Relevance of alumina grit analysis in zircaloy fabrication process

Zirconium based alloys are the natural choice for both fuel element and in-core structural components in the water cooled thermal reactors, namely BWRs, PWRs and PHWRs. Nuclear Fuel Complex (NFC), Hyderabad is engaged in the production of zirconium based alloys that are used as hardware in the nuclear industry. After hot working of zircaloy, due to its reactivity, an oxide layer is formed on its surfaces. Hence to remove this oxide layer grit blasting operation using alumina grit sand is followed during which the particles of the sand gets fragmented and the oxide layer on the material thus gets dislodged. Thus alumina grit plays a prominent role in the zircaloy fabrication process. In order to have an ideal and effective removal of the oxide layer from the zircaloy surface, knowledge about the composition of the grit with respect to Al2O3, SiO2, TiO2, Fe2O3, CaO and MgO is essential. Therefore the chemical compositional analysis of alumina grit for confirming to specification becomes an essential step in the Quality Assurance (QA) programme for acceptance of the material. The present paper describes the analytical methodology followed in our laboratory for the chemical analysis of alumina grit samples used in the grit blasting operations