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Grimsel Test Site: modelling radionuclide migration field experiments

Technical Report:

Abstract

In the migration field experiments at Nagra`s Grimsel Test Site, the processes of nuclide transport through a well defined fractured shear-zone in crystalline rock are being investigated. For these experiments, model calculations have been performed to obtain indications on validity and limitation of the model applied and the data deduced under field conditions. The model consists of a hydrological part, where the dipole flow fields of the experiments are determined, and a nuclide transport part, where the flow field driven nuclide propagation through the shear-zone is calculated. In addition to the description of the model, analytical expressions are given to guide the interpretation of experimental results. From the analysis of experimental breakthrough curves for conservative uranine, weakly sorbing sodium and more stronger sorbing strontium tracers, the following main results can be derived: (i) The model is able to represent the breakthrough curves of the migration field experiments to a high degree of accuracy, (ii) The process of matrix diffusion is manifest through the tails of the breakthrough curves decreasing with time as t{sup -3/2} and through the special shape of the tail ends, both confirmed by the experiments, (iii) For nuclide sorbing rapidly, not too strongly, linearly, and exhibiting a  More>>
Authors:
Heer, W; Hadermann, J [1] 
  1. Paul Scherrer Inst. (PSI), Villigen (Switzerland)
Publication Date:
Sep 01, 1994
Product Type:
Technical Report
Report Number:
PSI-94-13
Reference Number:
SCA: 540230; 052002; PA: AIX-26:008013; EDB-95:009816; SN: 95001301028
Resource Relation:
Other Information: PBD: Sep 1994
Subject:
54 ENVIRONMENTAL SCIENCES; 12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; GRANITES; LABORATORIES; SWITZERLAND; DIFFUSION; EXPERIMENTAL DATA; HYDRAULIC CONDUCTIVITY; ION EXCHANGE; MATHEMATICAL MODELS; R CODES; RADIONUCLIDE MIGRATION; SODIUM IONS; STRONTIUM IONS; THEORETICAL DATA; TRACER TECHNIQUES; 540230; 052002; RADIOACTIVE MATERIALS MONITORING AND TRANSPORT; WASTE DISPOSAL AND STORAGE
OSTI ID:
10104076
Research Organizations:
Paul Scherrer Inst. (PSI), Villigen (Switzerland)
Country of Origin:
Switzerland
Language:
English
Other Identifying Numbers:
Other: ON: DE95610899; TRN: CH9400365008013
Availability:
OSTI; NTIS; INIS
Submitting Site:
CHN
Size:
137 p.
Announcement Date:
Jun 30, 2005

Technical Report:

Citation Formats

Heer, W, and Hadermann, J. Grimsel Test Site: modelling radionuclide migration field experiments. Switzerland: N. p., 1994. Web.
Heer, W, & Hadermann, J. Grimsel Test Site: modelling radionuclide migration field experiments. Switzerland.
Heer, W, and Hadermann, J. 1994. "Grimsel Test Site: modelling radionuclide migration field experiments." Switzerland.
@misc{etde_10104076,
title = {Grimsel Test Site: modelling radionuclide migration field experiments}
author = {Heer, W, and Hadermann, J}
abstractNote = {In the migration field experiments at Nagra`s Grimsel Test Site, the processes of nuclide transport through a well defined fractured shear-zone in crystalline rock are being investigated. For these experiments, model calculations have been performed to obtain indications on validity and limitation of the model applied and the data deduced under field conditions. The model consists of a hydrological part, where the dipole flow fields of the experiments are determined, and a nuclide transport part, where the flow field driven nuclide propagation through the shear-zone is calculated. In addition to the description of the model, analytical expressions are given to guide the interpretation of experimental results. From the analysis of experimental breakthrough curves for conservative uranine, weakly sorbing sodium and more stronger sorbing strontium tracers, the following main results can be derived: (i) The model is able to represent the breakthrough curves of the migration field experiments to a high degree of accuracy, (ii) The process of matrix diffusion is manifest through the tails of the breakthrough curves decreasing with time as t{sup -3/2} and through the special shape of the tail ends, both confirmed by the experiments, (iii) For nuclide sorbing rapidly, not too strongly, linearly, and exhibiting a reversible cation exchange process on fault gouge, the laboratory sorption coefficient can reasonably well be extrapolated to field conditions. Adequate care in selecting and preparing the rock samples is, of course, a necessary requirement. Using the parameters determined in the previous analysis, predictions are made for experiments in a smaller an faster flow field. For conservative uranine and weakly sorbing sodium, the agreement of predicted and measured breakthrough curves is good, for the more stronger sorbing strontium reasonable, confirming that the model describes the main nuclide transport processes adequately. (author) figs., tabs., 29 refs.}
place = {Switzerland}
year = {1994}
month = {Sep}
}