Nuclear Risk Management on Stage: A Decision Analysis Perspective on the UK's Committee on Radioactive Waste Management

In 2003, the UK government set up a broad-based Committee on radioactive waste management (CoRWM) to look at the UK's policy on radioactive waste management with a view to jumpstarting a stalled policy process. The committee's brief was to come up with a set of recommendations that would protect the public and the environment, and be capable of inspiring public confidence. After consulting widely with the public and stakeholders, and drawing on advice from scientists and other experts, CoRWM arrived at a remarkably well-received set of recommendations. On the basis of our experiences of working on CoRWM's multi-criteria decision analysis of different management options, study of CoRWM documentation, and interviews with committee members, we describe the explicit and implicit principles that guided CoRWM. We also give an account of the process by which CoRWM arrived at its conclusions, covering four phases: framing, shortlisting, option assessment, and integration; and four cross-cutting activities: public and stakeholder engagement (PSE), science and engineering input, ethics and social science input, and learning from overseas practice. We finish by outlining some of the key developments in the UK's radioactive waste management process, which followed on from the publication of CoRWM's report, and present our reflections for the benefit of the risk and decision analysts of future committees that, like CoRWM, are charged with recommending to government on the management of technically complex and risky technologies, drawing on extensive public and stakeholder consultation.     

Health Risk Assessment of a Modern Municipal Waste Incinerator

During the modernization of the municipal waste incinerator (MWI, maximum capacity of 180,000 tons per year) of Metropolitan Grenoble (405,000 inhabitants), in France, a risk assessment was conducted, based on four tracer pollutants: two volatile organic compounds (benzene and 1, 1, 1 trichloroethane) and two heavy metals (nickel and cadmium, measured in particles). A Gaussian plume dispersion model, applied to maximum emissions measured at the MWI stacks, was used to estimate the distribution of these pollutants in the atmosphere throughout the metropolitan area. A random sample telephone survey (570 subjects) gathered data on time-activity patterns, according to demographic characteristics of the population. Life-long exposure was assessed as a time-weighted average of ambient air concentrations. Inhalation alone was considered because, in the Grenoble urban setting, other routes of exposure are not likely. A Monte Carlo simulation was used to describe probability distributions of exposures and risks. The median of the life-long personal exposures distribution to MWI benzene was 3.2·10^–5 g/m³ (20th and 80th percentiles = 1.5·10^–5 and 6.5·10^–5 g/m³), yielding a 2.6·10^–10 carcinogenic risk (1.2·10^–10–5.4·10^–10). For nickel, the corresponding life-time exposure and cancer risk were 1.8·10^–4 g/m³ (0.9.10^–4 – 3.6·10^–4 g/m³) and 8.6·10^–8 (4.3·10^–8–17.3·10^–8); for cadmium they were respectively 8.3·10^–6 g/m³ (4.0·10^–6–17.6·10^–6) and 1.5·10^–8 (7.2·10^–9–3.1·10^–8). Inhalation exposure to cadmium emitted by the MWI represented less than 1% of the WHO Air Quality Guideline (5 ng/m³), while there was a margin of exposure of more than 10⁹ between the NOAEL (150 ppm) and exposure estimates to trichloroethane. Neither dioxins nor mercury, a volatile metal, were measured. This could lessen the attributable life-long risks estimated. The minute (VOCs and cadmium) to moderate (nickel) exposure and risk estimates are in accord with other studies on modern MWIs meeting recent emission regulations, however.     

Nuclear Waste Management under Approaching Disaster: A Comparison of Decommissioning Strategies for the German Repository Asse II

This article compares different strategies for handling low‐ and medium‐level nuclear waste buried in a retired potassium mine in Germany (Asse II) that faces significant risk of uncontrollable brine intrusion and, hence, long‐term groundwater contamination. We survey the policy process that has resulted in the identification of three possible so‐called decommissioning options: complete backfilling, relocation of the waste to deeper levels in the mine, and retrieval. The selection of a decommissioning strategy must compare expected investment costs with expected social damage costs (economic, environmental, and health damage costs) caused by flooding and subsequent groundwater contamination. We apply a cost minimization approach that accounts for the uncertainty regarding the stability of the rock formation and the risk of an uncontrollable brine intrusion. Since economic and health impacts stretch out into the far future, we examine the impact of different discounting methods and rates. Due to parameter uncertainty, we conduct a sensitivity analysis concerning key assumptions. We find that retrieval, the currently preferred option by policymakers, has the lowest expected social damage costs for low discount rates. However, this advantage is overcompensated by higher expected investment costs. Considering all costs, backfilling is the best option for all discounting scenarios considered.     

