so it may be possible to justify a reduced scope for the monitoring of the LLW that is consigned to the repository.

In the case of ILW packages, there is a need to have an accurate inventory of the radionuclides emplaced in the repository and to monitor the integrity of the containers over the operational and care and maintenance periods, which could be a few hundred years. However, in contrast to the LLW packages, the ILW packages are generally from waste streams that are well characterised with relatively little variation, whereas the LLW packages that are consigned to Drigg are of a diverse random nature and are unconsolidated prior to compaction at the WAMAC facility at Sellafield. Thus, some reduction in the extent of monitoring relative to Drigg may be justified.

The most costly type of investigation per package in both financial terms and operator dose is the Level 3 destructive assaying. Intrusive sampling inevitably damages the waste matrix and (potentially) the waste container. It is likely that, in economic terms, such packages could only be made good, at specialised facilities such as a waste-conditioning centre. There is therefore an incentive to minimise the extent of such monitoring on receipt to the level that is considered necessary to verify the baseline value for the radionuclide content and the chemical and physical properties of each type of waste stream that is provided by the records. compiled by the waste producers. One option is to rely entirely on records. Such records could be supplemented by audits by Nirex of the monitoring carried out by the waste producers during packaging and with spot checks of the waste packages on receipt at the repository using non-destructive testing. If non-destructive techniques can not provide adequate information, then intrusive sampling of selected waste packages of each major waste stream may be necessary.

In principle, the records produced by the waste producers and the Level 1 and 2 checks would be all that is required to establish the radionuclide inventory. One complication is that beta emitters that may be significant for the long-term safety case, such as Cl-36, I-129 and C-14,

SAM-J078-R1 - 105 - can not be detected by Level 1 and 2 checks. In some cases, the quantities of such nuclides are assessed by the waste producers using fingerprints that relate their magnitude to those of other nuclides, such as Cs-137 and Co-60, even though they come from diverse routes on the plant where the waste was created. For these nuclides, checking the accuracy of the information provided by the waste producers would require intrusive sampling.

After the waste is emplaced, monitoring the characteristics of the waste is important for the reasons summarised in Section i) above. An important aspect is the rate of corrosion of the waste containers as a result of the internal environment. This will depend in part on the amount of free water that is available. The loss of free water will reduce the potential for corrosion and could be detected by changes in weight of the package.

Changes in volume would be indicative of significant corrosion of the container or the metallic waste, gas production due to corrosion or other reactions or phase changes of the waste. Significant changes in volume will lead to plastic deformation followed, in some cases, by cracking or, in the extreme, by disintegration of the waste. Phase changes and desecration could also lead to a reduction in the waste volume. Thus, changes in the volume of the waste packages will provide indirect information on the sorption, permeability and diffusivity of the wasteform, and thus its effectiveness as a barrier, and the generation of particulates or less robust forms, which will determine how the waste will behave in the case of an accident.

Some exothermic reactions will produce heat, and thus measuring heat generation will provide additional information on the occurrence of significant changes in the waste form. Thus, non-intrusive techniques could include: - The weighing of waste packages to indicate possible changes in the chemical structure where these lead to either a loss or gain in the overall weight, - Measuring the dimensions of waste packages to identify physical changes in the matrix, - Measuring the heat generation using a variety of techniques such as computer imaging, calorimeters and temperature gauges.

More detailed information on the creation of risks, significant changes in density etc. can be determined by more sophisticated non-destructive techniques such as real time radiography and high resolution segmented gamma scanning that are discussed below. Checks on the fissile content of waste packages could be carried out using passive neutron counting. More detailed information would require destructive techniques. In either case, withdrawing waste packages from the vaults may be time consuming and disruptive to the operation of the repository. It may be preferable to construct one or more test vaults that are maintained at bounding conditions with respect to temperature and relative humidity, place representative waste packages in them and withdraw a package of each type for monitoring at pre-defined intervals.

Thus, to obtain a robust inventory of the emplaced waste and establish a baseline to identify changes after the waste is emplaced, a possible scheme for monitoring on receipt could be as indicated below.

- 106 - SAM-J078-R1 Possible scheme of monitoring of waste packages at a deep repository Level 1. Documentation validation 100% of packages Visual Inspection of Package (and accessory) integrity

Level 2. Radiation All or a proportion of packages Contamination Level 3. [Non-destructive assay] Weight A proportion of packages Dimensions Heat generation. Real time radiography High-resolution segmented gamma scanning Passive neutron counting Level 4. [Destructive assay] Physical, chemical and radiochemical determinations A smaller proportion of packages

b) Techniques

Conventional techniques are sufficient for Level 1 and 2 testing, and these do not require further comment here. This also applies to measurements of weight, dimensions and heat generation.

For the non-destructive methods, it should be noted that current UK testing is mainly focussed on 200 litre non-consolidated drums. In contrast, the ILW would be in the larger 500 litre drums or in larger packages. Thus Real Time Radiography equipment would have to be more energetic than the 200 to 500 keV X-rays that are currently in use in the UK. Such equipment is available. Consolidated packages of ILW are routinely tested using gamma-ray radiography (Lierse and Wimmer, 1997, Odoj et al, 1997) and techniques are being developed in France (CEA brochure) and the USA (Bernandi, 1996).

High Resolution Segmented Gamma Scanning using gamma transmission corrections using an external reference source is recommended for scanning 500 litre cylindrical packages. This is recommended for scanning 500 litre cylindrical packages. This is because the transmission source will not only provide a means of corrections for the self absorption of gamma emissions and hence provide a better estimate of the nuclide content and its location (elevation) within the package, but it will also provide spatial information on any density variations. Using such techniques, a ‘round robin test’ of gamma scanning systems across

SAM-J078-R1 - 107 - quality checking laboratories in Europe has shown that an acceptable level of agreement between measurements at different laboratories can be achieved (van Velzen, 2000). The accuracy of the technique, even for 500 litre packages, is expected to be of the order ± 20%. Some development of the technique is required to enable hot spots at the edge of a drum to be distinguished from a more diffuse source. A current EU Fifth Framework funded project is addressing this (NRG, 2000).

The Nirex Operational Safety Assessment (Nirex 2001) assumes that waste packages contain no more fissile material than the Safe Fissile Mass (SFM) for that package. In general, a SFM of 50 g will apply to all waste packages, but a higher level may be permitted for specific waste streams subject to detailed assessment if this shows the increase is justified based on features of the waste package. Where verification that this requirement has been met is required, Passive Neutron Co-incidence Counting (PNCC), rather than a more complex active method, would be adequate. PNCC can be used for both encapsulated and un-capsulated waste. With PNCC, there are uncertainties associated with the self-moderation of emitted neutrons by the waste matrix, and other factors such as the distribution of the emitting nuclide within the package. The accuracy in this assay technique is of the order of ±50% and is limited by the accuracy with which the location of specific sources can be determined. For the best results, the technique needs to be supported by neutron physics computer modelling. A recent EC funded project has studied lattice arrays of neutron detector tubes in an attempt to localise emitting nuclides within the package in order to enhance the accuracy of the technique (Bucherl et al., 1999).

The localisation of both gamma emitters and neutron emitters within waste packages both on receipt and, for those packages selected, during the transition to closure, would give an indication of the degradation of the waste matrix.

Tomography, which uses gamma-rays or neutrons to produce two or three dimensional images of a waste package are available (Lierse et al., 1997; Lierse & Wimmer, 1997). They can identify the position of an identifiable item in a container, but not its material. Since the results of tomography depend on the material through which the beam passes, it is possible that further refinements, coupled with analytical techniques, could identify properties such as density and absorption cross sections and thus material properties. It has the potential to locate liquids and gasses that could be produced or the degradation of encapsulated material, such as Magnox. Thus, research into tomography may reduce the requirement for intrusive techniques over the care and maintenance phase of the repository. However, it is judged to be some time before the degradation of the containers due to the behaviour of the waste can be completely monitored using non-destructive techniques and the provision for destructive techniques and repackaging is an important consideration. c) Monitoring provisions and action levels

Section a) above has identified the need to monitor any change in the waste packages that may threaten the integrity of the container. This is to ensure that an uncontrolled release of waste into the vault does not occur during the operational and care and maintenance phases and to ensure that during these phases any waste package can be safely retrieved. This requirement is in addition to the requirement to ensure that any gaseous release from the waste does not produce a risk of fire or explosion in the facility or result in the authorised

- 108 - SAM-J078-R1 discharge limits being exceeded. These latter issues are discussed in Chapter 6. In addition, there is the need to obtain information on the behaviour of the waste packages if an accident were to occur during retrieval.

In order to monitor any changes in the waste that may threaten the integrity of the containers, it is necessary to have predictions of the long-term behaviour of each type of waste over the period up to the end of the care and maintenance phase. These could be used to relate threats to the containers to the parameters that can be measured as discussed in the previous section. In this way, actions levels could be set so that, if a parameter reached a pre-set level, action could be taken to retrieve and repackage the waste. These predictions are required to determine which of the available techniques are required and to what accuracy, as well as determining the action levels.

For example, the deterioration of wastes with a high metal content would result in the production of hydrogen. The hydrogen would be detected by gas analysers at the extract of the ventilation system for each vault and consideration could be given as to whether an action level could be set that related to the hydrogen production rate with the potential threat to the waste canisters. This action level would be different from that that represented a potential explosive mixture in the ventilation exhaust. However, the situation is complex because any relationship between the hydrogen production rate and processes that threaten the integrity of the waste container will depend on the waste stream and there may be waste from several waste streams in each vault.

Similarly, the deterioration of waste that contained organic material would lead to the production of CO2 and the formation of acids that would corrode the waste container. Again, it may be possible to develop a relationship between the CO2 concentration in the ventilation extract duct and a level of deterioration that would threaten the waste container. Alternatively, it may be necessary to rely on the detection of voids in the waste packages.

Similar relationships would be required for properties such as weight, dimensions, heat production, density and the other parameters discussed above. The most sensitive parameters would need to be determined and potential measurements, which did not give information that indicated when action is required, would not be necessary.

7.4 Corrosion

7.4.1 Waste containers i) Requirement

Most of the waste containers that are currently approved for use, and which are ultimately intended for repository storage, are manufactured from austenitic stainless steel, although other materials might be considered in the future and for specific circumstances, e.g. the WAGR box. During storage, above or below ground, the waste container constitutes the primary interface between the waste and the environment. In the Nirex disposal concept, the

SAM-J078-R1 - 109 - underlying safety rationale is to use multiple barriers to isolate the waste, and the waste container constitutes one such barrier. Thus it must have a high resistance to corrosion.

In addition to providing a containment of the radionuclides, the containers also have a function in enabling handling and transport of the waste to be carried out. This includes the ability to retrieve the waste from the phased disposal facility. It must also be robust enough to resist any impact damage that may result from transport or handling operations.

There is therefore a requirement to obtain information on all the parameters that may effect the resistance of the waste containers to corrosion. ii) Corrosion resistance

There are currently four Nirex standard containers: - 500 litre drum, - 3 m3 box, - 3 m3 drum, - 4 m box.

Currently austenitic stainless steel is the material of choice, although this does not exclude the use of other materials in the future. This material has been selected primarily for its good corrosion resistance. It has extremely low general corrosion rates in atmospheric and stored environments. In addition, it has a good corrosion resistance to the wastes that are currently scheduled to be placed in these containers. The types of stainless steel that are used for these waste containers are designated 304L and 316L. Both of these alloys are in common usage and there are a large amount of data that is available to demonstrate their performance. Type 316L is generally believed to have a superior localised corrosion resistance due to its molybdenum content, which increases it pitting resistance. The ‘L’ signifies a low carbon version of the alloy, which is required for these welded containers.

The main drawback to these stainless steels is their susceptibility to certain forms of localised corrosion. These effects are often highly local and can be due to small areas of the alloy being exposed to a particular contaminant. These forms of corrosion could ultimately cause a breach in the container, which might then allow an unfiltered release of radionuclides from the waste package. These types of localised attack include pitting, crevice corrosion and stress corrosion cracking. The primary contaminant of concern is chloride, which is implicated in many forms of localised attack. Chloride ions breakdown the tenacious air formed oxide film, which protects the stainless steel, and allow localised corrosion to occur.

The waste containers may undergo localised attack and still be considered to be essentially intact containers that are capable of being lifted and moved without releasing the bulk contents. Thus, a small area of pitting on a drum body may penetrate the wall and provide a release path that bypasses the filter in the vent unit which is provided each package to prevent them becoming over pressurised, but the drums may still be moved and transported.

