7.2.2. Timetables vary widely

Strategies for waste management are invariably phased or staged, due to the long duration of the activities. Nuclear power plants, the main source of wastes, run for decades; other nuclear technologies will continue, even if nuclear power does not; SF may be stored for decades, waste repositories take decades to implement and operate; post-closure safety must be assured for many thousands to millions of years. The timetables are so extended that many programmes define a series of phases or stages, each of which can last many years. A recent development is the proposal for ‘‘adaptively managing’’ such a staged development (NRC, 2003). This implies adopting a flexible process, in which the new knowledge gained at each stage is used to plan the content and duration of following stages – as opposed to attempting to rigorously define all milestones and deadlines at the outset (this is discussed in detail in section 7.4).

Waste management facilities for handling, treating, storing or disposing of SF following its removal from the reactor are also expensive to implement and difficult to site. However, the quantities of SF arising are modest compared to most other radioactive and non-radioactive wastes and experience over 40 years or more has shown that SF can be safely held in interim storage at reactor sites or in centralised facilities. Accordingly, in most countries there is little technical urgency for implementing facilities such as geological repositories.

This is reflected in the long timescales foreseen for such a step in many programmes. Japan and Germany intend to operate a deep repository by 2030; Switzerland only in 2040; the Netherlands, Australia and Slovenia on an indefinite timescale. The countries that plan earliest disposal are the USA (2017), Sweden and Finland (both around 2020). In the first of these, large quantities of SF have already been accumulated; in the others it is the goal of the implementers to demonstrate in practice, and as soon as is feasible, that safe geological repositories can be constructed and operated. A recent trend is that the security arguments mentioned above are being used to justify more rapid progress towards underground emplacement of nuclear materials. The surprisingly fast decision of the Italian government in late 2003 to rapidly develop a repository in a salt mine is an example of the security argument being strongly pushed – although the total lack of consultation led to intense local opposition and equally fast retraction of the decision in this instance.

Recently, the European Commission (EC) of the EU has decided that more pressure to implement waste management strategies should be exerted on its current and future Member States. However, the EC Directive (EU, 2002) that was drafted originally proposed unrealistically short timescales (e.g., 2018 for geological disposal implementation). In later drafts, the deadlines for disposal disappeared; instead it is proposed that Member States will be required by 2006 to submit to the EU national radioactive waste management plans, including their own deadlines for strategic decisions.

7.3. Activities in development of a geological repository

Development of a deep geological repository is a process that lasts for many years until waste emplacement operations can begin, continues for some decades through the

operational phase, and may have a final observation and monitoring phase lasting decades or even hundreds of years. This results in unusual and challenging tasks in planning, implementation and operation of major engineered facilities. The times needed to complete even the early phases involving choice of a disposal concept and repository sites have been massively underestimated in virtually all national repository programmes.

The unexpected delays have been due in part to the complexity of some of the technical tasks involved. For example, characterisation of the deep geological environment around a repository required development of new measurement techniques, new analysis methods and even new ways of thinking about how natural systems behave over long time periods. More often, however, delays have resulted from a failure to sufficiently integrate the technical and the societal issues associated with repository development. One consequence that has been drawn by many national disposal programmes is that a phased or staged approach, allowing one to learn from both technical and societal developments, is more constructive than a purely technocratic project aimed at rigidly defining all steps and deadlines at the outset (see also Chapter 9).

The most comprehensive discussion on staging is contained in the report ‘‘One step at a time’’ produced by the NRC. This report describes an approach called ‘‘adaptive staging’’ (NRC, 2003). The concept is described in some detail in section 7.4, following the description in the next sub-section of the actual stages involved in repository implementation. It has recently been adopted by the Canadian NWMO in its recommmendations to the government.

In the sub-sections, the sequential phases of development are first described. These are concept development, site selection and repository design, licensing, construction, operation, monitoring and sealing. Throughout all these phases, other accompanying activities are required; these include research and development (see also Chapter 8), iterative safety assessments (Chapter 6) and continual interaction with the public and other stakeholders (Chapter 9). Brief comments on each activity mentioned are given below.

