Development of the Supercontainer Design for Deep Geological Disposal of High-Level Heat Emitting Radioactive Waste in Belgium

2006 ◽  
Vol 932 ◽  
Author(s):  
Johan J.P. Bel ◽  
Stephen M. Wickham ◽  
Robert M.F. Gens
Keyword(s):  
Selection Process ◽  
Metal Corrosion ◽  
Preliminary Evaluation ◽  
Spent Fuel ◽  
Deep Geological Disposal ◽  
Reference Design ◽  
And Performance ◽  
High Level ◽  
Design Options ◽  
Future Work

ABSTRACTONDRAF-NIRAS has recently selected a Supercontainer with a Portland Cement (PC) buffer as the preferred new reference design for disposal of HLW and spent fuel. The selection process involved a multi-criteria analysis of alternative design options, which were evaluated against a range of long-term safety and feasibility criteria. A PC concrete has been chosen for the buffer because this will provide a highly alkaline chemical environment, which will last for thousands of years. In this environment the external surface of the overpack will be passivated and overpack corrosion will be inhibited. The concrete buffer also has low-hydraulic conductivity to slow the infiltration of external fluids to the overpack surface, and provides radiological shielding.ONDRAF-NIRAS has made a preliminary evaluation of the viability of the reference Supercontainer design. The following areas were reviewed and investigated: radiolysis, thermo-hydraulic (TH) behaviour of the concrete buffer, metal corrosion, the chemical and mineralogical evolution of the concrete buffer, and relevant industrial experience. This paper describes the main findings, and identifies remaining design and performance uncertainties. Prioritisation and recommendations for future work are also given.

Deep Borehole Repository of HLW and SF - State of knowledge by SITEX.Network

2021 ◽  
Author(s):  
Nadja Zeleznik ◽  
Muriel Richer ◽  
Colin Wales ◽  
Frédéric Bernier ◽  
Doncho Karastanev ◽  
...  
Keyword(s):  
Selection Process ◽  
Deep Borehole ◽  
Spent Fuel ◽  
Safety Issues ◽  
Technical Developments ◽  
Borehole Repository ◽  
Safety Case ◽  
High Level ◽  
A Site ◽  
Design Options

<p>Many countries develop geological disposal projects for high-level radioactive waste (HLW) and/or spent fuel (SF) when considered as waste. The most widely selected option is the deep geological repository (DGR) concept, a mined repository with galleries located underground in geological layers into which packaged waste would be placed; the sites for such DGR have been selected in Finland, France and Sweden, and a site selection process is on-going in several other countries, such as in the United Kingdom, Germany and Switzerland.</p><p>As an alternative concept to the DGR, the deep borehole repository (DBR) concept, where waste packages are placed into single boreholes, relies on a similar safety strategy: confining and isolating the waste from the biosphere and surface natural phenomena in order to respectively rely on the geological environment to ensure long term passive safety and reduce the risk of human intrusion. The concept of DBR was first considered in the 1950s, but was rejected until the 2000s as it was far beyond existing drilling capabilities among others, given the constraints for HLW and SF management.</p><p>New technical developments in the drilling field relaunched the interest of a safe management of HLW and SF based on DBR concept in several countries. Therefore, the SITEX.Network association developed an overview of the existing studies that have been published on the DBR concept with information on the concept itself, on deployment strategies and methods, on issues associated with requirements related to waste packages and borehole equipment, hydro-geology, disposal operation, backfilling and sealing, and finally on safety analyses. The main aim is to provide bibliographical overview providing the state of knowledge about the DBR concept, the technical solutions for its implementation or major obstacles evidenced as a basis to identify safety issues important to deal with in a Safety Case. This could be considered to identify for the future R&D as well. This paper discusses also the controversial issue of DBR trying to provide information from different viewpoints, like the design options, R&D programs required, societal concerns and regulatory needs.</p>

Preliminary evaluation of applicants to master's programs in speech-language pathology using vignettes and criteria from a holistic review process

