Laboratory Investigations on Radiolysis Effects on Rock Salt With Regard to the Disposal of High-Level Radioactive Wastes

1983 ◽  
Vol 26 ◽  
Author(s):  
Norbert Jockwer
Keyword(s):  
Radioactive Waste ◽  
Rock Salt ◽  
Host Rock ◽  
Thermal Cracking ◽  
Radioactive Wastes ◽  
Volatile Components ◽  
High Level Radioactive Waste ◽  
Laboratory Investigations ◽  
High Level

ABSTRACTAs a result of the heat producing high-level radioactive waste, volatile components which are in the host rock will be liberated and further gases will be generated by thermal cracking and radiolysis.

Mineralogical and hydraulic characteristics of mudstone in the Tamusu candidate area in northwest China for high-level radioactive waste geological disposal

Clay Minerals ◽  
2020 ◽  
Vol 55 (1) ◽  
pp. 71-82
Author(s):  
Long Xiang ◽  
Xiaodong Liu ◽  
Pinghui Liu ◽  
Xingfu Jiang ◽  
Chaocheng Dai
Keyword(s):  
Radioactive Waste ◽  
Clay Minerals ◽  
Host Rock ◽  
Single Layer ◽  
Northwest China ◽  
Lake Basin ◽  
Hydraulic Characteristics ◽  
High Level Radioactive Waste ◽  
High Level

AbstractThe Tamusu region in northwest China is a key candidate area for China's clay rock deep geological repositories (DGRs) for high-level radioactive waste (HLRW) as it is composed of a continuous layer of thick lacustrine mudstone. To evaluate this mudstone as a host rock, two special test boreholes were drilled to investigate its spatial distribution and mineralogical and hydraulic characteristics. The southwest boundary and depositional centre of the lake basin were well delineated by boreholes TZK-1 and TZK-2. The continuous single-layer thickness of the target mudstone formation was up to 300 m at a depth of 500–800 m. Three main mineral types were determined, namely carbonates (mainly dolomite and ankerite), analcime and albite, and their abundance was used to distinguish three different facies. Other mineral phases, such as clay minerals (mainly illite and kaolinite), pyrite, hematite, quartz and calcite, were present as admixtures. The presence of carbonates may increase the mechanical strength and analcime may enhance the radionuclide adsorption properties of the mudstone. The self-sealing properties, which may be affected by the small amount of clay minerals, remain to be investigated. The hydraulic conductivity of the mudstone determined via in situ pulse tests ranged from 10–13 to 10–10 m s–1, suggesting that the Tamusu mudstone has ultra-low permeability. The transmissivity of the Tamusu mudstone fluctuated in regions with varying lithologies, but remained relatively constant for consistent lithologies. In summary, these preliminarily results confirm the possible suitability of the target formation as a host rock for DGRs of China's HLRW.

scholarly journals Microscopic and spectroscopic bioassociation study of uranium(VI) with an archaeal Halobacterium isolate

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262275
Author(s):  
Stephan Hilpmann ◽  
Miriam Bader ◽  
Robin Steudtner ◽  
Katharina Müller ◽  
Thorsten Stumpf ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Rock Salt ◽  
Luminescence Spectroscopy ◽  
Spectroscopic Techniques ◽  
High Level Radioactive Waste ◽  
Long Term Storage ◽  
High Level ◽  
The Impact ◽  
Term Storage

The safe disposal of high-level radioactive waste in a deep geological repository is a huge social and technical challenge. So far, one of the less considered factors needed for a long-term risk assessment, is the impact of microorganisms occurring in the different host rocks. Even under the harsh conditions of salt formations different bacterial and archaeal species were found, e. g. Halobacterium sp. GP5 1–1, which has been isolated from a German rock salt sample. The interactions of this archaeon with uranium(VI), one of the radionuclides of major concern for the long-term storage of high-level radioactive waste, were investigated. Different spectroscopic techniques, as well as microscopy, were used to examine the occurring mechanisms on a molecular level leading to a more profound process understanding. Batch experiments with different uranium(VI) concentrations showed that the interaction is not only a simple, but a more complex combination of different processes. With the help of in situ attenuated total reflection Fourier-transform infrared spectroscopy the association of uranium(VI) onto carboxylate groups was verified. In addition, time-resolved laser-induced luminescence spectroscopy revealed the formation of phosphate and carboxylate species within the cell pellets as a function of the uranium(VI) concentration and incubation time. The association behavior differs from another very closely related halophilic archaeon, especially with regard to uranium(VI) concentrations. This clearly demonstrates the importance of studying the interactions of different, at first sight very similar, microorganisms with uranium(VI). This work provides new insights into the microbe-uranium(VI) interactions at highly saline conditions relevant to the long-term storage of radioactive waste in rock salt.

