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

Show full item record



Permalink

http://hdl.handle.net/10138/307102

Citation

Voutilainen , M , Kekäläinen , P , Poteri , A , Siitari-Kauppi , M , Helariutta , K , Andersson , P , Nilsson , K , Byegård , J , Skålberg , M , Yli-Kaila , M & Koskinen , L 2019 , ' Comparison of water phase diffusion experiments in laboratory and in situ conditions ' , Journal of Hydrology , vol. 575 , pp. 716-729 . https://doi.org/10.1016/j.jhydrol.2019.05.069

Title: Comparison of water phase diffusion experiments in laboratory and in situ conditions
Author: Voutilainen, Mikko; Kekäläinen, Pekka; Poteri, Antti; Siitari-Kauppi, Marja; Helariutta, Kerttuli; Andersson, Peter; Nilsson, Kersti; Byegård, Johan; Skålberg, Mats; Yli-Kaila, Maarit; Koskinen, Lasse
Contributor: University of Helsinki, Geological disposal of spent nuclear fuel
University of Helsinki, Geological disposal of spent nuclear fuel
University of Helsinki, Department of Chemistry
University of Helsinki, Department of Chemistry
Date: 2019-08
Language: eng
Number of pages: 14
Belongs to series: Journal of Hydrology
ISSN: 0022-1694
URI: http://hdl.handle.net/10138/307102
Abstract: In some countries the spent nuclear fuel produced by nuclear power plants will be deposited in crystalline granitic rock formations. In Finland, a repository for the spent nuclear fuel is being built at Olkiluoto. The safety assessment of the repository requires a careful determination of the transport properties of the bedrock. The porosity of the bedrock and the effective diffusion coefficients and distribution coefficients of different radio-nuclides for the bedrock are used as the main parameters in the safety assessment calculations. It has been questioned whether the parameters determined using laboratory experiments can be used to estimate the parameters in the in situ conditions. In this study, laboratory and in situ water phase diffusion experiments (WPDEs) were performed to resolve the issue. In the experiments, the transport of tritiated water (HTO), Cl-36, and Na-22 was studied using similar experimental setups. Mathematical models were constructed and solved to determine the transport parameters from the measured breakthrough curves. On average, the in situ WPDEs resulted in 20 (+/- 6)% smaller porosities and 32 (+/- 10)% smaller effective diffusion coefficients for HTO and Cl-36 than the laboratory WPDEs. It was also found that in veined gneiss, the most dominant rock type of the Olkiluoto bedrock, anion exclusion reduced the retention parameters of Cl-36 compared with those of HTO. Furthermore, the distribution coefficient of Na-22 for veined gneiss was 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.
Subject: In situ experiment
Diffusion
Sorption
Porosity
Radionuclide
Groundwater
MATRIX DIFFUSION
ANION EXCLUSION
GRANITIC ROCK
VEINED GNEISS
SORPTION
SCALE
OLKILUOTO
TRANSPORT
POROSITY
TRACER
114 Physical sciences
116 Chemical sciences
Rights:


Files in this item

Total number of downloads: Loading...

Files Size Format View
Advection_matri ... n_Journal_of_Hydrology.pdf 1.194Mb PDF View/Open

This item appears in the following Collection(s)

Show full item record