Stoichiometric circular shaped interstitial dislocation loop energies are calculated in stoichiometric UO2 by empirical potential simulation. The Burgers vector directions studied are < 110 > and < 111 >. The main structural properties of each type of interstitial dislocation loop are determined, including stacking fault energy. Defect energies are compared and a maximum size for stable < 111 > dislocation loops before transition to < 110 > dislocation loops is given. A model of dislocation loop energy based on elasticity theory is then fitted on the basis of these simulation results. (C) 2016 Elsevier B. V. All rights reserved.