ELECTRA Core Dynamics and Stability Analyses

An analytical model has been developed to study the core dynamic performance and stability of the European Lead Cooled Training Reactor (ELECTRA). A dedicated dynamics simulation tool solving simultaneously time-dependent equations for neutronics and thermal-hydraulics has been developed based on point kinetics for the former physics and on a lumped-parameter formulation of energy and momentum balances for the latter. Constitutive equations have been linearized around different working conditions so as to enable Linear Time-Invariant (LTI) analysis tools to be employed to investigate the core stability on the entire power range and to assess the impact of uncertainties affecting the Doppler coefficient. The reactor dynamic response has been studied against such fundamental neutronics parameter by simulating three typical design-basis transient scenarios initiated by a partial control drum rotation, by an undesired increase of core pressure drop, and by an enhancement of the coolant core inlet temperature.