In the framework of energy transition, the massive insertion of Variable Renewable Energies leads to think to new ways of controlling and stabilizing electrical networks. Small Modular Reactors (SMRs) could be a sustainable solution if they are proven to be flexible enough. Previous studies have shown the positive influence of SMRs on grids at short-time scales due to inertia and frequency regulation phenomena. In addition, this article aims at studying the influence of constrained grid events on nuclear systems safety and operation. The models of a power system dynamics (PowerFactory) and a nuclear dynamics software (CATHARE) are compared and chained. Two application cases are carried out to quantify the impact and the relevance of this chaining: a short-circuit and a load loss. This article finally concludes that this chaining is relevant to accurately simulate nuclear reactor behavior following grid events. Moreover, a chaining could be insufficient for electrical simulations after severe events such as shortcircuits or for high nuclear insertion's rate in an energy mix, a coupling, i.e co-simulation, could be considered.