Deterministic and Probabilistic Analysis Supporting the Safety Case for a Proposed Deep Geological Repository in Opalinus Clay in Northern Switzerland

2004 ◽  
pp. 3349-3354
Author(s):  
J. W. Schneider ◽  
L. Johnson ◽  
P. Zuidema ◽  
G. Mayer
Keyword(s):  
Probabilistic Analysis ◽  
Opalinus Clay ◽  
Deep Geological Repository ◽  
Northern Switzerland ◽  
Geological Repository ◽  
Safety Case

The Swiss Strategy for HLW Siting; Parallel Investigation of two Alternative Host Rocks

1994 ◽  
Vol 353 ◽  
Author(s):  
C. McCombie ◽  
I.G. McKinley ◽  
A. Lambert ◽  
M. Thury ◽  
P. Birkhäuser
Keyword(s):  
Opalinus Clay ◽  
Current Status ◽  
Alternative Host ◽  
Deep Geological Repository ◽  
Northern Switzerland ◽  
Geological Repository ◽  
Site Characterisation ◽  
Host Rocks ◽  
Year 2000 ◽  
Hlw Repository

AbstractRegional characterisation studies of two potential host rocks for a HLW repository - the crystalline basement and the Opalinus clay of Northern Switzerland - have now been completed and documented. Application is now proceeding for the legally required federal, cantonal and communal drilling permits to initiate parallel local investigations in both these formations. The decision to continue with work in both formations is a departure from previously published plans which is intended to maximise the probability that the next major milestone in the HLW programme - demonstrating the feasibility of siting for a deep geological repository in Switzerland - can be reached by the year 2000. This paper reviews the current status of the Swiss HLW programme and outlines the planned “Phase II” site characterisation of the two chosen sites.

Building the Safety Case for a Disposal Facility for Spent Fuel, HLW and Long-lived ILW in Switzerland

2002 ◽  
Vol 713 ◽  
Author(s):  
Paul A. Smith ◽  
Piet Zuidema ◽  
Lawrence H. Johnson ◽  
Jürg W. Schneider ◽  
Peter Gribi
Keyword(s):  
Development Strategy ◽  
Current Understanding ◽  
Opalinus Clay ◽  
Safety Concept ◽  
Spent Fuel ◽  
Northern Switzerland ◽  
Disposal Facility ◽  
Wide Range ◽  
Geological Repository ◽  
Safety Case

ABSTRACTThis paper describes a generic methodology for building the safety case for a geological repository, which is currently being applied to a possible facility for spent fuel, vitrified highlevel waste and long-lived intermediate-level waste in the Opalinus Clay of Northern Switzerland. The methodology involves:1. the identification of certain basic disposal principles,2. the choice of a disposal system, via a flexible repository development strategy,3. the derivation of the system concept, based on current understanding of the phenomena that characterise, and may influence, the disposal system and its evolution,4. the derivation of a safety concept, based on reliable, well understood and effective pillars of safety,5. the illustration of the radiological consequences of the disposal system through the definition and analysis of a wide range of assessment cases, and6. the compilation of the arguments and analyses that constitute the safety case, as well as guidance for future stages of the repository programme. A range of measures, including audits, are used to promote completeness of the phenomena considered in the safety case, and to avoid inadvertent bias.

Results of a Recent Safety Assessment of a Proposed Deep Geological Repository in the Opalinus Clay of the Zu¨rcher Weinland in Northern Switzerland

2003 ◽  
Author(s):  
J. W. Schneider ◽  
L. H. Johnson ◽  
P. Zuidema ◽  
P. Gribi ◽  
G. Mayer ◽  
...  
Keyword(s):  
Safety Assessment ◽  
Opalinus Clay ◽  
High Level Waste ◽  
Deep Geological Repository ◽  
Spent Fuel ◽  
Actual Performance ◽  
Northern Switzerland ◽  
Low Concentrations ◽  
Geological Repository ◽  
High Level