In general, preventing the deposition of chloride on the surface of waste packages, is important since most chlorides are highly soluble and may become mobilised and move to

- 110 - SAM-J078-R1 locations on the waste containers which, if corrosion occurred, could result in a enhanced release of radioactive material. Ensuring that waste containers and waste packages are kept clean and free from chloride is important from the time that the manufacturing process starts. Although chloride is the main corrosive agent, it is rarely deposited on surfaces alone. It is normally associated with other salts which, although they may not directly cause corrosion, they often activate the chloride ions. Many salts are hygroscopic, that is they absorb water from the atmosphere. The exact humidity varies widely from salt to salt. It is normally accepted that sodium chloride wets at about 60% Relative Humidity (RH), so, in dry atmospheres, a surface contaminated with sodium chloride would be considered not to be at risk. But many other salts wet at significantly lower RHs (some as low as 30% RH). If the salts on the surface were a mixture of sodium chloride and magnesium sulphate, then the wetting of the sulphate would occur at a lower RH. The chloride would then be able to dissolve in the micro solution formed by the sulphate.

In practice, most depositions are mixtures of salts. Sea spray for example is mainly sodium chloride but also contains magnesium sulphate. Salt deposition in urban areas also contains nitrates and sulphates.

It is therefore important to keep waste containers and packages free from salt contamination and to maintain control over the temperature and humidity levels within the vaults. Experience has shown that salt contamination can arise from many sources such as atmospheric deposition, sweat and other body fluids, marker pen ink and adhesive used for labelling. Contamination by salts particularly chloride can arise at various stages of the container’s life. The salts may be deposited after manufacture, before the container is used, as a result of handling and during storage outside and they may be deposited on the waste packages after they have been filled and are in surface stores. They may also pick up salt contamination during transport operations. This will mainly be a problem for containers such as the 4 m box, which is designed to be transported as an ISO container, whereas the 500 litre drums will be transported within a transport containment. Lastly they may become contaminated with salt during the storage phase in the repository. iii) Monitoring for salt contamination

Detection of these salts and/or their removal before emplacement is therefore a major consideration in order to minimise the risk of localised corrosion during repository storage. It is also important to examine the waste packages for signs of corrosion prior to emplacement.

All packages that show any signs of corrosion such as rust staining would need to be removed for further examination, decontamination and possible repackaging. Information on the level of salt contamination can be achieved by a number of methods, namely; - visually looking for surface deposits, - swabbing - direct flushing of the surface - using a conductivity based method - using tape lift - a conductivity based method.

SAM-J078-R1 - 111 - These will be time-consuming processes and it may be more practical to assume that all packages are contaminated to some degree and to wash each package to ensure that they are all cleaned to the same standard.

- Standards

There are currently no specific stands for measuring the chloride contamination of waste packages, but there are a number of relevant standards that relate to assessing surface cleanliness before coatings are applied to metal substrates, namely, BS EN ISO 8502 –2 (2000), -3 (2000), -6 (2000), -9 (2001) and BS 7079 – B10 (2000). These refer to possible techniques as described below.

- Swabbing

In this method, a defined area is wiped with one or more pieces of filter paper or cotton wool which have been dampened with deionised water, (BS EN ISO 8502 –2, 2000). The swabs are placed in sample bottles, which are filled with demineralised water to extract soluble chloride, and the solution is then analysed, either by titration, for example with mercury nitrate, or by ion chromatography. From the analysis, a surface chloride concentration can be calculated.

The sensitivity of this technique depends on the detection limit of the analytical equipment that is used, but surface concentrations as low as 0.1-0.2 µg cm-2 are readily achievable. The disadvantage of this method is that laboratory based analytical equipment is required.

- Direct flushing of the surface

In this technique, a liquid is placed in contact with the surface, and subsequently collected and analysed. The holder for the liquid may be an adhesive patch with a central compartment (the ‘Bresle’ patch [BS EN ISO 8502 –6, 2000]) or a rubber sleeve with an adhesive ring at one end. If an adhesive patch is used the liquid is injected into and out of the hollow compartment using a syringe, then removed for analysis. Commercial field kits (e.g. [Chlor web site]) are available for measuring the surface concentration of chloride by flushing the surface with a proprietary solution and then analysing the chloride concentration in the solution. The detection limit is approximately 5 µg cm-2. In a similar field kit [Bresle web site], the solution is applied in the same way but analysed by on-site liquid drop titration [BS 7079 – B10, 2000] or by using ‘titrator’ strips. The detection limit is approximately 2 µg cm - 2.

- Conductivity methods

Conductivity measurements [BS EN ISO 8052 –9, 2000] can be used to measure the chloride concentration on a dampened filter paper in contact with the test surface or to analyse the chloride concentration in a solution that is used to flush a surface.

Devices based on conductivity are regularly used to monitor chloride deposition on stainless steel during nuclear reactor construction (Allan et al 1995). Proprietary meters [KTA – Tator Inc web site] are available for measuring the concentration of chloride on the surface, by

- 112 - SAM-J078-R1 conductivity measurements. A dampened filter paper, which is mounted in the open face of the instrument, is placed on the surface of interest and the conductivity of the filter paper is measured. For a known volume of solution added to the filter paper, the conductivity can be related to the concentration of surface contamination. The sensitivity is 0.1-20 µg cm-2. A drawback with such measurements is that the conductivity may be due to various ionic species other than chloride. If required, the filter papers can be removed for further analysis in the laboratory, for example by extraction with water and subsequent analysis by titration or ion chromatography.

Conductivity measurements can also be used to analyse liquids that have been used to flush surfaces. For example, the solution removed from a Bresle patch [Bresle, 1995] can be transferred to a conductivity meter and the reading converted to a surface contamination level. To use this method an assumption has to be made about the chemical form of the chloride (e.g. sodium chloride).

- Tape lift

The total amount of dust accumulated on surfaces can be measured by a tape lift method [ASTM E1216, 1999 and BS EN ISO 8502, 2000]. In the aerospace and electronics industries, surfaces are regularly sampled by applying a standard grade of tape and analysing the adherent particles, for example by electron microprobe analysis or wet extraction. However, this technique is not suitable for measuring chloride contamination as experience in the nuclear construction industry shows that the tape can be a source of chlorine contamination.

- Chemical Analysis

The preferred analysis technique for chloride is ion chromatography, with atomic emission spectroscopy or mass spectrometry used as the detection technique. To ensure complete dissolution of chloride, it may be necessary to acidify the sample solution with a high purity mineral acid (e.g. nitric acid). The errors associated with this technique are ±10% and the limit of detection is typically 1 ng cm-3. iv) Chloride control of the vault atmosphere

Once emplaced within the repository, it is important that the air that is drawn into the vaults is free from salt and particularly chloride. It is also important to prevent groundwater, which may contain chloride, from coming into contact with the waste packages during their emplacement and storage phases.

Relatively small amounts of salts deposited onto packages may make it difficult to identify individual waste packages after a relatively short period of time. The laser etch identifiers, which are present on most packages, are very susceptible to salt attack which would result in a locally severe but usually shallow corrosion layer. This could render the laser etch illegible to the human eye although machine reading may not be as badly affected.

Local corrosion sites may cause some pitting or crevice corrosion. This is unlikely to be of sufficient size that the overall integrity of the package is compromised but, if it is left

SAM-J078-R1 - 113 - unchecked, it may lead to severe pitting and/or stress corrosion cracking, which could locally breach the package containment. If this resulted in a significant enhancement of the release of gases, it would be detected by other monitoring devices, such as combustible gas analysers and radioactive gas monitoring in the outlet ducts from the vaults, as described in Section 6. Visual examination of the packages for rusting would alert the operators to potential problems but the ability to see the surfaces of waste packages in the vaults would be limited to those that can be seen using cameras mounted on the cranes in the UILW vaults and similar arrangements for visual inspection that would be made in the other vaults. Drums for example will be in stillages, which will limit the ability of visual inspection.

In order to monitor the extent of corrosion more closely, the options include: – removing waste packages from the vaults at regular intervals (5 to 10 years) and inspecting them in a waste checking laboratory. The period between inspections would depend on the rate of corrosion that is observed in emplacement conditions. – placing dummy packages in the vaults that could be removed and inspected without the radiation levels associated with packages containing ILW. – placing representative waste packages or dummy packages in purpose built monitoring vaults which could be removed for examination without the need to perform operations in the main vaults.

These options would allow the surfaces to be swabbed for salts and for a full visual examination for corrosion. For drum stillages, this would allow the removal of the drums from the stillage to check that there had been no galvanic corrosion between the drum and stillage. Intrusive examination would also allow the containers to be examined for internal corrosion. v) Container seals

The seal between the lid and most waste containers is a compressed polymer ring. This will deteriorate with time due to radiation damage and chemical and microbial attack. If it were to occur, it may be possible to detect severe hardening and cracking of the seals of waste packages in the vaults but reliable monitoring would require periodic visual inspection of seals that had been removed from representative waste packages.

7.4.2 Other equipment in the vault i) Stillages

The stillages for the waste drums are currently made from Cromweld 3Cr12. This material has good corrosion resistance but is inferior to the austenitic stainless steels of the waste containers. In dry conditions, it is unlikely to be affected but, if the areas of contact were wet, it is likely that a galvanic cell would be set up in the crevice between the drums and the stillage. If this corrosion were severe, it could ultimately affect the retrieval of the four-drum stillage. Once again, dummy packages could be used to assess the type and level of

- 114 - SAM-J078-R1 corrosion, if any, and enable judgements to be made about backfilling or removal of packages for repackaging. ii) Rock bolts

The rock bolts will be inaccessible once the vaults are complete. Their possible failure due to corrosion from salts in groundwater would be difficult to trace. However, additional rock bolts could be incorporated into the design in accessible areas so that inspection of rock bolts can be carried out during the extended storage phase. iii) Crane rails

The Generic design utilises stainless steel crane rails in the ILW vaults. These will be subject to similar localised corrosion events if they are exposed to chloride containing salts during their life. Since they will be subject to work hardening stresses at the surface, they are likely to be more at risk from stress corrosion cracking than pitting. The rails could be visually inspected regularly using cameras mounted on the crane, but, cracks could only be successfully detected using ultrasonic testing as is carried out on railway lines. In this case, the ultrasonic system is mounted in a container on wheels and moved at a specified speed along the rails. These operations could be carried out using a manipulator mounted on the crane. Again, increased confidence could be gained if rail samples were placed in an accessible test vault that would allow samples to be withdrawn for a more thorough inspection over the life of the vaults. There would then be a need to simulate the relevant work hardening stresses.

7.4.3 Monitoring options for corrosion i) General requirements

Provided that all the waste packages are free from salt contamination, especially chloride, prior to emplacement, control of the air temperature and humidity will provide a good basis for maintaining very low corrosion rates. Prevention of salt contamination whilst in the vaults by ensuring that groundwater does not come into contact with packages or equipment is also important in the overall strategy.

However, there is a requirement to show that these assumptions are true over the period of up to a few hundred years prior to backfilling. Within each vault, or within a purpose built test vault, there could be dummy waste packages that could be removed for a detailed examination every 5 or 10 years. In addition to waste packages, a monitoring vault could have samples of equipment and rock bolts which could be examined regularly for signs of corrosion. The atmosphere of the vault would be maintained at conditions that were reasonably bounding of those in the emplacement vaults.

The options for a corrosion prevention and monitoring strategy could therefore consist of: – Carrying out conductivity measurements on receipt to ensure that all waste packages are clean and free from salts (especially chloride) to an acceptable

SAM-J078-R1 - 115 - standard prior to being accepted for emplacement, unless all waste packages are routinely washed. – Carrying out a visual inspection on receipt to ensure that all packages are free from signs of corrosion prior to being accepted for emplacement. – Continuously monitoring the environmental conditions in each vault, as described in Chapter 6, including the test vault(s) to ensure that low corrosion conditions are maintained. – Continuously monitoring the salt content of the ventilation supply air, the extract air from each vault, and any moisture that enters the inner vault drainage system to ensure that the ingress of salts (especially chloride) from the ventilation system or groundwater into the vaults is prevented. – Inspecting packages regularly for signs of corrosion by means of visual examinations via remote cameras and by removing randomly selected packages from the emplacement or test vaults. Monitoring the presence of radioactive emissions and combustible gases in the ventilation extract from each vault would also provide information on the integrity of the waste containers. – Inspecting the other in-vault equipment regularly for signs of corrosion using remote cameras, ultrasonic testing on crane rails and dummy equipment in a test vault. – Inspecting the laser etch identifiers regularly for legibility using remote cameras and by removing dummy packages from the emplacement or test vault(s).

