Publikationsserver der RWTH Aachen University
Investigation of the corrosion behaviour of U-Al material test reactor fuel elements in repository relevant solutions and characterisation of the secondary phases formed
Abstract
dc:descriptionThe safe embedding of direct-disposed irradiated U-Al material test reactor fuel elements is the main requirement of final disposal. To clarify the behaviour under these conditions corrosion experiments with non-irradiated fuel elements and with aluminium as cladding material were performed. The results are used to explain the corrosion mechanism and characterise the corrosion products formed. Twelve corrosion experiments were performed in different media (MgCl2-brine, NaCl-brine and granite water), with iron additives (Fe^0, Fe^II) and with different surface-to-volume ratios at 90°C under anaerobic conditions. The highest corrosion rate was determined in the MgCl2-brine with iron additives. A non-irradiated plate of the U-Al fuel element had a higher corrosion rate than an aluminium plate. The corrosion products formed in the MgCl2-brine were investigated with FTIR, XRD, SEM and ICP-MS. The main elements of the secondary phases are magnesium and aluminium. All dissolved aluminium and uranium precipitated in the secondary phases. The corrosion products consist mainly of bishofite and of Mg-Al-hydrotalcite. The latter compound was identified for the first time in corrosion experiments with aluminium and non-irradiated U-Al plates. To investigate the hydrotalcite properties with respect to final disposal conditions, ion-exchanged experiments with iodide, caesium and americium were performed as well as stability experiments. CO3-hydrotalcite and Cl-hydrotalcite are able to exchange these ions. CO3-hydrotalcite is stable in a wide pH field, but in the MgCl2-brine a Cl-hydrotalcite is formed immediately. These properties make hydrotalcites attractive as possible backfill material.
Degree
thesis:*- Grantor dc:publisher
- Publikationsserver der RWTH Aachen University
- Year dc:date
- 2003
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Mazeina, Lena
- Contributors dc:contributor
-
- Odoj, Reinhard
Subjects
dc:subject × 7Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- eng
Identifiers
dc:identifier.*- OAI identifier oai:identifier
- oai:publications.rwth-aachen.de:58897