Development of Improved Methodology for the Comparative Assessment of Potential Repository Concepts and Locations

2007 ◽  
Author(s):  
Hiroyuki Tsuchi ◽  
Akihisa Koike ◽  
Shoko Sato ◽  
Hideki Kawamura
Keyword(s):  
Radioactive Waste ◽  
Comparative Assessment ◽  
Careful Selection ◽  
Economic Issues ◽  
Attribute Analysis ◽  
Geological Repository ◽  
Pros And Cons ◽  
High Level ◽  
Technical Assessment ◽  
Selection Of

NUMO has adopted a volunteering approach to siting a geological repository for high-level radioactive waste (HLW). It is important for this process that the pros and cons of volunteers can be assessed from literature data in a clear and transparent manner, prior to the very careful selection of those sites that will be carried forward for more detailed characterisation. For this purpose, multi-attribute analysis (MAA) methodology has been developed that allows the technical assessment of criteria to be represented as scoring models. The trickier job of weighting different criteria involves expert opinion, which can be solicited by different methods. In particular, weighting of top-level attributes involves balancing a range of technical and socio-economic issues, which can be examined by considering the viewpoint of different stakeholders. The applicability of the MAA tool and its sensitivity to stakeholder viewpoints have been examined by simple case studies.

NUMO’s Open Solicitation of Volunteer Municipalities for a Potential Disposal Site

2003 ◽  
Author(s):  
Kazumi Kitayama
Keyword(s):  
Radioactive Waste ◽  
Preliminary Investigation ◽  
Disposal Site ◽  
Nuclear Waste Management ◽  
The Public ◽  
Construction Operation ◽  
High Level ◽  
Year 2000 ◽  
Selection Of

In the year 2000, the Japanese geological disposal program for high-level radioactive waste (HLW) moved from the phase of generic research and development into the phase of implementation. Following legislation entitled the “Specified Radioactive Waste Final Disposal Act” (hereafter “the Act”), the Nuclear Waste Management Organization of Japan (NUMO) was established as the implementing organization in October 2000. The assigned activities of NUMO include repository site selection, developing relevant license applications and construction, operation and closure of the repository. To initiate the first stage, NUMO has chosen an “open solicitation” approach for finding candidate sites in the belief that the support of local communities is essential to the success of this highly public, long-term project extending over more than a century. Based on this concept, NUMO announced the start of open solication for volunteer municipalities for selection of Preliminary Investigation Areas to the public on December 19, 2002. This paper describes NUMO’s open solicitation of volunteer municipalities for a potential disposal site.

Repository Site Characterization: Comparing International Experience

2009 ◽  
Author(s):  
Martin Goldsworthy ◽  
Till Popp ◽  
Knut Seidel ◽  
Johannes Bruns
Keyword(s):  
Radioactive Waste ◽  
Selection Process ◽  
International Experience ◽  
Geological Repository ◽  
Clay Cover ◽  
Under Construction ◽  
High Level ◽  
A Site ◽  
Hlw Repository ◽  
The Ideal

An important part of the work described here was a study of existing international experience in investigating deep geological repository sites. The objective of this study was to derive a basis for planning the content and extent of investigations which might be carried out in Germany in the future. Such investigations would be required in the course of a site selection process for a repository for HLW (high level radioactive waste). For this purpose information on suitable sites was gathered, mainly from literature sources. Suitable in this context meant two things. Firstly, the investigated site should be in rock similar to four being considered in Germany (salt, clay, crystalline and other hard rock under a clay cover). Secondly, the investigations carried out could reasonably be considered as being intended to lead to the use of the site as a repository. The investigation processes were presented, analysed and compared. The comparison was based on the quality and the intensity of the methods employed to obtain the information necessary for deciding between candidate repository sites in terms of safety and the feasibility of construction. In the final stage of the work the analysis and presentation method developed for the international sites was applied to the investigations already carried out at three German sites (Gorleben — a prospective HLW repository, Morsleben — an existing but now not operational repository for radioactive waste and Konrad — a repository currently under construction). The reported investigatory work was compared with the ideal investigations developed on the basis of the existing international experience.

Corrosion Behavior of Simulated LLW Glass in Deionized Water

2009 ◽  
Vol 1193 ◽  
Author(s):  
Toshikatsu Maeda ◽  
Tetsuji Yamaguchi ◽  
Katsutoshi Hotta ◽  
Tsuyoshi Mizuno ◽  
Tsunetaka Banba
Keyword(s):  
Radioactive Waste ◽  
Volume Ratio ◽  
Deionized Water ◽  
Water Volume ◽  
Dissolution Mechanism ◽  
Chemical Compositions ◽  
High Concentration ◽  
Geological Repository ◽  
One Year ◽  
High Level

AbstractStatic leach tests were conducted for simulated low-level radioactive waste (LLW) glass in deionized water at 90 °C for up to one year to investigate the dissolution mechanism of LLW glass. Widely studied leaching behavior of high-level radioactive waste (HLW) glass is referred in discussing the dissolution mechanism. LLW glass is characterized by higher sodium (Na) and aluminum (Al) contents than HLW glass, about twice as high as R7T7, with its SiO2 content close to HLW glass. Powdered simulated LLW glass of three different chemical compositions was tested with the glass-surface-to-water-volume ratio of 2,000 m−1. The release rates of boron (B), widely used as an indicator of dissolution for HLW glass, decreased with time during leaching, as commonly observed in similar tests for HLW glass. The pH of the leachate was stable around 11.3 - 11.6, which is higher than those in similar tests for HLW glass by one pH unit or more. The concentrations of Al in the leachates were higher compared to data for HLW glass by two orders of magnitude. The high concentration seems to be caused by higher pH. In the leachate condition of the present tests, a zeolitic mineral (analcime) is thermodynamically more stable than amorphous silica (SiO2(am)) which is known to control the concentration of dissolved silica (Si) with respect to HLW glass. The present results imply that dissolution of the LLW glass is accompanied with formation of analcime under virtually closed systems such as geological repository where the groundwater flow rate is quite low.

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