Incident beam

1. Kinetics of zirconium hydride precipitation and reorientation studied by synchrotron radiationArthur T. Motta, Pennsylvania State Univ University Park, DMR 0710616 In-situ X-ray diffraction in bulk sample has allowed a study of partial hydride reorientation. A ‘signature’ of hydride reorientation has been identified in the hydride peak broadening behavior. Further experiments are planned to investigate this phenomenon further especially in fully reoriented samples. APS Beamline Bulk samples Load cell This research focuses on developing new in-situ observation techniques to better understand hydride induced failures of zirconium alloy nuclear fuel cladding. During reactor exposure, zirconium alloy nuclear fuel cladding undergoes corrosion and hydriding. These brittle hydrides can cause early failure of the cladding during operation, transportation and storage. This research helps to better define and understand the failure mechanisms and limits of operation. In-situ experiments at the Advanced Photon Source synchrotron have been conducted to observe zirconium hydride precipitate reorientation under applied stress at temperature. The study of line broadening has enabled the identification of a particular reorientation signature in the diffraction patterns. More experiments on samples reoriented at different levels are planned to better understand this diffraction signature. reorientation signature Incident beam Incident beam furnace Micro beam X-ray diffraction experiments designed to investigate a more realistic sample geometry (pre-cracked) and study the effect of a stress concentration on hydrides strain and orientation . 2 Pre cracked samples Crack tip Load and Temperature Hydrides Experimental set-up

2. Kinetics of zirconium hydride precipitation and reorientation studied by synchrotron radiation Arthur T. Motta, Pennsylvania State Univ University Park, DMR 0710616 Broader Impact Operating nuclear fuel more safely: have a deterministic knowledge of nuclear cladding cracking behavior in dry storage conditions International collaboration: inter-American partnership between Penn State, USA, Queen’s University, Canada and CNEA, Argentina Education: Employment of PhD and post-doctoral students: One student has obtained her Master’s degree with this project and is staying for a PhD. Involvement of several undergraduate students for data analysis and sample preparation. Temperature and stress conditions during dry storage of spent fuel can lead to reorientation of hydrides Reorientation Reoriented hydrides lead to early cracking of the fuel cladding