The chemical effects of composition changes in irradiated oxide fuel materials

Fuel – cladding chemical interaction in MOX fuel rods irradiated to high burnup in an advanced thermal reactor

“…The shape of the fission yield spectrum is slightly different for 235 U and 239 Pu [3]. A clear difference between these two nuclei is the upward shift of the larger mass peak in the fission of 239 Pu.…”

Progress in understanding fission-product behaviour in coated uranium-dioxide fuel particles

“…It is usually assumed that the fission of uranium atoms (i.e., the burn-up) causes the oxygen potential of the fuel to increase [12]. In this way, during irradiation the fuel is assumed to become slightly hyperstoichiometric even if this evolution is tempered for TRISO fuel by the reaction of some of this oxygen with the carbon of the buffer layer.…”

The effects of irradiation condition and microstructural change on lattice parameter, crystal lattice strain and crystallite size in high burnup UO2 pellet

“…5. The lattice parameters of irradiated UO 2 reported by several groups [1][2][3][4]7,8,16] are also presented for comparison. As seen in the figure, the measured lattice parameters of this study tend to be lower than the reported values.…”

“…Irradiation-induced defects and dissolved fission gas tend to expand the crystal lattice of UO 2 and as a consequence, lattice parameter increases are observed in irradiated UO 2 . Several groups have reported the lattice parameter in irradiated UO 2 [1][2][3] by using X-ray diffractometry and observed lattice parameter increases with increasing burnup up to approximately 70 GWd/t. which may be the threshold burnup for rim structure formation.…”

“…: this study; 5: periphery, : mid radius, . : in the vicinity of the central hole; s, : Une et al (irradiated) [1]; d: Une et al (annealed) [1]; 4: Davies and Ewart[2]; }, +: Spino et al[3]; N: Nogita et al[7]; : Une and Oguma[8]; h: Amaya et al[4,16]. Local burnup dependence of non-uniform strain and crystallite size in irradiated UO 2 samples.…”