scholarly journals Investigating the contribution of claystone to the swelling pressure of its mixture with bentonite

2020 ◽  
Vol 195 ◽  
pp. 03043
Author(s):  
Zhixiong Zeng ◽  
Yu-Jun Cui ◽  
Nathalie Conil ◽  
Jean Talandier
Keyword(s):  
Radioactive Waste ◽  
Safety Assessment ◽  
Swelling Pressure ◽  
Radioactive Waste Disposal ◽  
Inert Material ◽  
Dry Density ◽  
Test Results ◽  
Pressure Tests ◽  
Volume Swelling

Compacted MX80 bentonite/Callovo-Oxfordian (COx) claystone mixture has been considered as a possible sealing/backfilling material in the French deep geological radioactive waste disposal. The swelling pressure of such mixture is an important factor in the design and long-term safety assessment of deep geological repositories. In this study, constant-volume swelling pressure tests were performed on the mixtures with different claystone fractions and dry densities. The test results show that the swelling pressure of the mixtures decreased with the increasing claystone fraction and decreasing dry density. According to the experimental results, the contribution of claystone to the global swelling pressure was further investigated. It was found that the deformation of claystone and its contribution to swelling pressure was highly dependent on the claystone fraction. As the claystone fraction was larger than 30%, the claystone in the mixture swelled, contributing to the global swelling pressure; On the contrary, as the claystone fraction was less than 30%, the swelling of claystone was inhibited by the bentonite and it worked an inert material without any contribution to the swelling pressure.

Hydrolysis of trivalent plutonium and solubility of Pu(OH)3(am) under electrolytic reducing conditions

2016 ◽  
Vol 45 (48) ◽  
pp. 19449-19457 ◽  
Author(s):  
Hye-Ryun Cho ◽  
Young-Sang Youn ◽  
Euo Chang Jung ◽  
Wansik Cha
Keyword(s):  
Radioactive Waste ◽  
Waste Disposal ◽  
Safety Assessment ◽  
Radioactive Waste Disposal ◽  
Reducing Conditions ◽  
System P ◽  
High Level ◽  
Hydrolysis Of

This paper focusses on the determination of the thermodynamic data of Pu(iii) hydrolysis, which are important for a long-term safety assessment of high-level radioactive waste disposal in a deep geological system.

scholarly journals Thermal Conductivity of Compacted GO-GMZ Bentonite Used as Buffer Material for a High-Level Radioactive Waste Repository

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yong-Gui Chen ◽  
Xue-Min Liu ◽  
Xiang Mu ◽  
Wei-Min Ye ◽  
Yu-Jun Cui ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Radioactive Waste ◽  
Water Content ◽  
Radioactive Waste Disposal ◽  
Dry Density ◽  
Gmz Bentonite ◽  
High Level Radioactive Waste ◽  
Buffer Material ◽  
High Level ◽  
Crucial Parameter

In China, Gaomiaozi (GMZ) bentonite serves as a feasible buffer material in the high-level radioactive waste (HLW) repository, while its thermal conductivity is seen as a crucial parameter for the safety running of the HLW disposal. Due to the tremendous amount of heat released by such waste, the thermal conductivity of the buffer material is a crucial parameter for the safety running of the high-level radioactive waste disposal. For the purpose of improving its thermal conductivity, this research used the graphene oxide (GO) to modify the pure bentonite and then the nanocarbon-based bentonite (GO-GMZ) was obtained chemically. The thermal conductivity of this modified soil has been measured and investigated under various conditions in this study: the GO content, dry density, and water content. Researches confirm that the thermal conductivity of the modified bentonite is codetermined by the three conditions mentioned above, namely, the value of GO content, dry density, and water content. Besides, the study proposes an improved geometric mean model based on the special condition to predict the thermal conductivity of the compacted specimen; moreover, the calculated values are also compared with the experimental data.

An Integrated Safety Assessment System for Near-Surface Disposal of Low- and Intermediate-Level Radioactive Waste in Korea

2003 ◽  
Author(s):  
JooWan Park ◽  
Chang-Lak Kim ◽  
Jin Beak Park ◽  
Eun Yong Lee ◽  
Youn Myoung Lee ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Safety Assessment ◽  
Assessment System ◽  
Intermediate Level ◽  
Radioactive Waste Disposal ◽  
System Level ◽  
Assessment Methodology ◽  
Regulatory Requirements ◽  
Near Surface ◽  
Intermediate Level Radioactive Waste

An integrated safety assessment system to be used for evaluation of near-surface disposal concept has been developed within the framework of safety assessment methodology taken for low- and intermediate-level radioactive waste disposal in Korea. It is to provide an evaluation of the safety of the disposal system in a clear, comprehensive and well-documented manner, and to integrate the results into a defensible package showing reasonable assurance of compliance with regulatory requirements for licensing application. This system is made up of two key components, a system-level safety assessment code and an input database/quality assurance module for safety assessment, which both are interfaced with each other.

