Dynamic Response of LFR in Cogeneration Mode

In this paper a novel object-oriented simulator capable of transient analysis of the Advanced Lead-cooled Fast Reactor European Design, based on the model envisioned by Ponciroli et al.[1], was developed within the Dymola software based on the Modelica language. The nuclear power plant (NPP) model was conceived as part of a more complete simulator capable of studying the technical feasibility of hybrid systems scenarios. The plant was built in such a way to enable steam extraction from the turbine unit therefore enabling the user to study different cogeneration options. The reactor core behaviour was implemented via point reactor kinetics coherently with ALFRED specifications. For the Steam Generator (SG) a single block modelling the combined effect of eight bayonet-type SGs was developed. Temperature of the extracted steam from the low-pressure turbine (LPT) can be determined by the sink pressure, which makes the model more flexible in studying the various cogeneration systems. Three scenarios were studied, namely: control rods step insertion and extraction, water mass flowrate linear increase and extraction valve regulation. Results highlight the time constants of the various components and show the potential of steam extraction which will indeed require further investigation and development of a suitable controller in order to efficiently use this system.