Disposal of high-level radioactive waste in crystalline rock: On coupled processes and site development

Zou, Liangchao; Cvetković, Vladimir

doi:10.1016/j.rockmb.2023.100061

Cited by 19 publications

(3 citation statements)

References 65 publications

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“…While recycling would allow the re-use of a large proportion of the components and structure of the micro-power units thus minimizing lower-level and medium-level nuclear waste, an increase in energy production from nuclear power would inevitably lead to an increase in spent fuel that would need to be processed and stored. This could be achieved at the site of the factory in the short to medium term, as is common practice at conventional large nuclear power plants, prior to long-term storage in geological disposal facilities currently planned or under construction for existing spent fuel in various countries [ 52 , 53 ].…”

Section: Economic Socio-political and Technical Implicationsmentioning

confidence: 99%

The commoditization of civil nuclear power

Patterson,

Taylor

2024

R. Soc. Open Sci.

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The commoditization of nuclear power through the factory production of sealed micro-power units within a digitally enabled holistic assurance framework is described. This would revolutionize nuclear power-plant design, construction, operation and decommissioning through a paradigm shift to manufacture–operate–remove–recycle (MORR). The potential impact of recent research on an integrated nuclear digital environment for large bespoke nuclear power plants and the design, build and operation of fusion power plants using such a digital environment is explored. These strands are interwoven to discuss the technical, economic and socio-political implications of MORR in the context of micro-reactors and to consider the potential evolution of safeguarding issues based on a digital assurance framework that leads to type approvals. Commoditization of nuclear power would lower costs in line with offshore wind and the output from a single production line in a factory could replace a third of current fossil fuel-based electricity generation in the UK over a 15-year period, making a significant contribution to achieving zero greenhouse gas emissions. The challenges associated with the changes in culture, both in the nuclear industry and in society, as well as the technology gaps, that need to be addressed in realizing this paradigm shift are identified and discussed.

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Section: Economic Socio-political and Technical Implicationsmentioning

confidence: 99%

The commoditization of civil nuclear power

Patterson,

Taylor

2024

R. Soc. Open Sci.

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“…In addition, since granite is a representative of the crystal rocks, which is considered to be one of the most favorable host rocks for the final disposal of high-level radioactive waste (HLW), several studies have also evaluated the change in permeability of a flow path by passing a highly alkaline Ca solution through a microflow cell with granite chips, taking into account various subsurface conditions. − Of them, Niibori et al evaluated the permeability using two kinds of granite chips; one chip was roughly ground, and another was polished to mirror-like surface. The results showed that the permeability decreased and partially increased due to the formation and extrusion of deposits for the rough surface, while the permeability change for the mirror-like surface was small.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Changes in Effective Fracture Aperture with Deposition of Calcium Silicate Hydrate on Granite Surface Under Highly Alkaline Saline Conditions Using a Microflow Cell

Seki,

Furiya,

Chida

et al. 2024

ACS EST Water

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In the highly alkaline environment caused by cementitious materials around radioactive repositories, C−S−H phases are expected to form on groundwater flow paths and retard radionuclide migration by clogging the flow paths. This study evaluated the effective fracture aperture of a flow path using a microflow cell under highly alkaline saline conditions. Experiments showed a decrease in the effective fracture aperture with time, even under 600 mM NaCl, due to the deposition of C−S−H gels. Furthermore, a mathematical model was proposed to estimate the apparent elution rate of silicic acid and the apparent formation rate of C−S−H gel with consideration given to the deposition and detachment of C−S−H gels in the flow path. These apparent rate constants increased slightly with the NaCl concentration. This may be due to the replacement of H + on silanol groups with Na + and the formation of Si−O−Na, which has a large ionic length and angle, and promotes the elution of silicic acid and the deposition of C−S−H gels. These suggest the potential for deposition of C−S−H phases and clogging of groundwater flow paths, even under saline conditions.

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“…It is also for the sake of retrievability that the French concept does not call for HL waste packages to be surrounded by an engineered barrier, as is the case with most other concepts in Scandinavia, Switzerland and Canada [3][4][5][6][7]. However, Andra is proposing that the liner should be surrounded on its extrados by an alkaline filling material, in order to limit technological voids, the effects of acidity of the geological environment [8] and the corrosion kinetics of the steels.…”

Section: Introductionmentioning

confidence: 99%

DIGIT: An In Situ Experiment for Studying the Diffusion of Water and Solutes under Thermal Gradient in the Toarcian Clay Rock at the Tournemire Underground Research Laboratory: Part 1—Goals, Scoping Calculations, Installation and First Results under Unheated Conditions

Humbezi Desfeux,

Marcoux,

Matray

et al. 2024

Minerals

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The DIGIT experiment was launched at the Tournemire Underground Research Laboratory URL with the aim of determining the effects of temperature on the transfer of analogues of most mobile radionuclides (i.e., 36Cl, 129I and 79Se) in the Toarcian clay rock, the properties of which are close to host rocks being considered for future deep geological disposal of high-level (HL) radioactive wastes. The experimental principle involves the monitoring of an exchange between a test water traced with stable halides and deuterium at constant concentration and the porewater of the Toarcian clay rock submitted to various temperatures. This experiment seeks to partially address questions regarding the potential spread of contaminants during the thermal phase of High Level Waste (HLW) waste packages. Specifically, the in situ experiment aims to evaluate the role of scale effects and thermodiffusion, a process that combines Fick’s law and the Soret effect, in the transfer of radionuclides. This paper presents the first steps of the study, including the scoping calculations, the experimental set-up and the first results obtained during the unheated phase. The study started with the acquisition of the initial parameters, including the rock thermal properties, the concentrations of the four tracers (chloride, bromide, iodide and deuterium) naturally present in the clay porewater and their diffusive transport parameters by using four diffusion exchange techniques (phase 0). A model coupling heat and mass transfers was then developed using Comsol Multiphysics®, integrating data acquired so far with existing literature data. A test water with a tracer concentration around 1000 times higher than those in the pore water was proposed with a temperature imposed at the test section wall of 70 °C. A large test zone of 50 cm height and 1 m in diameter and installed in a 3 m deep vertical well located in a sound zone at the URL was then proposed. The installation of the experiments required the realization of one shaft and of nine peripheral boreholes for the monitoring of temperature, water pressure and deformation. The experiment started with phase 1, involving a traced, unheated water start-up for a period of 5 months. Then, a core sampling was conducted in the emptied well, and the same diffusion exchange techniques were applied. The results of anionic tracers were compared to simulations based on initial parameters (phase 0), revealing that tracer penetration at the end of phase 1 exceeded simulated values by approximately 2 cm. This result is interpreted as an increase in the accessible porosity to tracers, possibly due to the excavation damaged zone. Future simulations should incorporate these adjusted diffusive transport parameters. Following phase 1, the heating system was activated, applying a temperature of 70 °C to the test zone. New data will enable the comparison of tracer penetration and assess the actual impact of temperature on tracer transfer.

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Disposal of high-level radioactive waste in crystalline rock: On coupled processes and site development

Cited by 19 publications

References 65 publications

The commoditization of civil nuclear power

The commoditization of civil nuclear power

Evaluation of the Changes in Effective Fracture Aperture with Deposition of Calcium Silicate Hydrate on Granite Surface Under Highly Alkaline Saline Conditions Using a Microflow Cell

DIGIT: An In Situ Experiment for Studying the Diffusion of Water and Solutes under Thermal Gradient in the Toarcian Clay Rock at the Tournemire Underground Research Laboratory: Part 1—Goals, Scoping Calculations, Installation and First Results under Unheated Conditions

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