The Role of Performance Assessment in the Regulation of Underground Disposal of Radioactive Wastes: An International Perspective

Much has been written about the development and application of quantitative methods for estimating under uncertainty the long-term radiological performance of underground disposal of radioactive wastes. Until recently, interest has been focused almost entirely on the technical challenges regardless of the role of the organization responsible for these analyses. Now the dialogue between regulators, the repository developer or operator, and other interested parties in the decision-making process receives increasing attention, especially in view of some current difficulties in obtaining approvals to construct or operate deep facilities for intermediate or high-level wastes. Consequently, it is timely to consider the options for regulators' review and evaluation of safety submissions, at the various stages in the site selection to repository closure process, and to consider, especially, the role for performance assessment (PA) within the programs of a regulator both before and after delivery of such a submission. The origins and broad character of present regulations in the European Union (EU) and in the OECD countries are outlined and some regulatory PA reviewed. The issues raised are discussed, especially in regard to the interpretation of regulations, the dangers from the desire for simplicity in argument, the use of regulatory PA to review and challenge the PA in the safety case, and the effects of the relationship between proponent and regulator. Finally, a very limited analysis of the role of PA in public hearings is outlined and recommendations are made, together with proposals for improving the mechanisms for international collaboration on technical issues of regulatory concern.Until August 13, 1997, the author was employed as a Principal Pollution Inspector by the Environment Agency (EA) of England and Wales. Responsible for managing the development and application of the regulatory postclosure assessment capability of Her Majesty's Inspectorate of Pollution (HMIP) between 1982 and 1996, when HMIP was merged with the National Rivers Authority and the Waste Regulatory Authorities to form the EA on April 1, 1996. Represented HMIP/EA on a number of international committees related particularly to PA; 20 Bonser Road, Twickenham, Middlesex TW1 4RG, U.K.     

Consideration of Background Exposures in the Management of Hazardous Waste Sites: A New Approach to Risk Assessment

The current approach to health risk assessment of toxic waste sites in the U.S. may lead to considerable expenditure of resources without any meaningful reduction in population exposure. Risk assessment methods used generally ignore background exposures and consider only incremental risk estimates for maximally exposed individuals. Such risk estimates do not address true public health risks to which background exposures also contribute. The purpose of this paper is to recommend a new approach to risk assessment and risk management concerning toxic waste sites. Under this new approach, which we have called public health risk assessment, chemical substances would be classified into a level of concern based on the potential health risks associated with typical national and regional background exposures. Site assessment would then be based on the level of concern for the particular pollutants involved and the potential contribution of site contaminants to typical background human exposures. While various problems can be foreseen with this approach, the key advantage is that resources would be allocated to reduce the most important sources of human exposure, and site remediation decisions could be simplified by focussing on exposure assessment rather than questionable risk extrapolations.     

Strategic Appraisal of Environmental Risks: A Contrast Between the United Kingdom's Stern Review on the Economics of Climate Change and its Committee on Radioactive Waste Management

In this article, we compare two high‐profile strategic policy reviews undertaken for the U.K. government on environmental risks: radioactive waste management and climate change. These reviews took very different forms, both in terms of analytic approach and deliberation strategy. The Stern Review on the Economics of Climate Change was largely an exercise in expert modeling, building, within a cost‐benefit framework, an argument for immediate reductions in carbon emissions. The Committee on Radioactive Waste Management, on the other hand, followed a much more explicitly deliberative and participative process, using multicriteria decision analysis to bring together scientific evidence and stakeholder and public values. In this article, we ask why the two reviews were different, and whether the differences are justified. We conclude that the differences were mainly due to political context, rather than the underpinning science, and as a consequence that, while in our view “fit for purpose,” they would both have been stronger had they been less different. Stern's grappling with ethical issues could have been strengthened by a greater degree of public and stakeholder engagement, and the Committee on Radioactive Waste Management's handling of issues of uncertainty could have been strengthened by the explicitly probabilistic framework of Stern.     

