scholarly journals Microbiology of Barrier Component Analogues of a Deep Geological Repository

2021 ◽  
Author(s):  
Rachel C Beaver ◽  
Katja Engel ◽  
W. Jeffrey Binns ◽  
Josh Neufeld
Keyword(s):  
Nuclear Fuel ◽  
Selection Process ◽  
Crystalline Rock ◽  
Opalinus Clay ◽  
Rrna Gene ◽  
Deep Geological Repository ◽  
Used Nuclear Fuel ◽  
Geological Repository ◽  
Clay Formation

Canada is currently implementing a site selection process to identify a location for a deep geological repository (DGR) for the long-term storage of Canada’s used nuclear fuel, wherein used nuclear fuel bundles will be sealed inside copper-coated carbon steel containers, encased in highly compacted bentonite clay buffer boxes and sealed deep underground in a stable geosphere. Because a DGR must remain functional for a million years, there is value to examining ancient natural systems that serve as analogues for planned DGR components. Specifically, studying the microbiology of natural analogue components of a DGR is important for developing an understanding of the types of microorganisms that may be able to grow and influence the long-term stability of a DGR. This study explored the abundance, viability, and composition of microorganisms in several ancient natural analogues using a combination of cultivation and cultivation-independent approaches. Samples were obtained from the Tsukinuno bentonite deposit (Japan) that formed ~10 mya, the Opalinus Clay formation (Switzerland) that formed ~174 mya, and Canadian shield crystalline rock from Northern Ontario that formed ~2.7 bya. Analysis of 16S rRNA gene amplicons revealed that three of the ten Tsukinuno bentonite samples analyzed were dominated by putative aerobic heterotrophs and fermenting bacteria from the Actinobacteria phylum, whereas five of the Tsukinuno bentonite samples were dominated by sequences associated with putative acidophilic chemolithoautotrophs capable of sulfur reduction.

scholarly journals SITE SELECTION FOR CANADA’S NATIONAL REPOSITORY FOR USED NUCLEAR FUEL

2015 ◽  
Vol 4 (2) ◽  
pp. 99-104
Author(s):  
Mahrez Ben Belfadhel ◽  
Bob Watts ◽  
Jo-Ann Facella
Keyword(s):  
First Nations ◽  
Nuclear Fuel ◽  
Site Selection ◽  
Selection Process ◽  
Well Being ◽  
Deep Geological Repository ◽  
Used Nuclear Fuel ◽  
Starting Point ◽  
Geological Repository ◽  
Initial Starting

In 2007, the Government of Canada selected Adaptive Phased Management as Canada’s plan for the long-term management of Canada’s used nuclear fuel. The approach provides for containment and isolation of the material in a deep geological repository at a safe site with an informed and willing host. The Nuclear Waste Management Organization is tasked through federal legislation with selecting the site and developing and managing all aspects of the plan. In May 2010, the organization published and initiated the site selection process that serves as a road map for decision making on the location for the deep geological repository. It continues to lead the site selection process for the repository and an associated Centre of Expertise. The screening process is advancing and, from an initial starting point of 22 communities expressing interest in learning about the project; as of September 2015, 9 communities are the focus of more detailed technical and community well-being studies. Preliminary Assessments, the third step in the 9-step site selection process are underway in these communities. The Assessments involve preliminary technical and social desktop and field assessments, engagement activities within and beyond each interested community, and involvement of Indigenous peoples and nearby municipalities in the planning and conduct of the work. This paper provides an update on the advancement of the site selection process. It describes the nature of the technical and social studies being conducted at this phase of work, including the progressively more detailed field studies that are the focus of technical work at the current stage, the approach to engagement and collaboration with communities to direct these studies, and the work underway to ensure the framework used for this assessment and engagement includes the range of priorities and perspectives of First Nations and Métis peoples and communities in the broader area.

A Numerical Simulation of Diffusion Experiment in Clay

2011 ◽  
Vol 322 ◽  
pp. 353-356
Author(s):  
Qing Chun Yang
Keyword(s):  
Numerical Simulation ◽  
Opalinus Clay ◽  
Isotropic Case ◽  
Diffusion Experiment ◽  
Deep Geological Repository ◽  
Transport Distance ◽  
Geological Repository ◽  
Geological Formation ◽  
Clay Formation ◽  
Anisotropic Case

Safety assessment of nuclear waste disposal in a deep geological repository requires understanding and quantifying radionuclide transport through the hosting geological formation. Determining diffusion parameters under real conditions is necessary for the performance assessment of a deep geological repository where high level wastes are placed for safety disposal. The in situ diffusion and retention (DR) experiments are designed to study the transport and retention properties of the Opalinus clay formation. In this paper, a scoping numerical simulation is performed in Opalinus Clay, The simulated results for all the traces illustrate that the maximum transport distance perpendicular to the bedding is larger in the isotropic case and those along the bedding is larger in the anisotropic case. Tracer depletion in the isotropic case is a little larger than in the anisotropic case. Deuterium and iodide can be detected in the other interval but strontium can’t. Since the length of injection interval is shorter than the transport distance, the anisotropy effect is clearly measurable. This numerical simulation of diffusion experiment aims at contributing to the optimum design of the experiment. The results of this experiment will provide additional insight into the role of diffusion anisotropy and sorption parameters for radionuclides in clays.

