Numerical Modeling and Column Experiments to Simulate the Alkaline Disturbed Zone Around a Cementitious Radioactive Waste Repository

1997 ◽  
Vol 506 ◽  
Author(s):  
K. Bateman ◽  
P. Coombs ◽  
D. J. Noy ◽  
J. M. Pearce ◽  
P. D. Wetton
Keyword(s):  
Numerical Modeling ◽  
Radioactive Waste ◽  
Predictive Modelling ◽  
Radioactive Waste Disposal ◽  
Column Experiments ◽  
Mineralogical Analysis ◽  
Coupled Models ◽  
Calcium Silicate Hydrates ◽  
Disturbed Zone ◽  
Waste Repository

ABSTRACTIn order to be able to describe the migration of an alkaline plume, coupled chemistry and flow computer models may be employed. A series of laboratory column experiments were conducted to test the capabilities of currently available coupled models to predict product solids and output fluid compositions as a function of time. The predictions did not replicate all the variations of Ca:Si observed during mineralogical analysis, probably due the unavailability of sufficient kinetic and thermodynamic data for the range of calcium silicate hydrates (CSH) phases of interest. However, the predictions do reproduce the variation of Ca:Si ratios with time and distance along the columns. A better understanding of the above processes will lead to greater confidence in predictive modelling of the migration of alkaline plumes away from the cementitious barriers of radioactive waste disposal facilities.

Planning of Large-Scale In-Situ Gas Generation Experiment in Korean Radioactive Waste Repository

2010 ◽  
Author(s):  
Juyoul Kim ◽  
Sukhoon Kim ◽  
Jin Beak Park ◽  
Sunjoung Lee
Keyword(s):  
Radioactive Waste ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Large Scale ◽  
Radioactive Waste Disposal ◽  
Gas Generation ◽  
Radioactive Waste Repository ◽  
Waste Repository

In the Korean LILW (Low- and Intermediate-Level radioactive Waste) repository at Gyeongju city, the degradation of organic wastes and the corrosion of metallic wastes and steel containers would be important processes that affect repository geochemistry, speciation and transport of radionuclides during the lifetime of a radioactive waste disposal facility. Gas is generated in association with these processes and has the potential threat to pressurize the repository, which can promote the transport of groundwater and gas, and consequently radionuclide transport. Microbial activity plays an important role in organic degradation, corrosion and gas generation through the mediation of reduction-oxidation reactions. The Korean research project on gas generation is being performed by Korea Radioactive Waste Management Corporation (hereafter referred to as “KRMC”). A full-scale in-situ experiment will form a central part of the project, where gas generation in real radioactive low-level maintenance waste from nuclear power plants will be done as an in-depth study during ten years at least. In order to examine gas generation issues from an LILW repository which is being constructed and will be completed by the end of December, 2012, two large-scale facilities for the gas generation experiment will be established, each equipped with a concrete container carrying on 16 drums of 200 L and 9 drums of 320 L of LILW from Korean nuclear power plants. Each container will be enclosed within a gas-tight and acid-proof steel tank. The experiment facility will be fully filled with ground water that provides representative geochemical conditions and microbial inoculation in the near field of repository. In the experiment, the design includes long-term monitoring and analyses for the rate and composition of gas generated, and aqueous geochemistry and microbe populations present at various locations through on-line analyzers and manual periodical sampling. A main schedule for establishing the experiment facility is as follows: Completion of the detailed design until the second quarter of the year 2010; Completion of the manufacture and on-site installation until the second quarter of the year 2011; Start of the operation and monitoring from the third quarter of the year 2011.

Use of the QUasI-Stationary State Approximation to Determine the Migration of Mineral Alteration Zones at a Natural Analogue for the Disturbed Zone of a Cementitious Radioactive Waste Repository

1993 ◽  
Vol 333 ◽  
Author(s):  
A.V. Chambers
Keyword(s):  
Radioactive Waste ◽  
Stationary State ◽  
Radioactive Waste Disposal ◽  
Natural Analogue ◽  
Radioactive Waste Repository ◽  
Alteration Zones ◽  
State Approximation ◽  
Quasi Stationary State ◽  
Waste Repository ◽  
Mineral Alteration

ABSTRACTCalculation of the movement of chemical fronts over long timescales could be important in underpinning performance assessments for radioactive waste disposal. A quasi-stationary state model, MARQUISS (Mineral Alteration Reactions using the QUasI-Statίonary State approximation), has been developed to achieve this objective by avoiding many of the problems encountered using more conventional approaches to coupled chemistry and transport calculations. MARQUISS simulates advective, dispersive and diffusive transport through a one-dimensional porous medium coupled with the chemical kinetics of mineral precipitation and dissolution. A description of its development and verification for simple systems is provided, together with its application in a study of the migration of mineral alteration zones at a natural analogue for a cementitious radioactive waste repository located at Maqarin in northern Jordan.

Experimental investigation on buffer/backfill materials for radioactive waste repository downward facing sorption additivity of cesium, strontium and cobalt with different concentrations

Kerntechnik ◽  
2021 ◽  
Vol 86 (5) ◽  
pp. 375-381
Author(s):  
C.-P. Lee ◽  
Y. Hu ◽  
Y. Sun ◽  
Y. Shi ◽  
N.-C. Tien ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Distribution Coefficients ◽  
Test Method ◽  
Radioactive Waste Disposal ◽  
Batch Test ◽  
Backfill Materials ◽  
Mixing Proportion ◽  
Synthetic Groundwater ◽  
Waste Repository ◽  
Sorption Characteristics

Abstract Buffer/backfill materials for radioactive waste disposal sites consist of pure bentonite or bentonite-rock mixtures. In this study, the batch test method was used to obtain the sorption characteristics of important radionuclides such as Cs, Sr and Co on buffer/backfill materials; i. e., mixing Wyoming MX-80 bentonite or local Taiwanese Zhi-Shin bentonite with possible host rock (argillite and granite) in different proportions (0∼100%). The distribution coefficients (Kd) for Cs, Sr and Co were obtained from the experiments. The distribution coefficient for the bentonite-rock mixtures were found, with more than 50% of mixing proportion of bentonite to argillite or granite, to have very similar values to that of pure bentonite. Furthermore, it was clearly found that the sorption of Cs, Sr and Co to bentonite-rock mixtures is decreased as ionic strength of the liquid phase is increased from 0.001M to 1M for NaCl solutions. According to the experimental results, in synthetic groundwater, it is quite convenient and helpful to assess the distribution coefficients (Kd) of Cs, Sr and Co for buffer/backfill materials using batch sorption experiments with bentonite-rock mixtures of fixed mixing proportions.

Sorption and transport behavior of radionuclides in the proposed low-level radioactive waste disposal facility at the Hanford site, Washington

2005 ◽  
Vol 93 (1) ◽  
Author(s):  
Wooyong Um ◽  
R. Jeffrey Serne
Keyword(s):  
Radioactive Waste ◽  
Waste Disposal ◽  
Radioactive Waste Disposal ◽  
Column Experiments ◽  
Hanford Site ◽  
Low Level ◽  
Batch Sorption ◽  
Transport Behavior ◽  
Disposal Facility ◽  
Low Level Radioactive Waste

AbstractA series of batch sorption and column experiments was conducted to investigate sorption and transport behavior of

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