Framatome ANP GmbH, Erlangen,
European Commission Joint Research Centre, Institute for Transuranium Elements, Karlsruhe,
Pages: 16 Published: Jan 2002
Advanced Zry-2 cladding materials exhibiting good corrosion behavior are a prerequisite for extending BWR operation towards high burnup. To assess the burnup potential of Zry-2, the behavior of the intermetallic second-phase precipitates was analyzed as a function of fluence and compared with the in-reactor corrosion behavior. Various Zry-2 cladding samples with particle densities between 3 and 13 mm-2 with an average particle diameter of 50 to 80 nm and irradiation times of up to 2400 EFPD, equivalent to neutron fluences of up to 1 ∙ 1022 cm-2 (En > 1 MeV), were analyzed by TEM/SEM. The measurements showed a significant decrease in the particle density within the first cycle of irradiation followed by a slow decrease up to high fluences. At the highest fluences, the precipitate structure underwent deterioration combined with a markedly reduced number density. However, about 1 to 2% new precipitates of the Zr3Fe-type were formed during irradiation.
Metallographic examinations of BWR fuel rods showed both nodular and uniform corrosion. Up to a local burnup of 65 MWd/kgU no change of the corrosion kinetics and no acceleration of corrosion was found.
zirconium alloys, precipitates, precipitate type, precipitate size, precipitate distribution, precipitate dissolution, neutron irradiation, nodular corrosion, uniform corrosion, nuclear application
Paper ID: STP11384S