Over the last few years, a major national programme of public consultation has been under way in the UK resulting, in 2006, in the announcement by government of geological disposal as the most appropriate solution for the long-term management of the UK’s long-lived and higher-activity radioactive waste and the launch, in 2008, of an implementation programme. The approach being pursued is to solicit volunteer communities to host a geological disposal facility, which may contain not only intermediate-level waste (ILW) and some low-level waste (LLW), but also high-level waste (HLW), any spent fuel (SF) declared as waste, and potentially other materials that may be declared as waste. These wastes have different physical, chemical, thermal and radiological characteristics, and different concepts will be required to accommodate their disposal, potentially in a single facility. The volunteer approach means that the geological environment that might eventually emerge as the preferred location is not known at the outset. Indeed, the siting process may require evaluation of several different geological environments because the UK has rich geological variability for such a small landmass. Consequently, the Nuclear Decommissioning Authority (NDA), which is charged with designing, developing and implementing a geological disposal facility, has investigated facility designs that could be appropriate for a wide range of host rocks and geological environments. This paper presents the results of a project carried out on behalf of the NDA to collate and report information on concepts for the geological disposal of ILW/LLW; a separate project carried out a parallel evaluation of options for disposing of HLW and SF. Initially, the range of geological disposal facility design options available worldwide for the disposal of ILW/LLW was evaluated. Nine disposal concepts were identified and reviewed that would cater for any geological environment likely to arise in the UK. These concepts have different engineering and operational aspects. The appropriateness of each option for implementation in five different generic geological environments was assessed using expert judgement, with input from the NDA, consultants and the UK regulatory agencies. The paper presents a set of generic designs derived from the study and discusses the key issues that would need to be addressed should any of these designs be considered for implementation in specific geological environments in the UK. The findings of this work are intended to provide a resource to support comparisons of alternative disposal concepts and the identification of designs suitable for the disposal of UK ILW/LLW in different geological environments.
NUMO (Nuclear Waste Management Organization of Japan) has the responsibility for implementing deep geological disposal of high-level (HLW) and transuranic (TRU) radioactive waste from the Japanese nuclear programme. A formal Requirements Management System (RMS) is planned to efficiently and effectively support the computerised implementation of the management strategy and the methodology required to drive the step-wise siting processes, and the following repository operational phase. The RMS will help in the comprehensive management of the decision-making processes in the geological disposal project, in change management as the disposal system is optimised, in driving projects such as the R&D programme efficiently, and in maintaining structured records regarding past decisions, all of which lead to soundness of the project in terms of long-term continuity. The system is planned to have information handling and management functions using a database that includes the decisions/requirements in the programme under consideration, the way in which these are structured in terms of the decision-making process and other associated information. A two-year development programme is underway to develop and enhance an existing trial RMS to a practical system. Functions for change management, history management and association with the external timeline management system are being implemented in the system development work. The database format is being improved to accommodate the requirements management data relating to the facility design and to safety assessment of the deep geological repository. This paper will present an outline of the development work with examples to demonstrate the system’s practicality. In parallel with the system/database developments, a case research of the use of requirements management in radioactive waste disposal projects was undertaken to identify key issues in the development of an RMS for radioactive waste disposal and specify a number of use cases to guide the overall development of the system. The findings of the case research will also be shown in the paper to provide general information on the application of an RMS in a radioactive waste disposal programme, the difficulties of successful implementation and suggestions on how these difficulties can be overcome.
The Full-Scale Demonstration Of Plugs And Seals (DOPAS) Project is a European Commission programme of work jointly funded by the Euratom Seventh Framework Programme and European nuclear waste management organizations (WMOs). The DOPAS Project aims to improve the industrial feasibility of plugs and seals, the measurement of their characteristics, the control of their behaviour over time in repository conditions, and their hydraulic performance with respect to safety objectives.Within the project, an approach has been developed and applied to assess the compliance of two of the full-scale experiments to their design bases. The approach involves a review of each requirement in the design basis and the strategy used to demonstrate compliance of the experiment with that requirement. Feedback in the form of proposed updates to the design statements is captured by this approach. Learning points on plugs and seals from the compliance assessment are also noted for consideration in the DOPAS Project outcomes. This developed compliance and assessment approach can be employed as part of, or in conjunction with, other more generic approaches used by WMOs, including monitoring, full-scale testing and the documentation of construction procedures.
Long-term surface storage of intermediate-level radioactive waste (ILW) has become an important issue for regulators and site operators in the UK following deferral of the Nirex deep repository for the disposal of ILW, and the resulting hiatus in Government policy. This paper identifies some key life-cycle issues associated with interim safe storage (ISS) of ILW, and also some of the key features of existing stores. Important risk management issues include store design and environmental controls, conditioning and packaging, package handling and cranes, operation, monitoring of waste packages, package retrieval, external environmental factors, stakeholder issues and costs. All of these issues will need to be addressed during the design, construction and operation of an ILW store. Given the wide and diverse range of issues requiring consideration, it may be difficult to choose between alternative design concepts or risk management strategies. We demonstrate a multi-criteria decision analysis approach to ILW storage in which the various attributes of alternative store designs and management strategies are scored and collectively compared using the program OnBalance. By varying the weighting of the different attributes, the sensitivity of the overall score of the various designs to their attributes may be evaluated. Ultimately, the technical issues related to store design, construction and operation will have to be balanced against the non-technical factors that may influence the development of a store, particularly those related to stakeholder interactions and public concerns. Developing a long-term interim storage strategy requires a holistic approach that embraces all of these factors.
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