One Step at a Time: The Staged Development of Geologic Repositories for High-Level Radioactive Waste (2003)

This chapter provides information on the activities that must be planned and executed to implement a geologic repository program. Section 3.1 describes decisions to be made and the activities to be carried out at each stage in a typical repository program.¹ The technical context of repository development enables deliberate learning through Adaptive Staging. However, a geologic repository program unfolds within equally important institutional and societal contexts, which are discussed in Section 3.2. Adaptive Staging can be instrumental in developing a repository that focuses simultaneously on the technical, societal, and institutional challenges. This section is meant to be descriptive, not prescriptive; any specific repository could have more, different, or fewer stages, depending on its circumstances.

The objective of a geologic repository program is to dispose safely of high-level waste deep below the Earth’s surface to isolate it from humans and the accessible environment (the biosphere). A geologic repository program is usually composed of the following phases²: (1) selection of geologic disposal option(s); (2) selection and characterization of a site or sites; (3) licensing; (4) construction; (5) operation; (6) closure; and (7) post-closure. The statement of task directs the committee to address the operational phases of a repository program, which is interpreted here to mean all phases after the site has been selected (Phases 3 through 7). For completeness the committee also briefly addresses the selection of a geologic disposal option and of a site (Phases 1 and 2).

Basic confidence in a waste disposal program is based on the findings from the early phases. Selection of an underground disposal option involves choosing the types of natural safety barriers (determined by the host rock type and its geologic setting) and engineered safety barriers (e.g., waste matrix and containers and backfill materials) that are best suited to achieving long-term (i.e., tens of thousands of years) isolation of the wastes. Examples of proposed natural barriers are: rock

types such as clay, salt, granite, and tuff; examples of proposed engineered barriers are: glass matrix of reprocessed wastes, the uranium dioxide matrix of spent fuel, fuel cladding, waste canisters, backfills, and drip shields.

In Belgium, Canada, Finland, Sweden, and Switzerland the implementer has made a generic safety case (see Sidebar 2.1) after the selection of an underground geologic disposal option. (This safety case is not required in all countries. For instance, in the United States, the regulations require a safety analysis, which is technically equivalent to a safety case.³) The implementer can use data available in the literature or acquire data from geologic sites to support the safety case.

The International Atomic Energy Agency (IAEA) identifies four stages in a “top-down” site selection and characterization process that is purely technical: (1) conception and planning; (2) area survey; (3) site characterization; and (4) site confirmation (IAEA, 1994). These are subdivided below based on the necessity and timeliness of decisions.

This stage establishes screening guidelines, key deadlines, funding, resources, safety assessment, and regulatory constraints. Screening guidelines factor in natural performance criteria as well as socioeconomic, political, and environmental considerations.

This stage focuses on finding suitable sites, using the previously developed screening guidelines, based on regional data obtained for sites of interest. Often major areas of a country are screened and a number of potential sites are identified. In a second round of screening the number of sites is narrowed. Only existing data are used, such as data available in the literature or existing laws and regulations. The number of sites selected for preliminary site investigation varies widely.

During site characterization the implementer investigates one or more sites to determine suitability with respect to safety and other screening criteria. Preliminary site investigations, including deep drilling or excavations, produce underground geologic data at the candidate site(s). Suitable sites are then subjected to detailed safety assessments, which may be reviewed by regulatory agencies. The implementer uses the newly acquired information to update the site-specific safety report and to apply for a permit for underground exploration by means of shafts or ramps connected to tunnels. Typically the site investigation lasts for several years, but in some cases it has extended over a much longer time period (e.g., two decades for the U.S. Yucca Mountain Project).

The conditions for beginning surface and underground explorations vary among countries. In some countries (e.g., Switzerland) hazardous and radioactive-waste-related laws require a permit, whereas in others (e.g., Germany) mining laws regulate permits. Underground explorations at a potential repository site are occasionally described as “underground laboratories of the second generation” to distinguish them from underground research laboratories, which are developed at sites not intended as repository candidates.

