Modelling transport of 14C-labelled Natural Organic Matter (NOM) in Boom Clay

Alice Ionescu, Norbert Maes, Dirk Mallants

Research outputpeer-review

Abstract

In Belgium, the Boom Clay formation is considered to be the reference formation for HLW disposal R&D. Assessments to date have shown that the host clay layer is a very efficient barrier for the containment of the disposed radionuclides. Due to absence of significant water movement), diffusion - the dominant transport mechanism, combined with generally high retardation of radionuclides, leads to extremely slow radionuclide migration. However, trivalent lanthanides and actinides form easily complexes with the fulvic and humic acids which occur in Boom Clay and in its interstitial water. Colloidal transport may possibly result in enhanced radionuclide mobility, therefore the mechanisms of colloidal transport must be better understood. Numerical modeling of colloidal facilitated radionuclide transport is regarded an important means for evaluating its importance for long-term safety. The paper presents results from modeling experimental data obtained in the framework of the EC TRANCOM-II project, and addresses the migration behavior of relevant radionuclides in a reducing clay environment, with special emphasis on the role of the Natural Organic Matter (NOM)[1]. Percolation type experiments, using stable 14C-labelled NOM, have been interpreted by means of the numerical code HYDRUS-1D[2]. Tracer solution collected at regular intervals was used for inverse modeling with the HYDRUS-1D numerical code to identify the most likely migration processes and the associated parameters. Typical colloid transport submodels tested included kinetically controlled attachment/detachment and kinetically controlled straining and liberation.

Original languageEnglish
Title of host publicationMaterials Research Society Symposium Proceedings - Scientific Basis for Nuclear Waste Management XXXI
PublisherMRS - Materials Research Society
Pages629-636
Number of pages8
Volume1107
ISBN (Print)9781605110790
DOIs
StatePublished - 1 Dec 2008
EventMRS 2007 - Materials Research Society - UK: 31st International Symposium on the Scientific Basis for Nuclear Waste Management - Materials Research Society, Sheffield
Duration: 16 Sep 200721 Sep 2007

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1107
ISSN (Print)0272-9172

Conference

ConferenceMRS 2007 - Materials Research Society - UK
Country/TerritoryUnited Kingdom
CitySheffield
Period2007-09-162007-09-21

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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