None of these options require novel technologies. It is noted, however, that a survey of surface stores for Nirex, found only about half carried out monitoring of the air temperature and only one in five monitored the relative humidity. None monitor the concentration of chloride in the air or the chloride contamination of the surfaces of the waste packages. ii) Monitoring vaults

It has been noted in Section 6 that the guidance notes to NII inspectors (HSE, 2001) state that "the design (of any future storage facilities) should provide access to all waste packages and the ability to retrieve any package in the facility within a reasonable period of time". In Appendix 6 of HSE (2001), this is defined as within a period of one week. However, to minimise operations in the main vaults the provision of a monitoring vault or vaults, which would see similar conditions to the main vaults is an important option for the overall strategy for achieving safety conditions over the operational and care and maintenance phases and to be able to retrieve the waste throughout this period. These monitoring vaults could contain samples of components or equipment, which are vital indicators of the state at any given time of the same equipment within the vaults. These monitoring vaults could be set up prior to the emplacing of any waste so that the corrosion of items in the vaults is ahead in time of any emplaced waste package or the in-vault equipment. Components that have been deliberately contaminated with salts, emplaced in a "worst case" monitoring vault would provide evidence of what components may be at risk in the future.

- 116 - SAM-J078-R1 7.5 References

Allan SJ, May R, Taylor MF and Walters J, 1995. The Effect of Salts on Steels and Protective Coatings, GEC Journal of Research 12(2), 86-92. Bernandi MT, 1996. Phase 1 Results of the Waste Inspection Tomography System, Paper 38- 8 in Proceedings of Waste Management 96, Tucson, USA, February 1996. Bresle A, 1995. Conductimetric Determination of Salts on Steel Surfaces, Materials Performance, pp. 35-37, June 1995. Bucherl T, Vicini G, Filss CP, Caspary G, Guldbakke S, Bruggeman M, Frazzoli FV and Lyoussi A 1999. Improvement of Passive and Active Neutron Assay Techniques for the Characterisation of Radioactive Waste Packages. EC Report, EUR 19121. CEA Brochure. Departement & Entreposage et de Stockage des Déchets Nuclear Wastes. Innovating today for tomorrow's operations. HSE 2001, Guidance for Inspections on the Management of Radioactive Materials and Radioactive Waste on Nuclear Licensed Sites, 13 March 2001.Iseghein et al, 1997 Gardner N and Grimwood PD, 1997. Waste Receipt Monitoring of Low Level Radioactive Waste. Proceedings of RADWAP 97, Würzburg, Germany, p. 483. Iseghein PV, Carchon R, DeRegge P, 1997. SUC-CEN as on Waste Characterisation Laboratory, p.219 of RADWAP, Radioactive Waste Products 97 (RADWAP 97) Würzburg, Germany, June 1997. Lierse C, Stover W, Kaciniel E and Neukel T, 1997. Representative Sampling of Waste Packages on the Basis of Non-Destructive Inspection Results. Proceedings of RADWAP '97, Wuerzburg, Germany, p 269. Lierse C and Wimmer H, 1997. Ten Years of Experience in Quality Control of Radioactive Waste. Proceedings of RADWAP 97, Wuerzburg, Germany, p 257 Newstead S, Leech NA and Daish SR, 2000. Independent Monitoring of Solid Low Level Radioactive Waste Disposals in the UK. Proceedings of Radwaste 2000, C584/014/2000, Institute Mechanical Engineers, London. Nirex 2001. Generic phased disposal system documentation - Operational Safety Assessment. Nirex Report N/030. NRG 2000. EC contract FIKW-CT-2000-00027 Large Waste Assay. Project Coordinator NRG, Arnhem, Netherlands. Odoj R; Filss P; Martins BR, 1997. Quality Control Installations of the Quality Control Group P230 of RADWAP 97 as also P257 of Radioactive Waste Products 97 (RADWAP 97) Würzburg, Germany, June 1997. SAM/NNC/Nagra 2001. Technical implications of retrievability on the Nirex phased disposal concept. Contractor eport to UK Nirex Ltd, SAM Report SAM-J064-R1. Suarez JA, Pina G, Rodriguez M, Espartero AG, Gascon JL, 1997. Radioactive Waste Characterisation in CIEMAT (Spain) p431 of RADWAP, Radioactive Waste Products 97 (RADWAP 97) Würzburg, Germany, June 1997. van Velzen LPM, 2000. Round robin test for the non-destructive assay of 220 litre radioactive waste packages. Proceedings of Radwaste 2000, C584/016/2000, Institute Mechanical Engineers, London.

SAM-J078-R1 - 117 - Williams CR, 1998. The Regulator’s Perspective. Institute of Nuclear Engineers Seminar on The Way Ahead for Deep Disposal in the UK, Gloucester.

- 118 - SAM-J078-R1 Table 7.1: Information requirements, parameters and monitoring related to retrievability

Requirement for information Area Parameter Monitoring Device /Sub Requirement 1. Integrity of Underground All Underground Areas Ground Movement Seismometers (Outside vaults) Excavations Static Angular Variations Clinometers (Outside vaults, on vault liners and floors)

Concrete Crack Growth Linear Variable Differential Transformers

2. Content and Integrity of Waste On receipt Physical and chemical properties Waste producer records Packages

On receipt Surface dose rate and gamma-ray Radiation monitor Repository waste checking spectrum Gamma-ray spectrometer laboratory for checks during pre- backfill period Weight Standard devices Dimensions Standard devices Heat generation Computer imaging Calorimeters Temperature gauges X-ray and gamma-ray images Real time radiography (Gamma-ray radiography for ILW) Radionuclide content of gamma High resolution segmented gamma emitters scanning. Location of gamma emitters Density variations Fissile content Criticality compliance documentation 2 Content and Integrity of On receipt from the waste producers Waste Packages (Continued) Repository waste checking Passive neutron coincidence counting laboratory for checks during pre- Two or three dimensional images Tomography backfill period

3. Control of Corrosion/ containers and in-vault

SAM-J078-R1 - 119 - Requirement for information Area Parameter Monitoring Device /Sub Requirement equipment 3.1 Surface Storage Conditions Waste producers stores Assessment of corrosion rate Records of storage conditions and analysis based on experimental data 3.2 Level of corrosion on Reception area Evidence of corrosion such as rust Visual inspection receipt Inlet cell for ILW packages with Evidence of corrosion such as rust CCTV shielding removed

3.3 Chloride contamination on Reception area Chloride contamination level Swabs receipt Inlet cell for ILW packages with Conductivity measurements shielding removed 3.4 Atmospheric conditions in Outlet duct of vault ventilation Temperature Ventilation Air temperature sensors vaults system

Relative humidity Humidistats Dew point sensors Inlet and outlet ducts Chloride level Gaseous sensors/analysers

3.5 Corrosion in vaults Waste packages and in-vault Evidence of corrosion CCTV structures Waste packages and samples of steel Evidence of corrosion CCTV or visual rails, rock bolts etc Waste packages removed to waste Chloride contamination Swabs conductivity measurement checking laboratory Package dimensions Standard devices Internal corrosion Intrusive examination 3.6 Visibility of waste package Vaults Visibility of identifier Visual for LLW & SILW identification Monitoring vaults CCTV for UILOW 3.7 Integrity of lifting features Waste containers Visual corrosion CCTV for UILW Visual for LLW & SILW Lift tests on dummy packages from main or monitoring vaults using load cell

- 120 - SAM-J078-R1 8 ENVIRONMENTAL ASSESSMENT

This chapter deals with information requirements for conventional environmental assessment studies, that is mainly related to potential impacts in the surface environment. (Baseline monitoring related to the geological environment which might also be part of an environmental assessment is addressed in Chapters 4 and 5). Monitoring requirements and methods of measurement are summarised in Table 8.1 (at end of this chapter).

The basic technical requirements for environmental monitoring in support of the Long Term and Operational Safety Cases are set forth in paragraphs 7.20 - 7.24 in the Guidance on Requirements for Authorisation (the GRA) (EA/SEPA/DoE NII, 1997)).

Requirement R9 – Monitoring 7.20In support of the safety case, the developer shall carry out a programme to monitor for changes caused by construction of the facility and emplacement of the waste 7.21The developer will need to establish a reasoned approach to monitoring of the site and facility and a programme for its implementation. The monitoring procedures proposed must not compromise the long-term safety of the facility. 7.22In order to provide a baseline for monitoring in later phases, the developer will need to undertake monitoring during the investigation programme. They should include measurements of pre-existing radioactivity in appropriate media, together with geological, physical and chemical parameters which are relevant to performance and safety and which might change as a result of construction and waste emplacement (e.g. groundwater properties such as pressures, flows and chemical composition). 7.23 During the construction and operational phases, radiological monitoring of the types undertaken at other nuclear sites will be required to provide evidence of compliance with authorised discharge limits and assurance of radiological protection of members of the public. In addition, such non-radiological parameters as are needed to confirm understanding of the effects that construction of the facility and emplacement of the waste have on the characteristics of the site should be monitored. In particular, the developer should demonstrate that the changes in and evolution of the monitored parameters are consistent with the safety case. 7.24In accordance with Principle No 1, assurance of safety of the facility must not depend on monitoring or surveillance after control has been withdrawn. Any subsequent monitoring will thus be primarily for public re-assurance.

SAM-J078-R1 - 121 - In addition to the above requirements that relate specifically to a radioactive waste repository, the developer may be required to provide additional monitoring as a condition of planning consent under the Town and Country Planning Acts. These monitoring requirements would relate to non-radiological environmental impacts identified in the Environmental Impact Statement which would be prepared by the developer as a statutory requirement under European and national law (CEC, 1993). This additional set of requirements would be similar in nature to those required for any major construction project, or new mine workings.

Taking account of the GRA, the principal monitoring requirements are therefore:

(a) During the pre-operational phase, baseline measurements of. (i) Pre-existing activity in environmental media (ii) Parameters affecting assessments of long-term performance (i.e. individual doses to current and future generations) of the repository system, and

(b) During the operational phase, measurement, focusing on detection of change in. (i) activity in environmental media to demonstrate compliance with public dose limits in connection with authorised discharges from the site, and (ii) confirmation of parameters affecting assessments of long-term repository performance. One of the main concerns in relation to requirement b (ii) is that site operations, and in particular the construction of the repository will effect groundwater flow paths and/or chemistry with implications for long-term safety performance.

(c) Following the operational phase, backfill and closure of the repository, it is expected that monitoring of the above sets of parameters would continue up to the end of the period of institutional controls. (i) Monitoring of environmental radioactivity would continue in support of public confidence, perhaps with an emphasis on possible fast, or early-warning pathways, such as radioactive gasses in the vicinity of former access points, or groundwater abstracted from deep boreholes. (ii) Parameters effecting repository performance would continue thus providing more information on their stability within parameter-ranges used as input to modelling in support of the safety-case.

8.2 Activity in environmental media

Before the receipt of active wastes, a baseline survey would be carried out in the vicinity of the site, and along proposed transport routes. In addition to natural background, there may be also a legacy of caesium-137 from the Chernobyl and weapons fallout, and other radionuclides released into the environment, for example from Nuclear Licensed Sites.

- 122 - SAM-J078-R1 The existing precedents for of environmental monitoring that could be carried out at the repository is the scope of that currently undertaken for Drigg and other nuclear facilities that are authorised to discharge radionuclides into the environment (FSA/SEPA, 1999).

In advance of repository operation, a baseline survey and future monitoring could include measurement of the following in areas that could potentially become contaminated by routine or accidental releases from the site: – Gamma dose rate (mSv hr-1) in air taken above terrestrial soils, sediments, and if applicable marine sediments – Concentrations of radionuclides (Bq litre-1) in potable water potentially contaminated by releases – Concentration (Bq kg-1) in agricultural products and feeds, and in free or wild foods – Concentration (Bq kg-1) in freshwater or marine aquatic organism – Concentration in air-borne particulates

Table 8.2 (from FSA/SEPA, 1999) (at end of Section 8) shows methods of measurements for samples, which depend on the radionuclide(s) released from site operations.

Additional monitoring of radionuclides from deep and shallow boreholes in the area may also be required. After the cessation of site operations, routine monitoring will still place at a lower level to provide continuing reassurance. In the early post-closure phase, monitoring may concentrate on detection of gaseous emissions around the former entrance to the shafts and drifts. Detection of radionuclides in deep-boreholes, such as for industrial process water abstraction, may provide early warning signs of poor containment by the repository and its natural and engineered barriers.

8.3 Parameters affecting long-term performance

These are conveniently characterised into two groups - Current and potential use of environmental resources - Biosphere and meteorological parameters a) Current and potential use of environmental resources

At the outset, collection of environmental data will be required as an input into the site selection process, which will assess the suitability of the site for a repository. An important factor at this stage is to collect information on both the current level of, and potential, utilisation of resources.