The Crucial Role of Nomothetic and Idiographic Conceptions of Time: Interdisciplinary Collaboration in Nuclear Waste Management

The disposal of nuclear waste involves extensive time scales. Technical experts consider up to 1 million years for the disposal of spent fuel and high‐level waste in their safety assessment. Yet nuclear waste is not only a technical but also a so‐called sociotechnical problem and, therefore, requires interdisciplinary collaboration between technical, natural, social sciences, and the humanities in its management. Given that these disciplines differ in their language, epistemics, and interests, such collaboration might be problematic. Based on evidence from cognitive psychology, we suggest that, in particular, a concept like time is presumably critical and can be understood differently. This study explores how different scientific disciplines understand extensive time scales in general and then focuses on nuclear waste. Eighteen qualitative exploratory interviews were conducted with experts for time‐related phenomena of different disciplines, among them experts working in nuclear waste management. Analyses revealed two distinct conceptions of time corresponding to idiographic and nomothetic research approaches: scientists from the humanities and social sciences tend to have a more open, undetermined conception of time, whereas natural scientists tend to focus on a more determined conception that includes some undetermined aspects. Our analyses lead to reflections on potential difficulties for interdisciplinary teams in nuclear waste management. We focus on the understanding of the safety assessment, on potential implications for communication between experts from different disciplines (e.g., between experts from the humanities and engineering for risk assessment and risk communication), and we reflect on the roles of different disciplines in nuclear waste management.     

Dangerous Climate Change: The Role for Risk Research

The notion of "dangerous climate change" constitutes an important development of the 1992 United Nations Framework Convention on Climate Change. It persists, however, as an ambiguous expression, sustained by multiple definitions of danger. It also implicitly contains the question of how to respond to the complex and multi-disciplinary risk issues that climate change poses. The invaluable role of the climate science community, which relies on risk assessments to characterize system uncertainties and to identify limits beyond which changes may become dangerous, is acknowledged. But this alone will not suffice to develop long-term policy. Decisions need to include other considerations, such as value judgments about potential risks, and societal and individual perceptions of "danger," which are often contested. This article explores links and cross-overs between the climate science and risk communication and perception approaches to defining danger. Drawing upon nine articles in this Special Issue of Risk Analysis, we examine a set of themes: limits of current scientific understanding; differentiated public perceptions of danger from climate change; social and cultural processes amplifying and attenuating perceptions of, and responses to, climate change; risk communication design; and new approaches to climate change decision making. The article reflects upon some of the difficulties inherent in responding to the issue in a coherent, interdisciplinary fashion, concluding nevertheless that action should be taken, while acknowledging the context-specificity of "danger." The need for new policy tools is emphasised, while research on nested solutions should be aimed at overcoming the disjunctures apparent in interpretations of climate change risks.     

Decidedly Different: Expert and Public Views of Risks from a Radioactive Waste Repository

A questionnaire with items that had been used in a national survey of the general public was administered to persons attending an American Nuclear Society meeting. The items asked about risks associated with high-level nuclear waste (HLNW), trust in nuclear-waste program managers, costs and benefits of a repository project, and images of a HLNW repository. The results suggest that nuclear industry experts may have very different opinions from the general public about most of these items and their images of a repository indicate a vastly different conceptual framework within which their opinions are formed.     

Developing and Testing a Facility Location Model for Canadian Nuclear Fuel Waste

The purpose of this paper is to develop and test a facility location model for the siting of a nuclear fuel waste disposal facility in Canada. The model is based on successful Canadian siting processes related to hazardous waste and low level radioactive waste facilities, as well as attributes of facility siting found in the literature. The proposed model was presented to a sample of participants in the federal environmental assessment review of the technical feasibility of the Canadian Nuclear Fuel Waste Disposal Concept (CNFWDC) held throughout Canada in 1990. Results demonstrate that despite the fact that over half of the survey respondents did not support the CNFWDC during the public hearings, the majority favorably rated the proposed facility location model. Components of the model that were tested included siting criteria and goals, decision-making groups, and siting safeguards. On the basis of these results, it is concluded that the siting of a nuclear fuel waste disposal facility must make the decentralization of decision-making authority to local communities and governments a priority.     

Advancing Risk‐Informed Decision Making in Managing Defense Nuclear Waste in the United States: Opportunities and Challenges for Risk Analysis

An omnibus spending bill in 2014 directed the Department of Energy to analyze how effectively Department of Energy (DOE) identifies, programs, and executes its plans to address public health and safety risks that remain as part of DOE's remaining environmental cleanup liabilities. A committee identified two dozen issues and associated recommendations for the DOE, other federal agencies, and the U.S. Congress to consider, as well as other stakeholders such as states and tribal nations. In regard to risk assessment, the committee described a risk review process that uses available data, expert experience, identifies major data gaps, permits input from key stakeholders, and creates an ordered set of risks based on what is known. Probabilistic risk assessments could be a follow‐up from these risk reviews. In regard to risk management, the states, in particular, have become major drivers of how resources are driven. States use different laws, different priorities, and challenge DOE's policies in different ways. Land use decisions vary, technology choices are different, and other notable variations are apparent. The cost differences associated with these differences are marked. The net result is that resources do not necessarily go to the most prominent human health and safety risks, as seen from the national level.     

