Speaker
Mr
Cyprian Mieszczynski
(Paul Scherrer Institute)
Description
Uranium dioxide nuclear fuel, UO2, with fissile 235U is normally used in commercial power plants. Fission of 235U generates light and heavy fission fragments and disturbs both cation-cation and cation-anion network in the fuel matrix. Uranium dioxide can also exist as a hyper-stoichiometric UO2+x following oxidation. Nonstoichiometry in UO2 fuel may result a decreased thermal conductivity, increased thermal expansion and/or a greater volatility and fission FP release rate. In this work micro-focused X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS) spectroscopy are used to examine the lattice structure of UO2 and next the neighbor atomic environment of uranium in a UO2 pellet irradiated to a medium burn-up condition. Micro-structures evolved at two different radial positions, the center-region and the rim-area, of the irradiated fuel pellet are examined. Results are compared with the corresponding results of an unirradiated (pristine) UO2 pellet. Structural changes in the irradiated UO2 grains, lattice parameters, local distortion and lattice dilation in the irradiated material are also measured from XRD data. All these results will be presented and discussed.
Please specify poster or talk
Poster
Please specify the session
Poster session I on 15.09.2011
Primary author
Mr
Cyprian Mieszczynski
(Paul Scherrer Institute)
Co-authors
Dr
Camelia Borca
(Paul Scherrer Institute)
Dr
Claude Degueldre
(Paul Scherrer Institute)
Dr
Goutam Kuri
(Paul Scherrer Institute)
Dr
Johannes Bertsch
(Paul Scherrer Institute)
Mr
Matthias Martin
(Paul Scherrer Institute)