Resources are key factors in sustaining populations in the area of the repository and also a route for individuals in the future to come into contact with contamination arising from the repository.

SAM-J078-R1 - 123 - Water is one of the most vital of all resources. Current, and estimated sustainable, abstractions from deep and shallow aquifers, and from surface water bodies could be collated and expressed in units of m3 year-1. The long-term frequency of both shallow and deep borehole abstractions would be expressed as (abstraction per m-2 year-1). Abstracted water may serve domestic, agricultural, and industrial requirements.

Secondly, data on current, and potential future sustainable, agriculture and associated land- management practices would need to be collected. Current usage and the quality of land (which depends on geology, soils, terrain and climate) indicate the intensity and type of agriculture that is likely to persist. Relevant data on the quantity of agricultural production (e.g. milk), and the grading of land quality are available from the Ministry of Agriculture.

Other resources relate to the exploitation of energy resources (e.g. fossil fuels, geothermal energy), mineral resources, building materials (quarrying, forestry) and other commodities. Much of the relevant data are in the public domain. b) Biosphere and meteorological parameters

The biosphere plays an important role in determining the performance of the repository in terms of the eventual exposure of members of the public to radiation in addition to that from natural background and other artificial sources.

In the biosphere, radionuclides can be both diluted and concentrated. For water-borne radionuclides, the primary factors controlling dilution and uptake into crops relate to the catchment water budget and soil properties. Key parameters are the catchment area (m 2); precipitation, infiltration, evapotranspiration, and groundwater up-welling, which may be expressed in units (m3 y-1 per m2); the height of the water table; surface runoff, through-flow and base-flow from the catchment and stream flow (m3 y-1).

At the site selection phase, data of sufficient detail are likely to be in the public domain, or commercially available from the Institute of Hydrology. Monitoring of catchment parameters to provide a more detailed picture of groundwater movements may be required for site characterisation and in support of the post-closure Safety Case.

Regarding radionuclide accumulation, the key parameters are concentration ratios for (a) soil particulate to pore-water; (b) plant to bulk soil (c) concentration in animal products per unit uptake rate of activity. For site-selection, data of sufficient detail are available from generic databases. In establishing a safety-case, more detailed site-survey and experimental work will be required.

For airborne radionuclides, the main parameters affecting distribution potential are atmospheric pressure – which effects release rates from the ground to the atmosphere - and the atmospheric dispersion rate. Dispersion in air is adequately parameterised by the Pasquil- Guifford stability category scheme. The stability category is determined in a number of alternative ways from readily available or measurable parameters, such as wind-speed, percentage cloud cover. Data would be obtained from a weather monitoring station similar to those maintained by the Meteorological Office or at nuclear facilities.

- 124 - SAM-J078-R1 8.4 Conventional environmental requirements of major construction projects

A list of conventional environmental impacts and appropriate monitoring devices is shown under requirement 4 in Table 8.1. Requirements to monitor these impacts would depend on the outcome of the Environmental Impact Assessment, which would be prepared for submission as an Environmental Impact Statement (EIS) to the relevant planning authorities and their response in conditions attached to planning consent. Useful guidance and good practice in relation to the preparation of an EIS is given in references (DETR, 1999) and (CEC (draft), in press).

8.5 References

CEC 1993. Commission of the European Communities. Report from the Commission of the Implementation of Directive 85/337/EEC on the Assessment of the Effects of Certain Public and Private Projects on the Environment and Annexes for the Member States. COM (93) 28 final - Vol. 12. CEC (draft, in press). Handbook on the Implementation of EC Environmental Legislation. Commission of the European Communities. In support of EU directive 85/337. DETR 1995. Preparation of Environmental Statements for Planning Projects that Require Environmental Assessment. A Good Practice Guide. Department of the Environment Transport and the Regions. EA/SEPA/DoE NI 1997. Radioactive substances Act 1993. Disposal Facilities on Land for Low- and Intermediate Level Radioactive Waste: Guidance on requirements for Authorisation. FSA/SEPA 1999. Radioactive materials in Food and the Environment, RIFE-5. Food Standards Agency, Scottish Environment Protection Agency.

SAM-J078-R1 - 125 - Table 8.1: Information requirements, parameters and monitoring for the surface environment

Requirement/ Sub Requirement Area Parameter Monitoring Device 1 Long-term potential resource use. Region of potential abstraction of Abstraction rate Desktop study 1.1 Groundwater and Surface Water contaminated water plus additional Abstraction lifetime localities in the region (see Figure Abstraction frequency 8.1) Abstraction depth 1.2 Agricultural Products Region of groundwater discharge Land quality class Desktop study To biosphere. Current agricultural production 1.3 Energy & mineral resources Area in vicinity of vaults plus Frequency of investigation/ Desktop study Region of potential exploitation (see exploitation Geological survey Figure 8.1) Depth of operation 2. Requirement to model the fate of radionuclides entering the environment

2.1 Near-surface Hydrology Area of potential groundwater Rainwater catchment Area (m2) Desktop study + discharge from repository, and Field survey subsequently contaminated areas. Stream Flow (m3 y-1) Stream-flow gauge Precipitation (m y-1) Rain-gauge Evapotranspiration (m y-1) Lysimeter, Calculation by empirical formula, such as that of Penman Artesian Upwelling (m y-1) piezometer Water Table Height (m y-1) Borehole logger. 2.2 Accumulation of Radionuclides Area of potential groundwater Soil Kds (litre kg-1) Scientific Literature, Compendia. on Environmental media discharge from repository, and Plant: Soil Concentration Ratios (-) Laboratory Analysis of samples. subsequently contaminated areas. Animal retention factors (day kg-1)

2.3 Requirement to model fate of General vicinity of site Barometric Pressure Barometer; Met. Office Records radioactive gasses arising from the

- 126 - SAM-J078-R1 Requirement/ Sub Requirement Area Parameter Monitoring Device repository. Pasquil Stability Category A variety of devices available for standard met. equipment is widely used for weather observations.

3 Requirement to Measure Environmental Radioactivity

3.1 Baseline measurements

3.1.1 Dose rate in air General vicinity of site (i.e. site Environmental Radiation Meter boundary to ~ few km) (e.g. with compensated Geiger- Over potentially effected freshwater Muller tubes) and marine sediments.

3.1.2 Environmental Samples General vicinity of site. Activity Concentration in Collected See Table 5a Area of potential groundwater Samples discharge from repository, and (Bq kg-1 or Bq litre-1 as appropriate). subsequently contaminated areas.

3.1.3 Radioactive Gasses General vicinity of site, especially Concentration (Bq/ m3) Gaseous Monitors, see also Table 3. near access or discharge points. Downwind of site

3.2 Changes in Environmental As baseline. Radioactivity as a during operation, and post closure

SAM-J078-R1 - 127 - Requirement/ Sub Requirement Area Parameter Monitoring Device 3 Requirement to Measure Environmental Radioactivity

3.1 Baseline measurements

3.1.1 Dose rate in air General vicinity of site (i.e. site Environmental Radiation Meter boundary to ~ few km) (e.g. with compensated Geiger- Over potentially effected freshwater Muller tubes) and marine sediments.

3.1.2 Environmental Samples General vicinity of site. Activity Concentration in Collected See Table 5a Area of potential groundwater Samples discharge from repository, and (Bq kg-1 or Bq litre-1 as appropriate). subsequently contaminated areas. 3.1.3 Radioactive Gasses General vicinity of site, especially Concentration (Bq/ m3) Gaseous Monitors, see also Table 3. near access or discharge points. Downwind of site

3.2 Changes in Environmental As baseline. Radioactivity as a during operation, and post closure

- 128 - SAM-J078-R1 Table 8.2: Methods for monitoring radionuclides in the surface environment

Radionuclides Sample Type Method of Measurement

3H3H (organic) 14C 32P 34S 45Ca 147Pm 241Pu All Beta counting by liquid scintillation

90Sr High-level aquatic samples Cerenkov counting by liquid scintillation

90Sr Terrestrial and low-level aquatic samples Beta counting by gas proportional detectors

99Tc 210Pb beta All Beta counting by gas proportional detectors

103+106Ru 131I 144Ce 134+137Cs Terrestrial samples Beta counting by gas proportional detectors

125I 129I Terrestrial samplesE/W Gamma counting by solid scintillation

Seawater 134Cs 137Cs Gamma counting by solid scintillation

51Cr 54Mn 57Co 58Co 60Co 59Fe 65Zn 95Zr 103Ru All Gamma spectrometry using germanium detectors 106Ru 110mAg 125Sb 134Cs 137Cs 144Ce 154Eu 155Eu 241Am 233Pa 234Th

125I 129I Terrestrial samplesS Gamma spectrometry using germanium detectors

129I 131I Aquatic samples Gamma spectrometry using germanium detectors

SAM-J078-R1 - 129 - Radionuclides Sample Type Method of Measurement

U Terrestrial samples Activation and delayed neutron counting

210Po 226Ra* 234U 235+236U 238U 237Np 228Th 230Th All Alpha spectrometry 238Pu 239+240Pu 241Am 242Cm 243+244Cm

226Ra Terrestrial samples Alpha counting using thin window proportional detectors

Alpha Dry cloths Alpha counting using thin window proportional detectors

- 130 - SAM-J078-R1 9 THE POLICY, LEGAL AND REGULATORY FRAMEWORK

Parts of this chapter are based on text taken from the Nirex Phased Disposal Concept report N/025 (Nirex 2001).

9.1 The current policy, legal and regulatory framework

Policy

Current UK policy on radioactive waste management is set out in the 1995 White Paper (HM Government 1995). The policy requires that radioactive waste should be managed in accord with the principle of sustainable development and in ways which protect the public, workforce and environment. Such principles are unlikely to change.

However, the Government is committed to undertaking a thorough review of radioactive waste management policy following a public consultation process that was initiated by the issue of a consultation paper in September 2001 (DEFRA et al. 2001). This follows the Government response to the House of Lords Select Committee Report on the Management of Nuclear Waste (House of Lords 1999; DETR 1999), which acknowledged the Committee’s recommendation for a detailed and wide ranging consultation to begin the process of finding a long-term management strategy that commands widespread public support, with the need for a scientific research programme to inform the debate. This review may well lead to changes in both preferred management options and the organisational framework by which radioactive waste management stratregy and solutions are developed in the UK.

Legislation

The phased development of a waste repository would be subject to a variety of established regulations and safety standards designed to ensure protection of the environment, the public and workforce:

• planning permission would be required under the Town and Country Planning Act;

• transport of radioactive wastes would be carried out in accordance with relevant national legislation, EU directives and international guidance;

• operation of a repository system is expected to be licensed and regulated by the Nuclear Installations Inspectorate;

• disposal of waste would be controlled under the Radioactive Substances Act by the Environment Agencies (the Environment Agency on England and Wales and its Scottish and Northern Irish equivalents);

SAM-J078-R1 - 131 - • under Article 37 of the EURATOM Treaty (EC 1996) the European Commission would need to deliver an opinion on the scope for radioactive contamination of the territory of other member States before a disposal authorisation could be granted.

Obtaining the necessary consents would be a lengthy process requiring the development of a number of site-specific assessments and safety cases along with other supporting documentation. Those safety cases would be subject to independent regulatory scrutiny by the Nuclear Installations Inspectorate and the Environment Agencies, and would need to demonstrate compliance with a range of radiological protection principles and safety standards. Ultimately these same agencies would regulate repository operation and closure.

The monitoring to provide the information needed to develop these safety cases is discussed under Objectives 3 and 4 (i.e. in Chapters 5 and 6 of this report). The concern here is that Nirex should follow any changes in the legal requirements.

Regulatory guidance

The safety of the transport of radioactive material through the public domain is governed by UK legislation. This is based on transport regulations published by the international Atomic Energy Authority (IAEA 1990) and incorporates relevant legislation from EU Directives (EC 1996).

The Health and Safety Executive regulates the nuclear industry through the Nuclear Installations Inspectorate (NII). The NII regulate through issuing licenses to construct and operate a nuclear facility and has powers of inspection to monitor and regulate operations. The NII has set out guidance for potential operators of nuclear plant in the form of the NII Safety Assessment Principles (HSE 1992)

The Environment Agencies have developed guidance on the requirements for authorisation of new disposal facilities in the UK, which sets out a series of principles and requirements against which they would assess any application for authorisation for the land-based disposal of radioactive waste (Environment Agency et al. 1997).

All these regulations may be subject to revision and supplemented by additional regulations and guidance over time. The concern here is that Nirex should follow any changes in the regulation and associated guidance.

