The investigation of the mechanical integrity of spent nuclear fuel rods in accidental scenarios is the main objective of this research, conducted at the hot-cell facilities of the Joint Research Centre (JRC) - Karlsruhe. Two devices for mechanical testing on fuelled, pressurized spent nuclear fuel rod segments have been developed for gravitational impact and 3-point bending tests. The main objectives of this program are the determination of rod response to external load, rod failure conditions and the characterization of fuel release in case of rod fracture. The campaign consists of two phases, namely the development and optimization of the testing devices in "cold" laboratories and their installation and application to test irradiated spent fuel in hot-cells. This paper focuses on the main stages of the development and optimization of the new devices, detailing the motivation behind them and their extended data acquisition capabilities. Representative results on the response of SNF to these dynamic and quasi static loads are presented. The load-deflection curves for the fuel/cladding ensemble and the characterization (mass/size distribution) of released fuel debris following SNF fracture are described.