The number of sites selected for confirmation through underground exploration varies. In the early 1980s the United States selected three sites for underground examination: Deaf Smith County, Texas; Hanford, Washington; and Yucca Mountain, Nevada. Sweden designated two sites to be investigated and Finland three. Subsequently, both the United States and Finland decided to concentrate resources on underground exploration of single sites; Sweden still intends to perform underground characterization at two sites.

In France, the current plan is to build two underground laboratories at potential sites in different types of host rocks, although problems are being encountered in the search for a second site in crystalline materials following the agreement with the Bure region to host an underground lab in clay. In Germany, the Gorleben site was originally nominated as the single site to be characterized from underground to judge its potential suitability for hosting a high-level waste repository. The rapid and nontransparent narrowing to this single site has been criticized because the public was not involved in the decision (Witherspoon and Bodvarsson, 2001). The latest siting efforts proposed in Germany during the search for alternatives strongly emphasize a transparent staged process, keeping more than one option open right through to the stage of underground exploration (AkEnd, 2002).

In this stage, the implementer studies the site in greater detail and gathers additional data to determine its suitability. The implementer confirms the suitability of the site through underground exploration, data collection, and analysis. The underground exploration area is located in close proximity to the proposed repository in the repository horizon. The data gathered are incorporated into the “main” safety report submitted to the regulator as part of the repository construction permit application. This confirmation stage could involve the preparation of environmental impact assessments to justify a license application. During site confirmation the implementer selects a baseline repository design to be submitted for license application. The sequential narrowing of the number of sites until confirmation is intended to increase the probability that the final site will be suitable.

An alternative approach, more societally-based, elicits volunteer sites and examines their potential suitability. This approach to siting has been used in Sweden, France, and Taiwan, and is currently being used in Japan. Asking a community or municipality whether it would be prepared to host a repository (assuming site suitability) and moving directly to characterization is recognized by the International Atomic Energy Agency as a justifiable alternative to the sequential narrowing process, provided the safety requirements are independent of how the site was originally identified (IAEA, 1994).

In its 1994 report, the IAEA also discusses siting guidelines for a geologic repository and the site volunteering process. The IAEA recommends that the approach used to assess safety at different sites be similar regardless of how the site is chosen. The key caveat is that it is neither essential nor possible to locate the best

possible site. The ultimate goal is a site (and system) that can be shown with a high level of confidence to offer long-term safety and be acceptable to the host community.

To date (2003), only the United States has progressed to the site confirmation phase through sequential narrowing of the number of potential sites. With the 1987 amendment to the Nuclear Waste Policy Act, the U.S. Congress decided that characterization should proceed at only one site, Yucca Mountain, Nevada. On July 9, 2002, the U.S. Congress confirmed that the Yucca Mountain site is suitable for repository development. The implementer (DOE) is now preparing the license application for Yucca Mountain.

Repository licensing is a complex process that lasts throughout the repository program. The regulator has two main roles in this phase: (1) set the health and safety standards for waste disposal and (2) decide whether the repository meets those standards. One or two regulators with unique competences are needed to fulfill this role. The role of the implementer is to select a repository design and to submit a license application demonstrating that the proposed repository is safe and complies with regulatory requirements. This “proof is not absolute in a mathematical sense; it involves showing with “reasonable confidence” that unacceptable risks can be avoided.

The implementer must first be licensed to construct the repository. Regulators are likely to require (no high-level waste repository to date has been licensed) that a license or a license amendment be obtained at each subsequent phase. The implementer applies for a license to receive and emplace waste, applies for a license to close the repository, and applies for a license to terminate repository activities.

The implementer presents to the regulator a construction license application based on the full-inventory safety case; that is, a safety case for the completed facility and the entire amount of the waste to be emplaced. Generally a repository is not developed, reviewed, and approved for only a fraction of the waste, with the idea of requesting approval for incrementally increasing the amounts of waste in the future. Maintaining a safety case for the entire inventory at all stages assures that the implementer chooses the most effective development approach in gaining knowledge to affirm or redirect the repository design. On the basis of the full-inventory safety case, and if the regulator allows this approach, the implementer can apply for construction authorization for a pilot plant in which a portion of the baseline design and a portion of any alternative designs can be implemented. The implementer generally needs a license to begin receiving waste and to operate the repository, and another to close the repository.

