Large-angle collisions (equivalently, knock-on collisions), while usually subdominant with respect to small-angle collisions in plasmas, can cause an exponential growth of the Runaway Electron (RE) population [1], the so-called runaway avalanche. In reactor-scale Tokamak disruptions RE generation is expected to be dominated by avalanches [2], which can turn a small seed population into a multi-megaampere RE beam whose interaction with the first wall could lead to destructive results [2]. Mitigating mechanisms such as enhanced radial transport can counterbalance this effect [3], but they are highly sensitive to the avalanche growth rate. Accurate modelling of the underlying physical mechanism is therefore essential to be able to correctly reproduce experimental data. This contribution describes the effort has been done to integrate the most complete avalanche model available to date in the drift-kinetic code LUKE [4]. Such a model, originally recovered by Émbreus [5], was derived from the linearised Boltzmann operator in the case of knock-on collisions, and presents a variety of challenges both from the analytical and the numerical point of view. Its implementation in the code has been tested in cylindrical geometries for a variety of numerical and physical parameters to ensure robustness. A first benchmark has been obtained against a simplified model, the Rosenbluth-Putvinski limit: the corresponding source term, implemented in the code [6], allowed for a direct comparison between the two models, and the expected growth rates were recovered. Cross-tests have been carried out against an alternative implementation derived for DREAM, as the similar analytical frameworks of the two codes allowed for natural comparison between the simulation results. [1] M. Rosenbluth and S. Putvinski. “Theory for avalanche of runaway electrons in tokamaks”. In: Nucl. Fusion (1997). [2] A. Boozer. “Runaway electrons and ITER”. In: Nucl. Fusion (2017). [3] J. Decker et al. “Expulsion of runaway electrons using ECRH in the TCV tokamak”. In: Nucl. Fusion (2024). [4] Y. Peysson J. Decker. LUKE: a fast numerical solver for the 3-D relativistic bounce-averaged electron Drift Kinetic Equation. Tech. rep. Association EURATOM-CEA sur la Fusion, CEA-Cadarache, (2004). [5] O. Embréus, A. Stahl, and T. Fülöp. “On the relativistic large-angle electron collision operator for runaway avalanches in plasmas”. In: J. Plasma Phys. (2017). [6] E. Nilsson et al. “Kinetic modelling of runaway electron avalanches in tokamak plasmas”. In: Plasma Phys. Control. Fusion (2015).