Full Field Measurements used for Assessing Industrial Issues-Two Examples

This paper presents two case studies in which the use of full field measurements could provide valuable information to allow the development of R&D methods having the potential of assessing industrial issues.The first example is related to the study of the fracture properties of the nuclear fuel rods after a postulated Loss of Coolant Accident (LOCA) event. It will be shown that 3-D Digital Image Correlation strain measurements performed on a non-conventional mechanical test (expansion due to compression) can help to assess failure properties and derive fracture criteria of highly oxydized and hydrided Zircaloy cladding. These fracture criteria are therefore used in the Safety Demonstrations due conducted by EDF in reply to the French Safety Authority.The second example is related to the investigation of potentially brittle failure of an irradiation aged nuclear reactor pressure vessel (RPV) during a Loss of Coolant Accident event. As a matter of fact, the reactor pressure vessel is one of the non replaceable components of a nuclear power plant. Consequently, the study of the RPV ageing is of major importance for assessing plants lifetime. One consequence of the RPV ageing is the increasing risk of brittle fracture during postulated LOCA events. As a first step to better characterize experimentally the embrittlement of RPV steel, the second example presents in-situ strain heterogeneities in the plastic response of bainitic-ferritic 16MND5 steel, with respect to crystalline phases and orientations. These local observations are then used by a specific identification procedure, in order to obtain experimentally the crystal plasticity hardening flow behaviour of RPV steel.