NuFuel & MMSNF 2015

First Workshop on Research into Nuclear Fuel in Europe
and Materials Modeling and Simulation for Nuclear Fuels Workshop
Karlsruhe, Germany, November 16th to 18th, 2015

Updated: Tue 08 Dec 2015, 14:27

Talk 5.5: Atomic-scale effects of chromium-doping on defect behaviour in uranium dioxide fuel

Zhexi Guo, Raoul A. Ngayam-Happy, Matthias Krack, Andreas Pautz
  • Paul Scherrer Institute, CH–5232 Villigen PSI, Switzerland

Abstract

The effects of doping conventional UO2 fuel with chromium are studied through atomistic simulations using empirical force field methods. We first analyse the stable structures of unirradiated doped fuel by determining the preferred lattice configuration of chromium ions and oxygen vacancies within the matrix. In order to understand the physical effects of the dopants, we investigate formation energies of isolated defects and Frenkel pairs in the vicinity of chromium. The behaviour of point defects is then studied with collision cascade simulations and relaxation of doped simulation cells containing Frenkel pairs. The defective structures are scanned in minute detail using a powerful and versatile analysing tool, called ASTRAM, developed in-house for the purpose. Results indicate definite effects of chromium-doping on the ease with which defects are formed and also on the residual damage in the fuel matrix, which can be extrapolated to phenomena following irradiation under real operating conditions. We also show that the extent of these effects is related to the dopant concentration.