[en] Large scale demonstration experiments in underground research laboratories (both onsite and off-site) are currently undertaken by most high level radioactive waste management organisations. The decision to plan and implement prototype experiments, which might have a life of several decades, has both important strategic and budgetary consequences for the organisation. Careful definition of experimental objectives based on the design and safety requirements is critical. The implementation requires the involvement of many parties and needs flexible but consequent management as, for example, additional goals for the experiments, identified in the course of the implementation, might jeopardise initial primary goals. The outcomes of an international workshop in which European and Japanese implementers (SKB, Posiva, Andra, ONDRAF, NUMO and Nagra) but also certain research organisations (JAEA, RWMC) participated identified which experiments are likely to be needed depending on the progress in implementing a disposal programme. Already earlier in a programme, large scale demonstrations are generally performed aiming at reducing uncertainties identified during the safety case development such as thermo-hydraulic-mechanical process validation in the engineered barrier system and target host rock. Also feasibility testing of underground construction in a potential host rock at relevant depth might be required. Later in a programme, i.e., closer to the license application, large scale experiments aim largely at demonstrating engineering feasibility and performance confirmation of complete repository components. Ultimately, before licensing repository operation, 1:1 scale commissioning testing will be required. Factors contributing to the successful completion of large scale demonstration experiments in terms of planning, defining the objectives, optimising results and main lessons learned over the last 30 years are being discussed. The need for international coordination in defining the objectives of new large scale demonstration experiments is addressed. The paper is expected to provide guidance to implementing organisations (especially those in their early stages of the programme), considering participating in and/or or conducting on their own large scale experiments in the near future. (authors)

[en] The Nuclear Waste Management Organization of Japan (NUMO) is presently establishing a Requirements Management System (RMS) which has two main goals: providing an overview of the complex balancing of technical and socio-political requirements which form the basis for decision making in the nuclear waste management field; serving as a tool to guide day-to-day management of long-term, multi-disciplinary projects. The complex interactions between different requirements and the way in which these change as the programme develops makes RMS implementation a challenging task, but this should be aided by a relational database software tool which is currently under development. (author)

[en] Based on the Act on Final Disposal of Specified Radioactive Waste, the Nuclear Waste Management Organization of Japan (NUMO) was established in October 2000 as the implementing organization for geological disposal of the radioactive waste. Since its establishment NUMO has been developing the technologies required for implementation of the project and initiated the solicitation of the disposal site by volunteering from the municipalities. However, no effective application has been received as yet to initiate the site investigation. Thus NUMO decided to prepare the NUMO 2010 Technical Report as a tool for improving the general understanding of the geological disposal project. The report will present the safety policy that describes how NUMO aims to achieve safety geological disposal through the ca.100-year-long project and will document the progress made with developing the technologies that support the safety concept. Three policies for ensuring safety are described namely a) staged and flexible project implementation and decision making based on iterative confirmation of safety, b) project implementation based on reliable technologies and c) technical activities for building confidence in NUMO's safety concept. The report also summarizes the technological development for implementation of the geological disposal project in Japan. (author)

[en] The Gas Migration Test (GMT) experiment was initiated in the summer of 1997 under the auspices of RWMC (Radioactive Waste Management Center, Japan). It is part of the experiments conducted within Phase V (1997-2002) of Nagra's Underground Rock Laboratory at Grimsel, in the Swiss Alps. The currents status and results from the site characterization activities and laboratory studies are presented. Future plans are also outlined. Copyright (2001) Material Research Society

[en] The Nuclear Waste Management Organization of Japan (NUMO) has initiated a volunteering approach to siting a repository for HLW. This places special constraints on the process of developing repository designs; in particular, the need for a high degree of flexibility in order to respond to the specific geological environments which may come forward. In order to meet this challenge, NUMO has developed a highly structured process for tailoring designs to siting environments, which comprises: establishment of a catalogue of design components which can be combined as required to meet site properties, a bottom-up approach to assess the limitations of specific repository components within the range of geological characteristics expected in Japanese sites, top-down use of multi-attribute analysis to compare sites and designs, iterative feedback from design studies to site characterisation and R and D plans, an integrated requirements management system; ensuring transparent documentation of all decisions and assisting co-ordination of project development. The staged site-selection procedure provides hard deadlines for input from the repository design team for deciding: on the basis of literature studies, which volunteers will be carried forward as 'Preliminary Investigation Areas' and subject to surface-based field work, which of these will then be nominated as 'Detailed Investigation Areas' and further characterised with an underground test facility, and the final choice of the repository site. As the first two of these deadlines should fall within the next decade, NUMO has leapfrogged the more traditional analysis of idealised repository concepts to concentrate on designs which would be practical and safe to construct and operate and on the 'next generation' PA tools required to analyse these on a site-specific basis. (author)

[en] The history of nuclear technology development has generated a legacy of nuclear fear in many people, which becomes more acute when the problem of radioactive waste is highlighted. Thus a significant element of increasing confidence in nuclear power is to generate confidence in the industry's ability to safely dispose of its waste. The use of natural analogues as a key vehicle for such communication is now recognised as an influential approach. This paper will examine how analogues can be used to convey difficult concepts to stakeholders and develop an outline communication programme. (author)

[en] Many of the present designs of repositories for radioactive wastes derive from generic feasibility studies which emphasize post-closure safety. These include little (or no) treatment of the practicality of safe and quality-assured construction of engineered barriers under the conditions (humidity, dust, etc.) and requirements (emplacement rate, remote handling, etc.) of an operational underground facility. Indeed, as soon as attempts are made to demonstrate such concepts in-situ at full scale, considerable practical problems are encountered and, in many cases, additional engineering components are introduced (liners, borehole caps, grouts, rock-bolts, drainage systems, etc.) which could be detrimental to - or at leas t complicate - the long-term safety case. As the discrepancy between the idealized concepts illustrated in performance assessment and the actual systems which are shown to be feasible grows, there is a critical need for design rationalization. Such a process needs to include careful balancing of factors influencing safety during the operational phase - which should not be compromised - with those which contribute to potential hazards which occur only in the distant future. Apart from such almost philosophical considerations, the robustness of the EBS construction procedure to possible operational perturbations needs serious consideration. Even if closed and sealed repositories are very insensitive to disruptive events such as earthquakes, hurricanes, industrial actions and terrorist actions, the operational system may be more vulnerable to perturbation. Designs should be introduced which, to the greatest extent possible, not only fail safe, but are also easy to remedy (or reverse) in case the assurance of EBS quality is lost. This paper will expand on ideas for a second generation of clay-based EBS designs, which are both practical and safe. Associated requirements for R and D and performance assessment model development will also be outlined, with a particular focus on issues directly related to highly compacted bentonite as a key component of the EBS. (authors)