Non-Modal Stability Analysis of the Zero-Dimensional Model of the TRIGA Mark II Reactor

Non-modal stability theory is a new approach to stability analysis focused on the shortterm behaviour of the system following a perturbation. Traditional modal techniques focus on the asymptotic response, missing finite-time instabilities and temporary growth of the parameters. Although widely used in the fluid-dynamics analysis, only seldom applications of this technique exist for nuclear reactors. Building upon previous works done by the author, in the following, the non-modal stability theory is used to study the stability of the zero-dimensional model of the TRIGA Mark II reactor, focusing on the short-term response to perturbations (power, inlet temperature). The primary aim of this work is to show how the widely-used modal stability techniques fail to predict transient growth of the perturbation for asymptotically stable systems, which, if repeated, could potentially lead to additional wear and tear of the system.