In situ Raman monitoring of materials under irradiation: study of uranium dioxide alteration by water radiolysis

Abstract

In situ Raman scattering studies allow following real-time evolutions of volume or surface structures under extreme conditions. In nuclear materials sciences, ion irradiation-induced atomic organization modification and water radiolysis are of a major interest. In order to better understand these phenomena, we have developed an in situ versatile portable Raman spectroscopy system coupled with a cyclotron accelerator, allowing monitoring of a solid/liquid interface under irradiation and thus giving access to effects of radiolysis. The different parts of the system and their improvements are described in details.The system efficiency is highlighted by a comparative study of the time dependence of UO 2 surface modification induced, on one hand by contact with water under irradiation by 5 MeV He 2+ particles, and on the other hand by pure chemical alteration, through contact with a hydrogen peroxide solution.

Detection and identification of solids, surfaces, and solutions of uranium using vibrational spectroscopy

“…The Raman spectra contains a v 1 uranyl band located at 831 cm −1 and a secondary v 1 (O=O) stretching mode at 870 cm −1 [95]. Both studtite and the dehydrated form (metastudtite [UO 2 (O 2 )(H 2 O) 2 ]) have been identified as a secondary alteration phase formed due to the alpha radiolysis of water using Raman spectroscopy as the main surface characterization technique [76,77,96,97]. …”

In situ Raman monitoring of He2+ irradiation induced damage in a UO2 ceramic

“…In situ Raman monitoring of He 21 irradiation induced damage in a UO 2 ceramic G. Guimbretière, 1,a) L. Desgranges, 2,b) A. Canizarès, 1 R. Caraballo, 3 F. Duval, 1 N. Raimboux, 1 R. Omn ee, 1 M. R. Ammar, 1 C. J egou, 3 The in situ Raman probing of a UO 2 ceramic in [Ar/H 2 , 95/5] gas atmosphere followed by exposure to He 2þ ionic irradiation coming from a cyclotron accelerator was implemented. It was observed that the growth of Raman defect bands exhibits a unique kinetic nicely modelized by a simple direct impact model, and with an annealing rate constant of 5.6 Â 10 À4 6 4 Â 10 À5 s À1 for an ionic flow of 50 nA and an ions-beam induced sample heating of 170 6 10 C. Also, it was observed that the Ar plasma induced by the ions-beam is a sensitive probe of the presence of the ions-beam.…”

“…2 For this purpose, at CEMHTI lab, we have developed a unique setup coupling of a cyclotron beam with a Raman spectrometer, allowing in situ probing of the solid/fluid interface under irradiation. 3 Such instrument was previously used for identification and observation of the growth of an alteration layer at the UO 2 /H 2 O interface. 3,4 Besides, we have recently shown that Raman spectroscopy is also a useful tool for the study of damage in the solid UO 2 : We observed from post-mortem Raman measurements that He 2þ irradiation induced the appearance of Raman defect-bands (called U 1 , U 2 , and U 3 ) that grow up with the energy deposited by the ions-beam.…”

“…3 Such instrument was previously used for identification and observation of the growth of an alteration layer at the UO 2 /H 2 O interface. 3,4 Besides, we have recently shown that Raman spectroscopy is also a useful tool for the study of damage in the solid UO 2 : We observed from post-mortem Raman measurements that He 2þ irradiation induced the appearance of Raman defect-bands (called U 1 , U 2 , and U 3 ) that grow up with the energy deposited by the ions-beam. 5 Next, in order to better understand the processes dynamic of damage formation in UO 2 and to build a true scheme of ionic alteration, a great knowledge of the kinetic of formation of the U n Raman defects bands is mandatory.…”

Ion irradiation and radiation effect characterization at the JANNUS-Saclay triple beam facility

“…[29][30][31][32][33][34] At JANNUS-Saclay, a Raman probe is now permanently installed in the triple beam chamber and IBIL has been tested. Both devices are described in this section.…”