Health Risk Assessment for Planned Waste Incinerators: Getting the Right Science and the Science Right

Health risk assessment is widely advocated in the United Kingdom as the most comprehensive means of assessing the health risks posed by the emissions of a planned waste incinerator. Its main advantage over other methods of assessment, such as air quality impact assessment, is its ability to address explicitly the direct (inhalation) and indirect (ingestion and dermal contact) health risks posed by different chemicals, including those that are not thought to have a threshold below which no adverse effect will take place. This article examines the level and quality of the emissions assessments included in 61 waste incinerator environmental statements (ESs); in particular, it focuses on the quality of the exposure assessment and risk characterization stages of the health risk assessment process. The article concludes that the ES has not always provided interested stakeholders with the best available information upon which to determine the tolerability of the health risks posed by waste incinerator emissions Some recommendations are made as to how this problem might be addressed in future environmental impact assessment (EIA) processes.     

Attitudes Toward Managing Hazardous Waste: What Should Be Cleaned Up and Who Should Pay for It?

Hazardous waste policy in the United States uses a liability-based approach, including strict, retroactive, and joint and several liability. To assess attitudes toward these basic principles of liability, and toward priorities for clean-up of wastes, a questionnaire was mailed to legislators, judges, executives of oil and chemical companies, environmentalists, and economists. The questionnaire consisted of abstract, simplified cases, which contrasted basic principles rather than dealing with real-world scenarios. Subjects were asked how they would allocate clean-up costs between companies and government as a function of such factors as adherence to standards, adoption of best available technology (BAT), and influence of penalties on future behavior. Most subjects felt that, if the company followed government standards or used the best available technology (BAT), it should pay for only a portion of the clean-up cost, with the government paying the rest. In general, responses did not support the principles underlying current law–strict, retroactive, and joint-and-several liability. Most subjects were more interested in polluters paying for damages than in deterrence or future benefit–even to the extent that they would have "harmless" waste sites cleaned up. A bias was found toward complete clean-up of some sites, or "zero risk." Different groups of subjects gave similar answers, although more committed environmentalists were more willing to make companies pay and to clean up waste regardless of the cost.     

The Rise and Fall of a Risk-Based Priority System: Lessons from DOE's Environmental Restoration Priority System

This paper presents the history of the Environmental Restoration Priority System (ERPS), a decision aid developed by the U.S. Department of Energy (DOE) to help determine how to allocate funds for cleaning up hazardous waste sites. Although praised in technical peer review, the system was strongly criticized by stakeholders external to the DOE. Ultimately, and in the midst of a National Academy of Sciences review, DOE shelved the system. The rise and fall of ERPS provides useful lessons for analysts hoping to improve risk management in the public sector.     

Applications of probabilistic risk assessments: the selection of appropriate tools

Probabilistic risk assessment (PRA) is an important methodology for assessing the risks of complex technologies. This paper discusses the strengths and weaknesses of PRA. Its application is explored in three different settings: adversarial policy processes, regulatory/licensing procedures, and plant safety audits. It is concluded that PRA is a valuable tool for auditing safety precautions of existing or planned technologies, especially when it is carried out as an interactive process involving designers and plant personnel who are familiar with actual, everyday operations. PRA has not proven to be as well-suited in providing absolute risk estimates in public-policy debates concerning the acceptability of a technology, or for the licensing and regulatory procedures. The reasons for this are discussed.     

The Role of the Community in the Implementation of the EPA's Rule on Risk Management Programs for Chemical Accidental Release Prevention

Regulations under the 1990 Clean Air Act Amendments (CAAA) include requirements for preventing accidental chemical releases. Section 112(r) of the CAAA, the Accidental Release Provisions, requires the U.S. Environmental Protection Agency (EPA) to develop and implement regulations for preventing accidental releases to the air of regulated substances and to minimize the consequences of releases that do occur. The regulations require regulated facilities to have in place the structural elements of a sound process safety program, and to practice, document, and communicate the elements of their program. The rule requires also that registered facilities calculate and make available worst case accidental chemical release information. The rule does not set a level of risk that a facility must achieve after it takes the required compliance steps, the level of risk a community must accept, the limit of consequences the community might suffer from a worst case chemical release, nor the specific actions a community must take in its response plan. These are issues that local communities and local officials must decide. Because the regulation involves the community in many unsettled risk issues the Wharton School initiated a project within the City Philadelphia to evaluate the proposition that productive dialogue on the implementation of the Rule and resolution of unsettled risk issues can take place in advance of a crisis occasioned by a major accidental release. This paper describes the steps taken by Wharton to bring together various stakeholders in the community to explore the implementation of the rule and the reaction of those stakeholders to be involved in such a process. It outlines some principal choices communities will have to make in order to implement 112(r) and explains some of the dilemmas associated with these choices. It describes the stakeholder-based implementation effort being undertaken in Philadelphia in the hope that others may benefit from what has been learned there.     

