Migration behavior of iron ion in compacted bentonite under reducing condition by using electromigration

Kazuya Idemitsu, Seiji Yano, Xiaobin Xia, Yoshiro Kikuchi, Yaohiro Inagaki, Tatsumi Arima

Research output: Contribution to journalConference articlepeer-review

12 Citations (Scopus)

Abstract

Carbon steel is one of the candidate overpack materials for high-level waste disposal and is expected to assure complete containment of vitrified waste glass during an initial period of 1000 years in Japan. The lifetime of the carbon steel overpack will depend on its corrosion rate. The corrosion rate of carbon steel is reduced by the presence of buffer material such as bentonite, Buffer material will delay the supply of corrosive materials and discharge of corrosion products through it. Carbon steel overpack will be corroded by consuming oxygen introduced by repository construction after closure of repository and then will keep the reducing environment in the vicinity of repository. The reducing condition will be expected to retard the migration of redox-sensitive radionuclides by lowering their solubilities. Therefore, the diffusion of corrosion products of iron in buffer material is important to discuss the corrosion rate of overpack, properties of buffer material and migration of redox-sensitive radionuclides. Electromigration experiments have been carried out with source of iron ions supplied by anode corrosion of iron coupon. Iron ions migrated as fast as 2mm in 2 or 3 hours under electrical field of 100V/m to the direction of cathode. Because the iron ions displaced exchangeable sodium ions in bentonite at a ratio of 1 to 2 during the electromigration, migrating iron ion could be ferrous ion.

Original languageEnglish
Pages (from-to)657-664
Number of pages8
JournalMaterials Research Society Symposium - Proceedings
Volume757
Publication statusPublished - Dec 8 2003
EventMATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDING: Scientific Basis for Nuclear Waste Management XXVI - Boston, MA, United States
Duration: Dec 2 2002Dec 5 2002

All Science Journal Classification (ASJC) codes

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

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