2021 ◽  
Author(s):  
Teresa Girolamo ◽  
Stephen Politzer-Ahles ◽  
Samantha Ghali ◽  
BRITTANY WILLIAMS
Keyword(s):  
Linguistic Diversity ◽  
Preliminary Evaluation ◽  
Barriers To Entry ◽  
Speech Language Pathology ◽  
Master's Programs ◽  
Cultural And Linguistic Diversity ◽  
Holistic Review ◽  
Language Pathology ◽  
High Level ◽  
Future Work

Purpose: Little is known about how others evaluate applicants to master’s programs in speech-language pathology along criteria used during holistic review, despite more programs adopting holistic review. This knowledge gap limits our understanding of whether holistic admissions may offer a more equitable pathway to entering speech-language pathology. This study investigated how faculty and Ph.D. students evaluated applicants to master’s speech-language pathology programs along criteria used during holistic review.Method: We administered a survey online through a Qualtrics platform. Respondents (N = 66) were faculty and Ph.D. candidates in U.S. speech-language-hearing departments. Survey blocks included demographics, professional background, and vignettes. Vignettes featured profiles of applicants to master’s programs in speech-language pathology. Vignettes systematically varied in the indicators of applicant criteria, which were specified at low, moderate, or high levels, or not specified. After reading each vignette, respondents rated the applicant and indicated their admissions decision. Analysis included descriptives.Results: Relative to an applicant who was at a high level for all indicators except cultural and linguistic diversity, respondents ranked applicants who varied in their indicators of criteria levels lower. Respondents were also less likely to make an explicit “accept” decision (versus “waitlist” or “reject”) for this latter group of applicants. Conclusion: Even when implementing criteria used during holistic review, applicants who vary from a “high-achieving” stereotype may still face barriers to entry. Future work is needed to understand the precise nature of how holistic admissions review may play out in actual practice and help increase diversity in the profession.

Centralization of Canada’s Spent Nuclear Fuel

2013 ◽  
Author(s):  
Krista Nicholson ◽  
John McDonald ◽  
Shona Draper ◽  
Brian M. Ikeda ◽  
Igor Pioro
Keyword(s):  
Nuclear Fuel ◽  
Site Selection ◽  
Nuclear Power ◽  
Power Plants ◽  
Spent Nuclear Fuel ◽  
Selection Process ◽  
Spent Fuel ◽  
Geologic Repository ◽  
Candu Reactors ◽  
High Level

Currently in Canada, spent fuel produced from Nuclear Power Plants (NPPs) is in the interim storage all across the country. It is Canada’s long-term strategy to have a national geologic repository for the disposal of spent nuclear fuel for CANada Deuterium Uranium (CANDU) reactors. The initial problem is to identify a means to centralize Canada’s spent nuclear fuel. The objective of this paper is to present a solution for the transportation issues that surround centralizing the waste. This paper reviews three major components of managing and the transporting of high-level nuclear waste: 1) site selection, 2) containment and 3) the proposed transportation method. The site has been selected based upon several factors including proximity to railways and highways. These factors play an important role in the site-selection process since the location must be accessible and ideally to be far from communities. For the containment of the spent fuel during transportation, a copper-shell container with a steel structural infrastructure was selected based on good thermal, structural, and corrosion resistance properties has been designed. Rail has been selected as the method of transporting the container due to both the potential to accommodate several containers at once and the extensive railway system in Canada.

Supporting Development of Practical Designs for a Japanese HLW Repository

2009 ◽  
Vol 1193 ◽  
Author(s):  
Hitoshi Makino ◽  
Hiroyuki Umeki ◽  
Yasuhiro Ochi ◽  
Kazumasa Hioki ◽  
Hiroo Okubo ◽  
...  
Keyword(s):  
Paradigm Shift ◽  
Knowledge Engineering ◽  
Companion Paper ◽  
Formal Knowledge ◽  
Reference Design ◽  
Novel Approaches ◽  
High Level ◽  
Design Options ◽  
Hlw Repository ◽  
Systematic Catalogue

