Author: AR. Barber Publisher: ISBN: Category : Nuclear fuel claddings Languages : en Pages : 14
Book Description
Rupture characteristics of internally heated Zircaloy-4 nuclear fuel cladding were investigated to develop rupture data that would provide a basis to bench-mark mathematical modeling of clad rupture. Single- and five-tube configurations of pressurized water reactor cladding were ruptured at constant pressures and heating rates with simulated reactor boundary conditions. The results showed that the ? + ? material property transformation region had a strong effect on the material ductility, and the clad rupture temperature varied linearly with hoop stress in the ? + ? region. Axial distribution of multitube ruptures was not coplanar. The rupture positions on all specimens were distributed normally about the point of maximum temperature. This paper emphasizes test techniques as well as the rupture characteristics of Zircaloy-4 clad.
Author: HM. Chung Publisher: ISBN: Category : Deformation Languages : en Pages : 16
Book Description
Information on the diametral expansion and rupture characteristics of Zircaloy-4 cladding has been obtained in a vacuum environment over a wide range of internal pressures at several heating rates. The effect of axial constraint of the cladding, exerted by a mandrel that simulated the pellets in a fuel rod, on the relationship between the maximum circumferential strain and the burst temperature also was investigated. The circumferential strain for unconstrained cladding was significantly larger than for axially constrained tubes, particularly for burst temperatures below ~850°C, in which cladding remains essentially in the ?-phase. Three superplastic strain peaks have been identified, namely, at rupture temperatures of ~850, ~1050, and ~1220°C. In the case of complete axial restraint, the failure strains were not dependent on heating rate for burst temperatures above ~920°C; however the low-temperature (~850°C) strain peak increases and moves to lower temperatures as the heating rate decreases. The deformation data in this investigation also have been used to evaluate instability criteria proposed for thin-wall tubes under a biaxial stress state. The onset of plastic instability or local ballooning in the cladding has been defined in terms of the effective stress and strain during transient-heating conditions.
Author: AR. Barber
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Author: American Society for Testing and Materials
Author: Dale A. Powers
Author: HM. Chung
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