Construction begins once the regulator grants the construction authorization license. The repository consists of surface and subsurface facilities. The surface facilities serve multiple purposes: receiving transportation vehicles, unloading transportation casks, handling waste containers, and preparing (packaging) waste for disposal. A further purpose of the surface facilities is to serve as buffer storage, i.e., to store the waste temporarily either before its emplacement or after retrieval from

underground. The subsurface facility consists of access tunnels and drifts serving as the final disposal area.

The construction of surface and subsurface facilities can be conducted in one continuous operation or can proceed in stages. Construction of adequate surface facilities and initial disposal drifts must be completed before waste emplacement can begin at the repository. This, however, does not imply that the final full-scale facilities above or below ground must be ready before shipments commence; successive parts of each may be constructed in parallel with operation.

The surface facility is built to allow for inventory optimization, accommodating various alternatives for waste aging and blending that influence thermal operating modes. Two of the determining factors in the cost of a surface facility are the thermal constraints imposed by the repository design and the measures taken to manage the thermal load of waste. The thermal operating mode also influences the ratio between the disposal volume and the surface of the repository footprint. The size and capacity of the surface storage facilities depend on emplacement and transportation logistics. Before construction, the implementer determines the transportation plan by deciding on shipment rates and underground emplacement rates and preferred transportation mode (i.e., rail, truck, or ship). The implementer then plans how to incrementally increase shipment rates and phase different transportation modes into operation.

The underground facility can be built in its entirety to follow the same baseline design, or it can be built in modules having different designs and operations. For instance, at the beginning of operations, options for thermal operating modes or distances between emplacement drifts can be tested on a pilot scale in different parts of the repository. The implementer proceeds to the next excavation stage once results from tests determine the best design option.

Before repository operation, the implementer must obtain a license to receive high-level waste from generator sites (typically nuclear power plants) or from centralized interim storage facilities and to emplace it underground. The operational phase consists of at least four activities: (1) waste receipt; (2) waste handling; (3) waste conditioning;⁴ and (4) waste emplacement and possibly waste retrieval (see Figure 3.1).

Waste arrives at the site by rail or truck (or by ship for coastal sites) and undergoes inspection. Waste is then removed from the transportation cask and is packaged for disposal. Waste is temporarily stored on the surface waiting for transfer to the subsurface for final emplacement.

Transportation rates can be coupled with underground emplacement rates, which could reduce surface buffer storage needs. If decoupled, the underground emplacement rate can be independent of the shipment rate but may result in an increase in surface buffer storage requirements.

FIGURE 3.1 Geologic repository system during the operational phase. High-level waste (HLW) from commercial nuclear power plants and other origins (e.g., defense activities or research reactors) is either reprocessed and the remaining waste immobilized (e.g., vitrified) before disposal or directly disposed. Waste is transported by rail, truck, or ship to the geologic repository. Waste is received, handled, packaged, and temporarily stored on the surface before final emplacement underground. SOURCE: This figure was adapted from DOE (DOE-OCRWM, 2001b).

During the early operational phase, the implementer demonstrates a capability to take title, transport, receive, handle, package, and emplace waste underground. In many repository programs the implementer is also required to demonstrate retrieval capability, implying the need for at least some planning for substantial surface storage.

The implementer may begin with pilot operations, after which underground emplacement rates are rapidly increased to full-scale implementation. (Some programs, such as that of the United States, intend to increase to full-scale emplacement in a few years.) The chosen design may be confirmed in a lengthy demonstration stage.

Some countries, such as Switzerland, propose the implementation of a test facility, which would operate in parallel with the repository, where important, unresolved questions on repository processes could be addressed, unhindered by the demands of waste disposal operations (EKRA, 2000, 2002). Test activities can last for many years or even decades as operations continue. Results from the test facility may lead to adjustments or even significant changes in the repository design or operational strategy if test results reveal significant issues for long-term repository safety. Different pilot operations may be used at different times in the program; for instance, a pilot for a new technology can be introduced during the full-scale operational phase.

