This paper presents 2D generalized plain strain simulations of the thermo-mechanical response of a pellet fragment and overlying cladding during a RIA transient. A fictitious hydride blister of increasing depth (25 to 90% of the clad thickness) is introduced at the beginning of the calculation. | 2D simulation of hydride blister cracking during a RIA transient with the fuel code ALCYONE EPJ Nuclear Sci. Technol. 2 22 2016 Nuclear Sciences J. Sercombe et al. published by EDP Sciences 2016 amp Technologies DOI epjn 2016016 Available online at http REGULAR ARTICLE 2D simulation of hydride blister cracking during a RIA transient with the fuel code ALCYONE Jérôme Sercombe1 Thomas Helfer1 Eric Federici1 David Leboulch2 Thomas Le Jolu2 Arthur Hellouin de Ménibus2 and Christian Bernaudat3 1 CEA DEN DEC Bâtiment 151 13108 Saint-Paul-lez-Durance France 2 CEA DEN DMN 91191 Gif-sur-Yvette France 3 EDF SEPTEN 69628 Villeurbanne Cedex France Received 16 September 2015 Received in final form 1 March 2016 Accepted 8 March 2016 Published online 18 April 2016 Abstract. This paper presents 2D generalized plain strain simulations of the thermo-mechanical response of a pellet fragment and overlying cladding during a RIA transient. A fictitious hydride blister of increasing depth 25 to 90 of the clad thickness is introduced at the beginning of the calculation. When a pre-determined hoop stress is exceeded at the clad outer surface radial cracking of the blister is taken into account in the simulation by a modification of the mechanical boundary conditions. The hoop stress criterion is based on Finite Element simulations of laboratory hoop tensile tests performed on highly irradiated samples with a through-wall hydride blister. The response of the remaining clad ligament beneath the cracked blister to the pellet thermal expansion is then studied. The simulations show that plastic strains localize in a band orientated at 45 to the radial direction starting from the blister crack tip and ending at the clad inner wall. This result is in good agreement with the ductile shear failures of the clad ligaments observed post-RIA transients. Based on a local plastic strain failure criterion in the shear band ALCYONE simulations are then used to define the enthalpy at .
