Migration behavior of plutonium affected by ferrous ion in compacted bentonite by using electrochemical technique

Daisuke Akiyama, Kazuya Idemitsu, Yaohiro Inagaki, Tatsumi Arima, Kenji Konashi, Shinichi Koyama

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The migration behavior of plutonium is expected to be affected by the corrosion products of carbon steel in compacted bentonite at high-level waste repositories. Electrochemical experiments were carried out to simulate the reducing environment created by ferrous iron ions in equilibrium with anoxic corrosion products of iron. The concentration profiles of plutonium could be described by the convection -dispersion equation to obtain two migration parameters: apparent migration velocity Va and apparent dispersion coefficient Da. The apparent migration velocity was evaluated within 1 nm/s and was found to be independent of the experiment duration and the dry density of bentonite in the interval 0.8-1.4 Mg/m3. The apparent dispersion coefficient increased with the experiment duration at a dry density of 1.4 Mg/m3. The results for other dry densities also showed the same trend. These findings indicate that plutonium migration likely starts after ferrous ions reach the plutonium, in other words, the reducing environment due to ferrous ions could change the chemical form of plutonium and/or the characteristics of compacted bentonite. The apparent diffusion coefficient was estimated to be around 0.5 to 2.2 um2/s and increased with decreasing the dry density of bentonite.

Original languageEnglish
Title of host publicationScientific Basis for Nuclear Waste Management XXXVII
EditorsLara Duro, Javier Gimenez, Ignasi Casas, Joan de Pablo
PublisherMaterials Research Society
Pages79-84
Number of pages6
ISBN (Electronic)9781605116426
DOIs
Publication statusPublished - 2014
Event37th International Symposium on the Scientific Basis for Nuclear Waste Management - Barcelona, Spain
Duration: 2013 Sep 292013 Oct 3

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1665
ISSN (Print)0272-9172

Other

Other37th International Symposium on the Scientific Basis for Nuclear Waste Management
CountrySpain
CityBarcelona
Period13/9/2913/10/3

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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