The purpose of a pilot stage is to learn about system behavior under the most realistic conditions possible (even if only for a relatively short period of time) and to apply this knowledge to affirm or modify the design and operations. The pilot stage is designed to provide improvement for the engineering and emplacement mode of the waste.⁵ In a pilot facility, tests can begin prelicensing with simulated radioactive waste packages and continue with hot radioactive waste packages once a license has been obtained to receive and emplace waste. The introduction of a pilot stage in a repository program is a relatively new idea for repository implementation, although it has already been proposed by SKB in Sweden (Lundqvist, 2001) and has been recommended by the EKRA group in Switzerland (EKRA, 2000). The pilot stage concept is developed in more detail in Chapter 4, Section 4.2.1.

Operations commence with pilot-scale waste handling and emplacement. Information from this pilot is applied to development of the next stage of construction and operation. This stage consists of larger, but still reduced, size or scope modules sufficient to conduct emplacement operations at a magnitude appropriate for evaluation of the issues associated with full-scale throughput. After the pilot stage, the chosen mode of operation for the repository (i.e., radioactive waste receipt, handling, and emplacement) is built up to full-scale operation.

During full-scale operations, waste emplacement underground is at the fastest scheduled rate. The operational phase ends when all waste has been emplaced underground.

Monitoring activities are an integral portion of operations, as well as throughout the lifetime of the repository program (see Sidebar 3.1). Information derived from monitoring can help the implementation to determine whether the repository is behaving as predicted, and quantitative, reliable information for future decision-making. Current attention in many repository programs is directed toward answering the challenging questions of what and how to monitor in the closure and post-closure phases.

The implementer applies for a license to close the facility by submitting an updated safety case and an implementation plan for closing and sealing the repository. The closure phase has two main purposes: (1) to monitor the repository before sealing, and (2) to prepare the facility so that the need for future human intervention to maintain safety is minimized.

The updated safety case demonstrates that knowledge gained during the operational phase has confirmed expectations or resulted in system adaptations that have reaffirmed confidence in the long-term safety of the repository. If the license for closure is approved, the implementer adapts the monitoring program and proceeds to prepare the repository for sealing and post-closure activities. The closure process itself entails constructing the final engineered barriers, buffers, backfills, and shaft seals for the facility; dismantling surface facilities; and restoring the surface of the site. Closure is considered the final phase of the operational stage. After final construction of engineered barriers, but before deciding whether to approve the sealing of access, a period of monitoring can help assure that at a minimum the seals are effective and stable. The United States has proposed that the monitoring period before sealing the repository last up to 300 years (DOE-OCRWM, 2001b).

Approval for closure implies that waste is not intended to be retrieved for future use or reprocessing and therefore must be safeguarded from external intrusion. Nevertheless, waste retrieval might be attempted after closure. Such circumstances include, for example, a response to a previously undetected flaw in the repository or a future technological breakthrough that makes re-treatment of high-level radioactive wastes viable and desirable. The need for safeguards to maintain security and the desire for continued assurance of safety will influence decisions about post-closure monitoring and about whether to emplace surface markers at, and near, the site to warn future generations of the presence of hazardous radioactive materials

in the subsurface. As for any other stage, closure may be performed in a staged manner maintaining reversibility throughout the process.

After site closure, the post-closure monitoring phase begins and can continue indefinitely. When all parties are assured of repository performance and safety, government authorities decide when to cease monitoring activities. Passive institutional controls will be maintained as long as society demands it to minimize the possibility of human intrusion—either intentional or accidental. During the post-closure phase the repository must be safeguarded from external intrusion. The implementer safeguards the repository in two ways: (1) by constructing physical barriers and (2) by engaging in active and passive institutional controls.

