Long-Term Leaching Experiments of Full-Scale Cemented Waste Forms: Experiments and Modeling

Kienzler, Bernhard; Vejmelka, P.; Herbert, Horst-Jürgen; Meyer, Herbert; Altenhein-Haese, C.

doi:10.13182/nt00-a3049

Cited by 27 publications

(26 citation statements)

References 8 publications

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“…As a preliminary test, a reaction path calculation using the computer code EQ3/6 (Version 8.0; Wolery and Jarek, 2003) and the YMP thermodynamic database were conducted to compare results with those obtained in long-term (~9.5 years) Ordinary Portland Cement (OPC) leaching experiments described by Kienzler et al (2000) and Metz et al (2004). This comparison is to a large extent qualititative since the EQ3/6 code results are time-independent.…”

Section: Cement Leaching Modeling Test Case: Preliminary Resultsmentioning

confidence: 99%

“…It should be noted that Metz et al (2004) conducted a similar trend analysis but with a different thermodynamic database and a different version of the EQ3/6 code. The reacting solution composition corresponds to that for the Q-brine which is essentially a concentrated MgCl 2 brine (Kienzler et al 2000). Activity coefficient corrections for the concentrated MgCl 2 brine are achieved through the use of the Pitzer approach which is implemented in the EQ3/6 code using parameter values from the Pitzer database developed for the YMP (see Appendix I of Mariner, 2007).…”

Section: Cement Leaching Modeling Test Case: Preliminary Resultsmentioning

confidence: 99%

“…The first article by Kienzler (2000) described experimental leaching of radionuclides from cement waste forms (Morsleben repository site in Germany in saline brines) over 19 year period. The authors focused their work on determining pore volumes of cement and relation to water/cement ratio of waste forms.…”

Section: Cement Chemistrymentioning

confidence: 99%

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Disposal systems evaluations and tool development : Engineered Barrier System (EBS) evaluation.

Rutqvist¹,

Liu²,

Steefel³

et al. 2011

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Eric Sonnenthal (LBNL) Engineered Barrier System (EBS) Evaluation This page is intentionally left blank Engineered Barrier System (EBS) Evaluation 5 Executive SummaryKey components of the nuclear fuel cycle are short-term storage and long-term disposal of nuclear waste. The latter encompasses the immobilization of used nuclear fuel (UNF) and radioactive waste streams generated by various phases of the nuclear fuel cycle, and the safe and permanent disposition of these waste forms in geological repository environments. The engineered barrier system (EBS) plays a very important role in the long-term isolation of nuclear waste in geological repository environments. EBS concepts and their interactions with the natural barrier are inherently important to the long-term performance assessment of the safety case where nuclear waste disposition needs to be evaluated for time periods of up to one million years. Making the safety case needed in the decision-making process for the recommendation and the eventual embracement of a disposal system concept requires a multi-faceted integration of knowledge and evidence-gathering to demonstrate the required confidence level in a deep geological disposal site and to evaluate longterm repository performance.The focus of this report is the following:• Evaluation of EBS in long-term disposal systems in deep geologic environments with emphasis on the multi-barrier concept;• Evaluation of key parameters in the characterization of EBS performance;• Identification of key knowledge gaps and uncertainties;• Evaluation of tools and modeling approaches for EBS processes and performance.The above topics will be evaluated through the analysis of the following:• Overview of EBS concepts for various NW disposal systems;• Natural and man-made analogs, room chemistry, hydrochemistry of deep subsurface environments, and EBS material stability in near-field environments;• Reactive Transport and Coupled Thermal-Hydrological-Mechanical-Chemical (THMC) processes in EBS;• Thermal analysis toolkit, metallic barrier degradation mode survey, and development of a Disposal Systems Evaluation Framework (DSEF).This report will focus on the multi-barrier concept of EBS and variants of this type which in essence is the most adopted concept by various repository programs. Empasis is given mainly to the evaluation of EBS materials and processes through the analysis of published studies in the scientific literature of past and existing repository research programs. Tool evaluations are also emphasized, particularly on THCM processes and chemical equilibria. Although being an increasingly important aspect of NW disposition, short-term or interim storage of NW will be briefly discussed but not to the extent of the EBS issues relevant to disposal systems in deep geologic environments. Interim storage will be discussed in the report Evaluation of Storage Concepts FY10 Final Report (Weiner et al. 2010). Engineered Barrier System (EBS) Evaluation 6This page is intentionally left blank Engineered Barrier System (EBS) Eva...

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Section: Cement Leaching Modeling Test Case: Preliminary Resultsmentioning

confidence: 99%

Section: Cement Leaching Modeling Test Case: Preliminary Resultsmentioning

confidence: 99%

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Disposal systems evaluations and tool development : Engineered Barrier System (EBS) evaluation.

Rutqvist¹,

Liu²,

Steefel³

et al. 2011

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“…The new database was validated by comparison of modelling to experimental results. 15) Assuming thermodynamic equilibrium between the solution and well defined solid phases (e.g., hydroxides), RN solubilities were calculated with the EQ3NR module of the EQ3/6 software package.…”

Section: Thermodynamic Databasementioning

confidence: 99%

“…Until 1978, about 126,000 drums of solidified waste forms were disposed off. The total radioactive inventory amounts to about 10 15 Bq of fission and activation products (presently) and a significant amount of -emitters, e.g., $102 t U, $87 t Th and $12 kg Pu. 19) The waste forms cover cemented NaNO 3 -bearing concentrates from reprocessing, operational wastes and activated metals from LWRs, as well as scrap metals, demolition wastes, and a variety of organic materials.…”

Section: Applicationmentioning

confidence: 99%

Geochemically Based Safety Assessment

Kienzler

Metz

Lützenkirchen

et al. 2007

J. Nucl. Sci. Technol.

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ÃÃPerformance assessment (PA) for nuclear waste disposal based on transport processes frequently neglects significant safety factors by overestimation of radionuclide mobilization and underestimation of radionuclide retention processes. To include well understood geochemical knowledge into PA, the quasi-closed system approach (QCS) was developed. The QCS approach is described and applied to a LLW disposal in a German salt mine with respect to the disposed waste forms, geo-engineered barriers, and backfill strategies. The geochemical tools and the thermodynamic database for modelling highly concentrated salt systems are discussed. Applications are demonstrated which cover the long-term geochemical environment in the disposal caverns, the optimization of buffer materials, radionuclide retention, and the overall robustness of the approach. Also the effect of a potential solution exchange between different emplacement caverns is investigated. It is shown that the QCS approach provides essential data concerning the long-term geochemistry and related radionuclide concentrations to be used in PA and safety analysis.

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Techniques to test cementitious systems through their life cycles

Rahman

Ojovan

2021

Sustainability of Life Cycle Management for Nuclear Cementation-Based Technologies

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Long-Term Leaching Experiments of Full-Scale Cemented Waste Forms: Experiments and Modeling

Cited by 27 publications

References 8 publications

Disposal systems evaluations and tool development : Engineered Barrier System (EBS) evaluation.

Disposal systems evaluations and tool development : Engineered Barrier System (EBS) evaluation.

Geochemically Based Safety Assessment

Techniques to test cementitious systems through their life cycles

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