On-line deformation measurements of nuclear fuel rod cladding using speckle interferometry

• An optical technique for on line and in situ measurement of nuclear fuel rod cladding is demonstrated.
• A model to produce ridges on fuel rod cladding has been developed.
• Speckle interferometry is defined and applied to real fuel rod cladding ridges.
• First results show a detection limit near 1 μm which is really promising for this application.

This paper reports an experimental setup developed to detect and quantify the deformations of the cladding surface of nuclear fuel pellets submitted to analytical transient conditions. It consists of an optical instrument based on the speckle interferometry technique, able to provide non-destructive measurements on scattering surfaces such as nuclear fuel rod claddings. Here are presented first results performed on-line and in situ, with micrometric resolution. Then, limitations of the system as well as further developments are discussed.