Development and implementation of a Nuclear Power Plant steam turbine model in the system code ATHLET

Abstract

In order to improve the simulation of the whole secondary loop with the system code ATHLET a steam turbine model has to be implemented. This paper deals with the development of a thermo-hydraulic model of a Nuclear Power Plant steam turbine and its implementation in the system code ATHLET. The model is based on Stodola’s cone law and simulates the pressure drop and the enthalpy drop along the different turbine stages as well as the steam and water extractions. The influence of the steam and water extractions on the turbine behaviour as well as the importance of an accurate model for the steam and water extrac-tions are carefully explained. Heat and mass balances of the Nuclear Power Plant Philippsburg 2 are used for reference purposes as well as for validation purposes of the implemented model. The comparison between steady state simulations and the real plant data indicate a satisfactory accuracy of the model and of the thermodynamic approach used.