Effects of irradiation temperature on the response of CeO2, ThO2, and UO2 to highly ionizing radiation

JOURNAL OF NUCLEAR MATERIALS

卷:525

Article

Cureton, William E.¹  Palomares, Raul, I¹  Tracy, Cameron L.^2,3  O'Quinn, Eric C.¹  Walters, Jeffrey¹  Zdorovets, Maxim^4,5,6  Ewing, Rodney C.²  Toulemonde, Marcel⁷  Lang, Maik¹ 

[1] Univ Tennessee, Dept Nucl Engn, Knoxville, TN 37996 USA

[2] Stanford Univ, Dept Geol Sci, Stanford, CA 94305 USA

[3] Harvard Univ, John F Kennedy Sch Govt, Belfer Ctr Sci & Int Affairs, Cambridge, MA 02138 USA

[4] Inst Nucl Phys, Alma Ata 050032, Kazakhstan

[5] LN Gumilyov Eurasian Natl Univ, Nur Sultan 010008, Kazakhstan

[6] Ural Fed Univ, Ekaterinburg 620075, Russia

[7] CEA CNRS ENSICAEN, CIMAP GANIL, Bd H Becquerel, F-14070 Caen, France

关键词: CeO2;    ThO2;    UO2;    Ion irradiation;    High temperature;    X-ray diffraction;    X-ray absorption spectroscopy;   

DOI  :  10.1016/j.jnucmat.2019.07.029

来源: Elsevier

【 摘 要 】

Microcrystalline CeO2, ThO2, and UO2 were irradiated with 198 MeV Xe-132 ions to the same fluence at temperatures ranging from 25 degrees C to 700 degrees C then characterized by synchrotron X-ray diffraction and X-ray absorption spectroscopy. All samples retain crystallinity and their nominal fluorite-type phase at a fluence of 1.5 x 10(13) ions/cm(2). Both CeO2 and ThO2 display defect-induced unit cell expansion after irradiation at room temperature (similar to 0.15% and similar to 0.10%, respectively), yet as irradiation temperature increases, the maximum swelling produced decreases to similar to 0.02%. Alternatively, UO2 shows an initial contraction in unit cell parameter (approximately -0.05%) for room temperature irradiation, most likely related to irradiation-enhanced annealing or irradiation-induced oxidation. At higher temperatures (above 200 degrees C) UO2 begins to swell, surpassing its unit cell parameter prior to irradiation (similar to 0.05%), an effect which could be attributed to minor reduction in uranium oxidation state in vacuum. However, while CeO2 irradiated at room temperature undergoes partial reduction, both UO2 and ThO2 exhibit no measurable change in cation oxidation state as evidenced by X-ray absorption spectroscopy. All samples display a decrease in irradiation-induced heterogeneous microstrain as a function of increasing irradiation temperature. (C) 2019 Elsevier B.V. All rights reserved.

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