9.2 Monitoring and response to changes

Policy

Nirex is a statutory consultee in the current consultation process and, also, commissions research that may inform the debate.

- 132 - SAM-J078-R1 Legal requirements and regulatory guidance

Nirex maintain a constant watch on legal and regulatory developments and also on international matters which may lead to developments in the requirements and guidance applicable in the UK. The current requirements and guidance are incorporated in Nirex Safety Standards.

Nirex has developed a Radiological Protection Policy Manual (Nirex 1998a) which sets out the Company’s policy on radiological safety. This is supported by Nuclear Design Safety Principles (Nirex 1998b) for the construction, design and operation of a deep waste repository. These provide constraints and criteria with which the results of the operational, transport and post-closure safety assessment work are compared by Nirex.

9.3 References

DEFRA et al. 2001. Managing Radioactive Waste Safely: Proposals for developing a policy for managing solid radioactive waste in the UK. DEFRA, DoE, National Assembly for Wales and the Scottish Executive, September 2001. DETR 1999. The Government response to the House of Lords Select Committee Report on the Management of Nuclear Waste, DETR, October 1999. EC 1996. Council Directive 96/29/EURATOM: Basic Safety Standards for the protection of the health of Workers and the General Public Against the Dangers arising from Ionizing Radiation, Dated 13 May 1996. Official Journal of the European Communities No. L159/1 Annex 2. Environment Agency, Scottish Environment Protection Agency, Department of the Environment for Northern Ireland, 1997. Radioactive Substances Act 1993: Disposal Facilities on land for Low and Intermediate level radioactive Wastes: Guidance on Requirements for Authorisation, Environment Agency, 1997. HM Government 1995. Review of Radioactive Waste Management Policy: Final Conclusions. Cm 2919, HMSO, London. House of Lords 1999. Management of Nuclear Waste. Report of the House of Lords Select Committee on Science and Technology, HMSO, March 1999. HSE 1992. Safety Assessment Principles for Nuclear Plant, Health and Safety Executive. IAEA 1990. Regulations for the Safe Transport of Radioactive Material, 1985 Edition (As Amended 1990). IAEA Safety Standards Safety Series No. 6, International Atomic Energy Agency, Vienna. Nirex 1998a. Radiological Protection Policy Manual. Nirex Report NA/98/002, 1998. Nirex 1998b. Nuclear Design Safety Principles. Nirex Report NA/98/003, 1998. Nirex 2001. The Nirex Phased Disposal Concept. Nirex Report N/025.

SAM-J078-R1 - 133 - 10 PUBLIC ACCEPTABILITY AND WIDER CONFIDENCE ISSUES

This chapter examines several social aspects of monitoring.

It starts, in Section 10.2, by presenting some general considerations of the nature of social engagement, and continues, in Section 10.3, by describing what is currently known about the public acceptability of monitoring strategies.

Different means of monitoring the public acceptability of the repository and the monitoring strategy are examined in Section 10.4, in relation to the needs of various participants. This analysis includes discussion of the information needs and the acceptability of different technical components of the monitoring strategy. Section 10.5 goes on to describe some potential opportunities and needs for dialogue, followed by a discussion of the different audiences and their requirements in Section 10.6.

Section 10.7 discusses the possibility of monitoring the institutional capability to manage and close the repository. This section explores the possibility of monitoring social stability in relation to the closure of the repository, concluding that this is not currently possible, and in any case has serious conceptual flaws. Instead, it suggests that monitoring social capability to manage and close the repository may be more warranted.

The concluding section, Section 10.8, presents some of the wider social conditions – including the extent to which the public and other stakeholders are engaged in the development of the monitoring strategy – which are relevant to the acceptability of a monitoring strategy.

10.2 The nature of social engagement with monitoring

When considering the social dimensions of a monitoring strategy, it is necessary to identify the different groups likely to be relevant. In broad terms, these can be categorised as: – the general public; – the local public; – specific stakeholder groups.

From this broad categorisation, subsets can also be identified in relation to the particular social context of a repository. Each group is likely to have particular requirements with

- 134 - SAM-J078-R1 respect to monitoring; the local public is most likely to articulate their views. This then implies that ascertaining the local acceptability of the monitoring strategy will require different techniques to ascertaining the acceptability to the general public, and to specific stakeholder groups. These are discussed in Section 10.6 “Different audiences and different requirements”.

The second major consideration is to clarify the purposes of engaging with the public and other stakeholders. Such purposes include: – identifying preferences; – developing confidence; – enhancing acceptability; – providing legitimacy; – demonstrating safety and control; – improving decision-making.

These purposes are inter-related: for example, identifying preferences and incorporating these into monitoring strategies should assist in developing confidence, acceptability and legitimacy as well as contributing to better decision-making. The purposes of consultation and dialogue in tandem with acceptability are discussed further in relation to methods and techniques in Section 10.4.1 “Purposes of monitoring acceptability”.

Five stages of public and other stakeholder engagement are relevant to at least each phase of repository development as identified (prior to site selection, site characterisation, underground access and exploration, repository design and construction, waste receipt and emplacement, underground storage, post vault backfill and post closure). These stages comprise: – establishing views and concerns about monitoring requirements, to inform the ‘what’ and ‘why’ of monitoring; – consultation regarding the design of monitoring programmes, to inform the ‘why’, ‘when’, and ‘whom’ of monitoring; – engagement with the implementation of the monitoring programme, to provide confidence and transparency through observation of monitoring in practice; – presentation and consultation on the results of monitoring and the implications, to inform further decisions on responses to monitoring results including potential remedial actions, planning development, and the decision to move to the next stage of repository development; – review of monitoring programmes, to inform decisions about changes to and development of these programmes.

SAM-J078-R1 - 135 - In some phases of the repository, as identified in this report, it is more appropriate to consider implementing these five phases with respect to different dimensions of the phases – for example, the design of the repository will require consultation separate to that concerned with the construction of the repository, which is likely to raise different issues and have different implications for monitoring. Different requirements for public and other stakeholder engagement in relation to the phases of the repository are discussed further under ‘Implications of different stages of the repository in relation to public acceptability and monitoring’.

10.3 Some characteristics of current public requirements for monitoring

Recent work has demonstrated the importance of comprehensive monitoring for publicly acceptable radioactive waste management (e.g. Hunt & Simmons, 2001; CSEC, 2001) From these studies, it is clear that in today’s UK society, a number of characteristics of a monitoring strategy can be identified; these are discussed below. This is not necessarily a complete list of all the required characteristics, but an indicative list of those characteristics that can be identified from existing work. The table below relates these characteristics to the five stages of public engagement discussed above; the remainder of this section describe public and other stakeholder views on each characteristic. – accessible information; – publication of results; – independent verification; – comprehensiveness of monitoring; – plans to respond to monitoring; – satisfying worst critics; – safety before cost.

10.3.1 Information and publication of results

The public and other stakeholders generally call for widely accessible information. Accessibility incorporates both physical accessibility (is the material available?) and communicative accessibility (can the user readily understand the material?). Where there is a specific site, information needs to be available in and around that location. The principles of openness (that information should be in the public domain) and accessibility are fundamental to public acceptability of monitoring requirements.

In practice, this implies that the results of monitoring should be published locally (e.g. in local papers, posted in Town Halls, libraries, community centres etc) as well as regionally and nationally, and that the form of information should be easily understandable without specialist knowledge. Temporal comparisons (i.e. demonstrating whether results are ‘higher’ or lower’ than previously) are often requested, and provide a simple and understandable measure to the general public of whether things are getting ‘better’ or ‘worse’, or remain

- 136 - SAM-J078-R1 unchanged. The precise form of dissemination of results should be identified in consultation with the relevant public groups.

Such publication and dissemination of general results would need to be supported by less widespread publication and dissemination of more detailed results, and of the monitoring strategy itself, including justification of the methodologies used. The development of such a strategy is a subject for stakeholder dialogue; here the point is that the reasoning behind the selection of a particular strategy, as well as the details of how that strategy is conducted, needs to be clear.

10.3.2 Independent verification

A strong finding of studies of the public in relation environmental risk management is the concern with quis custodiet ipsos custodes? For monitoring strategies, this translates into the need for independent verification of monitoring strategy, practice and results.

The current organisation of this, through regulatory oversight of strategy and practice, and verification of results by analysis conducted by other bodies, is neither well understood nor entirely accepted. The problem is that of independence: bodies concerned with nuclear activities, and having the relevant expertise and resources to conduct monitoring and analysis, are generally seen to be within the ‘magic circle’ of the nuclear industry, and thus their independence is called into question by their (inevitably) close relationship with those they are supposedly policing.

One potential solution to this is to utilise some form of independent oversight panel, which includes representation from arenas which are less closely implicated, and are generally seen to be more independent. The primary stakeholder groups that fall into this category are academic experts, and representatives of environmental groups (including expert consultants generally employed by these groups). There are currently few if any groups identified by the public as independent with the technical competence to conduct such verification, and the construction of such a body would need to be carefully considered in relation to public confidence.

It is essential that the body responsible for overall verification of the monitoring has the confidence of the public: if this is not the case monitoring strategies will not be publicly acceptable.

10.3.3 Comprehensive monitoring

A third dimension established by recent studies is the requirement for comprehensive monitoring. What this means in practice will need to be defined through dialogue and consultation. However, it is reasonable to predict that requirements will be for everything that can be monitored to be monitored, and that will include both direct monitoring of the wastes, and monitoring of the potential pathways of exposure for both humans and environment. There is also a public recognition, born of experience of unforeseen events (particularly examples of unpredicted contamination pathways which have later come to light), that monitoring needs to extend beyond predicted pathways and current knowledge to attempt to encompass a wider picture, so that unpredicted occurrences are identified.

SAM-J078-R1 - 137 - This can be interpreted as the need for a precautionary approach. That is, rather than a solely responsive monitoring strategy, monitoring that attempts to also be proactive in anticipating possible consequences is more likely to be acceptable. This can also be construed as monitoring for worst case possibilities and beyond, rather than monitoring for expected consequences. Extensive monitoring can be seen as an unnecessary use of resources better allocated elsewhere: the public response to this is that if resources are needed, then they must be found, most people being able to think of areas of public expenditure which they would happily see cut to fund other priorities. That said, it is probable that inclusion in the process of setting monitoring priorities will engender greater public confidence in the monitoring strategy, and define the appropriate level of resourcing.

As well as monitoring physical parameters, current social preferences are for extensive monitoring of the management and operation of facilities. Alongside this are strong requirements for the monitoring of security arrangements, both with respect to prevention of terrorism and prevention of unauthorised access with a view to protecting the public at large. The need for the confidentiality of some security arrangements is generally recognised, but that does not obviate the need for some form of independent oversight.

10.3.4 Plans to respond to monitoring

There is a public, as well as technical, awareness that monitoring alone is insufficient; monitoring needs to be tied to plans for responses should monitoring indicate a necessity to respond.

The requirement is not for plans to deal with every possible – and every unforeseen – eventuality. People generally recognise that it is not possible to predict every potential consequence, and whilst this inability may be used as a justification for not embarking on a course of action, in the case of already existing radioactive wastes, where action is accepted as necessary, provision for responding to unanticipated eventualities is not unrealistic. Rather, the requirement for plans for responses emphasises the perception that monitoring anomalies have been overlooked or disregarded in the past – the classic case here is the early indications of stratospheric ozone depletion, which were discounted as false results. Thus, the requirement for responses might more accurately be interpreted as the requirement that there is no over-riding assumption that all will go as planned, but that any anomalous results are thoroughly investigated, and thus that problems are identified. That problems are then dealt with goes without saying.

10.3.5 Satisfy worst critics

The public at large recognise that they do not possess the specialised expertise needed for detailed assessments of technically complex activities. They therefore require, at best, that disinterested expertise should conduct such assessments. When pushed to identify such experts, discussions generally rapidly recognise that there are few if any contenders. In the absence of disinterested expertise, the ‘next best’ is for different interests to be represented in making assessments and judgements. Within this ‘balancing of interests’, the worst critics are often cited as crucial players, on the understanding that if the worst critics can be satisfied, then the outcome is likely to be as robust as is possible. As the worst critics in the field of radioactive waste management are generally associated with environmental groups,

- 138 - SAM-J078-R1 this again indicates the need for the inclusion and engagement of such groups in assessing monitoring strategies.

10.3.6 Safety not cost

A fundamental premise of public judgement of the acceptability of activities such as these is that safety must not be compromised by cost. Budgets are not, in the public view, a legitimate constraint on what can be done. Rather, the best possible means should be implemented, and the price paid. The perception that economies are being made equates to the perception that safety is being compromised.

