Atomistic model of xenon gas bubble re-solution rate due to thermal spike in uranium oxide
W Setyawan and MWD Cooper and KJ Roche and RJ Kurtz and BP Uberuaga and DA Andersson and BD Wirth, JOURNAL OF APPLIED PHYSICS, 124, 075107 (2018).
Atomistic simulations are performed to study the response of Xe gas bubbles in UO2 to ionizing fission products through the thermal spike approximation. A portion of the total electronic stopping power (S-e) is taken as the thermal spike energy through a ratio variable zeta. The thermal spike energy causes extreme melting within the fission track cylindrical region. Molecular dynamics is employed to quantify the probability of a Xe gas atom to be re-solved (re-dissolved) back into the UO2 matrix. Subsequently, a re-solution model is developed and parametrized as a function of bubble radius (R), off-centered distance (r), and thermal spike energy (zeta S-e). The off-centered distance measures the shift of the thermal spike axis from the bubble center. To evaluate the re-solution model, independent fission product yield of U-235 fission due to thermal neutrons (0.0253 eV), taken from the JEFF-3.3 database, is used. The kinetic energy of the fission products is taken from the EXFOR database. Subsequently, the decay of S-e over distance for each fission product is simulated. Finally, the evaluated re-solution rate (re-solution probability per second) is presented as a function of bubble radius for a range of zeta. Published by AIP Publishing.
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