Iodide retention characteristics on oxidized Cu coupon in saline and alkaline environments: Perspectives on high-level radioactive waste disposal

Ja Young Goo, Seonggyu Choi, Seonyi Namgung, Yongheum Jo, Seung Yeop Lee, Jang Soon Kwon, Ho Young Jo

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Radioactive iodine, particularly 129I, is one of the most hazardous radioisotopes found in deep geological repositories for high-level radioactive waste (HLW). This study investigated the iodide retention capacity of Cu coupons, simulating Cu canisters, under potential repository conditions. In saline environments (0.1 M NaCl + 0.01 M MgSO4), iodide was immobilized through CuI(s) formation on the oxidized surface of Cu coupons. This process was facilitated by the favorable affinity between Cu+ oxidized from the Cu coupons and I. The iodide retention capacity of Cu coupons exhibited notable sensitivity to the pH and chemical composition of the solutions. Cu+ remained stably complexed with Cl under saline conditions, leading to the CuI(s) formation. However, in distilled water, iodide retention decreased over time due to the transformation of CuI to CuO through Cu oxidation. In an alkaline solution (0.1 M KOH), iodide retention was negligible. These results indicate that radioactive iodide ions, released in the event of canister failure, can be effectively immobilized, and their migration to the ecosystem can be impeded through CuI(s) formation on oxidized Cu canisters in saline conditions. Consequently, Cu canisters can serve as an effective barrier against radioactive iodide migration and as a long-term isolation medium for HLW, particularly under saline conditions.

Original languageEnglish
Article number150575
JournalChemical Engineering Journal
Volume488
DOIs
Publication statusPublished - 2024 May 15

Bibliographical note

Publisher Copyright:
© 2024 The Authors

Keywords

  • Cu canister
  • CuI
  • High-level radioactive waste
  • Iodide retention
  • Saline

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering

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