K. Nogita et al., Depth profiles of damage accumulation in UO2 and (U,Gd)O-2 pellets irradiated with 100 MeV iodine ions, J NUCL MAT, 273(3), 1999, pp. 302-309
To study the initial defect formation and accumulation process during fissi
on events, sliced pellet specimens of UO2 and (U,Gd)O-2 were irradiated at
ambient temperatures below 200 degrees C, with 100 MeV iodine ions over a f
luence range of 1.0 x 10(18) - 2.0 x 10(19) ions/m(2). The surface of the s
pecimens was analyzed by scanning electron microscopy (SEM) and X-ray diffr
actometry (XRD), and then the depth profiles of incident iodine ions and de
fect clusters were measured by secondary ion mass spectrometry (SIMS) and t
ransmission electron microscopy (TEM), respectively. Lattice parameter chan
ge, which is associated with point defect accumulation, increased with ion
fluence. Defect clusters of dislocations and dislocation loops were recogni
zed, and their depth profiles were in good agreement with the calculated da
mage profile. These profiles of iodine ions and dislocation loops in both U
O2 and (U,Gd)O-2 were discussed in terms of inelastic and elastic collision
s. (C) 1999 Elsevier Science B.V. All rights reserved.