The plastic deformation of UO2 single crystals is characterized by slip in the ½<110>{001} and, less frequently observed, ½<110>{110} and ½<110>{111} slip systems. Even though the edge dislocation is the slow character controlling the deformation in the primary slip systems, the screw dislocation also plays a major role i) as slow character for the two other modes, ii) in the context of composite slip and plastic anisotropy [1] and iii) in irradiation-hardening since it can be strongly pinned when forming helical turns through interaction with ½<110>{110} prismatic loops. Recently, the ½<110> screw dislocation core structure was shown to exhibit a transition of its core spreading plane, from a {001} plane at low temperature to {111} planes above a critical temperature of 1700 K. Above this temperature, the mobility of the screw dislocation in the {111} planes is favored [2]. In this talk, we will first confirm the transition in slip system of the screw dislocation for different stress and temperature conditions using molecular dynamics simulations. We will then present a cross-slip model for the ½<110> screw dislocation in UO2. This model, informed by the atomic scale, is based upon the core structure temperature evolution and is fitted on molecular dynamics simulations of dislocation mobility under an applied stress. The model validation as well as its implementation in the discrete dislocation dynamics code Numodis will be discussed. Finally, the model will be applied to the study of the interaction between a ½<110> screw dislocation and a prismatic loop, where screw dislocation cross-slip induces the formation of a Hirth junction through reaction with a prismatic loop segment.