scholarly journals Status of Geoscientific Site Evaluations for Canada’s Deep Geological Repository for Used Nuclear Fuel

2020 ◽  
Author(s):  
Sarah Hirschorn ◽  
Alec Blyth ◽  
Andy Parmenter ◽  
Maria Sanchez-Rico Castejon ◽  
Andre Vorauer
Keyword(s):  
Nuclear Fuel ◽  
Deep Geological Repository ◽  
Used Nuclear Fuel ◽  
Geological Repository

scholarly journals Lifetimes of Used Nuclear Fuel Containers Affected by Sulphate-Reducing Bacteria Reactions inside the Canadian Deep Geological Repository

2021 ◽  
Vol 11 (17) ◽  
pp. 7806
Author(s):  
Jorge A. Garcia-Hernandez ◽  
Kumaraswamy Ponnambalam ◽  
Mythreyi Sivaraman
Keyword(s):  
Nuclear Fuel ◽  
Host Rock ◽  
Bentonite Clay ◽  
Reaction Diffusion ◽  
Deep Geological Repository ◽  
Sulphate Reducing Bacteria ◽  
Used Nuclear Fuel ◽  
Geological Repository ◽  
Sulphide Production ◽  
Reducing Bacteria

The present work aims at approximating the reduction of sulphate to sulphide caused by sulphate-reducing bacteria (SRB) inside the Canadian deep geological repository in order to calculate the expected lifetime of used nuclear fuel containers (UFCs). Previous studies have assumed a conservative constant concentration of sulphide at the host rock interface. The novelty of this study resides in the use of first-order kinetics to explicitly account for the SRB-induced sulphide production. This reaction term is developed following an empirical approach using published results on actual sulphate reduction by SRB and included in a coupled reaction-diffusion system. Lifetimes of UFCs are subsequently calculated following the conditions of two scenarios: having SRB active only at the region closest to the host rock and having SRB active at the host rock and throughout the bentonite clay. This study shows that the mean lifetimes of UFCs in both cases are above one million years. However, more accurate results would require the characterization of the host rock and groundwater of the prospective emplacement, as well as additional experiments on growth and sulphide production by the microbial communities from the site.

Project Opalinus Clay – Geoscientific Basis for the Demonstration of Feasibility of Disposal (Entsorgungsnachweis) for SF, Vitrified HLW and Long-Lived ILW in Switzerland

2003 ◽  
Vol 807 ◽  
Author(s):  
A. Gautschi ◽  
A. Lambert ◽  
P. Zuidema
Keyword(s):  
Radioactive Waste ◽  
Host Rock ◽  
Opalinus Clay ◽  
Geological Environment ◽  
Deep Geological Repository ◽  
Geological Repository ◽  
National Cooperative

ABSTRACTNagra - the Swiss National Cooperative for the Disposal of Radioactive Waste - has completed a study to determine the suitability of Opalinus Clay as a host rock for a SF/HLW/ILW repository in a potential siting area (reference repository site) in the Zürcher Weinland in northeastern Switzerland. Geoscientific information has been used to a wide extent for the demonstration of siting and engineering feasibility, and for the demonstration of long-term safety. It is shown that the selected area in the Zürcher Weinland fulfils the fundamental requirements placed on a siting area for a deep geological repository and that, in terms of the Opalinus Clay host rock option, the geological environment is advantageous.

New Perspectives for the Spent Nuclear Fuel Radionuclides Release Model in a Deep Geological Repository

2006 ◽  
Vol 985 ◽  
Author(s):  
Christophe Poinssot ◽  
Cécile FERRY ◽  
Arnaud POULESQUEN
Keyword(s):  
Nuclear Fuel ◽  
Source Term ◽  
Spent Nuclear Fuel ◽  
Deep Geological Repository ◽  
Term Evolution ◽  
Geological Repository ◽  
Definition Of ◽  
Release Model ◽  
The Impact

AbstractSpent Nuclear Fuel (SNF) source terms are used to define the release rate of radionuclides (RN) in a direct disposal and to assess the performance of this waste form. They classically distinguish between two contributions: (i) the Instant Release Fraction (IRF) of RN which are directly leached when water contacts the fuel, (ii) the slow and long term release of RN which are embedded within the fuel matrix. Recent experimental results bring significant input in our understanding and assessment of both contributions. However, they have not yet been integrated in the definition of the SNF source term. This paper will present the impact on the RN source term of the latest results on the SNF long term evolution and the key remaining scientific issues.

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