10.4 Monitoring the public acceptability of the monitoring strategy and the repository development

10.4.1 Purposes of monitoring acceptability

There are a number of available methods for monitoring the public acceptability of the monitoring strategy and of the repository overall. These are drawn from social scientific research methods and from innovative and traditional forms of consultation.

It is important to distinguish between social research (social intelligence gathering) and consultation. The essential difference is that consultation implies a responsibility to respond to the issues raised, whilst social intelligence gathering does not necessarily enter into this sort of ‘contract’ with the participants. A important further consideration is that some consultation methods provide the means for deliberative engagement, and thus for developing positions, understandings, and opinions, rather than presuming these are fixed or static.

In terms of monitoring public acceptability, this distinction has a number of implications. The appropriate method for monitoring can only be selected once the aim of monitoring has been more clearly established.

Monitoring public acceptability can be undertaken for different reasons: a) to provide an answer to the question of whether the strategy and practices, and results, will be/are acceptable or not; b) to provide insight in why the strategy is acceptable or unacceptable ; c) to engage stakeholders (including the public) in dialogue about the acceptability of the strategy; d) to engage stakeholders in consultation over the acceptability of the strategy (the distinction between dialogue and consultation is used here to indicate a difference in commitment on the part of the sponsoring organisation: dialogue can remain a form of information gathering, whilst consultation implies that views will be taken into account. Both dialogue and consultation, however, have the potential to be deliberative. It is also

SAM-J078-R1 - 139 - possible to involve stakeholders in actual decision making, although this is beyond the remit of this document).

Obviously, it is necessary to decide the reason for which monitoring is being undertaken prior to selecting particular methods.

10.4.2 Methods for monitoring public acceptability

The methods discussed here are applicable both to the monitoring strategy, and to the wider repository programme. An overview of the techniques commonly used in social scientific research, and in consultation and dialogue, and their potential application, is presented below.

Quantitative Surveys (e.g. questionnaires)

At a basic level, a simple survey could be undertaken with a large number of respondents. This is of questionable validity in the current context, where the majority of the population have no idea what forms of radioactive waste management are being considered, let alone the more detailed issues of monitoring strategies. However, should radioactive waste management have a higher profile, with an associated wider public knowledge base, surveys can become legitimate. This may particularly be the case in the locality of the repository.

More detailed surveys, generally derived from detailed qualitative work, can be undertaken around more specific questions. For example, should (as is the case) qualitative studies indicate that trust and confidence is a key issue, and that a number of key institutions appear to be more or less trusted, this can be tested out in quantitative surveys to ascertain how widespread and generalisable such findings are, whether different social groups tend to trust particular institutions more or less, etc. The survey question ‘which of these institutions do you trust most or least, on a scale of 1-5’ is valid; the preceding question of ‘what are the important factors’ is unlikely to produce the response of ‘trust in institutions’ under the usual conditions of questionnaire delivery.

The advantages of these sorts of surveys are that they are relatively cheap, and can therefore be used to elicit a large number of responses, giving the possibility of statistical analysis of the results, and of relatively widespread coverage. The disadvantage is that they are suitable only for those sorts of questions where people are likely to have pre-existing views and opinions that can be articulated either quantitatively, or briefly (and where open ended questions are used, the coding of responses will necessarily bias the interpretation of those responses).

Surveys should therefore only be used where the questions are suitable for the method, and where large numbers of responses are required.

Interviews

Several forms of interviews are commonly used in social science. These range from: – highly structured interviews doing little more than delivering a preset questionnaire, and giving little room for the respondent to raise issues outside the framework of that questionnaire, to

- 140 - SAM-J078-R1 – semi-structured interviews, where the interviewer leads the respondent to discuss particular themes and issues, with a reasonable degree of flexibility, to – unstructured interviews, where the interviewer follows the respondent in encouraging them to discuss an issue in whatever terms the respondent wishes to use.

Interviews can take place face to face, by telephone, or through other media. Group interviews are also possible; these are discussed below under ‘Focus Groups’. Respondents are generally selected to represent particular social groups, or because of their particular social location. Interviews can be used to collect both qualitative and quantitative data, as well as to gather information and opinions.

The advantages of interviews, especially semi-structured interviews, is that they provide the opportunity to explore a subject in depth. A skilled interviewer can enable a respondent to consider and reflect on, as well as to articulate, their views and positions. However, interviews are time intensive and require skilled staff, and are thus expensive. The data gathered can often be more efficiently collected in a focus group. Nonetheless, where issues are likely to be sensitive, and people unlikely to be comfortable talking in a group context, interviews have their uses. Where individual, rather than interactive, views are sought, interviews may also be appropriate. In a highly contested, site specific investigation, for example, where communities may become fractured and people unwilling to ‘speak their mind’, individual interviews may overcome the reluctance and disempowerment of some people.

Focus Groups

Focus groups can take a number of different forms. They can be used as a group interview, when the comments above apply. However, they can also take the form of focussed discussion, taking advantage of the number of participants and their relatively equal status within the context of the group to generate debate and deliberation.

Focus groups are usually made up of around 8 people (generally considered the maximum for effective discussion) with a facilitator to guide the discussion. Usually, each group will be recruited to have demographic characteristics in common as this enables more successful group dynamics. Several groups are generally necessary on any one topic, in order to cover the range of views.

Although focus groups can be used to collect information and views, their real strength is in providing a space in which deliberative consideration of the topic can take place. That is, within the context of a focus group, participants can discuss the issue, try out different viewpoints, and reach a position. Focus groups, or discussion groups, are thus a useful and relatively cost efficient means of progressive consultation.

Ethnography

The study of culture has traditionally been carried out through ethnographic studies, whereby the researcher(s) live within a community and thus ascertain the practices, meanings, and structures through which it operates. Such studies have not commonly been undertaken

SAM-J078-R1 - 141 - within the rubric of consultation practices, although some ethnographic work was conducted in relation to the proposals for shallow burial of radioactive wastes in the 1980s. However, ethnography does offer some potential in relation to ‘community mapping’, and could provide a useful tool as a precursor to structured consultation through identification of features of particular communities relevant to the design of consultation.

Consultation techniques

A wide range of techniques have been developed over the past decade, and used in a number of different contexts, particularly local government and health provision. As noted above, consultation goes beyond social research in that it does more than ‘find out what people think/value/are concerned about’ to imply a contract to respond to those issues raised in consultation.

Most new techniques are premised on a notion of deliberative consultation. Deliberative techniques assume that people’s opinions and positions are not fixed, but open to change and developed through reasoned discussion. Some dialogic techniques also identify dialogue as a means to the generation of new meanings and understanding, and thus to the possibility of agreement.

The new practices include, amongst others: - focus groups used as discussion groups (see above), - citizens’ panels, - citizens’ juries and conferences.

Proactive and passive recruitment

Proactive recruitment means the active selection and recruitment of participants. Passive recruitment involves voluntary participation, the opportunity for consultation having been provided. The rationale for passive recruitment in consultation is that if people are not motivated to participate, they do not have strong views; this argument can be rejected on the grounds that many people do not feel able to participate in passive techniques, and that many people have latent views which are not articulated in passive contexts, but which become apparent when ‘push comes to shove’, e.g. people who do not respond to a consultation paper, but appear at a demonstration later in the process, or worse, do not articulate their views at all as they feel disempowered. Traditional consultation techniques tend to be passive.

Many techniques can be used actively or passively: for example, people can volunteer for interview, or be actively recruited.

Active recruitment involves defining the relevant groups for participation, and utilising appropriate means to enable their participation. For many, ‘appropriate means’ implies a general set of considerations such as physical and intellectual accessibility, appropriate information, contexts in which they feel able to speak and are motivated to so do, etc. There are also more specialised requirements, such as the physical accessibility requirements of those with mobility disabilities, the language needs of some ethnic groups, etc. As well as

- 142 - SAM-J078-R1 these ‘special needs’, many people exclude themselves from participation due to feeling disempowered, insufficiently informed, under pressure from others, or for other reasons. Active recruitment can overcome many of these difficulties, but the ‘invisible’ in society (notably the disabled and the illiterate) are invisible for good reasons, and can be hard to identify. If inclusion is a principle to be upheld, involvement of some groups is likely to be more challenging and need firstly the identification of excluded/invisible groups, and then the development of means to enable their inclusion.

Monitoring public acceptability over time

Under conditions of continuous social change, the acceptability of a repository is unlikely to remain static. It is therefore necessary to continue to monitor acceptability over time.

Two considerations are discussed here. Firstly, repeated use of the same methodology provides comparability of results. If longitudinal data are required, this must be built into the planned methodologies. However, this conflicts, to some extent with the second consideration: that the means of monitoring be appropriate both to the social conditions pertaining at the time, and to the different phases of the repository development. Changing social conditions may of themselves compromise the ‘repeatability’ of some methods. The selection of methods needs to balance these different considerations.

During longer phases of the repository, particularly that of monitored underground storage when there is anticipated to be little activity for what could be a long period, more superficial and more frequent monitoring of public acceptability (in the mode of social intelligence gathering) can be supplemented by less frequent, in depth, periodic review (in the form of consultative deliberation). This should be sufficient to be able to monitor and respond to changes in requirements for public acceptability, including changes in acceptability of the consultation and dialogue programme itself.

Independent monitors

In line with the widespread public requirement for technical monitoring to be undertaken by, or at the very least verified by, independent bodies, monitoring of social aspects, and conducting consultation, is also best conducted by independent bodies if the results are to be widely credible.

10.5 Opportunities and needs for dialogue

There are myriad opportunities to engage in dialogue with a host of stakeholders, including the public, during the process of developing and implementing a deep waste repository. Moreover, there are, at least in the current context, serious requirements for such dialogue to enable a repository to be sited and built. A genuine spirit of openness and a willingness to incorporate stakeholder concerns, even where these contradict existing institutional commitments, is a necessary precondition of successful implementation.

SAM-J078-R1 - 143 - Amongst this abundance, there are identifiable and specific needs for particular forms of dialogue in relation to particular issues and particular phases of a repository. These are outlined below.

10.5.1 Public acceptability of technical dimensions

Eight areas in which monitoring is required to demonstrate that various objectives have been met have been identified in Table 2.2. In Table 10.1, below, each area is considered in relation to specific aspects of the issues that are likely to be of current concern, and in relation to specific requirements for the monitoring of social acceptability that are required.

Table 10.1: Social acceptability issues and requirements within the monitoring areas identified in Table 2.1.

Area Specific issues Specific requirements Waste management The ways in which decisions are Widespread, open, accessible and and repository made, the inclusivity and responsive consultation. Sufficient strategic decisions independence of those decisions, time must be given to enable broadly and the content of decisions, are all acceptable decisions to be reached. highly likely to be closely observed and potentially contested. Repository design Siting is the single most contentious Siting criteria need to be widely and construction issue. Local populations are, debated and broadly agreed prior to the understandably, likely to be highly selection of potential sites. Early concerned about the potential for consultation with potential sites is hosting a repository. The criteria essential, as is their ongoing close for site selection, in relation to the involvement with the development of suitability of the repository design, the repository. are of central importance. Repository design is likely to be a The repository design will be tested more specialised concern, requiring against the principles of extensive stakeholder consultation. containment and retrievability, and in relation to intergenerational equity. Long-term safety Uncertainties in predictions of Uncertainties should be clearly case long-term safety are likely to acknowledged in the presentation of provide the basis of criticism. the LTS case. Extensive and inclusive stakeholder involvement in reviewing the LTS case would aid credibility (presuming their comments and criticisms are taken into account). Operational safety Confidence in the management of Proactive openness, particularly with case the repository will be essential. the local community but also with other interested groups, will assist in confidence (presuming the management of the repository is of an acceptably high standard)

- 144 - SAM-J078-R1 Reversibility and The ability to remove the wastes Special interest groups and retrievability from the repository is currently a environmental groups, as well as the primary concern. Assessment of general public, will need to be closely the ability to remove the wastes is involved in setting the criteria for what likely to include assessment of the constitutes retrievability, and in provisions for alternative storage, assessing whether the design meets should this become necessary. these criteria.

