In situ migration of tritiated water and iodine in Grimsel granodiorite, part II: assessment of the diffusion coefficients by TDD modelling

Ikonen, Jussi; Sardini, Paul; Siitari-Kauppi, Marja; Martin, Andrew J.

doi:10.1007/s10967-016-5041-9

Cited by 7 publications

(5 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to take into account the complicated geometry of the subsampling procedure in the overcores and time delays, a time domain diffusion (TDD) modelling tool [33][34][35][36] was applied to interpret the HTO and I concentrations obtained from the outleached subsamples. Evaluated diffusion coefficient results are given in detail in companion paper [37].…”

Section: Resultsmentioning

confidence: 99%

The tritiated water and iodine migration in situ in Grimsel granodiorite. Part I: determination of the diffusion profiles

Ikonen

Sardini

Jokelainen

et al. 2016

J Radioanal Nucl Chem

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

The tritiated water and iodine migration in situ in Grimsel granodiorite. Part I: determination of the diffusion profiles

Ikonen

Sardini

Jokelainen

et al. 2016

J Radioanal Nucl Chem

Self Cite

View full text Add to dashboard Cite

show abstract

“…The in-situ transport experiments have been performed in several countries e.g. Finland [21,22], Sweden [23,24], Switzerland [25,26,27] and Canada [28] to study the behavior of radionuclides in crystalline bedrock. The in-situ experiments provide important parameters and information for the safety assessment.…”

Section: Introductionmentioning

confidence: 99%

Comparison of water phase diffusion experiments in laboratory and in situ conditions

Voutilainen

Kekäläinen

Poteri

et al. 2019

Journal of Hydrology

Self Cite

View full text Add to dashboard Cite

In some countries, the spent nuclear fuel produced by nuclear power plants will be deposited in crystalline granitic rock formations. In Finland, such repository is being built at Olkiluoto. The safety assessment of the repository requires a careful determination of transport properties of the bedrock. Porosity of the rock and effective diffusion coefficient and distribution coefficients of different radionuclides for the bedrock are used as the main parameters in safety assessment calculations. It has been questioned if the parameters determined using laboratory experiments can be used to estimate the parameters in the in-situ conditions. Water Phase Diffusion Experiments (WPDE) performed in the laboratory and in-situ conditions were addressed to resolve this questions. In the experiments, transport of HTO, 36 Cl and 22 Na were studied using similar experimental setups in both conditions. Analytic models were constructed and solved to determine the transport parameters from the measured breakthrough curves. The in-situ WPDE resulted from 12 % to 38 % smaller porosities and from 30 % to 60 % smaller effective diffusion coefficients for HTO and 36 Cl than the laboratory WPDE. It was also shown that anion exclusion reduced the transport parameters of 36 Cl compared with the parameters of HTO in veined gneiss that is the most dominant rock type of Olkiluoto bedrock. Furthermore, the distribution coefficients of 22 Na for veined gneiss were found to be about one order of magnitude smaller in the in-situ conditions than in previous laboratory batch sorption experiments. The effects of the results on the safety assessment were evaluated and discussed.

show abstract

“…The TDRW method has been used to study the effect of centimeter-scale structural heterogeneities on diffusion in various cases [36,37,40,49]. The TDRW method has also been used to model transport in fractured media [28,29] and has been shown to be a powerful tool for analyzing results of in situ and laboratory experiments, especially when initial or boundary conditions are complex [1,15,16,49]. Previously, Dentz et al [9] modified the TDRW method to include sorption by using specific functions for trapping frequency and number of trapping events.…”

Section: Introductionmentioning

confidence: 99%

Modeling mass transfer in fracture flows with the time domain-random walk method

2019

View full text Add to dashboard Cite

The time domain-random walk method was developed further for simulating mass transfer in fracture flows together with matrix diffusion in surrounding porous media. Specifically, a time domain-random walk scheme was developed for numerically approximating solutions of the advection-diffusion equation when the diffusion coefficient exhibits significant spatial variation or even discontinuities. The proposed scheme relies on second-order accurate, central-difference approximations of the advective and diffusive fluxes. The scheme was verified by comparing simulated results against analytical solutions in flow configurations involving a rectangular channel connected on one side with a porous matrix. Simulations with several flow rates, diffusion coefficients, and matrix porosities indicate good agreement between the numerical approximations and analytical solutions.

show abstract

In situ migration of tritiated water and iodine in Grimsel granodiorite, part II: assessment of the diffusion coefficients by TDD modelling

Cited by 7 publications

References 7 publications

The tritiated water and iodine migration in situ in Grimsel granodiorite. Part I: determination of the diffusion profiles

The tritiated water and iodine migration in situ in Grimsel granodiorite. Part I: determination of the diffusion profiles

Comparison of water phase diffusion experiments in laboratory and in situ conditions

Modeling mass transfer in fracture flows with the time domain-random walk method

Contact Info

Product

Resources

About