Physical barriers may include fences, walls, and other features that inhibit access to the repository. Active institutional control implies the maintenance of measures (e.g., guards) controlling access to the repository area. Passive institutional control implies identifying the controlled area through signs, markers, and monuments, as well as distributing information on the repository and land use to local, regional, and national agencies. During post-closure, responsibility for controlling access to the

site may be transferred from the implementer to other appropriate government institutions because of the extremely long periods involved.

Currently, there are no definitive requirements for societal or government activities during the post-closure stage. Because the post-closure phase is so far into the future, it is not possible to predict when, and even if, it will begin. One objective of geologic disposal, however, is that the repository not impose on future generations any obligation for indefinitely long active institutional control (IAEA, 2001). Neither does it preclude it.

A geologic repository program unfolds in a broad societal and institutional context. This context establishes boundary constraints on decisions concerning the repository and may influence the ultimate success of the program. Some of these issues have been discussed in detail in a previous National Research Council report (NRC, 2001) and by Dunlap et al. (1993), while others, such as institutional challenges for repository implementers, remain to be addressed.⁶

The repository development process must be scientifically and technically sound, but the application of science and technology takes place in a broader context, a context that touches aspects of the larger society in which issues are often framed differently by scientists and technologists. Any successful solution to the disposal of nuclear waste must recognize this broader context. Institutional and societal issues in high-level waste disposal are related to public attitudes toward nuclear power and nuclear waste, public trust in institutions, public acceptance, and stakeholder participation. The committee’s definition of stakeholder is given in Sidebar 3.2.

An important basis for the tripartite distinction among different types of stakeholders lies with the respective roles of each. The role of institutional stakeholders is clearly specified in legislative mandates, in rules, and in regulations. Roles of stakeholders and the general public have no similar institutional standing; hence, their roles are specified in this report. The committee underscores the importance of maintaining a clear distinction between stakeholders and the general public, because each serves a distinct, separate role in the Adaptive Staging process.

A large fraction of the public is unconvinced that benefits of nuclear power outweigh the risks. Nuclear power continues to elicit strong and opposing views among large fractions of the public. The controversy generally includes concerns over safety and waste management (Rosa and Dunlap, 1994; Rosa, 2001). Recently, the events of September 11, 2001, may have heightened public concern over nuclear security.

Because of the public ambivalence about nuclear power, in general, and the deep dread of nuclear waste, any institution charged with managing its wastes may be tainted from the outset. The general public in almost every nation where data have been collected perceives nuclear technologies and radioactive wastes as the riskiest of all hazards and expresses great concern about them (Cha, 2000; Bastide et al., 1989; Englander et al., 1986; Keown, 1989; Rosa and Machlis, 2002; Slovic, 1987; Teigen et al., 1988). Nuclear fission and its applications, even before their uses could be harnessed and made practical, have been viewed with deep ambivalence and great suspicion (Weart, 1988).

This negative picture is balanced to some extent by considering the current status of nuclear power worldwide. In many ways and in many places, the public implicitly trusts nuclear power technology. Public trust allows over 100 plants in the United States and over 400 worldwide to operate. Recent sales and license extensions suggest that these plants are viewed optimistically for the future.⁷ New nuclear power plants are being constructed in the Far East, and Finland has recently decided to construct a new plant. Waste disposal facilities are also accepted by local communities at some locations, as is the case in the United States,⁸ Sweden, Finland, France, and Spain. There is, nevertheless, opposition to nuclear power in some countries, such as Sweden, Germany, and Belgium, strong enough for authorities to consider shutting down plants in the future (see Appendix D).

Levels of public trust have been monitored in the United States in a variety of surveys over the past four decades. Typically respondents are asked to express their level of confidence (trust) in the people running a society’s major institutions (e.g., the military, science, medicine, the press, and various branches of government). Since the 1970s, virtually none of these institutions has elicited a majority who say they have great confidence in the people running them.

When citizens are asked about their confidence in the institutions themselves, not in the people running them, a similar pattern emerges. With some exceptions, similar deficits of public confidence in the performance of its institutions are found throughout the European nations and Japan (Pharr and Putnam, 2000).