SAM-J078-R1 - 145 - Area Specific issues Specific requirements Environmental Non-radiological planning concerns Local populations, including local assessment are likely to be highly significant stakeholders, should be closely locally, as are impacts on involved with Environmental Impact employment, tourism, ‘local’ food Assessment, and with generating and production etc. assessing alternatives and means of ameliorating negative effects. Other social risks include community fragmentation and stress. Policy, legal and Particular stakeholders have Early consultation and dialogue with regulatory specific responsibilities in this wider stakeholder groups, and the framework arena. public, with appropriate responses, will provide the best chance of legal and If the repository is contested, regulatory success for the considerable delays and potential implementation of the repository. rejection of all or some of the Specific and responsive consultation repository design is possible. with stakeholders in particular arenas, e.g. local planning, will be necessary. Public acceptability Public acceptability and related The maintenance of public and wider confidence in the repository, and in acceptability will need both proactive confidence issues the monitoring of the repository, attention, in the form of ongoing are largely a product of the dialogue with the local community and successful implementation of the other stakeholders, and will itself need other 8 areas. monitoring.

10.5.2 Implications of different stages of the repository in relation to public acceptability and monitoring

The table below identifies technical monitoring activities in relation to the different stages of a repository. The table identifies aspects of different stages of the repository in relation to likely issues of concern and consultation and dialogue requirements.

Table 10.2, below, identifies social issues of concern, and consultation and dialogue requirements against different stages of repository development, as identified in Chapter 2.

- 146 - SAM-J078-R1 Table 10.2:Social issues and dialogue and consultation requirements against different stages of repository development.

Stage Issues Dialogue and consultation requirements Before site selection option selection widespread consultation, including front end consultation, leading to site selection identification and application of criteria maintenance of options vis a vis for option and site selection. packaging Site characterisation scientific credibility, and need for inclusive and extensive peer integrity and completeness of preview and review of knowledge base, knowledge base including public judgement on it adequacy local liaison and consultation in methods of site characterisation, especially with respect to local disruption local liaison and inclusion in findings of site characterisation Underground access as above as above, and and exploration (RCF) provision for visitor access to RCF Repository design as above re design inclusive and extensive peer preview and construction and review of design construction will require to be visibly compliant with all Local citizens’ and nominated specifications, and to minimise independent experts to be involved in and ameliorate local disruption inspection of construction all incidents and accidents will local consultation on minimisation of require full public reporting disruption and amelioration Waste receipt and credibility of processes of independent monitoring of validation emplacement validation for waste procedures emplacement will require independent (citizens) monitoring of monitoring for correct application emplacement of procedures public dialogue on responses to all incidents and accidents will incidents and accidents require full public reporting Monitored ongoing comprehensive ongoing consultation and dialogue underground storage monitoring Post vault backfill as above as above (underground access) Post closure as above as above

SAM-J078-R1 - 147 - (institutional control)

10.6 Different audiences and different requirements

Thus far we have been primarily considering the ‘general public’s’ requirements for monitoring. The general public is not, of course, an homogeneous group, and there are also other ‘stakeholder’ groups with particular requirements. This section considers these different groups and presents more specific suggestions for the methods through which they can be consulted, and the acceptability of the monitoring strategy be ascertained.

10.6.1 The Public

Taking the general public first, this broad group of people can be characterised and categorised in a number of ways, including the following:

 Demographically: age, gender, ethnicity, social class, educational attainment, employment etc.

 Geographic location: proximity to repository or otherwise. Proximity cannot be defined spatially as an absolute measure – different communities tend to define different sized areas as ‘local’. Residents of Oban and Fort William, for example, saw the whole of the west coast of Scotland, the Highlands and Islands as ‘local’ whilst residents of Lancaster do not, on the whole, see Heysham as ‘local’ due to the cultural boundaries between Lancaster and Morecambe & Heysham.

 Social group: these can be defined in many different ways, for example, by family/household membership, by activity (e.g. gardeners, sportspeople), by political or religious affiliation, disabled etc. Current social scientific thinking is that people have a number of different identities (one person can be a parent, a professional scientist, a musician, a member of the Labour Party, partially sighted, black, Catholic, etc) and that they take up different roles (rather than having one fixed identity) according to the context. Thus, one might expect that if a person is interviewed, for example, at work, they will respond differently to if they are interviewed at home. The way in which the interview context itself is set up is also relevant to the identity roles which are manifested. Thus, membership of different social groups is relevant to the appropriateness of different research, consultation and dialogic techniques.

 Particular commitments: there are clearly some people who are committed to particular views, or express particular concerns. These can be defined as a particular social group, or as a particular stakeholder group. In either case, these people are likely to be particularly critical if they are not provided with an opportunity to voice their opinions.

 Particular interests: the term ‘interests’ is used here in the sense of benefits, rather than fascination. Particular interest groups include those who would benefit or suffer financially, or have amenity losses due to particular monitoring strategies or repository

- 148 - SAM-J078-R1 designs. Particular interests are generally considered as influencing the views held by particular people and groups, and may well form lines of division within communities.

In terms of monitoring acceptability and engaging in dialogue, different groups patently have different generalised needs (although it should not be overlooked that individuals within a group may have very different needs to the group more generally, e.g. the disabled young person).

There are some general principles regarding accessibility, which include assessment of the different information needs of different groups. In terms of the requirements of different groups with respect to a monitoring strategy, these include - requirements for participation in dialogue, consultation, research, - requirements for information provision and formulation, and - requirements for different forms of monitoring.

As suggested above, inclusion is an important criterion and this has particular application in two dimensions: 1) that views are elicited from the public at large: this requires that proactive recruitment is used across different groups and different classifications of groups 2) that those who wish to participate are able to do so: this allows for passive recruitment, but has particular implications for a) publicising the means of participation and b) ensuring that the means of participation is not exclusionary.

The Local Public

The most obviously important distinction amongst the public at large is between those who define themselves as living near to a site, and those who consider the site not to be ‘local’. Local communities will have more intensive and specific requirements, both of the monitoring programme and of their participation in it. Local populations also provide very different possibilities and opportunities for different strategies.

Obviously, the local population cannot be identified prior to the identification of sites. Community mapping would then need to be undertaken to establish the particular social features of the local community, including aspects such as the dependence on the nuclear industry for employment and the availability of other employment opportunities, demographic characteristics, educational attainment in different sections of the community, the pre-commitments of particular groups, and divisions and coherence within the community.

The possibilities for engagement include the following.

 A local citizens ‘liaison group’. Such a group, run by local people rather than the implementer/operator, would provide an ‘early warning system’ of local concerns, and a mechanism for these to be discussed with the operator and others, and hopefully resolved. The operator would have to undertake funding for the group, as well as the

SAM-J078-R1 - 149 - provision of information as required. A citizens liaison group is very valuable as a means of ongoing monitoring of public acceptability.

 Public Meetings. Although the traditional public meeting has many drawbacks, there is a widespread expectation that open access meetings, with representation from implementers/proposers, will be held. However, the public meeting can be reformulated to provide a less confrontational setting whilst still meeting the requirement for open access and free speech. Experiments are currently taking place into alternative forms of public meeting for example as reported in the RISCOM project.

 Outreach Projects. To become an accepted part of a community, it is generally thought to be good practice for an implementor to engage in some form of ‘outreach’, e.g. visiting local groups, schools, and businesses, and making the facility available for visits on request.

 Surgeries. The Environment Agency believe the ‘surgeries’ they held as part of the Magnox consultations were more useful than the public meetings. These surgeries comprised EA staff making themselves available at designated times and locations for members of the public to discuss the issues. Surgeries also offer the possibility for confidential exchanges, which may be important if communities are divided.

 Liaison with local authorities and elected representatives. The established means of democratic representation need to be included in consultation and the assessment of public acceptability.

These possibilities all apply to the facility generally, as well as being applicable to monitoring specifically. With respect to monitoring, it is likely to be an ‘agenda item’ in most if not all of the above processes, and can be addressed as the content of any of these. In addition, a regular public meeting to present monitoring results offers the opportunity for specific feedback.

To assess the ongoing acceptability of the monitoring strategy specifically requires particular additional mechanisms. These could include:

 Citizens’ Panels. A repeated citizens’ panel, at different stages of the repository, would enable a group of local people to assess the monitoring strategy in detail. However, used at the local level, where many individuals are likely to have some interest in the repository, it is likely that the membership of the panel would need to itself be commonly agreed.

 Discussion Groups. Voluntary and actively recruited discussion groups would enable more detailed consideration of monitoring and its acceptability.

It is worth reiterating that none of these activities are worthwhile unless a clear and visible response to any issues raised is provided.

- 150 - SAM-J078-R1 10.6.2 Organised stakeholder groups

The term ‘organised stakeholders’ is used here to denote any form of organised group with an interest (in either sense) in the monitoring of the repository.

Organised stakeholders include: – environmental groups, – other special interest groups, – regulators, – policy makers, – politicians (local, regional, national), – financiers, – workers and Trades Unions, – local community groups, – scientific and technical peers, – nuclear industry groups, including contractors.

Again, different groups may well have different notions of what constitutes an acceptable monitoring strategy. Scientific peers, for example, may be interested in what monitoring results will enable in terms of adding to knowledge, whilst regulators will have relatively well-bounded requirements for authorisation. Workers and unions are likely to be concerned with monitoring associated with worker exposure, whilst local community groups are likely to be more concerned with possible contamination outside the facility. Nuclear contractors, by contrast, will be interested in the implications for their operations of monitoring requirements, and in the provision of monitoring services.

Dialogue with organised stakeholders is therefore an attempt to negotiate between different, and possibly conflicting, preferences.

One aspect of stakeholder dialogue is information gathering: to identify the preferences, constraints, and concerns of different stakeholder groups. This can best be conducted in small group discussions between implementers, facilitators, and members of the same stakeholder group.

The second aspect is to attempt to reach agreement between stakeholders, through the process of structured dialogue. There are different models of how such dialogue can be conducted; none claim to produce complete consensus. However, it is generally recognised that stakeholder dialogue generates greater agreement than if no dialogue had taken place: participants learn the constraints under which others are operating, and can sometimes find creative solutions.

Disagreement and difference

That there might be substantially different requirements for the monitoring strategies – and for the overall waste management programme – is perfectly possible. Different interest and

SAM-J078-R1 - 151 - commitment groups, particularly, may well have different preferences. To assume that consensus will result from dialogue and consultation is a misapprehension.

The question, then, is how to deal with disagreement and difference. Are some voices to be weighted more strongly then others (e.g. are more strongly held views weighted more heavily than less strongly held views), is an overall preference sufficient (and if so, how large a ‘majority’ is required?), are there particular groups whose views are more significant? These are judgements that need to be made, and made explicitly. Current conditions are such that most people might be expected to comply with the majority view, if they believe all views to have been fairly and fully articulated, and an impartial judgement made, and it is in the validity of the process that the (partial) solution to disagreement can be found. However, it needs to be recognised that disagreement and difference is an integral part of the interplay which makes up contemporary society, and in the current context, full consensus is highly unlikely.

10.7 Monitoring institutional capability and social stability

10.7.1 Institutional capability

The capability of the responsible institutions to manage a waste repository, and to close it if required, is one aspect of the ‘monitoring needs’ identified at the M & R workshops as needing attention [REF quote].

It is possible to identify a number of the institutional attributes that are currently required, and to speculate on those that might be required in the future.

Current attributes include: – access to resources, including finance, or to substitutes, – political influence, – knowledge management, – maintenance of institutional memory , – access to technical competence, – ability to dialogue, – good social intelligence, – decision making structures and authority.

These attributes – which may or may not need to be housed within one institution – are related to a wider range of social abilities described below.

However, presuming a comprehensive list of attributes can be identified, their maintenance is by no means unproblematic. Taking technical competence, for example, MacKenzie argues that tacit skills (those skills which are in some sense embodied, rather than being transferable solely by means of written or verbal instruction, such as being able to ride a bicycle) can be

- 152 - SAM-J078-R1 lost over time, and hence technologies can become lost. How attributes and abilities can be maintained over the long term is something we clearly can only speculate about4.

That does not mean that we should not speculate, and not attempt to develop means of maintaining the ability to manage a repository. The idea of a reflexive institution can be useful here: an institution which understands the (social and other) conditions of its own existence and which is able to respond and change (including reformulating itself into other institutions) as these conditions change. The idea of a reflexive institution also includes the recognition that social and environmental needs may well change over the lifetime of a repository, and thus institutional abilities are likely to need to respond to these.

A reflexive institution (or institutions) therefore needs to have good social intelligence and be well attuned to its social, cultural, political, economic, and environmental context. More than this, it requires to be able to respond to its inevitably changing context, and insofar as is possible, the technologies that it utilises should be capable of flexible responses. Flexibility and adaptability may well be primary attributes of institutions necessary for long term radioactive waste management.

10.7.2 Long lived institutions

Some suggestions have been made that maintaining the capability of responsible institutions requires that these institutions should be long lived. Other long lived institutions, such as the Catholic Church, or the Monarchy, are looked to for clues as to how such longevity can be achieved.