Instrumented Measurements on Radioactive Waste Disposal Containers During Experimental Drop Testing

2011 ◽  
Author(s):  
Thomas Quercetti ◽  
Andre Musolff ◽  
Karsten Mu¨ller
Keyword(s):  
Radioactive Waste ◽  
Motion Analysis ◽  
High Speed ◽  
Measurement Techniques ◽  
Radioactive Waste Disposal ◽  
Test Results ◽  
Federal Institute ◽  
Materials Research ◽  
Drop Tests ◽  
Main Basis

In context with disposal container safety assessment of containers for radioactive waste the German Federal Institute for Materials Research and Testing (BAM) performed numerous drop tests in the last years. The tests were accompanied by extensive and various measurement techniques especially by instrumented measurements with strain gages and accelerometers. The instrumentation of a specimen is an important tool to evaluate its mechanical behavior during impact. Test results as deceleration-time and strain-time functions constitute a main basis for the validation of assumptions in the safety analysis and for the evaluation of calculations based on finite-element methods. Strain gauges are useful to determine the time dependent magnitude of any deformation and the associated stresses. Accelerometers are widely used for the measuring of motion i.e. speed or the displacement of the rigid cask body, vibration and shock events. In addition high-speed video technique can be used to visualize and analyze the kinematical impact scenario by motion analysis. The paper describes some selected aspects on instrumented measurements and motion analysis in context with low level radioactive waste (LLW) container drop testing.

Heating Impact on Corrosion Mechanism of Carbon Steel Surrounded by Bentonite

2020 ◽  
Author(s):  
Masao Uyama ◽  
Hiroyuki Saito ◽  
Tomoya Iioka
Keyword(s):  
Carbon Steel ◽  
Radioactive Waste ◽  
Frequency Characteristic ◽  
Power Plants ◽  
Electric Heater ◽  
Dry Density ◽  
Corrosion Mechanism ◽  
Low Carbon ◽  
Corrosion Condition

Abstract The long-term safety of geological disposal of radioactive waste is studied through several simulations. Before underground disposal, radioactive waste is stored for 30 to 50 years at facilities near nuclear power plants to cool it down to around 100 degrees. It is then placed in steel canisters surrounded by artificial materials such as bentonite and concrete. To determine the long-term safety and stability of this disposal method, we’ve studied the corrosion rate of the steel canisters under different conditions using electro-chemical impedance spectroscopy (EIS). This paper describes the corrosion of the carbon steel and elucidates the corroded condition using EIS measurement. EIS was adopted to estimate the corrosion condition from the impedance frequency characteristic. In our experiment, samples of bentonite and carbon steel were compacted to Kunigel V1 of 1.37Mg/m3 dry density with several different water contents, and SM400 as a low carbon steel inside compacted bentonite. An electric heater was set inside the steel canister to maintain the temperature at 100 degrees Celsius. This model was made to a scale of around 1/120 as a current concept of a vertical disposal plan and reproduced the enclosed situation after underground emplacement of the radioactive waste. During heating, we conducted EIS measurements and set this data result as an equivalent circuit. We noted some different trends of impedance frequency characteristic depending on the bentonite’s water content and the heating time. From this result, we estimated the corrosion condition to analyze the corrosion products.

Soil Based Barriers for a Low and Intermediate Level Radioactive Waste Disposal

2003 ◽  
Author(s):  
Dimitar Antonov
Keyword(s):  
Moisture Content ◽  
Radioactive Waste ◽  
Intermediate Level ◽  
Radioactive Waste Disposal ◽  
Dry Density ◽  
Paper Strength ◽  
Maximum Dry Density ◽  
Soil Cement ◽  
Intermediate Level Radioactive Waste ◽  
Cement Mixtures

The loess terrains near “Kozloduy” NPP are among the prospective areas for the disposal of low and intermediate level radioactive waste. The analysis of the loess properties has shown two main problems: a loess collapsibility and water permeability. Using a soil-cement cushion under the repository foundation and a soil-cement backfill between the containers is a possibility to avoid these disadvantages. In this connection loess-cement mixtures with bentonite and clinoptilolite additives have been investigated. The aim of mixtures is to improve the impermeability and sorbtion properties against radionuclide migration. In the paper strength parameters of two kind of mixtures are discussed. According to their water content some are compacted at the optimum moisture content until the maximum dry density and others are compacted at higher moisture content equal to the liquid limit of loess. For the first type of mixtures the unconfined compressive strength (UCS) varies from 2 to 6 MPa depending on the cement and additives percents. Permeability measurements have shown satisfactory results. The UCS for the second type of mixtures is less than the first type, but is sufficient for a backfill between the waste containers. The conclusion is that the loess-cement mixtures, especially these with clinoptilolite additive, are prospective as barriers of a low and intermediate level radioactive waste repository.

scholarly journals Source Term Development For Tritium at the Sheffield Disposal Site

1984 ◽  
Vol 44 ◽  
Author(s):  
D. R. Mackenzie ◽  
R. E. Barletta ◽  
J. F. Smalley ◽  
C. R. Kempf ◽  
R. E. Davis
Keyword(s):  
Radioactive Waste ◽  
Waste Disposal ◽  
Source Term ◽  
Fuel Cycle ◽  
Radioactive Waste Disposal ◽  
Disposal Site ◽  
Waste Disposal Site ◽  
Groundwater Samples ◽  
Low Level Radioactive Waste

AbstractThe Sheffield low-level radioactive waste disposal site, which ceased operation in 1978, has been the focus of modeling efforts by the NRC for the purpose of predicting long-term site behavior. To provide the NRC with information required for its modeling effort, a study to define the source term for tritium in eight trenches at the Sheffield site has been undertaken. Tritium is of special interest since significant concentrations of the isotope have been found in groundwater samples taken at the site and at locations outside the original site boundary. Previous estimates of tritium site inventory at Sheffield are in wide disagreement. In this study, the tritium inventory in the eight trenches was estimated by reviewing the radioactive shipping records (RSRs) for waste buried in these trenches. It has been found that the tritium shipped for burial at the site was probably higher than previously estimated. In the eight trenches surveyed, which amount to roughly one half the total volume and activity buried at Sheffield, approximately 2350 Ci of tritium from non-fuel cycle sources were identified.

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