AbstractIn preparation for actual repository implementation, designs that could be tailored to specific sites need to be considered. This requires a paradigm shift in design philosophy, moving away from a single reference design towards a flexible and systematic “catalogue” of engineered barrier components and associated repository infrastructure. To support this development, novel methodology for both developing and comparing repository design options for Japanese vitrified high-level radioactive waste (HLW) has been examined. This paper will outline the background of the project and, in particular, some novel approaches examined for facilitating optimisation of practical repository designs. It is complemented by a companion paper - Matsumoto et al: Application of Formal Knowledge Engineering Approaches to Develop A Design Catalogue for A Japanese HLW Repository -, which describes the repository design process in more detail and illustrates results of first dry runs of the methodology.

scholarly journals Fabrication and Characterisation of Aligned Discontinuous Carbon Fibre Reinforced Thermoplastics as Feedstock Material for Fused Filament Fabrication

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4671
Author(s):  
Lourens Blok ◽  
Marco Longana ◽  
Benjamin Woods
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
Selection Process ◽  
Fibre Composite ◽  
Fibre Length ◽  
Fused Filament Fabrication ◽  
Continuous Fibre ◽  
And Performance ◽  
Reinforced Thermoplastics ◽  
High Level

In this work, aligned discontinuous fibre composite (ADFRC) tapes were developed and investigated as precursors for a novel 3D printing filament. ADFRCs have the potential to achieve mechanical performance comparable to continuous fibre reinforced composites, given sufficient fibre length and high level of alignment, and avoid many of the manufacturing difficulties associated with continuous fibres, e.g., wrinkling, bridging and corner radii constraints. Their potential use for fused filament fabrication (FFF) techniques was investigated here. An extensive down-selection process of thermoplastic matrices was performed, as matrix properties significantly impact both the processing and performance of the filament. This resulted in four candidate polymers (ABS, PLA, Nylon, PETG) which were used to manufacture ADFRC tapes with a Vf of 12.5% using the high performance discontinuous fibre (HiPerDiF) technology and an in-house developed continuous consolidation module. Tensile stiffness and strength up to 30 GPa and 400 MPa respectively were recorded, showing that a discontinuous fibre filament has the potential to compete with continuous fibre filaments.

Key Phenomena Governing HLW Glass Behavior in the French Deep Geological Disposal

2015 ◽  
Vol 1744 ◽  
pp. 127-138
Author(s):  
Stéphan Schumacher ◽  
Christelle Martin ◽  
Yannick Linard ◽  
Frédéric Angeli ◽  
Delphine Neff ◽  
...  
Keyword(s):  
Sustainable Management ◽  
Near Field ◽  
Steel Corrosion ◽  
Spent Fuel ◽  
Water Leaching ◽  
Residual Rate ◽  
Partially Saturated ◽  
Deep Geological Disposal ◽  
High Level ◽  
Glass Behavior

ABSTRACTAccording to the Planning Act of 28th June 2006, Andra is in charge of ensuring the sustainable management of all radioactive waste generated in France, especially the high-level and long-lived vitrified waste produced from spent fuel recycling.Since 2006, all the studies and research related to the components of HLW cells have been incorporated into a broader R&D program which aims at characterizing and modeling (i) the glass matrix dissolution, (ii) the corrosion of the overpack and the lining, and (iii) the claystone evolution in the near field, considering all the interactions between these surrounding materials. This program, coordinated by Andra, has involved up to eighteen laboratories.After closure of disposal cells and overpack failure, glass alteration is expected to begin in partially saturated conditions due to hydrogen production resulting from carbon steel corrosion in anoxic conditions. Therefore, the glass should at least partially be hydrated by water vapor during thousands of years until complete saturation. A part of the studies aimed to determine the glass behavior in such conditions, the influence of the main parameters (temperature, relative humidity) and consequences of vapor hydration on subsequent radionuclides release by water leaching.In addition, the major part of the work focused on the influence of the environment on glass alteration. The effect of clay pore water on glass alteration rates (initial rate, rate drop and residual rate) was determined and particularly that of pH and magnesium. The nature of steel corrosion products and their interactions with glass alteration were also investigated. All these studies relied on experiments in surface laboratories, in Andra’s underground laboratory, together with natural or archeological analogs and modeling studies.