Monitoring and Retrieval of High-Level Radioactive Waste

2020 ◽  
Author(s):  
Volker Mintzlaff ◽  
Joachim Stahlmann
Keyword(s):  
Radioactive Waste ◽  
Host Rock ◽  
Monitoring Program ◽  
Thermal Impact ◽  
Retrieval Process ◽  
Design Requirement ◽  
High Level Radioactive Waste ◽  
Research Platform ◽  
Holistic Analysis ◽  
High Level

<p><strong>Monitoring and Retrieval of High-Level Radioactive Waste</strong></p><p>The retrievability of high-level radioactive waste (HAW) is defined as the option to retrieve previously emplaced waste from a respository. This is a design requirement in many countries, as for example in Germany, justified by the need to react on possible failures in the repository system.</p><p>Retrievability affects the footprint of the repository (Léon-Vargas et al., 2017) and requires a monitoring program (Stahlmann et al., 2018), as the decision on retrieval should be justified on sound basis. For a holistic analysis of the design consequences of retrievability of high-level radioactive waste it is necessary to get information about the retrieval process itself. In TRANSENS, a transdisciplinary research platform for HAW disposal research, the retrieval process will be analyzed in general.</p><p>The presentation will focus on a generic repository approach based upon Stahlmann et al. (2018) modified for the analysis of the retrieval process. Main impacts of the retrieval works on the host rock were identified, as the effects of the redriven emplacement drifts on the repository system. The presentation will focus on these processes and give a short outlook on their consequences for a monitoring program.</p><p> </p><p>Leon Vargas, R.; Stahlmann, J.; Mintzlaff, V. (2017): Thermal impact in the geometrical settings in deep geological repositories for HLW with retrievability and monitoring. 16th International High-Level Radioactive Waste Management Conference (IHLRWM 2017), Charlotte, NC, April 9-13, 2017.</p><p>Stahlmann, J.; Mintzlaff, V.; León Vargas, R.P.; Epkenhans, I. (2018): Normalszenarien und Monitoringkonzepte für Tiefenlager mit der Option Rückholung. Generische Tiefenlagermodelle mit Option zur Rückholung der radioaktiven Reststoffe. ENTRIA-Arbeitsbericht-15. Braunschweig.</p>

scholarly journals Mobilized Mohr-Coulomb and Hoek-Brown Strength Parameters during Failure of Granite in Alxa Area in China for High-Level Radioactive Waste Disposal

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4237
Author(s):  
Cheng ◽  
Xu ◽  
Zheng
Keyword(s):  
Radioactive Waste ◽  
Host Rock ◽  
Axial Stress ◽  
Radioactive Waste Disposal ◽  
Lateral Strain ◽  
Mechanical Behaviors ◽  
Strength Parameters ◽  
High Level Radioactive Waste ◽  
High Level ◽  
Granite Samples

Strength parameters of the host rock is of paramount importance for modelling the behaviors of underground disposal repository of high-level radioactive waste (HLW). Mobilization of strength parameters should be studied for a better understanding and modelling on the mechanical behaviors of the surrounding rock, considering the effect of temperature induced by the nuclear waste. The granite samples cored from NRG01 borehole in Alxa candidate area in China for HLW disposal are treated by different temperatures (T = 20 °C, 100 °C and 200 °C), and then are used to carry out a series of uniaxial and tri-axial compression experiments under various confining pressures (σ3 = 0, 5, 10, 20, and 30 MPa) in this study. With the recorded axial stress—axial strain and axial stress—lateral strain curves, mobilization of both Mohr-Coulomb and Hoek-Brown strength parameters are analyzed with the increasing plastic shear strain. It has been found that NRG01 granite samples show generally similar cohesion weakening and friction strengthening behaviors, as well as the non-simultaneous mobilization of Hoek-Brown strength parameters (mb and s), under the effect of various treatment temperatures. Furthermore, the samples treated by higher temperatures show lower initial values of cohesion, but their initial friction angle and mb values are relatively higher. This should be mainly owing to the thermally induced cracks in the samples. This study should be helpful for a better modelling on the mechanical behaviors of NRG01 granite samples as the host rock of a possible HLW disposal repository.

