Recovery and restructuring induced by fission energy ions in high burnup nuclear fuel

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Vol. 267; no. 6; pp. 960 - 963
• Main Authors: Kinoshita, M., Yasunaga, K., Sonoda, T., Iwase, A., Ishikawa, N., Sataka, M., Yasuda, K., Matsumura, S., Geng, H.Y., Ichinomiya, T., Chen, Y., Kaneta, Y., Iwasawa, M., Ohnuma, T., Nishiura, Y., Nakamura, J., Matzke, Hj
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-03-2009
• Subjects: High burnup; Light water reactor; Nuclear fuel; Recovery; Rim structure; High burnup; Rim structure; Nuclear fuel; 25.70; Recovery; 28.41.Bm; Light water reactor
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2009.02.022

In light water commercial reactors, extensive change of grain structure was found at high burnup ceramic fuels. The mechanism is driven by bombardment of fission energy fragments and studies were conducted by combining accelerator based experiments and computer-science. Specimen of CeO
2 was used as simulation material of fuel ceramics. With swift heavy ion (Xe) irradiation on CeO
2, with 210
MeV, change of valence charge and lattice deviation of cations were observed by XPS and XRD. Combined irradiations of Xe implantation and swift heavy ion irradiation successfully produced sub-micrometer sized sub-grains, similar as that observed in commercial fuels. Studying components of mechanism scenarios, with first principle calculations using the VASP code, we found stable hyper-stoichiometric defect structures of UO
2+
x
. Molecular dynamics studies revealed stability of Xe planar defects and also found rapid transport mode of oxygen-vacancy clusters.