A safety assessment of a proposed deep geological repository for the direct disposal of spent UO2 or mixed-oxide fuel, vitrified high-level waste from the reprocessing of spent fuel and long-lived intermediate-level waste in the Opalinus Clay of the Zu¨rcher Weinland of northern Switzerland is described. The assessment methodology is systematic and transparent, and includes the analysis of a broad range of assessment cases, as well as complementary analyses and the formulation of more qualitative arguments. Analyses show compliance with Swiss regulatory Protection Objectives in all cases, and safety indicators complementary to dose and risk further illustrate the low concentrations and fluxes of radioactivity that are expected. No outstanding issues are identified with the potential to compromise safety. The existence of phenomena that are beneficial to safety, but are deliberately (and conservatively) excluded from the assessment (reserve FEPs) indicates that the actual performance of the repository will be even more favourable than the results of the analyses suggest.

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.

The Safety Case for a Deep Geological Repository: More Than Just Presenting Numbers

2001 ◽  
Author(s):  
Jürg W. Schneider ◽  
Lawrence H. Johnson ◽  
Piet Zuidema ◽  
Paul A. Smith ◽  
Peter Gribi
Keyword(s):  
Waste Management ◽  
Safety Assessment ◽  
Management Programme ◽  
Deep Geological Repository ◽  
Natural Analogue ◽  
Full Spectrum ◽  
Independent Evidence ◽  
Geological Repository ◽  
Safety Case

Abstract A convincing safety case is a prerequisite for positive decisions in the stepwise process of planning and implementing a deep geological repository. In addition to evaluations of dose or risk, a safety case must provide arguments that the system and its safety functions are well understood, that the methods, models and data used in the evaluations are applicable, and have been correctly applied, and that the full spectrum of possibilities for the characteristics of the repository system and its evolution has been taken into account in defining the cases to be evaluated. This paper takes examples from the Swiss waste management programme and from natural analogue studies to illustrate how the safety functions for a repository are taken into account in a safety assessment and how independent evidence can be used to support the statement that these safety functions will operate as expected.

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.

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.

Natural and Anthropogenic Analogues for High-Level Nuclear Waste Disposal Repositories: A Review

2021 ◽  
Author(s):  
Mostafa Fayek ◽  
Julie Brown
Keyword(s):  
Nuclear Waste ◽  
Spatial Scales ◽  
Deep Geological Repository ◽  
Geological Time ◽  
Geological Repository ◽  
Safety Case ◽  
Natural Analogues ◽  
High Level Nuclear Waste ◽  
High Level

ABSTRACT Projects involving deep geological disposal of nuclear waste are unique in that predictive models of long-term safety often involve geological timeframes. This manuscript provides a review of natural and anthropogenic analogues for high-level nuclear waste disposal in a deep geological repository. We also occasionally highlight analogues that have been used for low- and intermediate-level waste. Most studies define natural analogues as either naturally occurring or anthropogenic systems. In this paper, we distinguish between natural analogues and anthropogenic analogues because the latter generally provide non-technical (anecdotal) illustrations of concepts and processes for the safety case, whereas the former can provide technical and quantitative information. In addition, natural analogues can provide information over geological time scales (millions of years) and spatial scales (kilometers), whereas anthropogenic analogues provide information over a much more limited time scale (hundreds or thousands of years). Regardless of the definition, analogue studies provide one of the multiple lines of evidence intended to increase confidence in the safe geological disposal of high-level nuclear waste. They are deemed necessary because they complement the experiments that are carried out over a period of months or years. They also provide a way to validate numerical long-term safety assessment models with information and data covering geological time scales and spatial scales. The first part of this review describes the analogue concept. The second and third parts provide examples of natural and anthropogenic analogues for engineered barrier systems and natural barriers. Part four describes analogues for complex coupled transport processes. Finally, we discuss general and specific areas of future research. A concerted effort should be made to ensure that there is a transfer of data from the complex, natural analogue field studies to simplistic models which, by necessity, are used to evaluate the long-term safety of deep geological repositories. Field analogue studies should be planned to interface with laboratory experiments and, ultimately, with in situ field experiments, when the final repository site is selected. This will involve using natural analogue data in a quantitative way to support the deep geological repository safety case.

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