Revisiting the method to obtain the mechanical properties of hydrided fuel cladding in the hoop direction

• Published in: Journal of nuclear materials 2012-10, Vol.429 (1-3), p.276-283
• Main Authors: Martín-Rengel, M.A., Gómez Sánchez, F.J., Ruiz-Hervías, J., Caballero, L., Valiente, A.
• Format: Article
• Language: English
• Subjects: Applied sciences; Controled nuclear fusion plants; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Fuels; Hoops; Hydrogen storage; Installations for energy generation and conversion: thermal and electrical energy; Mathematical analysis; Nonlinearity; Nuclear fuels; Preparation and processing of nuclear fuels; Stress concentration; Stress strain curves; Stress-strain relationships; Tensile tests
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2012.06.003

The method reported in the literature to calculate the stress–strain curve of nuclear fuel cladding from ring tensile test is revisited in this paper and a new alternative is presented. In the former method, two universal curves are introduced under the assumption of small strain. In this paper it is shown that these curves are not universal, but material-dependent if geometric nonlinearity is taken into account. The new method is valid beyond small strains, takes geometric nonlinearity into consideration and does not need universal curves. The stress–strain curves in the hoop direction are determined by combining numerical calculations with experimental results in a convergent loop. To this end, ring tensile tests were performed in unirradiated hydrogen-charged samples. The agreement among the simulations and the experimental results is excellent for the range of concentrations tested (up to 2000wppm hydrogen). The calculated stress–strain curves show that the mechanical properties do not depend strongly on the hydrogen concentration, and that no noticeable strain hardening occurs. However, ductility decreases with the hydrogen concentration, especially beyond 500wppm hydrogen. The fractographic results indicate that as-received samples fail in a ductile fashion, whereas quasicleavage is observed in the hydrogen-charged samples.