Modelling sorption data for the actinides Am(III), Np(V) and Pa(V) on montmorillonite

2006 ◽  
Vol 94 (9-11) ◽  
Author(s):  
Michael H. Bradbury ◽  
B. Baeyens
Keyword(s):  
Near Field ◽  
High Level Waste ◽  
Spent Fuel ◽  
Data Set ◽  
Sorption Data ◽  
Deep Geological Disposal ◽  
Retention Characteristics ◽  
High Level ◽  
Trace Concentrations ◽  
First Time

The retention characteristics of the bentonite near-field engineered barrier proposed in most of the concepts for the deep geological disposal of high-level waste and spent fuel are an important component in repository performance assessment studies. Montmorillonite generally constitutes 65 to 90 wt.% of the bentonite. Sorption edge measurements have been performed at trace concentrations for the actinides Am(III), Np(V) and Pa(V) on purified and conditioned SWy-1 montmorillonite under anoxic, carbonate free conditions. To the best of the author´s knowledge, this is the first time a sorption data set has been measured for

scholarly journals Preliminary modelling of radionuclide migration in the argillaceous sediments of the Sumer Formation (Northwestern Bulgaria)

2020 ◽  
Vol 49 (3) ◽  
pp. 13-18
Author(s):  
Dimitar Antonov ◽  
Madlena Tsvetkova ◽  
Doncho Karastanev
Keyword(s):  
Radioactive Waste Disposal ◽  
High Level Waste ◽  
Spent Fuel ◽  
Radionuclide Migration ◽  
Geological Disposal ◽  
Disposal Facility ◽  
Deep Geological Disposal ◽  
High Level ◽  
Host Rocks ◽  
Selection Of

In Bulgaria, from the preliminary analyses performed for site selection of deep geological disposal of high-level waste (HLW) and spent fuel (SF), it was concluded that the most promising host rocks are the argillaceous sediments of the Sumer Formation (Lower Cretaceous), situated in the Western Fore-Balkan Mts. The present paper aims to compare the transport of three major radionuclides from a hypothetical radioactive waste disposal facility, which incorporates an engineering barrier of bentonite into the argillaceous (marl) medium. The simulations were performed by using HYDRUS-1D computer programme. The results are used for a preliminary estimation of argillaceous sediments as a host rock for geological disposal of HLW.

IAEA's Coordinated Research Programmes on Performance of High Level Wastes in Deep Geological Repositories

2006 ◽  
Vol 932 ◽  
Author(s):  
J.L. Gonzalez ◽  
P. Van Iseghem
Keyword(s):  
Waste Form ◽  
Spent Fuel ◽  
Significant Progress ◽  
Energy Agency ◽  
Basic Understanding ◽  
Research Programmes ◽  
Deep Geological Repositories ◽  
And Performance ◽  
High Level ◽  
Form Development

ABSTRACTThe main conclusions of a Coordinated Research Programmes organized by the International Atomic Energy Agency on the performance of high-level wastes in deep geological repositories are summarized in this paper. The programme ran from 1997 till 2004. Glass, spent fuel and ceramics were the waste forms considered. The 13 participating countries reported their R&D including waste form development, basic understanding of the waste form properties and the performance in simulated disposal conditions. Significant progress has been achieved on the various issues. Recommendations are formulated as to integrate the R&D with the geological disposal conditions and performance assessment considerations, or to conceive generic studies in preparation of the above approach.

Design Options for the UK’s ILW Geological Disposal Facility

2009 ◽  
Author(s):  
Tim Hicks ◽  
Matt White ◽  
Tamara Baldwin ◽  
Neil Chapman ◽  
Fiona Neall ◽  
...  
Keyword(s):  
Public Consultation ◽  
High Level Waste ◽  
Geological Environment ◽  
Spent Fuel ◽  
Geological Disposal ◽  
Disposal Facility ◽  
Wide Range ◽  
The Uk ◽  
High Level ◽  
Design Options

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.

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