The failure of most institutions to attract majority confidence represents not a momentary spike of opposition but the manifestation of a pattern that crystallized decades ago and has persisted to the present. Some students of institutional trust (Lipset and Schneider, 1987) have interpreted the data to reveal a three-decade-long downward trend in public confidence, while some polling firms interpret the

current levels of trust to be the lowest ever recorded (Harris, 1997). The more conservative and defensible interpretation of the data is that there is no evidence whatsoever that institutional trust has increased over the past three and one-half decades and, in fact, trust may have declined somewhat. Either interpretation of the available data—dramatic or slight decline—is troubling to the task of balancing trust between the expert and the layperson. Trust in society’s major institutions fails the test of majority support and is clearly far short of being compelling (Rosa and Clark, 1999).

Trust is intertwined with the constancy and continuity expected of institutions charged with managing the operational period of repositories over the time scales of many decades or even hundreds of years. The issue of constancy and continuity is developed more fully in Section 2.6.2 of this report. While there is little question about the connections between trust and constancy, and between trust and continuity, the causes have yet to be established.

It could be the case that a solid base of public trust in implementing and regulatory bodies is a prerequisite to demonstrating their commitment to the constancy and continuity. Or it could be that, where there is a deficit of trust, constancy and continuity are essential prerequisites to re-gaining trust. By this reasoning, the public will only trust institutions that have exhibited competency and fiduciary responsibility over long periods of time. The preponderance of evidence favors this second possibility and, as a consequence, the committee views Adaptive Staging as a promising means for demonstrating the essential prerequisites for regaining trust.

Trust is fundamentally asymmetric in two important ways: (1) trust-decreasing events have greater salience and therefore impact on perceptions than trust-increasing events (Slovic, 1993), and (2) trust is easily and quickly lost, even by a single event, but once lost is typically difficult to regain—if it can be regained at all (Slovic, 1993; Rosa and Clark, 1999). It is unrealistic to expect a rapid turnaround in levels of trust in society’s major institutions, and it is even more unrealistic to expect a rapid turnaround in the low levels of trust accorded the U.S. implementer of a waste repository.

Not all repository implementing organizations suffer from such low levels of trust. In Scandinavia the public regards the waste management organizations as the most reliable source of information (Isaacs, 2002). Nevertheless, the findings of the Eurobarometer 2001 confirm the low confidence of the European public in various institutions (INRA, 2002). Regaining lost trust will require an unswerving constancy in addressing public concerns and an extraordinary patience in awaiting positive results. An understanding of the magnitude of the task in building public trust of the implementer can be appreciated by recognizing that public distrust is deep and durable, having been forged by disenfranchisement of public input in the past, as well as by failures of nuclear institutions.

The highest rated trust-increasing event found by Slovic (1993) was a local board that had authority to close a large nuclear power plant in the local community. A key aspect of Finland’s 1987 legislation on nuclear waste was the introduction of the “decision-in-principle” concept to the decision-making process with the provision for “the absolute right of veto in the siting process” by candidate communities (Vira, 2001 a). This provision, along with the requirement that multiple sites be characterized, was likely a key factor that ensured legitimacy in the process and trust in the implementing bodies; after all, local residents could be confident that they had an absolute veto right and, therefore, a final say in the process. In Sweden, the regulator reviews the waste disposal program every third year and the government takes a

decision on whether it complies with legal requirements. Conditions for future work can be issued. This decision-process is comparable to the Finnish “decision-in-principle.” A decision by the regulator (supervising authority, government) is a potentially trust-increasing measure because it is a clear sign of engagement, evaluation, and acceptance of the repository program by high-level decision-makers.

Of course, having the above conditions is no guarantee for success. In Switzerland, the Wellenberg site was chosen from multiple possibilities in a process directly approved by bodies including local stakeholders (McKinley et al., 2001). The current law gives the region (canton) the veto rights mentioned. The outcome of the recent referendum, however, was that this veto right was used to prevent further progress (Kowalski, 2002). This veto was at the canton level, with the potential host community voting for the third time in favor of the project. This provides a sobering reminder that political and institutional realities must be balanced against the search for optimal processes leading to societal consensus. This is also a reminder that the community nearest to the repository may be in favor of the project, while communities further afield do not support the repository.⁹

There is universal agreement that a sufficient level of public acceptance is indispensable to the success of any program to manage high-level nuclear wastes (NEA, 2002), but this agreement raises the first of several challenging issues. It must be noted that it is not possible to characterize public acceptance in general terms: there are many types of public audiences and local representatives do not necessarily share the rationale of the representatives of each state or of the federal government.

