![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
The defect performance of Zircaloy-clad mixed-oxide fuel operating in a pressurized-water environment was studied from the standpoint of fission product activity release to the coolant and the effects of a defect on fuel behavior. The defect experiment described in this paper, which operated satisfactorily, was conducted over a range of linear heat rating conditions, including those that resulted in fuel melting, to investigate the effects of different operating parameters.
The results show that the activity release characteristics of the fuel rod are sensitive to the operating mode and that the major species released to the coolant are the fission product gases, iodine, the alkali metals, and tellurium.
There were no localized dimensional perturbations associated with the cladding in the defect region although the ingress of steam vapor into the rod resulted in oxidation of the mixed-oxide fuel.
Comparison of fuel structures formed in the defected rod and in a companion nondefected rod indicates that within the experimental uncertainties associated with this experiment, the effect of defecting on the melting heat rating is <10% and possibly insignificant.
An oxygen-rich atmosphere in the interior of the fuel rod during irradiation prevented massive hydriding of the cladding.