7.3.1. Concept development

The selection of a concept or concepts to be followed is a serious step since it can set in motion many years of work for large numbers of persons and can impact directly on the probability of success further down the line. Some countries have divorced the generic question of choosing concepts from further site-specific work. Sweden, Switzerland, Belgium, Japan and Canada are all examples of countries that have completed one or more major integrated projects aimed at providing a decision basis for the choice of a national disposal concept. In Sweden (SKB, 1983), the generic studies led on to specific siting work in crystalline rock. In Switzerland, concept studies have been performed for both crystalline (Nagra, 1985) and sedimentary options (Nagra, 2002), with the latter being chosen thereafter as the first priority option. Belgium has also studied clay concepts, using data obtained from their underground laboratory (ONDRAF/NIRAS, 2001a,b). Japan has not yet chosen a preferred host rock and is retaining concepts for both clay and crystalline rock (JNC, 2000). In Canada, where perhaps the largest of all studies of a concept was carried out (AECL, 1994), the decision taken at government level was that, although disposal could be technically safe, the level of public acceptance of the concept was insufficient to allow the proponents to progress to a siting stage.

7.3.2. Siting

Due to its crucial role in repository development, the challenges associated with siting repositories were selected for more extensive discussion in Chapter 4. Here, the emphasis is only on some overarching issues concerning the process of site selection.

Over the past decades, there has been an evolution in approaches to selecting specific potential sites. In the early days of nuclear technology, sites for facilities were commonly chosen to be remote, occasionally because of the military connections, often simply to minimise numbers of directly affected persons. Subsequently, additional facilities were often sited adjacent to existing installations because the infrastructure was available and often public acceptance was easier, because of prior familiarity of the locals with nuclear activities.

With time, new locations were needed for different nuclear facilities like repositories, which must fulfil additional, very site-specific requirements. This was the phase in which ‘‘expert judgement’’ was common – often exercised, however, behind closed doors. Groups, primarily of technologists, would, in good conscience, gather in order to select specific sites and they would proceed then to plan how best to ‘‘decide, announce and defend’’ their decisions. This was not highly successful. Following this, hope was then placed in developing a logical, traceable procedure, which would narrow in progressively to single sites, which everyone must logically recognise as the ‘‘best choice’’. This kind of approach was described in early international documents, e.g., those of the IAEA produced through the 1980s. It would, of course, be an ideal solution for politicians who would have the perfect defence of siting choices. Unfortunately, the approach is not feasible. The element of subjective judgement in narrowing the options remains high enough to fuel disputes amongst the experts. Moreover, the technical criteria that were proposed for use commonly neglected key societal aspects.

The next approach – and currently the most common – is to use a multi-attribute analysis (MAA). This is a technique that attempts to identify all criteria influencing the choice of options, to quantify how well each option matches the criteria and to combine the quantified scores, using appropriate weighting factors to give a ranking of preferences. The scores, and especially the weightings, can be allocated by different stakeholder groups, which allow the wider non-technical issues to be included. This approach is promising – provided that there is full transparency concerning the parameters and also the weighting factors that are employed when combining judgements on the individual parameters.

A final approach is to select potential sites by soliciting volunteer communities. Siting guidelines from the IAEA recognise the validity of the volunteering approach with one key provision, namely that ‘‘the selected site provides an adequate level of safety’’. One of the most important developments in the geological disposal field over the past decades has been the methodology for quantitatively assessing the level of safety. This is done by safety analysis or safety assessment (SA). Although not a precise tool, the methodology is mature enough to allow traceable analysis and, therefore, makes it legitimate from a safety angle to bring any potential site into the discussion, regardless of how it was selected.

7.3.3. Repository design

It is important to note that this activity is, in practice, performed originally iteratively along with site selection. The reason is that the geological setting of the repository,