There is little agreement over how to define “public acceptance.” What are the criteria to judge that a procedure for the management of high-level waste has been deemed acceptable? Unlike elections with “one-person-one-vote,” where preferences can be reasonably gauged, in most countries no such formalized procedure or rules for judging preferences exist for deciding nuclear waste issues. In countries where referenda are possible (e.g., Switzerland) the question arises of who is entitled to vote: local, regional, or national populations. There is the possibility of taking the point of view that public acceptance is established when there is little public opposition, either directly or through activist organizations, to policies and procedures or when those who can stop a project choose not to. Yet this position attracts its own share of challenges, such as when to judge that levels of opposition have been validly assessed or how to determine that opposition has permanently subsided. The challenging question remains for society and for the implementer of high-level waste programs: when is public acceptance attained?

More troubling is the possibility that it may be impossible in some countries, at least within the near foreseeable future, to generate sufficiently wide public acceptance—however defined—of a high-level waste repository or any other method of high-level waste disposition. The public in most countries, wary of nuclear technol-

ogy in general, is particularly concerned about the risk of radioactive wastes, has low levels of trust in society’s major institutions, and has even lower levels of trust in the implementing bodies. Under such conditions, public acceptance for the foreseeable future may be elusive.

There is growing recognition of the need to more actively engage stakeholders and the general public in making key decisions about nuclear waste management (NEA, 2002). The first law of public involvement could be: ignoring the public in such decisions all but guarantees a policy failure. Engaging stakeholders and the general public does not, however, guarantee success. The implications are:

1. there is a higher probability, but not certainty, of success with stakeholder and general public involvement and, therefore,

2. this is the most prudent path to take in a controversial project, but

3. a myriad of further political, institutional, and technical issues are inextricably entwined with the question of public involvement.

The term “interested and affected party”—introduced in a previous National Research Council report (NRC, 1996) and often used as a broad definition of stakeholder (see Sidebar 3.2)—opens a variety of unresolved operational issues. First among these is the relative standing of the respective stakeholders: (1) Should all who are franchised have equal standing in the decision-making process? (2) If so, by what procedures should preferences inform decisions? For example, should each citizen’s views be given the same weight as long-standing institutional parties? Or, how are the value differences that define and separate stakeholder groups to be aggregated? (3) If not all who are franchised have equal standing, by what principles are differential standings accorded to the variety of stakeholders?

A second operational challenge is the decision over the most effective institutional mechanism for facilitating public involvement. This is one of the fastest growing areas in research on risk and public decision-making, but research is still in its experimental stage. A wide and growing variety of mechanisms have been developed and field-tested to engage the public in scientific and technological decision-making, and others are currently under development. Some of the more well-known public involvement mechanisms include citizen juries, electronic democracy, deliberative opinion polls, consensus conferences and other consensus techniques, stakeholder dialogues, and cooperative discourse. A few of these mechanisms are theoretically derived, such as the work of Renn and his colleagues and that of Wene and Espjo, but most are pragmatically derived with a focus on arriving at acceptable policies (Webler et al., 1995; Renn et al., 1995; Wene and Espejo, 1999; Klinke and Renn, 2002).

Typically these mechanisms are applied broadly in science and technology policy (e.g., policies on biotechnology or on genetically modified organisms) or to the siting of local facilities (e.g., non-nuclear power plants), often noxious ones (e.g., landfills and incinerators). There are no examples where the public has been engaged in technological decision-making in a situation similar to the complex development

of a geologic repository for radioactive waste.¹⁰ Hence, the potential success of any of these techniques, either alone or in combination, to address high-level waste issues, including the siting of a repository, remains untested.