Attitudes and Risk Perceptions of Stakeholders in a Nuclear Waste Siting Issue

Stakeholders are often regarded as a critically important group in such issues as the siting of nuclear facilities. In this article, stakeholders were identified on the basis of self-reported activities with regard to a nuclear waste siting issue under debate in four communities. Data were obtained in an extensive mailed survey from a total of 2,548 respondents, approximately an equal number from each community. The overall response rate was 43.9%. Some of the results and telephone interviews with a sample of the nonrespondents indicated that the data are reasonably representative of the respective populations. Stakeholder activities were measured by 20 questions and combined with an index of stakeholder activity level, dichotomized at the 90th percentile. Stakeholders were found to have a higher level of education than others, but otherwise they did not differ in demographics. They did not tend to see risks in general as high, but were quite interested and involved in the nuclear waste siting issue. The stakeholder activity level correlated with risk perception and attitudes in the waste siting issue, but with different signs for those who were for and those who were opposed: stakeholders of both types had more extreme views than others, but in different directions. In addition, stakeholder opponents were much more likely to strongly espouse extreme statements regarding the project than were supporters who also were stakeholders. Implications for risk management and communication are discussed.     

Multicriteria Decision Analysis: A Comprehensive Decision Approach for Management of Contaminated Sediments

Contaminated sediments and other sites present a difficult challenge for environmental decisionmakers. They are typically slow to recover or attenuate naturally, may involve multiple regulatory agencies and stakeholder groups, and engender multiple toxicological and ecotoxicological risks. While environmental decision-making strategies over the last several decades have evolved into increasingly more sophisticated, information-intensive, and complex approaches, there remains considerable dissatisfaction among business, industry, and the public with existing management strategies. Consequently, contaminated sediments and materials are the subject of intense technology development, such as beneficial reuse or in situ treatment. However, current decision analysis approaches, such as comparative risk assessment, benefit-cost analysis, and life cycle assessment, do not offer a comprehensive approach for incorporating the varied types of information and multiple stakeholder and public views that must typically be brought to bear when new technologies are under consideration. Alternatively, multicriteria decision analysis (MCDA) offers a scientifically sound decision framework for management of contaminated materials or sites where stakeholder participation is of crucial concern and criteria such as economics, environmental impacts, safety, and risk cannot be easily condensed into simple monetary expressions. This article brings together a multidisciplinary review of existing decision-making approaches at regulatory agencies in the United States and Europe and synthesizes state-of-the-art research in MCDA methods applicable to the assessment of contaminated sediment management technologies. Additionally, it tests an MCDA approach for coupling expert judgment and stakeholder values in a hypothetical contaminated sediments management case study wherein MCDA is used as a tool for testing stakeholder responses to and improving expert assessment of innovative contaminated sediments technologies.     

A Review of the High-Level Nuclear Waste Repository Siting Analysis

We critique two 1986 Department of Energy reports concerning the selection of sites for characterization as the nation's first high-level nuclear waste repository. We find that the multiattribute utility analysis of the five nominated sites was well done, although we express concern about the assessed probabilities, question the construction of two important attribute scales, and disagree with some of the value tradeoffs that were used. In contrast, we find the logic of the recommendations report to be weak and unconvincing.     

Role of Comparative Risk Assessment in Addressing Environmental Security in the Middle East

During the 21st century, environmental challenges are likely to intensify across the world and possibly lead to violent conflicts. Strategies for conflict avoidance will be incomplete unless they recognize, discuss, and mitigate regional environmental stress factors. Comparative risk assessment (CRA) is one of the most critical tools emerging to influence modern environmental policies and is increasingly used to create a common language to help reconcile competing interests in development and environmental disputes around the world. This article considers the environmental challenges facing the Middle East in light of their "transboundary" nature and proposes CRA as a framework for setting environmental priorities and reducing tensions in the region.