Optimal ways of disposal of highly radioactive waste

Pusch, Roland; Knutsson, Sven; Al-Taie, Laith; Mohammed, Mohammed Hatem

doi:10.4236/ns.2012.431118

Cited by 20 publications

(16 citation statements)

References 4 publications

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“…First, the buffer and backfill materials are assumed to have a high permeability of 10 −13 m 2 , either by design-i.e., no hydraulic safety function is assigned to these materialsor as a result of thermal, mechanical, or chemical degradation processes [21,28,59,60], which generate leakage pathways in the backfill itself or along the interface between the backfill and the formation. Because the buffer has no hydraulic barrier function in this scenario, it is simply referred to as backfill, so is the material in the access hole.…”

Section: Disruptive Scenariosmentioning

confidence: 99%

Sealing of a Deep Horizontal Borehole Repository for Nuclear Waste

Finsterle¹,

Cooper

Muller

et al. 2020

Energies

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The depth and layout of a horizontal borehole repository has the potential to offer strong isolation of nuclear waste from the surface. However, the isolation may be compromised by the borehole used to access the repository, as it could provide a direct fast-flow path transporting radionuclides from the disposal section to the accessible environment. Thus, backfilling the disposal section and sealing the access hole are considered essential engineered safety components. To analyze the importance of plugging the open space between canisters and sealing the access hole, we numerically calculate non-isothermal fluid flow and radionuclide transport through the borehole and the surrounding geosphere for a variety of scenarios, which include backfill materials with different sealing properties and configurations that potentially induce strong driving forces along both the horizontal and vertical sections of the borehole. The simulations indicate that the dose contribution of radionuclides released through the access hole is small, even if the backfill material is of poor quality or has deteriorated, and even if considerable horizontal and vertical pressure gradients are imposed by assuming the underlying formation is overpressured and that the disposal section is intersected by faults activated during a seismic event. The modeling also reveals that the low influence of backfill integrity on repository performance partly arises from the very high length-to-diameter ratio of the borehole, which favors the radial diffusion of radionuclides—as well as pressure dissipation and associated advective transport—into the surrounding formation rather than axial transport along the borehole. The integrated modeling approach also exposes the importance of accounting for the connections and feedback mechanisms among the various subcomponents of the repository system.

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Section: Disruptive Scenariosmentioning

confidence: 99%

Sealing of a Deep Horizontal Borehole Repository for Nuclear Waste

Finsterle¹,

Cooper

Muller

et al. 2020

Energies

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“…These systems are used for radioactive waste repositories of different levels of activity and are intended to provide safe storage for several hundreds or thousands years due to their high adsorption capacity for radionuclides and low water permeability [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Montmorillonite Structure and Transformation of Its Properties under Treatment with Inorganic Acid Solutions

et al. 2017

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This paper discusses the mechanism of montmorillonite structural alteration and modification of bentonites' properties (based on samples from clay deposits Taganskoye, Kazakhstan and Mukhortala, Buriatia) under thermochemical treatment (treatment with inorganic acid solutions at different temperatures, concentrations and reaction times). Treatment conditions were chosen according to those accepted in chemical industry for obtaining acid modified clays as catalysts or sorbents. Also, more intense treatment was carried out to simulate possible influence at the liquid radioactive site repositories. A series of methods was used: XRD, FTIR, ICP-AES, TEM, nitrogen adsorption, and particle size analysis. It allowed revealing certain processes: transformation of montmorillonite structure which appears in the leaching of interlayer and octahedral cations and protonation of the interlayer and -OH groups at octahedral sheets. In turn, changes in the structure of the 2:1 layer of montmorillonite and its interlayer result in significant alterations in the properties: reduction of cation exchange capacity and an increase of specific surface area. Acid treatment also leads to a redistribution of particle sizes and changes the pore system. The results of the work showed that bentonite clays retain a significant portion of their adsorption properties even after a prolonged and intense thermochemical treatment (1 M HNO 3 , 60 • C, 108 h).

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“…These systems are used for radioactive waste depositories of different activity and intended to provide storage safety for several hundreds or thousands years due to the high adsorption capacity and low water permeability [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Montmorillonite Structure and Transformation of its Properties under the Treatment of Inorganic Acid Solutions

Krupskaya

Закусин

Tyupina

et al. 2016

Preprint

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Abstract:The paper discusses the mechanism of montmorillonite structure alteration and bentonites properties modification (on the example of samples from clay deposit Taganka, Kazakhstan) due to the thermochemical treatment (treatment with inorganic acid solutions at different temperatures, concentrations and reaction times). With the use of the suit of methods certain processes were distinguished: transformation of montmorillonite structure, which appears in the leaching of interlayer and octahedral cations, protonation of the interlayer and OH groups at octahedral sheets. Changes in the structure of the 2:1 layer of montmorillonite and its interlayer result in significant changes in the properties -reduction of cation exchange capacity and an increase of specific surface area. The results of the work showed that bentonite clays retain a significant portion of its adsorption properties even after the long term and intense thermochemical treatment (6M HNO3, 60°C, 108 hours)

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Optimal ways of disposal of highly radioactive waste

Cited by 20 publications

References 4 publications

Sealing of a Deep Horizontal Borehole Repository for Nuclear Waste

Sealing of a Deep Horizontal Borehole Repository for Nuclear Waste

Experimental Study of Montmorillonite Structure and Transformation of Its Properties under Treatment with Inorganic Acid Solutions

Experimental Study of Montmorillonite Structure and Transformation of its Properties under the Treatment of Inorganic Acid Solutions

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