Overview of 14C release from irradiated zircaloys in geological disposal conditions

Research output: Contribution to journalArticle

Authors

  • Sophia Necib
  • Crina Bucur
  • Sébastien Caes
  • Florence Cochin
  • Benjamin Z. Cvetković
  • Manuela Fulger
  • Jean-Marie Gras
  • Michel Herm
  • Laëtitia Kasprzak
  • S. Legand
  • Volker Metz
  • S. Perrin
  • Tomofumi Sakuragi
  • Tomo Suzuki-Muresan

Institutes & Expert groups

  • ANDRA - National Agency for Radioactive Waste Management - France
  • RA TEN ICN Pitesti - Institute for Nuclear research
  • ORANO (previous AREVA) - France
  • PSI - Paul Scherrer Institute - Switzerland
  • IKET KIT INR - Karlsruhe Institute of Technology: Institut für Neutronenphysik und Reaktortechnik (INR) - Germany
  • CEA Saclay - Commissariat à l'énergie atomique
  • Université Paris-Saclay
  • CEA – Service d’Etude et Comportement des Matériaux de Conditionnement (SECM), CEA, F-30207 Bagnolssur- Cèze
  • RWMC, 1-15-7 Tsukishima Chuo-ku, Tokyo 104-0052

Documents & links

DOI

Abstract

Carbon-14 (radiocarbon, 14C) is a long-lived radionuclide (5730 yr) of interest regarding the safety for the management of intermediate level wastes (ILW). The present study gives an overview of the release of 14C from irradiated Zircaloy cladding in alkaline media. 14C is found either in the alloy part of Zircaloy cladding due to the neutron activation of 14N impurities by 14N(n,p)14C reaction, or in the oxide layer (ZrO2) formed at the metal surface by the neutron activation of 17O from UO2 or (U-Pu)O2 fuel and water from the primary circuit in the reactor by 17O (n,α)14C reaction. Various irradiated and unirradiated Zircaloys have been studied. The total 14C inventory has been determined both experimentally and by calculations. The results seem to be in good agreement. Leaching experiments were conducted in alkaline media for several time durations. 14C was mainly released as carboxylic acids. Further, corrosion measurements were performed by using both hydrogen measurements and electrochemical measurements. The corrosion rate (CR) ranges from a few nm/yr to 100 nm/yr depending on the surface conditions and the method used for measurement. From a safety assessment point of view, the instant release fraction (IRF) was determined on irradiated Zircaloy-2. The results showed that the 14C inventory in the oxide was significantly below the 20% commonly used in safety case assessments.

Details

Original languageEnglish
Pages (from-to)1757–1771
Number of pages15
JournalRadiocarbon
Volume60
Issue number6
DOIs
StatePublished - 1 Dec 2018
Event2018 - CAST Final Symposium - Lyon, France

Keywords

  • activated Zircaloy, alkaline media, corrosion, 14C speciation, geological disposal

ID: 5291657