We have prepared a range of Advanced Gas-cooled Reactor (AGR) SIMFUELs at a range of simulated burn-ups and, using Raman spectroscopy, have studied the effect of the SIMFUEL dopants on the UO 2 crystal structure. We have also studied the effect of exposure to hydrogen peroxide solutions on the SIMFUEL surface. The intensity of the fundamental U-O stretch (445 cm-1) decreases as the amount of dopant increases in each SIMFUEL burn-up composition. A simultaneous increase in the lattice damage (500-700 cm-1) peak is observed as the UO 2 cubic fluorite lattice structure becomes more distressed and moves towards a tetragonal structure. Exposure to 100 µmol dm-3 H 2 O 2 further decreases the fundamental U-O stretch and increases the lattice damage peak, suggesting that additional point defects are established as the concentration of interstitial oxygen is increased in the lattice via the H 2 O 2-induced corrosion of the SIMFUEL.
Pure UO2 pellets and, for the first time, AGR SIMFUEL pellets simulating 25 (pellet interior) and 43 GWd/tU burn-up (rim structure) have been fabricated. Using combined electrochemical and Raman spectroscopic studies, we have investigated the effect of the AGR SIMFUEL dopants on the structure of the UO2 crystal matrix and studied the effect of H2O2 on the SIMFUEL surface as a simulant for the effect of α radiolysis of water within intruding groundwater in the near field. Preliminary results of electrochemical studies of AGR SIMFUEL samples held in direct contact with the AGR fuel cladding material, 20/25/Nb stainless steel, in modified simplified groundwater (10 mmol dm-3 NaCl, 2 mmol dm-3 NaHCO3, pH 6.8) indicate that the open circuit potential of the coupled system is (i) negative of that adopted by the isolated SIMFUEL and (ii) positive of that adopted by the isolated cladding in electrolytes of the same composition. This implies that the SIMFUEL is protected against corrosion at the expense of the steel cladding, an observation that is currently the subject of further work in our laboratories.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.