Natural, Thermal and Radiolytical Gas Liberation in Rock Salt as a Result of Disposed High-Level Radioactive Waste

1985 ◽  
Vol 50 ◽  
Author(s):  
Norbert Jockwer ◽  
Sabine Gross
Keyword(s):  
Radioactive Waste ◽  
Quantitative Determination ◽  
Rock Salt ◽  
Pressure Increase ◽  
Volatile Components ◽  
Crystal Water ◽  
Radiolytic Decomposition ◽  
High Level ◽  
Crystal Boundaries

AbstractRock salt contains crystal water of the hydrated minerals, water in the form of brine inclusions or adsorbed to the crystal boundaries, as well as primary gases. Further gases are produced or liberated due to the disposed high-level, heat producing wastes resulting from the thermal and radiolytic decomposition of the main and secondary constituents.All volatile components which are present in a final repository have an influence on the disposal horizon, promote the spreading of possibly liberated radionuclides, increase corrosion of the containment and may lead to a pressure increase in a disposal borehole. Therefore a qualita-tive and quantitative determination of the components which could be lib-erated from the rock salt as a result of the disposal of high-level wastes is of significance for a final repository.

scholarly journals A systematic approach for surface exploration of sites – a database to research and evaluate suitable methods

2021 ◽  
Vol 1 ◽  
pp. 53-55
Author(s):  
Raphael Dlugosch ◽  
Thies Beilecke ◽  
Tilo Kneuker ◽  
Lukas Pollok ◽  
Lisa Richter ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Waste Disposal ◽  
Rock Salt ◽  
Site Selection ◽  
Systematic Approach ◽  
Crystalline Rock ◽  
Radioactive Waste Disposal ◽  
High Level Radioactive Waste ◽  
Surface Exploration ◽  
High Level

Abstract. The site selection procedure for a high-level radioactive waste repository in Germany is based on the Repository Site Selection Act (StandAG, 2017), which comprises three phases. In phase 2, the Federal Company for Radioactive Waste Disposal (BGE) will conduct surface exploration. Based on the exploratory findings, the further developed preliminary safety analyses, the common requirements and criteria, and socioeconomic potential analyses will be applied feeding into proposed sites for underground exploration. Commissioned by the BGE, the Federal Institute for Geosciences and Natural Resources (BGR) contributes to this procedure with the projects “GeoMePS” and “ZuBeMErk”, which compile and assess geoscientific and geophysical methods and programs for surface exploration. Their common goal is to develop recommendations for surface exploration of siting regions. For this purpose, the BGR has developed a systematic approach that includes (1) deducing 186 exploration targets (Kneuker, 2020) based on the requirements defined by StandAG, (2) compilation of geoscientific and geophysical exploration methods in a database structure, and (3) analysis of case studies of national and international exploration programs for high-level radioactive waste disposal. During step (2) the BGR developed the database “GeM-DB” which utilizes MS SQL Server 2017 and PHP scripts for a browser-based interface (Beilecke, 2021). Both lead to a highly customizable, user-friendly database enabling further adaptations, expansions and analyses of the contents. Merging the knowledge of about 100 BGR experts, the database currently comprises approx. 140 geoscientific and geophysical exploration methods, including basic information and essential metadata to evaluate the general applicability of the methods for surface exploration of the three defined host rocks (crystalline rock, claystone, rock salt). Additionally, the methods are rated according to their suitability for the previously defined exploration targets. An example for a method selection, which is suitable to target fault zones (exclusion criterion 2, StandAG) is given in Fig. 1. In step (3) the BGR screens national and international waste disposal programs exploring for crystalline rock, claystone, and rock salt and feeds the obtained information back into “GeM-DB”. The entire systematic approach of the projects “GeoMePS” and “ZuBeMErk” aims to develop recommendations for a non-destructive and minimally invasive surface exploration program of siting regions in Germany, regarding the lithological, structural, mechanical, and hydrogeological characterization of the different host rock formations.

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