DAMAGE RECOVERY IN THE U-SUBLATTICE OF ION-IMPLANTED UO2 BETWEEN 5-K AND 2000-K

Radiation damage was produced in U02 single crystals by controlled ion implantation with Kr- and Xe-ions in the energy range of 40 to 500 keV, and at implantation temperatures of 5, 77 or 293 K. The RBS/channeling technique was used to measure damage formation and recovery in the U-sublattice during postimplantation anneals. About 50 % of the defects (probably U-interstitials) annealed below room temperature (77 and 110 K), the remaining defects (probably U-vacancies) annealed at 700 - 900 K. At high doses, recovery was not complete before 2000 K were reached (extended defects in the U-sublattice). The concept of mobility of U-interstitials below room temperature contrasts theoretical work postulating a high migration energy for U-interstitials. © 1991, Taylor & Francis Group, LLC. All rights reserved.