An alternative perspective is that it is not necessary for an institution to have a long life. Rather, it is the attributes necessary for maintaining and closing the repository that need to survive. Institutions themselves are more likely to need to be able to adapt and change to social conditions, with different alignments and locations of particular attributes able to emerge at different times. The recent history of UK Government Departments demonstrates this: the coverage and emphasis – generated by a complex of social, cultural, political factors, among others - of agriculture or transport, for example, has resulted in different institutional formulations in an attempt to meet ever changing needs, including those that are inherently unpredictable.

Thus, it is not that an institution needs to be able to survive of itself, but that a series of attributes and abilities need to survive, which may be embodied in a variety of institutional formulations. An initial identification of some of these attributes is made above.

10.7.3 Monitoring social stability

One argument put forward for disposal, rather than indefinite storage, of radioactive wastes, is that society may become in some sense unstable, and/or may lose the ability to be able to

4 The NII have recently stated, in their review of BE’s Strategy for Decommissioning (June 2001, pp 26- 27), that ‘NII believes that BE needs to start to address how to deal with such issues as: what records need to be kept; what minimum level of documentation is required during safestore; how to compile accurate historic records; archiving and retrieving records from archives;…and the impact of future technology’ and obviously record and information management need to be addressed. This does not, however, encompass the additional issue of how tacit, experiential skills can be maintained.

SAM-J078-R1 - 153 - manage the storage of the wastes, or to close the repository. The corollary of this is that society should be monitored for some level of social stability, and if society becomes sufficiently unstable, the repository should be closed.

In a less dramatic form, this argument also implies that there are potential implications of social instability for other stages of the repository, for example post closure monitoring.

However, there is a fundamental misconception in the idea that measurable social indicators of social stability are needed. This misconception is that what counts as social stability will itself change over time, and is by no means commonly agreed across different groups within any society.

More significantly, what counts as a sufficient ‘threat’ to warrant closure of a repository will itself be a decision which will be contested, or not, dependent on a host of other contingent factors relevant at that time.

To exemplify: if such a set of indicators were derived for the present, one might look to items such as the level and type of terrorist activity, the reliability of market structures to provide required resources, the education sector production of appropriately skilled workforce, political stability and commitment to maintenance of an appropriately resourced and enabled repository, global military security, the threat of invasion and by whom, robustness of relevant industrial sectors, and the pliability of the general population.

These are reasonable things to monitor; indeed, it would be foolish not to be taking all these and more into account in the ongoing management of a repository. However, if any, or all, were put forward as reasons for closure of the repository, at the present time, this would be strongly contested. Counter arguments would be produced – the store should have better security arrangements, materials should be stockpiled, a workforce trained. The point is that what counts as a sufficient level of social instability to warrant closure is itself the product of social interaction, negotiation and dialogue. Thus, it can be dealt with under the consideration of those factors, below.

Social stability is therefore not an absolute concept, amenable to measurement is some objective fashion, but of is itself socially constructed. Any definition of social stability, particularly in relation to the need for action, is likely to be contested.

Considerations of intergenerational equity can also lead to the argument that it is inappropriate to define for the future what requirements for monitoring social stability might be. If one inteprets intergenerational equity as enabling future generations to make choices, then that also gives them a responsibility for defining themselves the conditions under which a repository should be closed.

The ‘fail-safe’ position, insofar as there is one, is that a repository should maintain on its own site the means of closure, in terms of the physical resources required. This obviates dependence on an external supply of resources – commonly one of the first things to be disrupted in times of social upheaval. If this is coupled to the skills needed, and some form of revisable emergency decision making apparatus, then there is the potential, at least, to close the repository under emergency conditions. Whether such an act might later be judged

- 154 - SAM-J078-R1 to be acceptable is another question, as are the issues of the location of decision making authority bypassing normal procedures, and the conditions under which such authority can be used.

10.7.4 Indicators of social stability

Potential indicators of social stability include: – level and type of terrorist activity, – resource production and distribution, – training of skilled workforce, – global and national military security (especially in relation to the potential of a repository as either a target for destruction or a source of radioactive materials), – threat of invasion, physically, politically and economically, – robustness of relevant industrial sectors, – public acceptability, resistance, trust and alienation.

In relation to the general public, a number of indicators have been used as measures of social stability, for example: – levels of employment/unemployment and labour unrest, – levels of divorce and single parenting, – levels of criminality, – welfare provision, – levels of participation, – extent of racial, ethnic, gender divisions, – youth unrest.

Other potential indicators exist, which may have more or less relevance to notions of social stability.

However, little thought is required to see that it is not possible to simply translate indicators of social stability into provisions for radioactive waste management. As argued above, the relationships between social stability, however measured and monitored, and radioactive waste management, are themselves the legitimate subject of dialogue and deliberation. A selection of indicators could and have been argued to indicate some level of social stability, but the relationship of these with decisions such as that to close a repository is unclear. Particularly if one considers the transition from social ‘stability’ to social ‘instability’ 5, it becomes difficult to see just how a decision to close a repository on these grounds might be made.

5 Descriptions of unstable societies can be found, for example, in the novels of William Gibson, or in Doris Lessing’s ‘Mara and Dann’, as well as other dystopian novels. Even in the conditions described in these, however, there might well be disagreement about whether they constituted a degree of social instability necessary to close a respository.

SAM-J078-R1 - 155 - 10.7.5 Social Capacity

Rather than examining social stability, perhaps we should instead examine social capacity. As with the discussion of institutional capacity, above, it is the ability to continue to manage, and if required, to close, a repository which is significant. The emphasis is shifted, however, from considering what indicators might be required to suggest closure of a repository, to what capacities might be required to keep it open.

Monitoring the social capacity to manage and close a repository requires a detailed identification of the plans for a repository, and the associated requirements, although some general comments can be made here. Social capacity is obviously closely related to, and forms the wider context for, institutional capability. Thus, components of social capacity which might well be relevant include: – educational provision, training, and maintenance of an appropriately skilled labour pool, – resources and transport, – maintenance of a decision making structure, – development of maintenance of appropriate dialogic and consultative structures, – broader organisational capacities, including economic organisation, – maintenance of security, – maintenance of scientific and technical knowledge.

If management and closure of a repository is seen as requiring a combination of knowledge, organisation, and material resources, then identification of the detailed requirements under these headings should provide a ‘check-list’ of the social capacities required.

Comparison of options for radioactive waste management, and the development of plans for implementing options, need to consider the plausibility of mechanisms for maintaining institutional capabilities and social capacities in relation to extended periods of repository operation, closure, and post-closure monitoring. Determining the plausibility of such mechanisms and the means of monitoring their ongoing competence will itself require consultation and dialogue.

10.8 The social aspects of monitoring - conclusions

Part of the value of monitoring public acceptability, and engaging in dialogue and consultation more generally, is in the insight it provides to implementers into the concerns, values and positions – latent, deliberated and fixed – of the public and other stakeholders. This insight, in principle, then provides the wherewithal to adjust and amend plans and practices to increase their public acceptability, in response to the issues that arise.

This ability to respond implies an openness and a willingness to have core values and agendas fixed by external agents – be they the public or other stakeholders – on the part of

- 156 - SAM-J078-R1 implementers. It implies, also, that implementers are operating in a context where they can respond, and are not constrained by the requirements of specific stakeholders, such as government or regulators. In turn, then, this suggests that the stakeholders who have traditionally held the remit of determining core values and agendas are themselves open to being influenced by other stakeholders.

Public acceptability itself is dependent on the public perception that their concerns are being taken into account. This, too, pushes the analysis of the social aspects of monitoring to the conclusion that institutional responsiveness is a fundamental requirement for successful implementation in contested arenas. Looked at from a different angle, it should also be recognised that engagement with the public and other stakeholders of itself contributes to the public acceptability of the overall strategy.

Consultation and associated responsiveness, though a necessary condition, is not alone sufficient for a broadly acceptable management and monitoring strategy. It should not be overlooked that there are other social conditions which influence, or are likely to influence, the overall acceptability of a repository. What these conditions are is likely to change over time, and can be identified – at least at present – through the methods described. There are strong indications that a current condition is the cessation of production of waste in order to generate the sense of shared social responsibility which itself is a precondition of implementable radioactive waste management. Similarly, the existence an independent, disinterested body overseeing development and implementation is a current precondition, as is the need for public consultation and participation. Such conditions are clearly visible in recent studies, and the failure to respond to them is likely to severely compromise the possibility of progress towards implementation in the near future.

Monitoring – and consulting – on the public acceptability of the monitoring strategy will need to take place as part of a wider consultation strategy on the development and implementation of any repository. A detailed consultation strategy, however, cannot be fully planned in the absence of proposals. There is, however, more than can be done in relation to a generic proposal in terms of identifying the ‘front end’ concerns of the public and other stakeholders which need to contribute to ‘what’ ‘why’ ‘when’ and ‘whom’ of a monitoring strategy, including focussed expert stakeholder dialogue, and wider public consultation focussed on monitoring. The first principle of enhancing the public acceptability of monitoring strategies is to engage the public in the earliest stages of development of that strategy, as well as in later stages, in order that their concerns and priorities can be identified and taken into account.

SAM-J078-R1 - 157 - 11 CONCLUSIONS

An important aspect of the phased disposal concept is that monitoring would be carried out at all stages of the repository development in order to provide assurance of the current and future safety, and to provide input to the technical and societal decision-making related to the repository development. The aim of the present study is to identify monitoring options taking a broad view of the possible information requirements. This is the first step in the development of an overall strategy for monitoring within a phased disposal concept.

The report outlines a methodology for the identification of monitoring options and discusses monitoring under several broad objectives associated with the phased development of a geological repository. Further work is required to develop a fuller understanding of the possible monitoring requirements with respect to different objectives. In addition, there are different levels of experience in the relevant monitoring techniques. The work provides a basis that should be of value in future work by Nirex, for example to support Nirex participation in the now ongoing European Commission thematic network study on “The role of monitoring in a phased approach to geological disposal”. Account will also be taken of results from the recent Nirex Workshop on the monitoring and retrievability of radioactive waste (UK CEED 2002).

This study has identified information requirements and possible monitoring options in relation to eight overall objectives, based on the questions: – why is monitoring required? – what monitoring is required? and – how can that monitoring be carried out?

In order to develop a comprehensive strategy for monitoring, work is needed to define more specific objectives of an integrated monitoring programme at each stage of a repository development programme, i.e. addressing the question when is the monitoring needed? Some preliminary comments on this topic are provided in Section 2.3 of this report.

Reference UK CEED 2002. Workshop on the monitoring and retrievability of radioactive waste. Manchester, February 2002, UK Centre for Economic and Environmental Development report.

- 158 - SAM-J078-R1 Acknowledgement

This report is based on a programme of work that was carried out by

 NNC Ltd. (NNC), Knutsford,

 National Cooperative for the Disposal of Radioactive Waste (Nagra), Switzerland,

 Centre for the Study of Environmental Change (CSEC), Lancaster University, and co-ordinated by

 Safety Assessment Management Ltd. (SAM), Reading.

The following staff contributed to the work and should be considered as authors.

Chapters 1, 2, 3, 9 and 11 T.J.Sumerling and T.J.McEwen (SAM)

Chapters 4 and 5 P.Blümling, M.Hugi, and P.Zuidema (Nagra)

Chapters 6, 7 and 8 M.Dutton, J.Stansby, K.Christie, R.May, R.Major, S.Poutney, G.Till (NNC)

Chapter 10 J.Hunt (CSEC)

SAM-J078-R1 - 159 - Document Issue Record

Client: United Kingdom Nirex Limited

Client ref.: SC2803 / 009

Project: Monitoring Options

Document: SAM-J078-R1 Options for Monitoring During the Phased Development of a Repository for Radioactive Waste

Responsible author: Mr. T. J. Sumerling

Issue and revisions

Version Date of issue Checked Copies to Comment

1 Dec 2001 TJS B.McKirdy, Nirex For review by Nirex and parallel M.Dutton, NNC final checking by contractors. M.Hugi, Nagra J Hunt, CSEC SAM file 2 May 2002 TJS As above Taking account of comments by Nirex and contractors. 3 June 2002 TJS B.Breen, Nirex Taking account of final and as above comments by Nirex.

This Report has been prepared by Safety Assessment Management Limited for United Kingdom Nirex Limited under the terms of Nirex Contract Instruction SC2803/009.

. . . . Date . . . . . 14 June 2002 ......

T. J. Sumerling Safety Assessment Management Ltd. Beech Tree House, Hardwick Road Whitchurch-on-Thames Reading RG8 7HW United Kingdom Tel: 0118-984-4410 Fax: 0118-984-1440

- 160 - SAM-J078-R1