In many countries, the Environmental Impact Assessment and the Environmental Impact Statement initiate important processes by which stakeholders are formally (and also in reality) engaged and given a specified role. The Environmental Impact Assessment may start at different phases and have a somewhat different application in different countries, but is important in the construction, operational, and in closure phases of a geologic repository.

In principle, any approach to the development of a geologic repository that addresses public concerns and enhances trust in the institutions increases chances of success. Adaptive Staging offers opportunities (see Section 4.11.1) and mechanisms to address societal and institutional challenges.

A repository program is a suitable candidate for application of Adaptive Staging. Section 2.7 demonstrated that a repository meets the criteria for Adaptive Staging. Unlike many other high-technology ventures, a repository has inherent characteristics that facilitate the use of a cautious management approach with scope for learning in both technical and societal areas.

The committee believes that Adaptive Staging can lead to a number of important benefits in a repository development program.

• It allows the program to improve performance, both pre- and post-closure (e.g., environmental health and safety, cost, schedule, public, and implementer confidence) by building in an approach that seeks and values improvement based on experience.

• It allows the program to improve confidence by narrowing the uncertainties (although some uncertainty will inevitably remain, and with it residual risks).

• It could improve the level of stakeholder and general public trust in implementers and regulators by enhancing prospects of recognizing either a deficient engineering component or an unsuitable site and by providing the mechanism to accept and respond to that finding (e.g., by adaptation, reversibility, or retrievability).

• It gives the program better opportunities for earning stakeholder and public trust by building in numerous stages where the implementer can demonstrate readiness and ability to fulfill promises, work competently, and respond to stakeholder concerns.

• It transforms the implementation of a repository program from a commitment to emplace waste by a fixed deadline to a more measured approach that has as its prime objective the desire to provide a solution defined by current generations that does not preclude future generations from choosing alternative solutions.

To be effective, Adaptive Staging should involve the implementer, the regulator, stakeholders, and the general public. It must be accepted and understood throughout the management system and by all stakeholders in terms that include consideration of technical, societal, political, institutional, as well as regulatory systems. Adoption of Adaptive Staging requires, on the part of all involved parties, a readiness to accept and address uncertainties and to acknowledge that unexpected outcomes and occurrences, which are inevitable, are also learning opportunities to improve the system.

Adaptive Staging can bring significant benefits, in the committee’s view, to the extent that it can be implemented credibly by the organizations charged with waste management. A fundamental frailty of waste management programs is the ambivalence of societies to undertake the irreversible steps required for final disposal of wastes, even though safe management is seen as essential everywhere. Adaptive Staging can be a way to build the trust needed to take these irreversible steps, but Adaptive Staging itself requires some trust as a precondition, if the long, slow process of learning is to be permitted to unfold in the face of surprises and changes in the guiding hypotheses (i.e., the safety case).

If Adaptive Staging is effective, program changes are likely to decrease with time, as ways are found by the learning-driven process to make the design more robust within a given budget, or more cost-effective for a given level of technology. That is, Adaptive Staging would be expected to converge to Linear Staging from a technological and natural scientific perspective, assuming a stable social environment. This trajectory will not be followed, of course, if unexpected events continue happening. It may be possible to develop and maintain a technical consensus on the likely performance of the repository system, so that the Adaptive process would, over time, build increasing public confidence in the behavior of the repository geology and engineered barriers.

It seems less likely that the social environment of the program can be similarly well defined. The repository is planned to be open for a time period several times as long as the time that has elapsed since the rise of the environmental movement. The social setting of nuclear energy changed with remarkable speed from postwar optimism to one in which dread became the dominant political and economic factor by the late 1970s. These changes occurred in less time than the economic lifetime of the power plants built for civilian purposes, being among the factors leading in some cases to large-scale stranding of expensive capital assets. The social context is historical; it has been and will continue to be path-dependent, so that both extrapolation from the past and causal predication will be unreliable for some time to come. Adaptive Staging not only affects the geologic repository but also has impacts on the entire radioactive waste management system, as described in the next chapter.