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7.3.8. Research and development
As noted in Chapter 8, over the past 30 years, huge efforts have been devoted to research and development (R&D) in the area of geological repository development. These have included laboratory studies into waste matrices, container material and buffer properties. There have also been extensive field studies in hydrogeology, geoand hydrochemistry, rock mechanics and tectonic evolution. Has all the necessary R&D been done (see also comments in Chapter 8)?
The proponents of geological disposal believe that sufficient research has been done to allow the implementation of safe repositories – not because everything is known, but because existing knowledge can be complemented by sound engineering and conservative assumptions. The doubters point out the gaps existing, particularly in the accuracy with which one can describe the spatial characteristics of host rocks or the temporal evolution of all safety barriers. Given the enormous times for which the repository behaviour is to be assessed, they believe that there is a justification for taking more time for R&D before beginning implementation.
A compromise that can be easily reached is that R&D continues into and throughout the operational phase, a solution that takes account of the fact that new knowledge might emerge over the coming decades. This compromise does not, however, define the level of investment in continuing R&D, and this will remain a hotly discussed issue for a long time. For example, the USDOE, the implementer of the Yucca Mountain project, in 2003 initiated a long-term R&D programme that will run, at a funding level of some US$20 million a year, in parallel with other repository implementation activities.
7.4. The staging process
It is acknowledged by most national radioactive waste management programmes that some form of staged process is useful, or even necessary, for developing a geological repository. A recent report (NRC, 2003) by the NRC supports this view and develops a refined staged development concept which it terms ‘‘adaptive staging’’2.
Staged development has been defined by the NEA as a process in which ‘‘. . . discrete, easily overviewed steps facilitate the traceability of decisions, allow feedback from the public and/or their representatives, and promote the strengthening of public and political confidence in the safety of a facility along with trust in the competence of the regulators and implementers of disposal projects’’ (NEA, 1995). Staged development for geological repositories (also called ‘‘repository staging’’) has become a topical issue in many national geological disposal programmes. Repository staging has never been defined in operational terms – although there has been extensive discussion of stepwise, or staged, procedures for implementing repositories, there is no precisely defined or generally agreed definition on the operational meaning of the term.
The NRC report focuses on one approach to staging, ‘‘adaptive staging’’, and contrasts it with ‘‘linear staging.’’ Linear staging is a rigid process, characterised by a single, predetermined path to a selected, defined endpoint, where stages are defined principally as milestones at which costs and schedules are reviewed. This path and endpoint are
2 The idea developed from the concept of adaptive management, introduced by Holling (1978).
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re-evaluated only if compelling new evidence requires it, rather than systematically throughout the programme.
Adaptive staging is a flexible process characterised by work stages and decisionpoints. Decision-points mark the transition between stages. Decision-points involve a structured decision-making process. During this process, the implementer evaluates results and decides how to proceed to the next stage. The number and timing of decision-points and stages may change during the development of the programme. Therefore, subsequent stages are predicated upon the outcomes of previous ones. This approach emphasises continued learning throughout programme development.
7.4.1. Attributes of adaptive staging
The overarching attribute of adaptive staging is that it aims to increase repository safety and to reduce repository performance uncertainties through systematic incremental learning. The safety case is at the heart of adaptive staging and drives the identification and choice of options at each stage. The following attributes characterise adaptive staging and underlie the overarching safety attribute:
Commitment to systematic learning: designing stages specifically to increase the body of available knowledge, including scientific, technical, societal, institutional and operational knowledge. Needs and questions to be addressed are made explicit at the outset. Information gained will be accepted and incorporated into the available knowledge base. A central feature of adaptive staging is that it intentionally seeks, is open to, and learns from, stakeholder input and participation in all knowledge areas. To realise the opportunities presented by a commitment to learning, it is also essential that appropriate institutional arrangements are in place.
Flexibility: adapting in response to available technical and non-technical knowledge, conservative interpretation of current knowledge and experience gathered in previous stages. That is, adaptive staging is an iterative process. Flexibility implies that, before moving on to the next stage, a number of options are considered, including the possibility of changing course or reversing to a previous stage. A decision to retreat to a previous stage should be evaluated with the same rigour as a decision to move ahead to a subsequent stage. Because evidence and logic will accumulate as the project moves through stages and makes choices, the likelihood of reversal will probably decrease as the project develops. Similarly, choices between alternatives will likely reduce the number of future choices and the scope of flexibility. Flexibility and reversibility are intrinsic attributes of adaptive staging and are therefore available to the decision process at each stage.
Auditability: Auditability requires complete documentation of this dialogue and of the basis for decisions. The implementer ensures that all documents are readily available to all interested parties and can be easily obtained. To improve auditability, it is also valuable to ensure that the key data are not buried indistinguishably within a surfeit of less relevant information.
Transparency: Transparency implies that the decision-making process is well documented and available to all stakeholders throughout the programme. Policy and technical considerations are clearly differentiated. For instance, a statement of intent and rationale behind each stage and decision-point is developed and tested for
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understandability and then broadly publicised to stakeholders. The attribute of transparency creates the basis for a dialogue between the implementer, regulator, external review bodies and stakeholders.
Integrity: Integrity implies honesty. It means saying what you will do and doing what you say you will do. In the context of geological repositories, integrity implies maintaining focus on safety at all times. It requires objective and complete disclosure of information, whether positive or negative. Uncertainties, assumptions and indeterminates are identified and labelled as such. Technical results are accurately and objectively reported and placed in context at each stage. Data applicability and limitations remain openly acknowledged by all parties. All relevant results, including those offered by external parties, are also incorporated in the decisionmaking process.
Responsiveness: Responsiveness requires the implementer to seek, acknowledge and act upon new information and on input from other stakeholders. Schedules should be planned to allow timely integration of new data into decision-making and includes time to implement changes responding to newly acquired information. Planning and evaluation periods, to integrate lessons learned from prior stages, are integral parts of an adaptively staged programme’s schedule. The NRC calls these evaluation periods ‘‘decision-points’’.
7.4.2. The decision-making process
Adaptive staging relies heavily on the use of the safety case, which is at the heart of the repository programme, to guide the decision-making process. During the decisionmaking process, the programme implementer:
1.systematically gathers, synthesises, evaluates, and applies the information learned up to that point;
2.develops options for the next stage, including explicit consideration of reversing to an earlier stage;
3.generates options, evaluates and updates the safety case;
4.makes the findings publicly available;
5.solicits comments;
6.decides on the next stage based on all of the above; and
7.disseminates the decision and its rationale.
In summary, the key characteristics of adaptive staging are:
A reference staged process is defined at the outset – but it is not assumed that adaptations will occur only if forced by circumstances.
Rather, the stages are deliberately planned with the objective of gaining further knowledge or experience that might lead to amendments of a subsequent stage.
At the decision-points between stages (and at any other major decisions that might arise), a broad and open participation in the decision process is designed into the overall staging.
To the maximum extent possible, the steps are designed to be reversible, in case subsequent experience reveals that the chosen direction does not help progress towards the chosen goals.